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Technical Committee on Fire Investigations

M E M O R A N D U M

TO: NFPA Technical Committee on Fire Investigations

FROM: Elena Carroll

DATE: September 18, 2009

SUBJECT: NFPA 921 ROP Letter Ballot

The ROP letter ballot for NFPA 921, Guide for Fire and Explosion Investigations, is attached. The ballot is for formally voting on whether or not you concur with the committee’s actions on the proposals. Reasons must accompany all negative and abstention ballots.

Please do not vote negatively because of editorial errors. However, please bring such errors to my attention for action.

Please complete and return your ballot as soon as possible but no later than October 9, 2009. As noted on the ballot form, please return the ballot to Elena Carroll either via e- mail to [email protected] or via fax to 617.984.7056. You may also mail your ballot to the attention of Elena Carroll at NFPA, 1 Batterymarch Park, Quincy, MA 02169.

The return of ballots is required by the Regulations Governing Committee Projects.

Attachment Report on Proposals – November 2010 NFPA 921 ______921-1 Log #CP1

______Technical Committee on Fire Investigations, Review entire document to: 1) Update any extracted material by preparing separate proposals to do so, and 2) review and update references to other organizations documents, by preparing proposal(s) as required. To conform to the NFPA Regulations Governing Committee Projects.

The Committee is revising the following material in Chapter 13 Sources of Information to read: 13.5.4.9.2 Move this paragraph to 13.5.4.14.3 under US Department of Homeland Security. 13.5.4.10. Change the title from Department of the Treasury to Internal Revenue Service and insert the current sentence, "The Internal Revenue Service maintains public records regarding compliance with all federal tax laws." 13.5.4.10.1 Move this paragraph to 13.5.4.14.1 under US Department of Homeland Security. Change U.S. Customs Service to U.S. Customs and Border Protection (CBP) 13.5.4.10.3 Move this paragraph to 13.5.4.14.2 under US Department of Homeland Security 13.5.4.11.1 Insert a paragraph describing the Bureau Of Alcohol Tobacco Firearms and Explosives (BATFE). Text to be provided by John Comery. Renumber subsequent subparagraphs 13.5.4.11.2 through 13.5.4.11.6 13.5.4.11.5 Move this paragraph to 13.5.14.4 under US Department of Homeland Security. Change Immigration and Naturalization Service to Immigration and Customs Enforcement 13.5.4.14 Change the title from United States Fire Administration to US Department of Homeland Security, with FEMA and USFA described in subparagraphs. The paragraphs from 13.5.4.9.2 through 13.5.4.14.6 will appear as follows: 13.5.4.9 Department of Transportation. Under this department, the Environmental Safety and Consumer Affairs Office maintains public records regarding its programs to protect the environment, to enhance the safety and security of passengers and cargo in domestic and international transport, and to monitor the transportation of hazardous and dangerous materials. 13.5.4.10 Internal Revenue Service. The Internal Revenue Service maintains public records regarding compliance with all federal tax laws. 13.5.4.11 Department of Justice. Under this department, the Antitrust Division maintains public records regarding federal sources of information relating to antitrust matters. 13.5.4.11.1 The Bureau of Alcohol Tobacco Firearms and Explosives (BATFE)…………..text to be provided by John Comery. 13.5.4.11.2 The Civil Rights Division maintains public records regarding its enforcement of all federal civil rights laws that prohibit discrimination on the basis of race, color, religion, or national origin in the areas of education, employment, and housing, and the use of public facilities and public accommodations. 13.5.4.11.3 The Criminal Division maintains public records regarding its enforcement of all federal criminal laws except those specifically assigned to the Antitrust, Civil Rights, or Tax Divisions. 13.5.4.11.4 The Drug Enforcement Administration maintains public records regarding all licensed handlers of narcotics, the legal trade of narcotics and dangerous drugs, and its enforcement of federal laws relating to narcotics and other drugs. 13.5.4.11.5 The Federal Bureau of Investigation maintains public records regarding criminal records, fingerprints, and its enforcement of federal criminal laws. 13.5.4.11.6 The Immigration and Naturalization Service maintains public records regarding immigrants, aliens, passengers and crews on vessels from foreign ports, naturalization records, deportation proceedings, and the financial statements of aliens and persons sponsoring their entry into the United States. 13.5.4.12 U.S. Postal Service. The U.S. Postal Service maintains public records regarding all of its activities. The investigative activities of the U.S. Postal Service are contained in the Office of the Postal Inspector. 13.5.4.13 Department of Energy. The Department of Energy is an executive department of the U.S. government that works to meet the nation’s energy needs. The department develops and coordinates national energy policies and programs. It promotes conservation of fuel and electricity. It also conducts research to develop new energy sources and more efficient ways to use present supplies. The secretary of energy, a member of the president’s cabinet, heads the department. 13.5.4.14 United States Department of Homeland Security. The Department of Homeland Security, established after the terrorist attacks of 9/11/2001, is an executive department of the U.S. government that works to maintain the security

Printed on 9/18/2009 1 Report on Proposals – November 2010 NFPA 921 of the nation’s needs. The department develops and coordinates national security policies/programs through a variety of border, transportation and infrastructure protection. The Secretary of Homeland Security, a member of the President’s cabinet, heads the department. 13.4.4.14.1 U.S. Customs and Border Protection (CBP) maintains public records regarding importers; exporters; customhouse brokers; customhouse truckers; and the registry, enrollment, and licensing of vessels not licensed by the Coast Guard or the United States that transport goods to and from the United States. 13.5.4.14.2 The U.S. Secret Service maintains public records regarding counterfeiting and forgery of U.S. coins and currencies and records of all threats on the life of the president and his immediate family, the vice president, former presidents and their wives, wives of deceased presidents, children of deceased presidents until age sixteen, president- and vice president–elect, major candidates for the office of president and vice president, and heads of states representing foreign countries visiting in the United States. 13.5.4.14.3 The United States Coast Guard maintains public records regarding persons serving on U.S.–registered ships, vessels equipped with permanently installed motors, vessels over 4.9 m (16 ft) long equipped with detachable motors, information on where and when ships departed or returned from U.S. ports, and violations of environmental laws. 13.5.4.14.4 The Federal Emergency Management Agency, a component of the Department of Homeland Security, provides the planning, preparation, response to and recovery from all types of natural and man-made disasters; provides federal support of disaster relief response, assistance, support and recovery to State and local entities impacted by federally declared disasters. 13.5.4.14.5 The U. S. Fire Administration maintains a wide array of fire service based programs, training, education, technical and statistical information for the overall planning/prevention/control of fire issues within the U.S., including: Alerts, advisories, Arson, Juvenile Fire setting, communications, Critical Infrastructure Protection(EMR-ISAC), emergency medical services, rescue, fire service administration, firefighter health and safety, hazardous materials, incident management, professional development, terrorism and wild land fire. 13.5.4.14.5.1 The United States Fire Administration maintains an extensive database of information related to fire incidents through its administration of the National Fire Incident Reporting System (NFIRS). 13.5.4.14.5.2 In addition, the administration maintains records of ongoing research in fire investigation, information regarding arson awareness programs, and technical and reference materials focusing on fire investigation, and it coordinates the distribution of the Arson Information Management System (AIMS) software.

Printed on 9/18/2009 2 Report on Proposals – November 2010 NFPA 921 ______921-2 Log #22

______Robert Bourke, Northeastern Regional Fire Code Development Committee Revise text to read as follows: Revise “fireman” to “Firefighter”

The correct term is firefighter not fireman.

Printed on 9/18/2009 3 Report on Proposals – November 2010 NFPA 921 ______921-3 Log #30

______Dennis J. Merkley, Fire Facts Incorporated All photographs, graphs and drawings must be depicted in colour. We, in the Fire Investigation Community rely on viewing fire patterns and other fire scene indicators to perform our chosen vocation—all are surveyed in real world colour. Even our fire scene photographs are taken in real world colour. Portraying photographs, graphs and drawings in ancient black and white does not cut it in the 21st century in a document as important to our industry as NFPA-921. We are constantly preaching professionalism let's act professionally and have the document printed in state-of-art colour. The black and white photos in the present document that attempt to portray fire patterns that an investigator should look for during fire scene examination have little educational value due to the lack of colour. All of the recent text on the topic of fire investigation, ("Scientific Protocols for Fire Investigation," Lentini; "Kirk's Fire Investigation, Sixth Edition," DeHaan; "Ignition Handbook," Babrauskas and the soon to be published "Fire Investigator, Second Edition," IFSTA) have their photographic references in colour which makes them of great value to the student of the craft. The rookie Fire Investigator who picks up the current edition of NFPA-921 gains little or no educational in-site in viewing black and white photographs of what is said to be "Variability of Char Blister," Figure 6.2.4.3; "Spalled Concrete Floor," Figure 6.2.5.1; "Steel I-beam Girders Deformed by Heating Under Load," Figure 6.2.9.1; "Clean Burn on Wall Surface," Figure 6.2.11; "Crazed Window Glass," Figure 6.2.13.1.4; "A Typical 'Pulled' Bulb Showing That the Heating Was from the Right Side," Figure 6.2.15 or Figure 6.3.4.2, Page 52, to name but a few. It is difficult to determine what some of the referenced photographs throughout the document are trying to depict and exemplify let alone understand and learn from their depiction, due to the lack of colour. This document is called "GUIDE for Fire & Explosion Investigations." There is little guidance for the "Cub" Fire Investigator when he or she must look at the present illustrations and try to decipher what they are depicting due to the lack of colour. Again, lets get into the 21st century ... this document is too important a treatise to be portrayed in antiquated black and white. Let's not hide behind the issues of—"none of the other NFPA documents are in colour" or "the cost would be unacceptable." Let's not be hauled kicking and screaming into the 21 st century some years later when all treatises are printed in colour, let's be leaders in the Fire Investigation community now!

Technical Committee has no authority as to the format of any images in the document. Although, the committee believes that the proposal is appropriate.

Printed on 9/18/2009 4 Report on Proposals – November 2010 NFPA 921 ______921-4 Log #50

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Revise the current text of sections 1.1 Scope; 1.2.1 Purpose; 1.3.4; 1.3.5; and add a new section 1.4 as follows:

This document is designed to assist individuals who are charged with the responsibility of investigating and analyzing fire and explosion incidents and rendering opinions as to the origin, cause, responsibility, or prevention of such incidents, and the damage and injuries which arise from such incidents.

The purpose of this document is to establish guidelines and recommendations for the safe and systematic investigation or analysis of fire and explosion incidents, and which fire investigators and fire analysts can cite as an authoritative source of appropriate fire science, technology, and methodology as applied to fire investigations; and as an authoritative, peer-reviewed training and reference text. Fire investigation or analysis and the accurate listing of causes is are fundamental to the protection of lives and property from the threat of hostile fire or explosions. It is through an efficient and accurate determination of the cause and responsibility that future fire incidents can be avoided. This document has been developed as a model for the advancement and practice of fire and explosion investigation, fire science, technology, and methodology. In addition, it is recognized that the extent of the fire investigator’s assignment, time and resource limitations, or existing policies may limit the degree to which the recommendations, principles, and methodologies in this document will be applied in a given investigation. This document has been developed as a model for the advancement and practice of fire and explosion investigation, fire science, technology, and methodology.

This document is not intended as a completely comprehensive scientific chemistry or engineering text. Although many chemical scientific and engineering concepts are presented within the text, the user is cautioned that these concepts are presented at an introductory elementary level and additional technical sources, training, and education may often need to be utilized in an investigation.

As the information expressed herein is intended to be as current as practicable, the provisions, science, methodology, principles, and recommendations of this guide should be considered retroactive, supersede all previous editions, and should be applied to the study of any fire investigation or analysis of any incident which may have occurred prior to the current date of publication. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The proposed revised and new text more accurately reflects the actual Scope and Purpose of the document and how it is currently being accepted by the courts and used in the field. Many courts have recognized that NFPA 921 is an “authoritative source of appropriate fire science and technology as applied to fire investigations and authoritative, peer-reviewed training and reference text” including, but not limited to:

Perry Lumber Co. v. Durable Services, Inc., 710 N.W.2d 854, 271 Neb. 303 (Neb., 2006) Presley v. Lakewood Engineering and Manufacturing Company, No. 07-3846 (8th Cir. 1/21/2009) (8th Cir., 2009)

Printed on 9/18/2009 5 Report on Proposals – November 2010 NFPA 921 People v. Jackson, No. 272776 (Mich. App. 5/13/2008) (Mich. App., 2008) Gilmore v. Village Green Management Company, 2008 Ohio 4566 (Ohio App. 9/11/2008), 2008 Ohio 4566 (Ohio App., 2008) Fireman's Fund Insurance Company v. Canon U.S.A., Inc., No. 03-3836 (Fed. 8th Cir. 1/12/2005) (Fed. 8th Cir., 2005) Farmland Mut. Ins. Companies v. Chief Inds., 170 P.3d 832 (Colo. App., 2007) State v. Sharp, 928 A.2d 165, 395 N.J. Super. 175 (N.J. Super., 2006) State v. Thompson, 2008 Ohio 316 (Ohio App. 1/31/2008), 2008 Ohio 316 (Ohio App., 2008) Abon, Ltd. v. Transcontinental Ins. Co., 2005 Ohio 3052 (OH 6/16/2005), 2005 Ohio 3052 (OH, 2005) Royal Ins. Co. v. Joseph Daniel Const., Inc. (S.D.N.Y. 2002), 208 F.Supp. 423, 426; Travelers Property & Cas. Corp. v. General Electric Co. (D. Conn. 2001), 150 F.Supp. 360, 366.

Revise text to read as follows: Chapter 1 Administration 1.1 Scope. This document is designed to assist individuals who are charged with the responsibility of investigating and analyzing fire and explosion incidents and rendering opinions as to the origin, cause, responsibility, or prevention of such incidents, and the damage and injuries which arise from such incidents. (Accept) 1.2 Purpose. 1.2.1 The purpose of this document is to establish guidelines and recommendations for the safe and systematic investigation or analysis of fire and explosion incidents, and which fire investigators and fire analysts can cite as an authoritative source of appropriate fire science, technology, and methodology as applied to fire investigations; and as an authoritative, peer-reviewed training and reference text. Fire investigation or analysis and the accurate listing of causes is are fundamental to the protection of lives and property from the threat of hostile fire or explosions. It is through an efficient and accurate determination of the cause and responsibility that future fire incidents can be avoided. This document has been developed as a model for the advancement and practice of fire and explosion investigation, fire science, technology, and methodology. (Reject) 1.3.4 In addition, it is recognized that the extent scope of the fire investigator’s assignment, time and resource limitations, or existing policies may limit the degree to which the recommendations, principles, and methodologies in this document will be applied in a given investigation. This document has been developed as a model for the advancement and practice of fire and explosion investigation, fire science, technology, and methodology.(Accept in Principle) 1.3.5 This document is not intended as a completely comprehensive scientific chemistry or engineering text. Although many chemical scientific and engineering concepts are presented within the text, the user is cautioned that these concepts are presented at an introductory elementary level and additional technical sources, training, and education may often need to be utilized in an investigation. (Accept in Principle) 1.4 Retroactivity. As the information expressed herein is intended to be as current as practicable, the provisions, science, methodology, principles, and recommendations of this guide should be considered retroactive, supersede all previous editions, and should be applied to the study of any fire investigation or analysis of any incident which may have occurred prior to the current date of publication. (Reject) (“is to are” is editorial) Section 1.2.1: While the committee believes this document is a model for modern fire investigations, it is for others, not the committee, to declare the text to be authoritative. In addition, under the NFPA process, this document is produced using a consensus process and is not technically a peer reviewed document. 1.3.4 Changes were editorial 1.3.5 Changes were editorial 1.4: Recognition of retroactivity is beyond the purview of this document and is regulated by users of the document.

Printed on 9/18/2009 6 Report on Proposals – November 2010 NFPA 921 ______921-5 Log #161

______Melvin Robin, ATF New and revise text to read as follows: Add: “The consensus process system relative to changes, additions and/or deletions to this guide involves the use of a 2/3 affirmative vote by committee members to approve those changes, additions and/or deletions. These committee members are selected from public and private agencies representing various interests related to fire investigation.” Problem--Consensus process needs to be clarified in order to explain that non-unanimous decisions can approve changes, additions and deletions

It is unclear if submitter wishes proffered text to replace existing text, serve as new text, and where new text should be added. Further, existing text in section 1.3 is worthwhile and should remain in the document. The proposed text is unnecessary and incomplete.

Printed on 9/18/2009 7 Report on Proposals – November 2010 NFPA 921 ______921-6 Log #157

______Melvin Robin, ATF New and revise text to read as follows: “Investigators should, when appropriate, consider the use of additional generally accepted texts and documented sources of information regarding fire and explosion investigation (such as those listed as references in this document) in conjunction with this guide.” Problem--Document may improve results if used properly, not definitive though Change “can” to “may” ... ‘improve results of investigation, etc.’

It is unclear if submitter wishes proffered text to replace existing text, serve as new text, and where new text should be added. The proposed text is unnecessary and already addressed in 1.3.5 as modified (see committee action on 921-4 (Log #50)).

Printed on 9/18/2009 8 Report on Proposals – November 2010 NFPA 921 ______921-7 Log #31

______Mark A. Beavers, Rimkus Consulting Group, Inc. Revise text as follows: ABYC A-32 A-30 Cooking Appliances with Integral LPG Cylinders, 2006. Should read ABYC A-30, Cooking Appliances with Integral LPG Cylinders, 2006. ABYC A-32, Cooking Appliances with Integral LPG Cylinders, 2006 does not exist in the American Boat & Yacht Council Standard & Technical Information Reports for Small Craft. Current reference is a typographical error or misquote. The correct reference would be ABYC A-30, Cooking Appliances with Integral LPG Cylinders, 2006 as identified in the July 2008 edition of the American Boat & Yacht Council Standard & Technical Information Reports for Small Craft.

Printed on 9/18/2009 9 Report on Proposals – November 2010 NFPA 921 ______921-8 Log #98

______Bob Eugene, Underwriters Laboratories Inc. Revise text to read as follows: 2.3.8 UL Publications. Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096. ANSI/UL 263, Standard for Safety Fire Tests of Building Construction and Materials, 2003. ANSI/UL 969, Standard for Marking and Labeling Systems, 1995, revised 2001 2008. UL 1500, Standard for Safety Ignition Protection Test for Marine Products, 1997, revised 2007. Update standards titles to indicate ANSI approvals and revision dates.

Printed on 9/18/2009 10 Report on Proposals – November 2010 NFPA 921 ______921-9 Log #CP14

______Technical Committee on Fire Investigations, Revise text to read as follows: 3.3.X Competent Ignition Source. An ignition source that has sufficient energy and is capable of transferring that energy to the fuel long enough to raise the fuel to its ignition temperature. (See Cause Chapter, Ignition Source Analysis) The committee feels that a definition on Competent Ignition Source is warranted. This definition matches text in the section on Ignition Source Analysis in the Revised Cause Chapter.

Printed on 9/18/2009 11 Report on Proposals – November 2010 NFPA 921 ______921-10 Log #95

______Joseph Carey, Robinson & Cole LLP New text to read as follows: Insert the following definition in chapter 3.

There is no definition in Chapter 3 of a competent ignition source. The term is extremely important and it should be included in the definitions chapter.

The proposed definition is incorrect.

Printed on 9/18/2009 12 Report on Proposals – November 2010 NFPA 921 ______921-11 Log #51

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add a new definition: An ignitable gas, vapor, dust, fines, particulate, aerosol, mist, fog, or hybrid mixture of these, suspended in the atmosphere, which is capable of being ignited and propagating a flame front. The phrase “diffuse fuel” is used or alluded to twelve times in the document, but is never actually defined.

Printed on 9/18/2009 13 Report on Proposals – November 2010 NFPA 921 ______921-12 Log #110

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: Overhaul is the final stage in the extinguishment of a fire and ensuring the structure is either safe or suitable guarded. It includes activities such as checking for fire extension and hotspots. While overhaul activities may have a significant effect on the investigation, it is not part of the origin and cause investigation. The word overhaul is used 20 times in the 2008 edition of NFPA 921, but never defined. The misconception that overhaul is part of, or the beginning of the origin and cause investigation may lead to inappropriate activities during overhaul such as evidence modification or destruction (for instance the unnecessary movement of artefacts, switching or resetting of circuit breakers, unplugging of electrical cords, etc.) A person attired for fire extinguishment (typically turnout gear) is not usually equipped for origin and cause investigation (typically with camera, notebook, sample and artefact collection paraphernalia). A reasonable definition of overhaul is a good starting point to delineate these activities and responsibilities and thus minimize the unnecessary and unwarranted disturbance of the evidence.

Revise the definition to: A firefighting term involving the process of final extinguishment after the main body of the fire has been knocked down. All traces of fire must be extinguished at this time.

This is the preferred NFPA definition. The technical committee did not necessarily agree with all the submitter’s substantiations.

Printed on 9/18/2009 14 Report on Proposals – November 2010 NFPA 921 ______921-13 Log #52

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Replace the current 3.3.9 definition of Area of Origin with the following: A structure, part of a structure, or general geographic location within a fire scene, in which the “ of a fire or explosion is reasonably believed to be located. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The current definitions of Origin, Area of Origin, and Point of Origin are inexact, confusing and do not conform to how the terms are actually used in the field. This proposal sets a new, simple, and understandable definition for Area of Origin.

Printed on 9/18/2009 15 Report on Proposals – November 2010 NFPA 921 ______921-14 Log #14

______Ahemd H. Zahran, Saudi Aramco Revise text as follows: 3.3.21 Calorie. The amount of heat necessary to raise 1 gram of water 1 °C at the pressure of 1 atmosphere and temperature of 15 °C; a calorie is 4.184 joules, and there are 252.15 calories in a British Thermal unit (Btu). The original text is missing one of the conditions of measuring the calorie, which is the pressure of 1 atmosphere. This proposal is to correct the definition to the correct scientific definition.

Printed on 9/18/2009 16 Report on Proposals – November 2010 NFPA 921 ______921-15 Log #101

______Glossary of Terms Technical Advisory Committee / Marcelo Hirschler, Revise text as follows: 3.3.28* Combustible. Capable of undergoing combustion. Capable of burning, generally in air under normal conditions of ambient temperature and pressure, unless otherwise specified; combustion can occur in cases where an oxidizer other than the oxygen in air is present (e.g., chlorine, fluorine, or chemicals containing oxygen in their structure). A.3.3.28 A combustible material is capable of burning, generally in air under normal conditions of ambient temperature and pressure, unless otherwise specified; combustion can occur in cases where an oxidizer other than the oxygen in air is present (e.g., chlorine, fluorine, or chemicals containing oxygen in their structure). Also, add a definition for the term combustion, as follows: Combustion. A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either a glow or flame. It is important to have consistent definitions of terms within NFPA. The term combustible at present has 6 definitions, as follows: A substance that will burn. (430) A material or structure that will release heat energy on burning. ( ) Capable of burning, generally in air under normal conditions of ambient temperature and pressure, unless otherwise specified; combustion can occur in cases where an oxidizer other than the oxygen in air is present (e.g., chlorine, fluorine, or chemicals containing oxygen in their structure). ( ) Any material that, in the form in which it is used and under the conditions anticipated, will ignite and burn or will add appreciable heat to an ambient fire. (1144) Capable of undergoing combustion. (69, 82, 99, 120, 122, 214, 502, 804, 805, 820, 851, 853, 1126) Capable of reacting with oxygen and burning if ignited. (77, 220, 1141) It is therefore recommended, in order to improve consistency within NFPA documents that a simple definition which is widely used be employed in all documents. The document responsible for this definition is NFPA 220 and the same recommendation will be made to that document. This definition is also used by ASTM E 176 for committee ASTM E05 on Fire Standards. The existing definition in NFPA 921 is more of a discussion and is recommended as an annex section. There are 5 definitions of combustion in NFPA and the one chosen is the most widely used, including NFPA 1. This definition is also used by ASTM E 176 for committee ASTM E05 on Fire Standards. I am the chairman of the NFPA Advisory Committee on the Glossary on Terminology. The committee was created by NFPA Standards Council to provide consistency in terminology throughout the NFPA documents.

Printed on 9/18/2009 17 Report on Proposals – November 2010 NFPA 921 ______921-16 Log #102

______Glossary of Terms Technical Advisory Committee / Marcelo Hirschler, Revise text as follows: Heat, gases, solid particulates, and liquid aerosols produced by burning. The gases, volatilized liquids and solids, particulate matter, and ash generated by combustion.

It is important to have consistent definitions of terms within NFPA. The term combustion products at present has 4 definitions, as follows: Combustion products Constituents resulting from the combustion of a fuel with the oxygen of the air, including the inert but excluding excess air. (54) The gases, volatilized liquids and solids, particulate matter, and ash generated by combustion. (99) Constituents resulting from the combustion of a fuel with the oxygen of the air, including the inerts but excluding excess air. (211) Heat, gases, solid particulates, and liquid aerosols produced by burning. (921) It is therefore recommended, in order to improve consistency within NFPA documents that a simple definition be used and the most appropriate seems to be the one from NFPA 99. The document responsible for this definition is NFPA 54 and the same recommendation will be made to that committee. The recommendation that primary responsibility be assigned to NFPA 921 is based on the fact that the definition in NFPA 54 is too limiting for other NFPA documents. I am the chairman of the NFPA Advisory Committee on the Glossary on Terminology. The committee was created by NFPA Standards Council to provide consistency in terminology throughout the NFPA documents.

Insert the word “heat” in the first sentence between the word “the” and “gases”to read: The heat, gases, volatilized liquids and solids, particulate matter, and ash generated by combustion. Proposed definition required modification to include all products of combustion. The committee agrees that this should be the preferred NFPA definition.

Printed on 9/18/2009 18 Report on Proposals – November 2010 NFPA 921 ______921-17 Log #48

______Michael Albo, Southfield Fire Dept. Revise text as follows: Fire Scene Reconstruction. The process of recreating the physical scene during fire scene analysis investigation or through the removal of debris and the replacement re-placement of contents or structural elements in their pre-fire positions. It will eliminate confusion and the potential removal of contents (evidence) in an unaccepted manner. (See placement, re-, & replacement in Merriam-Webster's Collegiate Dictionary, 11th Edition.

Change “replacement” to “placement” to read: Fire Scene Reconstruction. The process of recreating the physical scene during fire scene analysis investigation or through the removal of debris and the replacement replacement of contents or structural elements in their pre-fire positions. The committee believes that the change better clarifies the issue.

Printed on 9/18/2009 19 Report on Proposals – November 2010 NFPA 921 ______921-18 Log #53

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add additional wording as follows: The flaming leading edge of a propagating combustion reaction zone through a diffuse fuel. ( ) The additional wording makes the definition more restrictive and therefore correct.

Delete: “through a diffuse fuel. (see Diffuse Fuel)” at the end of the proposed definition. The committee believes limiting the definition to a diffuse fuel would create unnecessary conflict with the definition application to other chapters.

Printed on 9/18/2009 20 Report on Proposals – November 2010 NFPA 921 ______921-19 Log #103

______Glossary of Terms Technical Advisory Committee / Marcelo Hirschler, Revise text as follows: 3.3.68 Flammable. Capable of burning with a flame. 3.3.68* Flammable. A combustible that is capable of easily being ignited and rapidly consumed by fire. A.3.3.68 Flammable. Flammables can be solids, liquids, or gases exhibiting these qualities.

It is important to have consistent definitions of terms within NFPA. The term flammable at present has several definitions. The preferred definition, which is recommended, is used in NFPA 1126 and in NFPA 99. It is therefore recommended, in order to improve consistency within NFPA documents that this definition be used. The document responsible for this definition is NFPA 1126. The recommendation that primary responsibility be assigned to NFPA 921 is based on the fact that the scope of NFPA 921 seems more appropriate. I am the chairman of the NFPA Advisory Committee on the Glossary on Terminology. The committee was created by NFPA Standards Council to provide consistency in terminology throughout the NFPA documents.

The committee believes the current definition is adequate and that the proposed text is too subjective. The proposed definition includes ease of ignition which is not associated with the fuel’s ability to produce flame. Further, the rate in which the fuel is consumed is not associated with its ability to produce flame.

Printed on 9/18/2009 21 Report on Proposals – November 2010 NFPA 921 ______921-20 Log #54

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add additional phrase as follows: A fire that spreads by means of a flame front, rapidly through a diffuse fuel, such as dust, gas, or the vapors of an ignitible liquid, without the production of damaging pressure. The addition of the proposed phrase makes the definition more descriptive.

Printed on 9/18/2009 22 Report on Proposals – November 2010 NFPA 921 ______921-21 Log #55

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add the additional word “fire” to the title: Any arrangement of materials and heat sources that presents the potential for harm, such as personal injury or ignition of combustibles. The definition currently in the document is NOT the definition of a hazard. It is the definition of a fire hazard as used in numerous other NFPA codes.

Printed on 9/18/2009 23 Report on Proposals – November 2010 NFPA 921 ______921-22 Log #56

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add additional wording as follows: A classification of the cause of a fire that is intentionally ignited under circumstances in which the person knows that the fire should not be ignited. The current definition is not of a fire cause, but a fire cause classification, as per chapter 19.

Printed on 9/18/2009 24 Report on Proposals – November 2010 NFPA 921 ______921-23 Log #125

______Kevin Crawford, Thornton, CO Revise text as follows: A fire … in which the person igniting the fire knows that the fire should not be ignited. This addition further defines the perpetrator of the ignition.

This change needs to also be made in the first sentence of 19.2.1.3 (page 159 in 2008 edition).

Printed on 9/18/2009 25 Report on Proposals – November 2010 NFPA 921 ______921-24 Log #10

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: A joule is the heat produced when one ampere is passed through a resistance of one ohm for one second, or it is the work required to have move a distance of one meter against a force of one newton. This would correct a typographical error and restore the sentence to the correct definition of a joule.

Printed on 9/18/2009 26 Report on Proposals – November 2010 NFPA 921 ______921-25 Log #79

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: ....or it is the work required to have move a distance of one meter against a force of one newton. I believe that this is editorial.

Printed on 9/18/2009 27 Report on Proposals – November 2010 NFPA 921 ______921-26 Log #104

______Glossary of Terms Technical Advisory Committee / Marcelo Hirschler, Revise text as follows: The fuel that is first set on fire by the heat of ignition; to be meaningful, both a type of material and a form of material should be identified.

It is important to have consistent definitions of terms within NFPA. The term material first ignited at present has 2 definitions, which are very similar. However, the preferred one is in NFPA 921 and the one in NFPA 901 is in two sentences. It is recommended that they be made the same, and in one sentence. I am the chairman of the NFPA Advisory Committee on the Glossary on Terminology. The committee was created by NFPA Standards Council to provide consistency in terminology throughout the NFPA documents.

Submitter does not provide any new or revised text.

Printed on 9/18/2009 28 Report on Proposals – November 2010 NFPA 921 ______921-27 Log #105

______Glossary of Terms Technical Advisory Committee / Marcelo Hirschler, Revise text as follows: A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat; materials that are reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C, shall be considered noncombustible materials. A material that, in the form in which it is used and under the condition anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Also called incombustible material (not preferred). It is important to have consistent definitions of terms within NFPA. The term noncombustible material at present has several definitions, many of which are very similar. However, the preferred one is in NFPA 220. The Glossary Advisory Committee agreed on the definition recommended because it is in a single sentence and captures all essential elements. The existing definition in NFPA 921 is different from the NFPA preferred definition, contained in NFPA 220. The NFPA 220 definition reads: “Noncombustible Material. A substance that will not ignite and burn when subjected to a fire.” It is also different from the NFPA 5000 definition, which reads: “Noncombustible Material. A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat. Materials that are reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C, shall be considered noncombustible materials.” In practice, the only thing that matters is whether the material complies with ASTM E 136 and that is what is being used in NFPA 211, in NFPA 101 and in NFPA 5000 (as well as in other codes) for classifying a material as noncombustible. The NFPA 220 definition does not address this and the NFPA 5000 and 921 definitions are contained in two sentences. It is therefore recommended, in order to improve consistency within NFPA documents that the definition from NFPA 5000, revised to contain a single sentence, be used, as shown. This does not require adoption of NFPA 5000 or reference to NFPA 5000. Proposals are being made to other committees to adopt the same definition so as to obtain consistency in terminology. This proposal is similar to other proposals submitted so as to lead to more consistency within NFPA definitions. The committee was created by NFPA Standards Council to provide consistency in terminology throughout the NFPA documents.

Revise text to read as follows: 3.3.112 Noncombustible Material. A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat. Move the last section of the proposed text to the Annex: A.3.3.112 Materials that are reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C, shall be considered noncombustible materials.

The committee believes that the reference to the ASTM standard should not be part of the definition. The committee believes the current definition has broader application than that stated in the ASTM standard.

Printed on 9/18/2009 29 Report on Proposals – November 2010 NFPA 921 ______921-28 Log #57

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Delete current definition of origin and replace with: A generalized term for the place where a fire or explosion began.

Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The current definitions of Origin, Area of Origin, and Point of Origin are inexact, confusing and do not conform to how the terms are actually used in the field. This proposal sets a new, simple and understandable definition for Origin.

Delete: “A generalized term for” should be deleted from the beginning of the sentence. Insert: “the general location” as the first part of the first sentence. Delete: “place” To read:The general location where a fire or explosion began. (See 3.3.122, Point of Origin, or 3.3.9, Area of Origin.)

The Committee believes that the committee’s proposed wording best explains the concept.

Printed on 9/18/2009 30 Report on Proposals – November 2010 NFPA 921 ______921-29 Log #8

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: An overload current is usually but might not always be combined confined to the normal intended conductive paths provided by conductors and other electrical components of an electrical circuit. This would correct a typographical error and restore the intent of the sentence to show that overloads usually are contained within the normal conductor path.

Printed on 9/18/2009 31 Report on Proposals – November 2010 NFPA 921 ______921-30 Log #58

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Replace the current text with the following : The smallest location which a fire investigator can define within an “area of origin,” in which a heat source, source of oxygen, and a fuel interacted with each other and a fire or explosion began.

The proposed definition would allow the use of this terminology to define a large volume of space, far beyond a specific point, as determined by the investigator. Such use of the term would define the area of origin and not the point of origin.

Printed on 9/18/2009 32 Report on Proposals – November 2010 NFPA 921 ______921-31 Log #111

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: The chemical decomposition of a compound into one or more substances by heat alone A process in which material is decomposed, or broken down, into simpler molecular compounds by the effects of heat alone; pyrolysis often precedes combustion. Previous objections to this submission stated that this definition 1. did not allow for rearrangement of bonds within a single compound. That is correct because the rearrangement of bonds in a molecule is the process of isomerisation, not pyrolysis. See the definitions from authoritative dictionaries and encyclopaedias below. 2. and that simpler is a subjective term and not always accurate. Simpler is the term used in all the other authoritative dictionaries and encyclopaedias (see below). , a process that changes a substance into an isomer, such as butane into isobutane. (Academic Press Dictionary of Science and Technology, 1992 edition, page 1151) , one of two or more substances that have the same chemical composition but different structural form. (Academic Press Dictionary of Science and Technology, 1992 edition, page 1151) [CHEMISTRY] The phenomenon whereby a compound is changed into an isomer, for example, conversion of butane into isobutane. (McGraw-Hill Dictionary of Chemistry, 1997 edition, page 207) [CHEMISTRY] One of two or more chemical substances having the same elementary percentage composition and molecular weight but differing in structure, and therefore in properties; there are many ways in which such structural differences occur; one example is provided by the compounds -butane CH3(CH2)2CH3 and isobutane, CH3CH(CH3)2. (McGrawHill Dictionary of Chemistry, 1997 edition, page 207) [CHEM] A process whereby a compound is changed into an isomer, for example, conversion of butane into isobutane. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th edition, page 1124) [CHEM] One of two or more chemical substances having the same elementary percentage composition and molecular weight but differing in structure, and therefore in properties; one example is provided by the compounds

-butane CH3(CH2)2CH3 and isobutane, CH3CH(CH3)2. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th edition, page 1124) ( ) The decomposition of a substance by heat. (Chambers Dictionary of Science and Technology, 1999 edition, page 936) ( ) The breaking down of a substance into simpler molecules or atoms. (Chambers Dictionary of Science and Technology, 1999 edition, page 307) . A process of decomposition by heat. Thus, pyrolytic. (Academic Press Dictionary of Science and Technology, 1992 edition, page 1764) . A process in which one or more substances break down into simpler molecular substances, as from the effects of heat, light, chemical or biological activity, and so on. (Academic Press Dictionary of Science and Technology, 1992 edition, page 596) [CHEMISTRY] The breaking apart of complex molecules into simpler units by the use of heat, as in the pyrolysis of heavy oil to make gasoline. (McGraw-Hill Dictionary of Chemistry, 1997 edition, page 323) [CHEM] The breaking apart of complex molecules into simpler units by the use of heat, as in the pyrolysis of heavy oil to make gasoline. Also known as thermolysis. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th edition, page 1710) Quoting from John DeHaan’s fourth edition of Kirk’s Fire Investigation, page 15 in a paragraph titled : The word or stems from the Greek words: (meaning fire) and (meaning decompose or decay). Therefore, pyrolysis can be defined as the decomposition of a material into simpler compounds brought about by heat.

Printed on 9/18/2009 33 Report on Proposals – November 2010 NFPA 921 ______921-32 Log #59

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Delete the wording of the current 3.3.139 Scene and replace it with the following wording for Fire Scene with the appropriate new paragraph numbering: The general physical location of a fire or explosion incident (geographic area, structure or portion of a structure, vehicle, boat, piece of equipment, etc.) designated as important to the investigation because it may contain physical damage or debris, evidence, victims, or incident-related hazards. This is the area to be processed during the scene examination. The current definition deals with a discussion which is fairly specific the text of the chapter on Complex Investigations. This modified definition of a “Fire Scene” is more general to the entire document.

Title should be changed to “Scene” (deleting the word “fire”) Delete the last sentence: “This is the area to be processed during the scene examination.” Typo in first line, change 139 to 138. The second sentence was not appropriate to this definition, that is, it should not define the scope of the process area.

Printed on 9/18/2009 34 Report on Proposals – November 2010 NFPA 921 ______921-33 Log #149

______Elizabeth C. Buc, Fire and Materials Research Laboratory, LLC Add new text as follows: The systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of a hypothesis. *Provide a reference or citation for this definition of the scientific method in the annex (*) or under general references.

Submitter provides no new text. Submitter’s substantiation does not explain why new text or why a reference is needed.

Printed on 9/18/2009 35 Report on Proposals – November 2010 NFPA 921 ______921-34 Log #60

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Change wording as follows: A crater-like indentation created at the point of origin of an some explosions explosion. Explosion seats occur only in some explosions, not all. Suggested text is correct.

Printed on 9/18/2009 36 Report on Proposals – November 2010 NFPA 921 ______921-35 Log #25

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows:

The ratio of the average molecular weight of a given volume of gas or vapor to the average molecular weight of an equal volume of air at the same temperature and pressure.

The average molecular weight of a gas, vapor or air does not depend on the gas, vapor or air's volume (in thermodynamics it is what is called an "intensive property," see any introductory text on thermodynamics or the Wikipedia explanation at: http://en.wikipedia.org/wiki/Intensive_property). In similar manner the average molecular weights do not change with either temperature or pressure. So stating a given volume of gas or vapor, an equal volume of air and at the same temperature and pressure is not only wrong, it implies that the average molecular weight of gas, vapor or air changes with the volume, the temperature or the pressure present.

Printed on 9/18/2009 37 Report on Proposals – November 2010 NFPA 921 ______921-36 Log #26

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: The ratio of the mass of a given volume of a substance to the mass of an equal volume of water at a temperature of 4°C average molecular weight of a given volume of liquid or solid to the average molecular weight of an equal volume of water at the same temperature and pressure. The existing definition is completely wrong. The average molecular weight of a liquid or solid generally has little effect on its specific gravity. As a simple example, the molecular weight of butane is 58 and the molecular weight of water is 18, and yet the specific gravity of liquid butane is around 0.60 (compared to 1 for water) (see http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=8). The concept of the ratio of molecular weights applies only to the specific gravity of gases that follow the Ideal Gas Law.

Printed on 9/18/2009 38 Report on Proposals – November 2010 NFPA 921 ______921-37 Log #17

______Leo O'Campo, Aramco POB-4197 Add a definition for stoichiometric and stoichiometric ratio. No definition is available, term used in document.

Submitter offers no text.

Printed on 9/18/2009 39 Report on Proposals – November 2010 NFPA 921 ______921-38 Log #9

______Thomas H. Claxton, ClaxCo, Inc. Revise text to read: The increase in length, volume or superficial surface area of a body with rise in temperature. Although correct, superficial is not a common usage term in this instance for fire investigators. The term "surface" expresses the same meaning and is readily recognized.

Printed on 9/18/2009 40 Report on Proposals – November 2010 NFPA 921 ______921-39 Log #91

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add wording to the second sentence so that it reads: The compilation of factual data, as well as an analysis of those facts, should be accomplished objectively, and truthfully, and without expectation bias, preconception, or prejudice. Added text enhances to concept of objectivity and includes phraseology used elsewhere in the text.

Printed on 9/18/2009 41 Report on Proposals – November 2010 NFPA 921 ______921-40 Log #28

______Steve McCarthy, Ottawa County Sheriff’s Office Add new text to read as follows:

To include in Chapter 4.2 Systematic Approach: Each Investigative agency or entity should implement a written policy on Fire & Explosion Investigation that dictates a systematic approach using the scientific method.

When researching NFPA 921 and 1033, I was not able to find any reference to an investigative agency whether it be private or public instituting a written policy spelling out a systematic approach using the scientific method for the investigation of fires and explosions. It is my opinion that if implemented, this would require agencies to have a written guideline for the investigator to follow. This would be beneficial as new investigators are hired and trained. Having been a field training officer in my early career I am a firm believer in written policies. If the guidelines follow the recommended systematic approach using the scientific method this would assist in standardizing our science throughout the nation. That would in theory reduce the number of erroneous investigations.

This document, the NFPA, and the Technical Committee is not able or willing to dictate to agencies on preparing written policies. The NFPA documents are voluntary standards and it is up to the AHJ (Authority Having Jurisdiction) to adopt.

Printed on 9/18/2009 42 Report on Proposals – November 2010 NFPA 921 ______921-41 Log #150

______Elizabeth C. Buc, Fire and Materials Research Laboratory, LLC Revise text as follows:

The scientific method is not represented by the current text (i.e., deductive versus abductive reasoning). The committee should form a task group to better apply the proposed use of the scientific method to fire investigation. The task group should consist of fire investigators, fire scientists and non-fire or traditional scientists. The National Research Council is releasing a report (in 2009) on "Strengthening Forensic Science in the United States: A Path Forward" that will provide the committee and task group with guidance. The problems with the proposed use of the scientific method in this section as discussed in the attached reference: Brannigan, V., Buc E., , Forensic Fire Investigation: An Interface of Science, Technology and Law, Interscience Communications, UK. Note: Supporting material is available for review at NFPA Headquarters.

Submitter offers no revised text.

Printed on 9/18/2009 43 Forensic Fire Investigation: An Interface of Science, Technology and Law

Vincent M. Brannigan J.D Professor Emeritus Elizabeth Buc PhD, PE Department of Fire Protection Engineering Fire and Materials Research Laboratory, LLC, U. of Maryland, College Park, MD. 20742 Livonia, MI 48150 [email protected] [email protected]

ABSTRACT

Forensic fire investigation (FFI) is an extremely complex field combining science, technology and law. Advances in the fire sciences over the past 20 years have challenged some of the most widely held beliefs about purported “evidence” of intentionally set fires or causation in fire related products liability. NFPA 921 is unquestionably an advance in the collection of fire scene documentation and evidence collection for developing a putative explanation of a fire’s cause. Changes in the law of evidence have demanded much higher levels of proof for forensic expert testimony. Determining the origin and cause of a fire for legal purposes is not itself a field of “science” at least as that term is used in the scientific or legal community but FFI often uses the tools of science and engineering to a greater or lesser extent depending on the circumstances. In NFPA 921, the guide states that it uses the “scientific method” when in fact it is at best what philosophers of science call “abduction”, or formal reasoning towards the “best explanation” of a phenomenon in the opinion of the person doing the reasoning. FFI testimony is susceptible to what the Supreme Court describes as the “ipse dixit” problem of “scientific” testimony depending ultimately on the subjective and often poorly controlled inference process of the individual investigator. Such “ipse dixit” testimony was rejected by the court in Kumho Tire. The key for the future of NFPA 921 is separating the “data” from the inference in FFI and following the lead of related evidentiary fields to improve the credibility of the inference process inherent in FFI.

INTRODUCTION: FORENSIC FIRE INVESTIGATION

In the Middle Ages when a diligent witch finder needed to know exactly what procedure to use to identify a witch he turned to the Malleus Maleficarum authored by the renowned inquisitors Kramer and Sprenger. There were detailed instructions on witch finding and even precise descriptions as to how the interrogating tortures are to be carried out to produce reliable answers. The authors were experts with experience from many witchcraft trials and their techniques had produced many convictions of witchcraft. They would have been stunned if anyone had suggested that their testimony was nonsense and their procedures useless. The witchcraft example has been replicated in modern times. The promotion, use and eventual collapse of the faulty FBI ‘analysis’ of bullet lead content identification serves as a cautionary tale to anyone claiming the ability to infer conclusions from technical data that was not thoroughly researched before its use in trials.1

Forensic Fire Investigation (FFI) is the systematic examination of the physical aftermath of a fire or explosion to attempt to determine the “origin and cause” of the event. The claim is that it is routinely possible to examine a fire scene at a later time and “turn back the clock” to identify the early-fire origin and cause. This is trivial in a simple fire and almost impossible in very complex fires. Some investigators use the term “black hole” for fires that are so large that no useful information can “come out”. But how do we “know” that fire investigators can examine fire debris and “wind the clock backwards” to arrive at the origin and cause of a fire? As one practitioner puts it “Until the fire

Log 150 Supporting Material

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 1 of 12 investigation community can raise its own standards from its current amateur level to a professional level, we will remain a profession that is as much an art as a science”2

The adjective forensic indicates that the primary operational rationale for FFI is the use of the output of the investigation as Evidence in the legal process. The NFPA 921 Guide For Fire and Explosion Investigations (2008) (NFPA 921) 3 provides excellent and detailed guidance on properly processing a fire scene regardless of the extent of damage. Following NFPA 921ensures proper documentation of the fire scene and the identification and collection of evidence. FFI activities may also include weather history, MSDS reviews; calculations and/or modeling; non-destructive and destructive laboratory examinations. The authors of this paper accept that NFPA 921 is a single step forward in the quality of information and data gathering and will not examine data gathering or laboratory analysis any further.

DATA AND INFERENCE

However, at some point, and often initiated at the fire scene, the information and data collected are mentally processed by the investigators toward arriving at a “conclusion” concerning the fire’s initiation. The inferences from the data are the critical and most difficult step in FFI. The inferential process includes assessing a variety of potential ignition sources and first material ignited. The process retains some and eliminates others. Conclusions are drawn based on the observed data that infer the origin and cause of the fire. The inference process involves resolving various uncertainties in the scene. NFPA 921 recognizes and recommends the utilization of special experts that may assist fire investigators in developing the inferences. It contains many suitable caveats on inferences from the data. The goal for litigation is normally a requirement for ‘scientific and engineering’ certainty in any conclusion.

Kumho Tire and Ipse Dixit

Kumho Tire v Carmichael 4 is the leading US Supreme Court case on admission of expert testimony. The Court was presented with an inferential process by a highly qualified expert in tire failure. The Court affirmed a lower court opinion rejecting the expert’s testimony because of the weakness of the inferential process. The Court quoted language from an earlier case and stated: "Nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert."

Ipse Dixit is Latin for ‘I say it is so myself” The Court went on to write: Nor, on the other hand, does the presence of Daubert’s general acceptance factor help show that an expert’s testimony is reliable where the discipline itself lacks reliability….

The requirements of Kumho Tire are: 1) the expert must testify in accordance with a methodology supported by the discipline or profession, and 2) the discipline must be able to show that the methodology produces the kind of result it claims. That is the challenge for NFPA 921 and fire investigators. What exactly is the NFPA 921 methodology and how can it be proved to produce correct results?

Development of Forensic “Science”

The process of data collection and inferential analysis is typical of all forensic fields. Forensic Fire Investigation falls broadly in the area first described as Criminalistics, a term and study invented by Austrian Prof. Hans Gross in the 1890’s in his Handbuch fur Untersuchungsricter als System Der Kriminalistik. Gross was a lawyer and judge--not any kind of a scientist. Criminalistics was the physical component of a group of techniques that came to call themselves in German Forensische Wissenschaften and translated as forensic “sciences”. It should be noted that the German Wissenschaft translates as “science” but it is very clear that the English use of the word science is very different from

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 2 of 12 the German use of Wissenshaft. A Wissenshaft is any type of organized knowledge, it does not have to amount to an English language science. The organized study of law is Rechstswissenshaft but few think of legal scholars as scientists. FFI can be a Wissenschaft without being a “science”.

Confusion over what it means to be a “science” has persisted to the present day. It is well known that the claim to be a “science” is often made to help establish a shaky new field. Sometimes the name sticks as in Computer Science, while in others it fails to convince anyone the practitioners are scientists cf Police Science and Fire Science for training respectively police and fire officers. But still the allure of being called a science is overwhelming, particularly in the forensic evidence environment. Courts deal with a practical problem. Fact finders can be overwhelmed by claims that testimony is science rather than merely an opinion. So how would a court know if forensic fire investigation is some kind of “Science”? Or more to the point does FFI produce scientific evidence?

JURIDICAL FACT FINDING AND SCIENTIFIC EVIDENCE

Analyzing FFI as a forensic science requires understanding the role of scientific evidence. The legal system differentiates law from facts and within the area of facts creates a distinction between evidence and verdict. Juries act as “fact finders’. They reduce the raw “data” i.e. testimonial evidence to legal “Facts” to which the system can apply the Law. Very roughly the court allows the fact finder to hear admissible “evidence” to create “juridical facts” in the form of a verdict (literally to “speak the truth”). But these juridical facts are not truth or facts in any ultimate sense but are merely used to determine the legal outcome of the case. The meaning of fact in the legal system is therefore very different from the meaning of fact in science or engineering. Juridical facts are constructs created for and by the legal system for its own operational purposes. They are not necessarily expected or intended to have any validity outside of that process. In creating these juridical facts, juries or other fact finders review admissible “evidence”. However admissibility does not guarantee credibility or weight with the jury. That is a separate step. Juries are instructed to weigh the reliability of ordinary or “lay” evidence against their own common sense. E.g. could the witness have seen what he or she claims? Are the records reliable? Since the fact finder is to weigh the credibility of this evidence, the standard for admissibility of some types of testimonial evidence may be very low, and the underlying confidence in the “truth” of juridical “facts” found by the legal process may also be low.

The legal system routinely uses a variety of “levels of proof” to align social demands for an acceptably “correct” answer with the requirements for factual determination in the courts. “Proof beyond a reasonable doubt” clearly imposes a higher standard than “clear and convincing evidence” or the lowest ”preponderance of the evidence”. As a result, a body of evidence may be more than adequate for a civil case but totally inadequate for a criminal case. The level of proof directly affects the weight a jury might give to specific testimony, as well as the overall quantum of proof. Levels of proof have been analogized to confidence intervals in statistics. The confidence interval chosen is simply a policy judgment on whether the researcher prefers to make errors accepting a null hypothesis or rejecting it.

Courts developed “rule of evidence to structure this juridical fact finding process. These rules are designed to assure that evidence always has a minimum quantum of credibility before the legal system will admit it in the legal process. But these rules were developed for “lay” evidence, the ordinary testimony of witnesses who recount what they observed. Courts have always wrestled with testimony that was not accessible to ordinary people and with evidence that could not be directly evaluated by the jury using the ordinary tools of human experience. This has produced the very long debate over the admissibility of scientific or expert testimony.

Forensic fire investigations may involve, among others, fire investigators, materials scientists, mechanical, electrical, chemical & fire protection engineers, or automotive mechanics. But these can

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 3 of 12 represent widely differing types of expertise. Courts have always accepted demonstrable practical expertise. For example a ship captain or Mississippi river pilot clearly had an expertise that was demonstrable and potentially useful. These types of expertise had a real world feedback loop that could be used to show that the expert actually had the type of expertise claimed. But abstract science was another proposition. Because science has such a high claim of authority, for the past 80 years the courts have wrestled with the question of what makes something “scientific” as opposed to merely un-testable claims based on supposed experience. How “good” does the “science” have to be to admit it into the courtroom? The archetypical product on the cutting edge of this argument is the lie detector or polygraph. Despite 80 years of polygraph testing and numerous claims, virtually all courts still refuse to accept the results as evidence. The rationale may be specific to polygraphs, in that it tends to invade the jury’s province of the credibility of the witness, or it may involve a more general problem of the inability to demonstrate reliably that practitioners can actually do what they claim to do.

The Problem of Ground Truth

Forensic fire investigation shares a common issue with polygraph testing; the problem of determining “ground truth”. Ground truth is defined as demonstration of the fact at issue by some other means other than the measuring tool whose credibility is being tested.* For example, the ground truth relating to a diagnosis of Alzheimer’s disease can only be confirmed by an autopsy that finds the distinctive anatomical signs in the brain. Ground truth is a powerful tool in distinguishing expert knowledge from quackery. But polygraphs and FFI have great difficulty in establishing ground truth.5 How do we check the correctness of an FFI investigation? Few arsonists keep detailed records and few accidental fires are recorded by monitors. How would we determine the error rate of forensic fire investigation when we have no “outside” method of checking its accuracy? This problem is at the heart of the debate over the nature of FFI and particularly its claim to being some kind of “science”.

IS FORENSIC FIRE INVESTIGATION “SCIENCE”?

The claim to the status of science in NFPA 921 starts at the very beginning of the guide with a bold claim that the investigatory technique is the scientific method: 3.3.139 Scientific Method. The systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of a hypothesis. NFPA 921 2008

No reference is given for this definition, or for the claims made in subsequent chapters where NFPA 921 (2008) defines the scientific method as using the following steps:† 4.3.3 Collect Data. Facts about the fire incident are now collected by observation, experiment, or other direct data-gathering means. 4.3.4 Analyze the Data ….…analysis of the data is based on the knowledge, training, experience, and expertise of the individual doing the analysis. …… 4.3.5 Develop a Hypothesis (Inductive Reasoning). Based on the data analysis, the investigator produces a hypothesis or hypotheses to explain the phenomena…. These hypotheses should be

* The origin of the term is ground truth lost in myth, but one candidate was that pilots’ claims of shooting down enemy aircraft had to be verified by finding the plane wreck “on the ground”. † It should be noted that there are differences in the 2008 version of the guide compared to the 2004 edition. However there is no suggestion that a fundamental change was intended. The version being used will be indicated The 2008 language is clearly a compromise given the suggestions for improvement that were rejected in the committee process http://www.nfpa.org/assets/files/PDF/ROP/921-F2007-ROC.pdf

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 4 of 12 based solely on the empirical data that the investigator has collected and then developed into explanations for the event….. 4.3.6 Test the Hypothesis (Deductive Reasoning). The investigator does not have a provable hypothesis unless it can stand the test of careful and serious challenge. Testing of the hypothesis is done by the principle of deductive reasoning, in which the investigator compares his or her hypothesis to all known facts…. A hypothesis can be tested……analytically by applying scientific principles in “thought experiments”…..If the hypothesis cannot be supported, it should be discarded and alternate hypotheses should be tested. This test may include the collection of new data or the reanalysis of existing data. The testing process needs to be continued until all feasible hypotheses have been tested and one is determined to be uniquely consistent with the facts….. . NFPA 921 claims that this process involves induction, deduction and cognitive tests (2004) or thought experiments (2008) and describes the Scientific Method. But there is no documentation or reference supporting this claim, even to other forensic sciences. Leading publications imply that because the process uses scientific knowledge as part of the inferential process it must somehow itself be the scientific method.6 But this confuses the preliminary stage of the scientific method i.e. hypothesis generation, with the complete process, which involves generating falsifiable scientific hypotheses and properly testing them with scientific tests.

Is Fitting the Facts to a Hypothesis “Science”?

There are many kinds of decision making which are rigorous but not scientific. Consider for example a person who is considering a marriage partner. A reasonable and thoughtful person could follow all the NFPA 921 steps noted above. Empirical data would be collected and a hypothesis concerning the proposed marriage would be developed. The hypothesis could be ‘tested’ by a variety of cognitive tests or real world experiments e.g. by marrying the person. If the hypothesis fails the test, a new hypothesis is tested either with another partner or with different expectations of marriage. At the end of the day, the decision maker makes a decision about the hypothesis and the ability to predict the marriage. This may be completely rational, logical, thinking and analysis. If it is not routinely used for marriages it is arguably the most efficient method of choosing which race horse to gamble on or which stock investment to make. It is rigorous rational decision making. But is it science? Is the process science simply if it uses only scientific data as an input? There is an entire discipline of the philosophy of science that attempts to grapple with the nature of the scientific method or more properly methods since sciences clearly range on a continuum from the hard or “predictive” sciences such as physics to the soft or observational sciences such as sociology. 7 Numerous scholars have discussed the process of hypothesis creation. Since the 19th century there has been a clear demarcation between mere rational decision making and “science”. Science is a peculiar word and involves a wide variety of processes. By consulting that literature it is clear that NFPA 921 actually describes a well known logical process for determining the “best fit” to a set of facts since that process is widely used for the creation of scientific hypotheses.

Abduction- The finding of the Best fit

The process of logical inference of the best fitting answer from a set of facts is not deduction as defined in NFPA 921 but Abduction. It follows a classic form as articulated by CS Peirce(with our comments):

The surprising fact, C, is observed; (a specific fire event with pattern “C”) But if A were true, C would be a matter of course, ( fire pattern is distinct for flammable liquid “A”) Hence, there is reason to suspect that A is true. ( We suspect the fire was initiated with a liquid)

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 5 of 12 this reasoning is invoked as a means of providing fallible evidential support to explanatory hypotheses that go beyond the observational data“…..Peirce was the first to put a name to, and discuss . . .inference to the best explanation, or what Peirce called ‘abduction’” 8 citing 9

Abduction deals with creating explanatory hypotheses for unknown events (emphasis supplied) : Abduction, or inference to the best explanation, is a form of inference that goes from data describing something to a hypothesis that best explains or accounts for the data. Thus abduction is a kind of theory-forming or interpretive inference. The philosopher and logician Charles Sanders Peirce (1839-1914) contended that there occurs in science and in everyday life a distinctive pattern of reasoning wherein explanatory hypotheses are formed and accepted. He called this kind of reasoning abduction.10

It is argued here that validation crucially operates by means of inference to the hypothesis that best explains the evidence, called the method of hypothesis, inference to the best explanation, or abduction” 11

The important distinction is that abduction does not test a hypothesis; Abduction can be used to create testable hypotheses, or the abduction stands on its own as sophisticated reasoning: One of Peirce's important points, however, is that abduction alone is merely the generation of potential hypotheses, not a form of scientific proof or even demonstration.12

The power of abduction is in its logical structure. The popular confusion between abduction and deduction dates back to the time of Sherlock Holmes: Sherlock Holmes, the hero of Arthur Conan Doyle’s novels, often amazed his loyal friend Dr. Watson by drawing a correct conclusion from an array of seemingly disparate and unconnected facts and observations. The method of reasoning used by Sherlock Holmes is abduction. 13

Other scholars concur that Holmes engaged in abduction, not deduction: “In their intriguing book The Sign of Three: Dupin, Holmes, Peirce Umberto Eco and Thomas A. Sebeok propose that Holmes (and his prototypes in Dr. Bell and in Poe's Dupin) actually reasons, not by "deduction" as he himself [Doyle] claims, but rather by what American linguist and early semiotician Charles S. Peirce called "abduction" …..what he is really doing is what Peirce claimed to be our chief mode of understanding —the abduction, what some would call enlightened guessing. 14

Holmesian analysis almost always ends with a “ground truth” that can be used to “confirm” his abductive hypothesis, although even Holmes was fallible and made errors. Abduction describes the user’s determination of a best fit given the data available. Medical differential diagnosis is almost always abduction,15 as is good detective work. Medical authors draw directly from Holmes: Holmes did not generally apply either deduction (from the general to the particular) or induction (from particular to general) but rather abduction. 16

The Holmesian hypothesis is an abductive inference that a present state of facts indicates that a particular state of facts existed in the past. A wide variety of tools including scientific knowledge can be used to fit the present facts to the past. Differential diagnosis certainly uses science. Holmes routinely used a “cognitive test” (or thought experiment) of the hypothesis to show that it is the “best fit”. But it is not scientific proof and more specifically it is not deduction. As the Court of Appeals wrote in Bitler: Unlike a logical inference made by deduction where one proposition can be logically inferred from other known propositions, and unlike induction where a generalized conclusion can be inferred from a range of known particulars, inference to the best explanation - or "abductive inferences" - are drawn about a particular proposition or event by a process of eliminating all

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 6 of 12 other possible conclusions to arrive at the most likely one, the one that best explains the available data.17

Peirce’s Abduction clearly describes the NFPA 921 process. It is not deduction. Deduction has much more stringent requirements than abduction. For a scientific deduction to be valid, if the premises are true then the conclusion must be true. There is no room for doubt. Deduction is a powerful tool but the conclusion being deduced must normally be so narrowly drawn as to preclude any alternative explanation. 18 If the conclusion depends on the opinion of the investigator it is Abduction. Holmes of course limited his abductions to those which had accessible ground truth, even if they resulted in his being proved wrong: "Watson, if it should ever strike you that I am getting a little overconfident in my powers, or giving less pains to a case than it deserves, kindly whisper 'Norbury' in my ear, and I shall be infinitely obliged to you." 19

SCIENTIFIC AND EXPERT TESTIMONY: KUMHO TIRE

The proper understanding of FFI as abduction and not deduction is critical since the testimony rejected in Kumho Tire was developed using essentially the same analytical approach outlined in NFPA 921. The tire expert (Carlson) was a highly qualified engineer who examined the tire physically and conducted a thought experiment that demonstrated to his satisfaction that the tire was defective by rejecting all the hypotheses that indicated the tire was abused. It is worth noting that all parties agreed that the process was not science, even thought it used scientific facts and theories. It was based on the expertise and skill of the observer and his particular “thought experiment”. That process did not make it inadmissible but the Court held that Carlson’s individual idiosyncratic opinions were inadmissible: The particular issue in this case concerned the use of Carlson’s two-factor test and his related use of visual/tactile inspection to draw conclusions on the basis of what seemed small observational differences. We have found no indication in the record that other experts in the industry use Carlson’s two-factor test or that tire experts such as Carlson normally make the very fine distinctions about, say, the symmetry of comparatively greater shoulder tread wear that were necessary, on Carlson’s own theory, to support his conclusions. Nor, despite the prevalence of tire testing, does anyone refer to any articles or papers that validate Carlson’s approach. Of course, Carlson himself claimed that his method was accurate, but, as we pointed out in Joiner, “nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert.” 522 U.S., at 146.

Kumho Tire was specifically dealing with analysis that did not even claim to be science. Carlson’s investigation certainly rested on abductive inference. But the Court held that any cognitive tests or thought experiments must not be personal to the investigator but at a minimum accepted by the field as a whole. It is not enough for the field to set out a framework for performing such a test, the specific test must be broadly acceptable. Failure to show that the specific test method meets disciplinary standards meant the testimony fails the Kumho Tire test, but a claim to use the scientific method demands more.

Hypothetico Deductive Method

Forensic fire investigation purports to be a physical science driven by disciplines such as chemistry, physics, and to a lesser degree biology. But NFPA 921 contains a key error involving the concept of a provable hypothesis 4.3.6. While abduction can use a provable hypothesis, science as described in Daubert does not try to prove hypotheses, it tries to disprove them. The most obvious problem under NFPA 921’s approach an inadequate “cognitive test” or “thought experiment” will tend to produce an inadequate challenge to the “hypothesis” and lead to an incorrect hypothesis being accepted.

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 7 of 12 For this reason the modern standard description of science and the scientific method uses the hypothetico/deductive method. Science, as described by Popper and others has a far more stringent set of requirements for creating and testing hypotheses than that contemplated by NFPA 921. Popper’s work is critical since it was the key definition for scientific testimony in the Supreme Court Decision in Daubert: "Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry." Green, at 645. See also C. Hempel, Philosophy of Natural Science 49 (1966) ("[T]he statements constituting a scientific explanation must be capable of empirical test"); K. Popper, Conjectures and Refutations: The Growth of Scientific Knowledge 37 (5th ed. 1989) ("[T]he criterion of the scientific status of a theory is its falsifiability, or refutability, or testability").20

For Popper and most philosophers of science, it is not enough to have a hypothesis to trigger the scientific method; it has to be a scientific hypothesis. A hypothesis classed as scientific when it is scientifically testable using the tools of the appropriate science. Until then it is just a speculation. But scientific testing is not designed to find support but to see if the hypothesis can be disproved. In a strict Popperian world, the hypothesis must be structured to be falsifiable i.e. the hypothesis must create a prediction and suggest a reproducible test or experiment that could show the prediction wrong and thus disprove the hypothesis. As a result no hypothesis can be accepted simply because the investigator can’t disprove it in a specific experiment. In addition the acceptance of a hypothesis that has withstood testing is effectively done by the discipline as a whole, not the investigator and until then it is simply Ipse dixit. This distinction is critical since NFPA 921 implies that an individual investigator can accept a hypothesis when he can’t disprove it, without requiring that the hypothesis be framed in a manner which makes a prediction and supports a test which would disprove it. The NFPA 921 committee specifically rejected language incorporating the Popperian concept of falsifiability required for science in Daubert21. As a further example the NFPA 921 even claims that the “scientific method” includes supporting conclusions for which there is no positive evidence: 18.2.2 For example, an investigator may properly conclude that the ignition source came from an open flame, even if the device producing the open flame is not found at the scene. This conclusion may be properly reached as long as the analysis producing the conclusion follows the scientific method as discussed in Chapter4

But a hypothesis of a flame without any physical evidence is not falsifiable. There is simply no scientific way to prove that it did not happen. An open flame may in fact be the best fit but such analysis is abductive inference, not the scientific method. An example from DeHaan (2007) shows the difference. A car in a garage is involved in an explosion. Careful investigation shows gasoline on the floor and the time sequence and physical evidence is consistent with the fuel tank leaking and an electrical ignition. The author positively concludes on p669: The fire was entirely accidental with gasoline vapors the culprit. But this conclusion while very plausible, and even very likely correct, is not supported by the scientific method but instead represents abductive inference. The proffered explanation is plausible but not deductively required given the known facts. As an alternative explanation, suppose the owner knew of the leaking tank and arranged to place the car in the suitable location in the hope it would cause the explosion? It would be completely consistent with the same technical facts. Neither the hypothesis nor the testing is adequately “scientific” since the test results support both the hypothesis and its converse.

NFPA 921 appears to have developed in isolation from the key debates over the nature of scientific proof, which have turned on this precise point since before Daubert. The litigation over the teaching of “Creation science” turned on the role of falsifiability. Intelligent design may state a hypothesis but it is not scientifically testable or falsifiable. There is no way to disprove it, so it is not science: In the end, the Kitzmiller court's test for whether intelligent design is science and the Supreme Court's test for whether proffered expert scientific evidence is admissible amount to the same

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 8 of 12 thing because both seek to measure reliability, in light of the scientific community's judgments about what science is and what it involves.22

Similarly, the hypothesis mentioned above about a potential spouse might be testable but unless the testing is scientific, the hypothesis is not scientific. NFPA 921 allows but does not require that a hypothesis be scientific. It sets no requirement whatever on the hypotheses generated in the process. Nor does it focus on the falsifiability of the hypothesis but instead uses the language of “supporting” the hypothesis. This is not “science” as the term was defined in Daubert or Kumho Tire

Analyze the data?

NFPA 921 also has a peculiar step which is difficult to classify as part of the scientific method. The step takes place prior to forming the hypothesis: 17.4 Analyze the data ….Analysis of the data is based on the knowledge, training, experience, and expertise of the individual doing the analysis ….understanding the meaning of the data will enable the investigator to form hypotheses based on the evidence, rather than on speculation or subjective belief

Pierce and Popper would both agree that Abduction (or educated guesswork) is clearly a part of the scientific method when forming a properly testable scientific hypothesis, but this section subverts the claim of scientific method because the subjective data analysis can “predetermine” the later “deductive” process by inserting subjective beliefs about the meaning of the data in this earlier stage. As one example NFPA 921 suggests that fire patterns are analyzed at this step (17.4.1.). But the meaning of fire patterns is itself often a controverted question which means that the interpretation of a fire pattern must be determined by applying the overall 921 method, including testing the hypotheses of specific meaning . The NFPA 921 data analysis stage allows the ipse dixit of the investigator to control the output of a supposedly scientific process by simply moving the Ipse Dixit into the 17.4 data analysis stage so it no longer requires testing or peer acceptance. This type of data analysis is exactly what the Supreme Court rejected in Kumho Tire: We have found no indication …. that tire experts such as Carlson normally make the very fine distinctions about, say, the symmetry of comparatively greater shoulder tread wear that were necessary, on Carlson’s own theory, to support his conclusions.

In other words Carlson could not show that he had not analyzed or tailored the data to support his hypothesis. Like any test, under Kumho Tire data analysis must be shown to meet disciplinary, not individual standards. Since the text of NFPA 921 itself contains numerous cautions on known errors in inference the problems of this analytical step prior to the hypothesis creation should be obvious. For example in 2004 the text says : 6.5.5 Interpretation of Char. The appearance of the char and cracks has been given meaning by the fire investigation community beyond what has been substantiated by controlled experimentation. So the meaning of char is part of the hypothesis which must be tested. Unless a rigorous process is applied to the analysis in 14.4.1 the untested Ipse dixit as to the meaning of the pattern is now used to prove the hypothesis. This is not what Daubert called “science”.

Testing the hypothesis

The scientific method is a process of inference which is more tightly structured than abduction or simple rational analysis. In particular, not only must the hypothesis be capable of being tested, the testing itself must be scientific. Scientific testing is a rigorous process which is supposed to be operator independent. In other words in real science it doesn’t matter if a test is done by a Nobel Prize winner or a graduate student. The testing stands on its own and does not depend on the background or experience of the analyst. The double blind test is the gold standard of biomedical science, where neither the patient nor

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 9 of 12 the physician knows which patient gets what medication. As one source NIST defines critical terms relating to the testing level to ensure that scientific conclusions are credible:

Reproducibility means that the information is capable of being substantially reproduced, subject to an acceptable degree of imprecision. For information judged to have more (less) important impacts, the degree of imprecision that is tolerated is reduced (increased). With respect to analytic results, "capable of being substantially reproduced'' means that independent analysis of the original or supporting data using identical methods would generate similar analytic results, subject to an acceptable degree of imprecision or error.

Transparency ……"The purpose of the reproducibility standard is to cultivate a consistent agency commitment to transparency about how analytic results are generated: the specific data used, the various assumptions employed, the specific analytic methods applied, and the statistical procedures employed. If sufficient transparency is achieved on each of these matters, then an analytic result should meet the reproducibility standard." In others words, transparency – and ultimately reproducibility – is a matter of showing how you got the results being disseminated. 23

The core of scientific testing is therefore that 1) it is reproducible based on a description of the test, and 2) the result is fundamentally operator independent; that is the result does not depend on the unique skill- training or insight of the person doing the testing. Neither of these requirements are found in NFPA 921 although it cautions in 17.7.3 that differences in opinions may arise from the weight given to certain data by different investigators or the application of differing theoretical explanations…. NFPA 921 provides no scientific way of resolving this issue. NFPA 921 claims to test the hypothesis with “cognitive” tests (2004) and thought experiments (2008). However in no way does it distinguish a cognitive test from the personal opinion of the investigator. Carlson’s testimony in Kumho tire was a “thought experiment”. NFPA 921 has no rules for either the hypothesis formulation or the cognitive test or thought experiment. While this is perfectly suitable for abduction, it is not a reproducible scientific experiment. Normally, a scientific test method is evaluated by round robin testing by a variety of test laboratories. How is a cognitive test reproduced in a round robin protocol? A test which depends on the unique skill of the investigator cannot escape the ipse dixit limitation inherent in the Kumho/Daubert line of cases. NFPA 921 specifically allows the ipse dixit opinion of the investigator as the touchstone of proof: 18.6 Opinions. When forming opinions from hypotheses about fires or explosions, the investigator should set standards for the level of certainty in those opinions. Two levels of confidence have significance with respect to opinions: (1) Probable. This level of certainty corresponds to being more likely true than not. At this level of certainty, the likelihood of the hypothesis being true is greater than 50 percent. (2) Possible. At this level of certainty, the hypothesis can be demonstrated to be feasible but cannot be declared probable. If two or more hypotheses are equally likely, then the level of certainty must be “possible.”

In real science the opinion of the investigator is enough to justify testing the hypothesis but not to accept it. NFPA 921 goes on to give this subjective opinion the blessing of “science” 18.6.2 Ultimately, the decision as to the level of certainty in data collected in the investigation or any hypothesis drawn from an analysis of the data rests with the investigator.

Under NFPA 921 the value of the data and any conclusion rests solely on the personal opinion of the investigator. This is not the scientific method. But it is a clear statement of Ipse Dixit as prohibited by Kumho Tire.

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 10 of 12 WHAT CAN BE DONE?

It is clear that NFPA 921 is becoming the ‘standard of care’ in fire scene processing and evidence collection and as noted above these subjects in the guide are an outstanding contribution to the field. Many of the inferential caveats in NFPA 921 are also substantial advances in the field. It is critical not to throw the baby out with the bathwater. However presenting Ipse Dixit opinions as “Science” can only harm the progress of the field. We propose the following:

Embrace abduction and discard the entire NFPA921 pseudo-structure of the Scientific Method and replace it with a clear rigorous and evidence supported abductive inference process. Physicians express reasonable medical certainty in differential diagnosis using an abductive process. The abductive methods of Sherlock Holmes are appropriate for FFI, even if he made the same mistake in terminology. Many if not all of the inferential processes described in NFPA 921 would be very suitable for a rigorous abductive process. To satisfy Kumho Tire the conclusion of the abductive process should be stated in terms of collective professional not individual norms of confidence.

Transparency requires that every step in the abductive inference process be transparent and fully accessible to peer analysis. Every step means any fire pattern analysis is just as much an abductive inference as any hypothesis. At each stage alternative inferences must be discussed and their treatment explained. Transparent reasoning means that nothing is accepted because the investigator says so, no matter how eminent or experienced the practitioner. There is no secret knowledge or understanding.

Reproducibility says that another investigator should be able to reach the same conclusions about the origin NFPA 921 17.7.3. The first step in convincing the courts of the capability of FFI and NFPA 921 would be provided by a round robin test of fire investigators. A group of certified fire and explosion investigators or teams would be provided with material that contains a full NFPA 921 documentation of a range of fire scenes ranging from ‘simple’ to complex. They are then asked to independently reconstruct the origin and cause of the fire. In advance of the process the researchers describe a professionally acceptable level of divergence in the methodology, confidence in the data and ultimate opinions. Such round robins have been conducted in many other forensic sciences, often with surprising results. NFPA 921 clearly indicates that labs can give divergent results, but it is far more important to test the practitioners. Blind Round Robin testing is a method that will tend to reduce the Ipse Dixit of the fire investigator.

Ground Truth is critical. While reproducibility is a necessary component of expertise, in some cases it can simply indicate that all investigators share the same erroneous belief. Continuous scientific and engineering research is required into the development of fires and the patterns and information they leave behind.

FFI must create professional norms. Credible professions have professional decision norms to which the individual must adhere. FFIs should routinely be published for rigorous peer review, conflicts of interest should be identified and avoided and decision processes should be identified as acceptable and unacceptable. The standard of confidence should be reasonable certainty in accordance with the published norms of the profession. The profession, not the individual should stand behind the precise tests.

Whisper Norbury. The FFI output should be transparent abductive reasoning in accordance with disciplined professional norms and standards. It should be the best that can be done, but it should always be submitted with appropriate doubts and cautions. It should be driven by the demonstrable disciplinary confidence in the result, not by a perceived “need” for evidence or positive conclusions.

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 11 of 12 CONCLUSION

NFPA 921 represents a tremendous improvement in data gathering and contains a great deal of suitable professional guidance for the inferential process. But NFPA 921’s attempt to describe its inferential process as the scientific method must inevitably end in failure. In attempting to describe its reasoning as science NFPA 921 has more loops and exclusions than a Ptolemaic solar system. If it were truly scientific, these caveats would not be necessary, the science would stand on its own and the conclusions would not be described as individual opinions. In its current state, FFI is at its best not science but an abductive process of reasoned, rigorous and logical decision making. Improvements can only come when methods of fire investigation origin and cause determination are subject to round-robin testing to ensure quality control and the profession rather than individuals can assign levels of certainty. Research to focus on ground truth is also critical. A change in description of the underlying philosophy will allow FFI to move forward in tandem with fire science, fire engineering and similar technical fields.

REFERENCES

1 Forensic Analysis: Weighing Bullet Lead Evidence National Academies Press 2004 2 Churchward D. L. Keynote Address, ‘Fire Investigation is Still Art and Not Science’, Proc. International Symposium on Fire Investigation Science and Technology, 2008. 3 NFPA 921: Guide for Fire and Explosion Investigations 2008 NFPA 4 KUMHO TIRE CO. V. CARMICHAEL (97-1709) 526 U.S. 137 (1999) 5 Kelly J The Truth About the Lie Detector Science, Pseudoscience, Or Con Game? It’s A Little Bit Of Each. Invention & Technology Magazine Winter 2004 Volume 19, Issue 3 6 De Haan JD Kirk's Fire Investigation, by De Haan, 6th Edition Prentice Hall 2007 7 Gower B Scientific Method: A Historical and Philosophical Introduction Routledge, 1997 8 McKaughan DJ From Ugly Duckling to Swan: C. S. Peirce, Abduction, and the Pursuit of Scientific Theories Transactions of the Charles S. Peirce Society Jun 2008, Vol. 44 Issue 3, 9 Misak, C.. “Peirce,” in A Companion to the Philosophy of Science, W. H.Newton-Smith, ed2000. Oxford: Blackwell Publishers 10 Josephson JR, Josephson SG Abductive Inference Computation, Philosophy, Technology Cambridge 1996 11 Crawford C, Handbook of Evolutionary Psychology: Ideas, Issues, and Applications, Erlbaum, 1998, 12 Schroeder JL Just So Stories: Posnerian Methodology 22 Cardozo L. Rev. 351, 2001 13 Patokorpi, E. Logic of Sherlock Holmes in Technology Enhanced Learning. Educational Technology & Society, 10 (1(2007). 14 Coffman at http://ednet.rvc.cc.il.us/~fcoffman/NewDoyle.html quoting Eco, Umberto and Thomas A. Sebeok, editors. The Sign of Three: Dupin, Holmes, Peirce. Bloomington: Indiana UP, 1983. 15 Schleifer R, Vannatta J The Logic of Diagnosis: Peirce, Literary Narrative, and the History of Present Illness Journal of Medicine and Philosophy, Volume 31, Issue 4 August 2006 16 Rapezzi, C Ferrari R , Branzi A White coats and fingerprints: diagnostic reasoning in medicine and investigative methods of fictional detectives BMJ 2005;331:1491-1494 (24 December) 17 Bitler v. A.O. Smith Corp 391 F.3d 1114; 18 Josephson JR, Abductive Inference: On The Proof Dynamics Of Inference To The Best Explanation 22 Cardozo L. Rev. 1621, 2001 19 Doyle AC Adventure of the Yellow Face The Strand Magazine, 1893. 20 Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993) 21 http://www.nfpa.org/assets/files/PDF/ROP/921-F2007-ROC.pdf 22 Katskee RB “Religion In The Public Schools: Article: Why It Mattered To Dover That Intelligent Design Isn't Science” 5 First Amend. L. Rev. 112 Fall, 2006 23 National Institute Of Standards And Technology Guidelines, Information Quality Standards, And Administrative Mechanism at http://www.nist.gov/director/quality_standards.htm

Fire and Materials Conference 2009, San Francisco, CA Jan 26-28, 2009 Page 12 of 12 Report on Proposals – November 2010 NFPA 921 ______921-42 Log #33

______Hal C. Lyson, Fire Cause Analysis Revise text as follows: Facts about the fire incident are now collected by observation, experiment, or other direct data gathering means. The data collected is called empirical data because it is based on observation or experience and is capable of being verified. The facts and data collected used in the analyses must be capable of being verified or known to be true, which is called empirical data. This data may include artifacts form the fire scene, observations, research, experiments or other evidence that may have a bearing on the origin and or cause. During the last revision we lost the discussion on what is empirical data, and that is the data used. Also see my proposal on 4.3.4 to also capture what was lost during the last revision.

Reinsert the second sentence. Delete “that may have a bearing on the origin and or cause” from the last sentence. It should now read: 4.3.3 Collect Data. Facts about the fire incident are now collected by observation, experiment, or other direct data gathering means. The data collected is called empirical data because it is based on observation or experience and is capable of being verified. The facts and data collected used in the analyses must be capable of being verified or known to be true, which is called empirical data. This data may include artifacts from form the fire scene, observations, research, experiments or other evidence. that may have a bearing on the origin and or cause. The committee believes existing text is sufficient and has included the examples for additional clarification.

Printed on 9/18/2009 44 Report on Proposals – November 2010 NFPA 921 ______921-43 Log #34

______Hal C. Lyson, Fire Cause Analysis Revise text as follows: The scientific method requires that all empirical data relevant to the origin and cause that was collected be analyzed. This is an essential step that must take place before the formation of the final hypothesis. The identification, gathering, and cataloging of data does not equate to data analysis. Analysis of the data is based on the knowledge, training, experience, and expertise of the individual doing the analysis. If the investigator lacks expertise to properly attribute meaning to a piece of data, then assistance should be sought. Understanding the meaning of the data will enable the investigator to form hypotheses based on the evidence, rather than on speculation. Subjective or speculative information cannot be included in the analysis, only facts that can be proven clearly by observation or experiment. During the last revision we lost the importance that only data that can be shown to be true and relevant to the O & C be evaluated (not the for sale sign, issue in another area of the building, etc.) be used in the alalyses.

Delete empirical from first sentence. The word “relevant” in the first sentence is new text. It was deleted. Delete “to the origin and cause that was” from the first sentence. Delete “only facts that can be proven clearly by observation or experiment.” From the last sentence. 4.3.4* Analyze the Data. The scientific method requires that all empirical data relevant to the origin and cause that was collected be analyzed. This is an essential step that must take place before the formation of the final hypothesis. The identification, gathering, and cataloging of data does not equate to data analysis. Analysis of the data is based on the knowledge, training, experience, and expertise of the individual doing the analysis. If the investigator lacks expertise to properly attribute meaning to a piece of data, then assistance should be sought. Understanding the meaning of the data will enable the investigator to form hypotheses based on the evidence, rather than on speculation. Subjective or speculative data information cannot be included in the analysis. only facts that can be proven clearly by observation or experiment. The committee believes the additional text clarifies the issue.

Printed on 9/18/2009 45 Report on Proposals – November 2010 NFPA 921 ______921-44 Log #115

______Linda Matusz, General Motors Corp. Revise text to read as follows: 4.3.6* Test the Hypothesis (Deductive Reasoning). The investigator does not have a provable final hypothesis unless it can stand the test of careful and serious challenge. Problem: Many hypothesis are inherently not “provable”, consequently this is a poor word choice. Suggestion: Use the word “final” instead as this more accurately describes the hypothesis in this stage of the scientific method, and it ties in nicely with Figure 4.3 which uses this wording in the final step of the flow chart (Select Final Hypothesis).

Revise text to read as follows: 4.3.6* Test the Hypothesis (Deductive Reasoning). The investigator does not have a provable final supportable hypothesis unless it can stand the test of careful and serious challenge.

Technical Committee believes “supportable” relates to the intent of this section better than the proposed word “Final.” Furthermore, one does not need to reach a final hypothesis to establish that a hypothesis is capable of standing the test of careful and serious challenge.

Printed on 9/18/2009 46 Report on Proposals – November 2010 NFPA 921 ______921-45 Log #CP13

______Technical Committee on Fire Investigations, In existing 4.3.6, change “phenomenon” to “phenomena”. The sentence that reads: Testing of the hypothesis is done by the principle of deductive reasoning, in which the investigator compares his or her hypothesis to all the known facts as well as the body of scientific knowledge associated with the phenomenon phenomena relevant to the specific incident.

This is editorial changing the singular to the plural.

Printed on 9/18/2009 47 Report on Proposals – November 2010 NFPA 921 ______921-46 Log #146

______Dennis W. Smith, Kodiak Enterprises, Inc. New text to read as follows: 4.3.6.1 Any hypothesis is incapable of being tested, or falsified, is an invalid hypothesis. A hypothesis based on the absence of evidence is an example of a hypothesis that is incapable of being tested. . *4.3.6.1 Vaughn, Lewis, The Power of Critical Thinking, Effective Reasoning About Extraordinary Claims, 2nd ed. Oxford University Press, New York/Oxford, 2008 Damer, Edward, T. Attacking Faulty Reasoning. A Practical Guide to Fallacy·Free Thinking, 4th ed., WadsworthfThomson Learning, Belmont, CA, 2001 Kahane, Howard and Cavender, Nancy, Logic and Contemporary Rhetoric, The Use of Reason in Everyday Life, 9th ed. Wadsworth-Thomson Learning, Belmont, CA, 2002 Developing a hypothesis in the absence of evidence is a reasoning fallacy referred to as the The appeal to ignorance is arguing that an absence, or lack, of evidence proves something. However, the absence of evidence proves nothing. The absence of evidence provides no reason to believe any claim or allegation. A lack of evidence simply reveals the claimant is "ignorant" and reveals what the claimant does not know about something, as opposed to what is known. The responsibility for providing proof for a claim rests with the person making the claim. The burden of proof principle requires that the person making an allegation or claim must provide evidence to support their claim. However, the person asserting an argument based on the absence of evidence places the burden of proof on the wrong side, in effect, asking the opposing side to find positive evidence in order to refute the claim. Instead of providing positive evidence of the claim, the claimant does the opposite and asserts and relies on the absence of evidence to support their claim. This means the opposing party must provide the evidence that the claim is not true, clearly putting the challenging party on the wrong side. In essence, the opposing or challenging party must do all the work to prove the claim false, notwithstanding the fact that refuting a negative assertion is generally impossible.

Add the word “that” after hypothesis and before “is” in the first sentence Remove “or falsified” from the first sentence. In the second sentence add the word develop; remove the word evidence and replace with data. Change the second part of the proposal to the appendix by adding “*” in the first part of the text and adding an “A” in second part to read: 4.3.6.1* Any hypothesis that is incapable of being tested, or falsified, is an invalid hypothesis. A hypothesis developed based on the absence of data evidence is an example of a hypothesis that is incapable of being tested. A.4.3.6.1. Vaughn, Lewis, The Power of Critical Thinking, Effective Reasoning About Extraordinary Claims, 2nd ed. Oxford University Press, New York/Oxford, 2008; Damer, Edward, T. Attacking Faulty Reasoning. A Practical Guide to Fallacy•Free Thinking, 4th ed., Wadsworth Thomson Learning, Belmont, CA, 2001. Adding “that” is editorial. The Committee believes the new text more clearly expresses the concept of the submission.

Printed on 9/18/2009 48 Report on Proposals – November 2010 NFPA 921 ______921-47 Log #147

______Dennis W. Smith, Kodiak Enterprises, Inc. New text to read as follows: 4.3.6.2 The inability to refute a hypothesis is not the same thing as proving the hypothesis true. *A 4.3.6.2 Vaughn, Lewis, The Power of Critical Thinking, Effective Reasoning About Extraordinary Claims, 2nd ed. Oxford University Press, New York/Oxford, 2008 Darner, Edward, T. Attacking Faulty Reasoning. A Practical Guide to Fallacy-Free Thinking, 4th ed., Wadsworth/Thomson Learning, Belmont, CA, 2001 Kahane, Howard and Cavender, Nancy, Logic and Contemporary Rhetoric, The Use of Reason in Everyday Life, 9th ed. Wadsworth- Thomson Learning, Belmont, CA, 2002 Someone may incorrectly allege that their claim must be true because it hasn't been shown to be false. However, the inability to refute a claim is not the same thing as proving it true. For example, it is occasionally asserted that because it cannot be proven that an ignitable liquid was present, the hypothesis that an ignitable liquid was present cannot be refuted, and is therefore, true. There is no method to prove an ignitable liquid was not present in a fire, or in any fire. This is another example of an untestible and invalid hypothesis.

Add the proposed the wording to the end of 4.3.6.1 along with the annex material. New text to read as follows: 4.3.6.21* The inability to refute a hypothesis does not mean that is not the same thing as proving the hypothesis is true. A 4.3.6.21. Vaughn, Lewis, The Power of Critical Thinking, Effective Reasoning About Extraordinary Claims, 2nd ed. Oxford University Press, New York/Oxford, 2008 Darner, Edward, T. Attacking Faulty Reasoning. A Practical Guide to Fallacy-Free Thinking, 4th ed., Wadsworth/Thomson Learning, Belmont, CA, 2001 Kahane, Howard and Cavender, Nancy, Logic and Contemporary Rhetoric, The Use of Reason in Everyday Life, 9th ed. Wadsworth- Thomson Learning, Belmont, CA, 2002. The committee believes this satisfies the NFPA Manual of Style. Further, the rewording is more clearly stated.

Printed on 9/18/2009 49 Report on Proposals – November 2010 NFPA 921 ______921-48 Log #18

______James Mazerat, Unified Investigations Revise text as follows: Until data have been collected, no specific hypothesis can be reasonably formed or tested. Until all available data is collected, the null hypothesis that the cause of the incident is undetermined should be maintained. A “null hypothesis” is, “The statistical hypothesis that states that there are no differences between observed and expected data.” When used, the null hypothesis is presumed true until statistical evidence, in the form of a hypothesis test, indicates otherwise All investigations of fire and explosion incidents should be approached by the investigator without presumption as to origin, ignition sequence, cause, fire spread, or responsibility for incident until the use of scientific method has yielded a provable hypotheses. It is important to bring this point into the process of using the scientific method of conducting the investigation. This wording brings the intention that there should not be any preconceptions as to the cause of the incident into the recognized methodology for using the scientific method.

The committee action on 921-49 (Log #83) is sufficient. This section addresses more issues than only “cause.” The language as originally written is more clear and understandable.

Printed on 9/18/2009 50 Report on Proposals – November 2010 NFPA 921 ______921-49 Log #83

______John Lentini, Scientific Fire Analysis, LLC / Rep. ASTM Committee E30 on Forensic Sciences

Until data have been collected, no specific hypothesis can be reasonably formed or tested. All investigations of fire and explosion incidents should be approached by the investigator without presumption as to origin, ignition sequence, cause, fire spread, or responsibility for incident until the use of scientific method has yielded a provable testable hypotheses, which cannot be disproved by rigorous testing. There is no such entity as a “provable hypothesis.” There exist only those hypotheses that cannot be disproved. As Dr. Einstein said, “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”

Printed on 9/18/2009 51 Report on Proposals – November 2010 NFPA 921 ______921-50 Log #116

______Linda Matusz, General Motors Corp. Revise text to read as follows: All investigations of fire and explosion incidents should be approached by the investigator without presumption as to origin, ignition sequence, cause, fire spread, or responsibility for incident until the use of the scientific method has yielded a provable final hypotheses hypothesis. Problem: Many hypothesis are inherently not “provable”, consequently this is a poor word choice. Suggestion: Use the word “final” instead as this more accurately describes the hypothesis in this stage of the scientific method, and it ties in nicely with Figure 4.3 which uses this wording in the final step of the flow chart (Select Final Hypothesis).

Committee believes the text as amended in 921-49 (Log #83) is acceptable.

Printed on 9/18/2009 52 Report on Proposals – November 2010 NFPA 921 ______921-51 Log #84

______John Lentini, Scientific Fire Analysis, LLC / Rep. ASTM Committee E30 on Forensic Sciences

Expectation bias is a well-established phenomenon that occurs in scientific analysis when investigator(s) reach a premature conclusion too early in the study and without having examined or considered all of the relevant data. The phrase proposed for deletion is unnecessarily redundant, as it means the same thing as “premature.” (Your submitter apologizes for failing to catch this obvious grammatical error in the last cycle.)

Printed on 9/18/2009 53 Report on Proposals – November 2010 NFPA 921 ______921-52 Log #85

______John Lentini, Scientific Fire Analysis, LLC / Rep. ASTM Committee E30 on Forensic Sciences

Different hypotheses may be compatible with the same data. When using the scientific method, testing of hypotheses should be designed to the hypothesis. Confirmation bias occurs when the investigator instead tries to prove the hypothesis. This can result in the failure to consider alternate hypotheses. No hypothesis can ever be proven to an absolute certainty. A hypothesis can be said to have sufficient support only when rigorous testing has failed to disprove the hypothesis. For a discussion of concrete examples of confirmation bias and its potential for causing erroneous interpretations of data, see Wason, P. C.(1960) “On the failure to eliminate hypotheses in a conceptual task,” ,12:3,129 — 140 (A copy of this article has been supplied to the Technical Committee Secretary) Expectation bias is a subset of confirmation bias, which is more subtle and more prevalent. It is imperative that our readers become aware of this concept, as the failure to entertain alternative hypotheses that also comport with the observed data is a leading cause of error in fire investigation and in all of forensic science. The recent National Academy of Sciences report, “Strengthening Forensic Science in the United States: A Path Forward” (http://www.nap.edu/catalog/12589.html) devoted several pages to a wide-ranging discussion of the kinds of bias that can influence a scientific inquiry and lead to errors. (A copy of the NAS report has been supplied to the Technical Committee Secretary)

Revise text to read as follows: 4.3.9* Confirmation Bias. Different hypotheses may be compatible with the same data. When using the scientific method, testing of hypotheses should be designed to disprove the hypothesis. Confirmation bias occurs when the investigator instead tries to prove the hypothesis. This can result in the failure to consider alternate hypotheses. No hypothesis can ever be proven to an absolute certainty. A hypothesis can be said to have sufficient support only when rigorous testing has failed to disprove the hypothesis. A.4.3.9 For a discussion of concrete examples of confirmation bias and its potential for causing erroneous interpretations of data, see Wason, P. C.(1960) “On the failure to eliminate hypotheses in a conceptual task,” The Quarterly Journal of Experimental Psychology,12:3,129 — 140 (A copy of this article has been supplied to the Technical Committee Secretary). The removed sentence is not necessary to the discussion of “Confirmation Bias.”

Printed on 9/18/2009 54 Report on Proposals – November 2010 NFPA 921 ______921-53 Log #154

______Melvin Robin, ATF New and revise text to read as follows: “Optimally, investigators representing different parties will all examine the scene either in concert or individually. Use of scene documentation from another investigator to analyze the fire event and to draw conclusions is only recommended if the scene is unavailable for examination. Examination of the fire scene at different time may lead to different data gathered as unattended scenes or previously processed scenes will not necessarily remain undisturbed. Therefore, an origin and cause determination based on the review of documentation and no actual scene investigation will bear more scrutiny.” Clarification that those not attending scenes may not have all of the data and information to complete as thorough an Origin ad Cause investigation as those who did examine the scene, and that this is the Origin and Cause investigative method of last resort.

Submitter’s intent is not clear as to where the proposed wording should be placed in 4.4.3.3 and what if any existing text should be replaced.

Printed on 9/18/2009 55 Report on Proposals – November 2010 NFPA 921 ______921-54 Log #CP12

______Technical Committee on Fire Investigations, Insert the following text and renumber existing text 4.5 Reporting Procedure as 4.6. 4.5 Level of Certainty. The level of certainty describes how strongly someone holds an opinion (conclusion). Someone may hold any opinion to a higher or lower level of certainty. That level is determined by assessing the investigator’s confidence in the data, in the analysis of that data, and testing of hypotheses formed. That level of certainty may determine the practical application of the opinion, especially in legal proceedings. 4.5.1 The investigator should know the level of certainty that is required for providing expert opinions. Two levels of certainty commonly used are probable and possible: (1) Probable. This level of certainty corresponds to being more likely true than not. At this level of certainty, the likelihood of the hypothesis being true is greater than 50 percent. (2) Possible. At this level of certainty, the hypothesis can be demonstrated to be feasible but cannot be declared probable. If two or more hypotheses are equally likely, then the level of certainty must be “possible.” 4.5.2 If the level of certainty of an opinion is merely “suspected,” the opinion does not qualify as an expert opinion. If the level of certainty is only “possible,” the opinion should be specifically expressed as “possible.” Only when the level of certainty is considered “probable” should an opinion be expressed with reasonable certainty. 4.5.3 Expert Opinions. Many courts have set a threshold of certainty for the investigator to be able to render opinions in court, such as “proven to an acceptable level of certainty”, “a reasonable degree of scientific and engineering certainty”, or “reasonable degree of certainty within my profession”. While these terms of art may be important for the specific jurisdiction or court in which they apply, defining these terms in those contexts is beyond the scope of this document.

This text, that previously was located in Chapter 18, more appropriately fits into Chapter 4. This discussion on level of certainty now applies not just to cause determination, but more broadly to the range of opinions developed in an overall fire investigation.

Printed on 9/18/2009 56 Report on Proposals – November 2010 NFPA 921 ______921-55 Log #CP2

______Technical Committee on Fire Investigations, Insert into document at 4.6 the following text and renumber following sections accordingly: 4.6 Review Procedure. A review of a fire investigator’s work product [e.g. reports, documentation, notes, diagrams, photos, etc.] by other persons may be helpful, but there are certain limitations. This section describes the types of reviews and their appropriate uses and limitations. 4.6.1 Administrative Review. An administrative review is one typically carried out within an organization to ensure that the investigator’s work product meets the organization’s quality assurance requirements. An administrative reviewer will determine whether all of the steps outlined in an organization’s procedure manual, or required by agency policy, have been followed, whether all of the appropriate documentation is present in the file, and may check for typographical or grammatical errors. 4.6.1.1 Limitations of Administrative Reviews. An administrative reviewer may not necessarily possess all of the knowledge skills and abilities of the investigator or of a technical reviewer. As such, the administrative reviewer may not be able to provide a substantive critique of the investigator’s work product. 4.6.2 Technical Review. A technical review can have multiple facets. If a technical reviewer has been asked to critique all aspects of the investigator’s work product, then the technical reviewer should be qualified and familiar with all aspects of proper fire investigation and should, at a minimum, have access to all of the documentation available to the investigator whose work is being reviewed. If a technical reviewer has been asked to critique only specific aspects of the investigator’s work product, then the technical reviewer should be qualified and familiar with those specific aspects and, at a minimum, have access to all documentation relevant to those aspects. A technical review can serve as an additional test of the various aspects of the investigator’s work product. 4.6.2.1 Limitations of Technical Reviews. While a technical review may add significant value to an investigation, technical reviewers may be perceived as having an interest in the outcome of the review. Confirmation bias (attempting to confirm a hypothesis rather than attempting to disprove it) is a subset of expectation bias (see §4.3.8). This kind of bias can be introduced in the context of working relationships or friendships. Investigators who are asked to review a colleague’s findings should strive to maintain a level of professional detachment. 4.6.3 Peer Review. Peer review is a formal procedure generally employed in prepublication review of scientific or technical documents and screening of grant applications by research-sponsoring agencies. Peer review carries with it connotations of both independence and objectivity. Peer reviewers should not have any interest in the outcome of the review. The author does not select the reviewers, and reviews are often conducted anonymously. As such, the term “peer review” should not be applied to reviews of an investigator’s work by co-workers, supervisors, or investigators from agencies conducting investigations of the same incident. Such reviews are more appropriately characterized as “technical reviews,” as described above. 4.6.3.1 The methodologies used and the fire science relied on by an investigator are subject to peer review. For example, NFPA 921 is a peer reviewed document describing the methodologies and science associated with proper fire and explosion investigations. 4.6.3.2 Limitations of Peer Reviews. Peer reviewers should have the expertise to detect logic flaws and inappropriate applications of methodology or scientific principles, but because they generally have no basis to question an investigator’s data, they are unlikely to be able to detect factual errors or incorrectly reported data. Conclusions based on incorrect data are likely to be incorrect themselves. Because of these limitations, a proper technical review will provide the best means to adequately assess the validity of the investigation’s results.

The committee believes that reviews can be an important component of an investigation. As such, appropriate terminology describing review processes is necessary.

Printed on 9/18/2009 57 Report on Proposals – November 2010 NFPA 921 ______921-56 Log #CP5

______Technical Committee on Fire Investigations, The Committee is revision the following items in Chapter 5 to correct errors in the 2008 Edition: Section 5.10.3.2 – Revise referenced Figures 5.10.2.4, Figure 5.10.2.6, and Figure 5.10.2.7 Proposal: Revise Figure 5.10.2.4, Figure 5.10.2.6, and Figure 5.10.2.7 to include a “NP” mark, denoting the location of the neutral plane, at the height of the direction of flow change, in line with the door opening, as currently described in Section 5.10.3.2.

***Insert Figure 5.10.2.4 Here*** FIGURE 5.10.2.4 Preflashover Conditions in Compartment Fire

***Insert Figure 5.10.2.6 Here*** FIGURE 5.10.2.6 Flashover Conditions in Compartment Fire

***Insert Figure 5.10.2.7 Here*** FIGURE 5.10.2.7 Postflashover or Full Room Involvement in Compartment Fire

Section 5.10.3.3.3 – Revise equation and modify variables in text. Add text – The maximum heat release rate supportable by the air flow (stoichiometric assumption that the fuel will be burned completely based on the available air), into the compartment with a single vent is given by ***Insert Equation E921-20 Here***

Where:

***Insert Equation E921-21 Here*** maximum heat release rate based on air flow (kW) = area of opening (m2) = height of opening (m) Revise 5.10.4.4 as follows: Replace with Section 5.10.4.4 Revise text and equation as follows: An approximation of the minimum heat release rate required for flashover for a compartment with a single opening can be found from the following relationship:

***Insert Equation E921-22 Here***

Where:

***Insert Equation E921-23 Here*** = area of opening (m2) = height of opening (m)

The last line of Section 5.10.3.2 currently includes the language, “Neutral planes are marked as NP in Figure 5.10.2.4, Figure 5.10.2.6, and Figure 5.10.2.7.” In the 2008 edition the figures listed above do not have the neutral plane locations identified.

Substantiation: The equation as described in section 5.10.3.3.3 was missing the area multiplier. Further the variables for opening area and opening height should be consistent with the variables and format used in Sections 5.10.4.4 and 5.10.4.5. “Q dot” is typically used in the literature as notation for heat release rate.

Substantiation: Improve the consistency and clarity of the difference between the heat release rate equations presented Printed on 9/18/2009 58 Report on Proposals – November 2010 NFPA 921 in Section 5.10.3.3.3 and Section 5.10.4.5.

Printed on 9/18/2009 59

Includes File 921 CP#5

Chapter 5Basic Fire Science

Revise Figure existing 5.10.2.4, Figure 5.10.2.6, and Figure 5.10.2.7 as indicated to mark NP for Neutral Plane

1. Figure 5.10 2.4

FIGURE 5.10.2.4 Preflashover Conditions in Compartment Fire.

2. Figure 5.10.2.7

FIGURE 5.10.2.6 Flashover Conditions in Compartment Fire.

3. Figure 5.10.2.7

FIGURE 5.10.2.6 Flashover Conditions in Compartment Fire.

4. Section 5.3.3.3 Revise this section to read as follow:

Section 5.10.3.3.3 – Revise equation and modify variables in text.

Add text – The maximum heat release rate supportable by the air flow (stoichiometric assumption that the fuel will be burned completely based on the available air), into the compartment with a single vent is given by

Q stoich  1500 HA oo

Where:

Q stoich  maximum heat release rate based on air flow (kW)

2 Ao = area of opening (m )

H o  height of opening (m)

5. Revise 5.10.4.4 as follows:

Replace h0 with H o

6. Section 5.10.4.4 Revise text and equation as follows:

An approximation of the minimum heat release rate required for flashover for a compartment with a single opening can be found from the following relationship:

 fo  750 HAQ oo

Where:

Q fo  approximate minimum heat release rate for flashover

2 Ao  area of opening (m )

H o  height of opening (m) Report on Proposals – November 2010 NFPA 921 ______921-57 Log #7

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: The combustion reaction can be characterized by four components: the fuel, the oxidizing agent, the heat and the uninhibited chemical chain reaction. These four components have been classically symbolized by a four sided solid geometric form called a tetrahedron pentahedron (see figure 5.1.2). Fires can be prevented or suppressed by controlling or removing one or more of the sides of the tetrahedron pentahedron. A tetrahedron has four vertices, four surfaces and six edges. A pentahedron has five vertices, five surfaces and eight edges and is also known, in this case, as a square pyramid. The four surfaces at a tetrahedron never meet at one point, thus the four combustion reaction components would never meet. There are numerous other instances where this needs to be corrected.

The tetrahedron is an evolution of the fire triangle, it is a metaphor, and one that is understood by most fire investigators. Introducing the concept of the pentahedron would be confusing.

Printed on 9/18/2009 60 Report on Proposals – November 2010 NFPA 921 ______921-58 Log #6

______Thomas H. Claxton, ClaxCo, Inc. Revise the lines on each face of the figure to be parallel to the bottom line of that face of the figure. This alignment will more clearly show the shape of the figure.

The current figure already has lines parallel to the bottom of the face where the two bases are visible. Adding additional lines would add confusion, particularly with respect to the bottom face.

Printed on 9/18/2009 61 Report on Proposals – November 2010 NFPA 921 ______921-59 Log #80

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: Both premixed and diffusion flames are important in fire investigation. I believe the addition of "investigation" completes the sentence.

The current text is adequate; the paragraph is about fire and not about investigation.

Printed on 9/18/2009 62 Report on Proposals – November 2010 NFPA 921 ______921-60 Log #12

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: Premix flame spread may proceed as a deflagration, subsonic combustion and or as a detonation, supersonic combustion. As fire investigators, we only classify the flame spread as deflagration or detonation. Not as a combination of deflagration and detonation.

Revise the sentence to read premixed flame spread can proceed as a deflagration (subsonic combustion) or as a detonation (supersonic combustion). While the committee is accepting the submitter’s proposal additional changes to the sentence are made to make it more grammatically correct.

Printed on 9/18/2009 63 Report on Proposals – November 2010 NFPA 921 ______921-61 Log #11

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: For example, the lower and upper temperature (°C) flammability limits of methane are 5 percent and 15 percent, respectively, in air at ordinary temperatures. Section 5.2.3.2 is a discussion of flammability limits.

See committee action on 921-62 (Log #81), flammable limits is the appropriate term.

Printed on 9/18/2009 64 Report on Proposals – November 2010 NFPA 921 ______921-62 Log #81

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: For example, the lower and upper temperature (oC) flammable limits of methane are 5 percent and 15 percent, respectively, in air at ordinary temperatures. I believe this is editorial as flammable limits is correct and temperature is incorrect.

Printed on 9/18/2009 65 Report on Proposals – November 2010 NFPA 921 ______921-63 Log #1

______Manouchehr Sarfehnia, National Iranian Gas Company Revise text as follows: The rate of heat transfer to the solid is a …..---- The rate of heat absorbed by the solid is a ……… I have changed the transfer word to absorbed word, because: 1- Heat transfer is prior to absorbed (heat transfer by the hot gas and then absorbed by solid) 2- In the text your focus is on solid and it's temperature and properties, It is important for us to know how much temperature of solid will be rise and it strongly depend on ability of heat absorption.

Printed on 9/18/2009 66 Report on Proposals – November 2010 NFPA 921 ______921-64 Log #2

______Manouchehr Sarfehnia, National Iranian Gas Company Revise text as follows: Radiant energy can be transferred only by line of sight and will be reduced or blocked by intervening materials.--- Radiant energy can be transferred only by line of sight and will be reflect or blocked by intervening materials. I suggest that change reduce word to reflect word because: 1- In text you are talking about reply of materials to radiant energy. 2- Reduce word is result of reflect or blocked, so in this text it is more important for us, to know reply of materials to radiant no result of that.

The current text adequately conveys the concept as there are more than two methods of reducing radiant energy.

Printed on 9/18/2009 67 Report on Proposals – November 2010 NFPA 921 ______921-65 Log #3

______Manouchehr Sarfehnia, National Iranian Gas Company Revise text as follows: Fuel Iterms and Fuel package----- Fuel Items and Fuel package Wrong dictation.

While this may have been an error in previous printings, it has since been corrected.

Printed on 9/18/2009 68 Report on Proposals – November 2010 NFPA 921 ______921-66 Log #108

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: 5.6.4.6 Fuel Package Location; Flames against walls generally have the same a higher flame height as than fires away from a wall. However, Flames in corners are generally taller than their counterparts away from a corner. It is my understanding that due to reduced air entrainment where a flame is against a wall or in a corner that the subsequent flames are taller depending on their location. This change also makes this paragraph consistent with 5.10.6.2 Location of the Fire in the Compartment where the temperatures of fires against a wall, away from a wall and in a corner all have different hot layer absolute temperatures due to different air entrainment.

See committee action on 921-67 (Log #CP11).

Printed on 9/18/2009 69 Report on Proposals – November 2010 NFPA 921 ______921-67 Log #CP11

______Technical Committee on Fire Investigations, Replace 5.6.4.6 with the following sections: 5.6.4.6* Fuel Package Location.

***Insert FIGURES 5.6.4.6(a) through (b) Here***

FIGURE 5.6.4.6(a) Average Flame Heights for Replicate Wood Crib Fires in the Open. The Range of Measured Heat Release Rates and Estimated Average Flame Heights were 24 to 26 kW and 27 to 30 inches, Respectively

FIGURE 5.6.4.6(b) Average Flame Heights for Replicate Wood Crib Fires Against the Wall. The Range of Measured Heat Release Rates and Estimated Average Flame Heights were 21 to 25 kW and 27 to 20 inches, Respectively

FIGURE 5.6.4.6(c) Average Flame Heights for Replicate Wood Crib Fires in a Corner Configuration. The Range of Measured Heat Release Rates and Estimated Average Flame Heights were 25 to 26 kW and 37 to 40 inches, Respectively

5.6.4.6.1 Air Entrainment. When a burning fuel package is positioned away from a wall, air is free to flow into the plume from all directions and mix with the fuel gases. If the fuel package is placed against a wall or in a corner (formed by the intersection of two walls), air entrainment into the plume can be restricted, creating an imbalance in the airflow. As a result of the imbalance in airflow, the flame and thermal plumes will bend toward the restricting surface(s). 5.6.4.6.2 Flame and Plume Attachment. In cases where the flame or thermal plume bends sufficiently to become attached to the wall(s), the air entrainment is reduced. The fuel package must be sufficiently close to the wall(s) to cause the flame or thermal plume to attach to the wall(s) in order for the effects of restricted air entrainment to occur. The extent of the bending of the flame toward and the attachment to the wall(s) is dependent on the geometry of the fuel and the position of the fuel package relative to the wall(s). 5.6.4.6.3 Effect of Reduced Air Entrainment. A decrease in air entrainment has an effect on plume and upper layer temperatures as well as on the height of the flame. 5.6.4.6.3.1 Plume and Upper Layer Temperatures. A reduction in ambient air being entrained into the thermal plume lessens the amount of mixing of cooler ambient air with the thermal plume, resulting in less dilution and higher temperatures. Since the plume transports thermal energy to the upper layer, an increase in temperature in the plume will also produce an increase in the upper layer temperature. 5.6.4.6.3.2 Flame Height. For diffusion flames, the mixing of fuel vapor and air controls the location where flaming combustion occurs; thus, the flame height at any given time represents the vertical distance (i.e. the mixing length) over which the fuel and air must be transported to complete the combustion process. Therefore, a reduction in air entrainment can result in greater flame heights, since the fuel vapor must be transported over a longer mixing length in order to completely mix with the reduced amount of air. 5.6.4.6.4 Effect of Walls. If the fuel package is positioned adjacent to one wall in a manner sufficient to reduce the air entrainment, there will be an increase in the absolute temperature of the upper layer when compared with the same fire positioned away from the wall. In contrast, experimental results have shown no significant increase in flame length for fire against a wall. Figures 5.6.4.6.4 (a) and 5.6.4.6.4 (b) provide an example of this finding for a fire away from and against a wall. 5.6.4.6.5 Effect of Corners. When the same fuel package is placed in a corner sufficient to further reduce the air entrainment, there will also be an increase in the absolute temperature of the upper layer when compared with the same fire positioned away from corners. Similarly, a significant increase in the flame height is observed when the flames are attached to the walls in a corner configuration. Figures 5.6.4.6 (c) provide an example of the increase in flame height for a fire in a corner configuration. 5.6.4.6.6 Analysis of Wall Effects. The possible effect of the location of wall(s) relative to the fire should be considered in the analysis of the fire and/or the interpretation of damage patterns produced by the fire. 5.6.4.6.7 Outdoor Fires. It should be noted that similar effects to those described above for indoor fires will also be observed for outdoor fires.

Printed on 9/18/2009 70 Report on Proposals – November 2010 NFPA 921 Add the following appendix: A.5.6.4.6 For additional information, see the following references: (1) Beyler, C. L., “Plumes and Ceiling Jets,” Fire Safety Journal, 1986. (2) Hasemi, Y., and Tokunaga, T., “Some Experimental Aspects of Turbulent Diffusion Flames and Buoyant Plumes from Fire Sources Against a Wall and in a Corner of Walls,” Combustion Science and Technology, 40, pp. 1-17, 1984. (3) Mizuno, T., and Kawagoe, K., “Burning Rate of Upholstered Chairs in the Center, Alongside a Wall and in a Corner of a Compartment,” Fire Safety Science, Proceedings of the First International Symposium, pp. 849-857, 1985. (4) Zukoski, E. E., “Properties of Fire Plumes,” Combustion Fundamentals of Fire, Cox, G., Ed., Academic Press, London, 1995. (5) Karlsson, B., and Quintiere, J. G., “Fire Plumes and Flame Height,” Enclosure Fire Dynamics, CRC Press, New York, 2000. (6) Mowrer, F. W., and Williamson, R. B., “Estimating Room Temperatures from Fires Along Walls and in Corners,” Fire Technology, Vol. 23, No. 2, pp. 133-145, 1987. (7) Back, J., Beyler, C., DiNenno, P., “Wall Incident Heat Flux Distributions Resulting from Adjacent Fire,” Proceedings of the Fourth International Symposium on Fire Safety Science, International Association of Fire Safety Science, 1994. (8) Heskestad, G., “Fire Plumes, Flame Height, and Air Entrainment”, Section 2, Chapter 1, SFPE Handbook of Fire Protection Engineering, 3rd ed., DiNenno, P.J., editor, Society of Fire Protection Engineers, National Fire Protection Association, Quincy MA, 2002.

There is a need to get away from the very simplistic descriptor of a fire “against” a wall or corner since this is a subjective concept. The discussion needs to focus more on the ability for flame and thermal plumes to attach to the potential restricting surface in order to have an effect on the air entrainment. This rewritten section provides a more detailed technical description and increased clarity.

Printed on 9/18/2009 71

INCLUDES FILE 921 CP#11

FIGURE 5.6.4.6 (a) Average flame heights for replicate wood crib fires in the open. The range of measured heat release rates and estimated average flame heights were 24 to 26 kW and 27 to 30 inches, respectively.

FIGURE 5.6.4.6 (b) Average flame heights for replicate wood crib fires against the wall. The range of measured heat release rates and estimated average flame heights were 21 to 25 kW and 27 to 29 inches, respectively.

FIGURE 5.6.4.6 (c) Average flame heights for replicate wood crib fires in a corner configuration. The range of measured heat release rates and estimated average flame heights were 25 to 26 kW and 37 to 40 inches, respectively.

Report on Proposals – November 2010 NFPA 921 ______921-68 Log #13

______Thomas H. Claxton, ClaxCo, Inc. Revise text as follows: These limits are normally expressed as the lower °C flammability limit (LFL), the lowest concentration of flammable gas in the air that will support flame propagation, and the upper °C flammability limit (UFL), the highest concentration of flammable gas in air that will support flame propagation. To correct the terms to standard engineering notations. The use of LFL, UFL and LEL, UEL are both used inconsistently in other sections of 921-2008.

Revise text to read as follows: These limits are normally expressed as the lower °C flammability flammable/explosive limit (LFL/LEL), the lowest concentration by volume of flammable gas in the air that will support flame propagation, and the upper °C flammability flammable/explosive limit (UFL/UEL), the highest concentration by volume of flammable gas in air that will support flame propagation. Committee is providing additional details to further clarify the concept.

Printed on 9/18/2009 72 Report on Proposals – November 2010 NFPA 921 ______921-69 Log #15

______Ahemd H. Zahran, Saudi Aramco Revise text as follows: 5.7.2.1 Flammable gases can only be ignited by a spark or pilot flame over specific ranges of gas concentration. These limits are normally expressed as the lower flammable/explosive °C limit, the lowest concentration of flammable gas in air that will support flame propagation, and the upper flammable/explosive °C limit, the highest ...... The original text describes the flammability/explosive limits by "TEMPERATURE (°C)". The proposed correction revises this error.

Add (LFL/LEL) in second sentence after the word “limit” and before the word “the lowest” Add the words “by volume” after the word concentration and before the word “of volume” This should read as follows: 5.7.2.1 Flammable gases can only be ignited by a spark or pilot flame over specific ranges of gas concentration. These limits are normally expressed as the lower flammable/explosive °C limit (LFL/LEL), the lowest concentration by volume of flammable gas in air that will support flame propagation, and the upper flammable/explosive °C limit (UFL/UEL), the highest See committee action on 921-68 (Log #13).

Printed on 9/18/2009 73 Report on Proposals – November 2010 NFPA 921 ______921-70 Log #82

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: These limits are normally expressed as the lower oC flammable limit, the lowest concentration of flammable gas in air that will support flame propagation, and the upper oC flammable limit.... I believe this is editorial as flammable is correct and oC is incorrect.

See Committee Action on 921-68 (Log #13).

Printed on 9/18/2009 74 Report on Proposals – November 2010 NFPA 921 ______921-71 Log #107

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: 5.7.3.1 Flashpoint. ... the flammable gases vapors above the liquid surface by a pilot source. The flammable gas vapor concentration at the surface must reach .... The liquid temperature above which an ignitable concentration of flammable-gasses vapors in generated in known as the flash point. I believe that this is editorial. It is flammable vapors above a flammable liquid rather than gases. This makes it consistent with the definitions of gas and vapor given in 3.3.81 and 3.3.172.

Printed on 9/18/2009 75 Report on Proposals – November 2010 NFPA 921 ______921-72 Log #16

______Ahemd H. Zahran, Saudi Aramco Revise text as follows: 5.7.4.1.1.4 The term smoldering is sometimes inappropriately used to describe a nonflaming response of a solid fuel to an external heat flux. Solid fuels, such as thermoset plastics thermoplastics, when subjected to a sufficient heat flux, will degrade, gasify, and release vapors. There usually is little ...... The original text states that thermoplastics degrade, gasify and release vapors when subjected to heat. The correct is that thermoset plastics degrade, gasify and release vapors, while thermoplastics will melt. The proposed change corrects this error.

Printed on 9/18/2009 76 Report on Proposals – November 2010 NFPA 921 ______921-73 Log #4

______Manouchehr Sarfehnia, National Iranian Gas Company Revise text as follows: And as the pile size increase, the ability to dissipate heat to surrounding increase. And as the pile size increase, the ability to dissipate heat to surrounding decrease. It would be better that change increase word by decrease word because: 1- As you wrote in continue on the text, both high ambient temperature and large pile sizes favor self-heating processes, it is right, but it's prerequisite is the large pile size dissipate less heat than small pile size. It means that as the pile sizes increase, the ability to dissipate heat to surround decrease.

Submitter is referring to a typographical error that has been previously corrected in subsequent printings.

Printed on 9/18/2009 77 Report on Proposals – November 2010 NFPA 921 ______921-74 Log #112

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: In Figure 5.7.4.1.3.3 revise the labels as follows: Ambient temperature Irradiance Heat dissipation Critical mass Reaction surface area Oxygen (1) Insufficient reaction surface area (2) Insufficient oxygen concentration or diffusion (3) Ambient temperature too low (4) Insufficient insulation--heat radiates away dissipates (5) Insufficient material This recommendation was accepted for the 2008 edition of 921 (Report on Comments F2007 921-32 Log #119) but was inadvertently omitted in the final publication. 1. Irradiance refers specifically to heat transfer by the mechanism of radiation. Under conditions leading to spontaneous combustion, the heat that is generated is transferred and thus dissipated primarily by convection and the effects of insulation and low external surface area are primarily to inhibit convective heat transfer. Radiative heat transfer is minor at temperatures below ignition. So use the term heat dissipation which is more generic and includes heat transfer by all three mechanisms: convective, conductive, and radiative. 2. The surface area referred to in this part of the diagram is the area where the exothermic reactions can occur. Make that clear so it is not confused with the external surface area of the volume of material. High reaction surface area promotes self-heating. High external surface area promotes heat dissipation and thus inhibits self-heating. 3. Lack of ambient oxygen concentration by intentional or inadvertent inerting, will inhibit self-heating. Also, oxygen has to diffuse into the volume of material to reach the area where exothermic reactions are occurring. Thus, conditions that inhibit oxygen diffusion into the area of reaction also inhibit self-heating.

Log #119 in the previous ROC; it was accepted.

Printed on 9/18/2009 78 Report on Proposals – November 2010 NFPA 921 ______921-75 Log #5

______Manouchehr Sarfehnia, National Iranian Gas Company Revise text as follows: Figure 5.10.2.6 flashover condition in compartment fire----- Figure 5.10.2.6 post flashover or full room involvement in compartment fire Figure 5.10.2.7 post flashover or full room involvement in compartment fire----- Figure 5.10.2.7 flash over in compartment fire.. None.

Submitter provides no substantiation and the committee believes the current figure descriptions are correct.

Printed on 9/18/2009 79 Report on Proposals – November 2010 NFPA 921 ______921-76 Log #109

______James N. Macdonald, Macdonald & Associates LLC Revise text to read as follows: 5.10.3.3.3 the formula needs to be changed at follows; Q = A h6 I believe that this is editorial. The only way for the formula in 5.10.3.3.3 to give results shown in 5.10.3.3.4 of 4000 kW or 4 MW and 1600 kW or 1.6 MW is to have the area of the opening A included in the formula. Either the formula in 5.10.3.3.3 is wrong or the numbers in 5.10.3.3.4 are wrong.

Revise text to read as follows: 5.10.3.3.3: The formula needs to be changed at follows; Q = A h6. We believe that this is editorial. Change equation as follows: Q=1500A (H)0.5 In other words: Insert “A” between 1500 and square root symbol.

An “A” has been added into the equation to correct the formula.

Printed on 9/18/2009 80 Report on Proposals – November 2010 NFPA 921 ______921-77 Log #153

______Melvin Robin, ATF New text to read as follows: “Depth of char, while indicative of fuel loads and ventilation effects of a fire, may exhibit damage and patterns consistent with fire growth and movement relative to that item (wall, etc.), and not for the overall event or for purposes of determining origin and cause.” Depth of Char and Calcination phenomenon description needs clarification as a movement pattern.

Proposed text is redundant and does not add clarification to existing text.

Printed on 9/18/2009 81 Report on Proposals – November 2010 NFPA 921 ______921-78 Log #61

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Insert Figure 6.2.8.6.2 and caption and reference to the photo at the end of the paragraph ( )

Photo illustrates alloying of copper gas pipe

The committee is accepting this photograph of a non laboratory test phenomena because the conditions within the photograph were verified by laboratory analysis.

Printed on 9/18/2009 82 Patrick Kennedy Proposal for 6.2.8.6.2 Page 2

Figure 6.2.8.6.2 Hole in copper gas line caused by alloying when molten aluminum [melting temperature ~649 C. (~1200 F.)] dripped onto the copper pipe [melting temperature ~1082 C. (~1980 F.)]. Report on Proposals – November 2010 NFPA 921 ______921-79 Log #62

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add new text as sections 6.2.10.3* et seq.

In many cases, the nature of soot deposition on certain surfaces of typical single or multiple station smoke alarms can show that the smoke alarm sounded during a fire. is a phenomenon whereby the soot particulate in smoke forms identifiable patterns on such surfaces of the smoke alarm as: the internal and external surfaces of the smoke alarm cover near the edges of the “horn” (sound) outlet(s); the edges of and “horn” sound outlet(s) of the interior “horn” enclosures if present; and surfaces of the “horn” disks themselves. Acoustic waves in the smoky atmosphere and mechanical vibrations of the surfaces of the smoke alarm itself, both caused by the high frequency vibrations (~4000 hz) of the activated smoke alarm “horn” disk, cause the soot particles to adhere to each other (agglomerate) in the atmosphere and be deposited on the surfaces of the smoke alarm in identifiable patterns (Chladni figures*). ( ) The absence of such acoustic soot agglomeration on a smoke alarm may be indicative of a smoke alarm’s failure to sound during a fire event depending on the nature of the burning fuel and its smoke, the existence of high percentages of smoke obscuration in the atmosphere, and the amount of time that the smoke alarm was exposed to the smoke. Scene investigators should be cognizant of the importance of smoke alarms which may bear physical evidence of alarm activation, and consider more detailed documentation, examination, and collection of such evidence. Acoustic soot agglomeration evidence can be delicate and easily disturbed or wiped away by careless handling or evidence packaging of the smoke alarm(s) in question. Care should be taken not to disturb any suspected agglomerated soot deposits. Evidence of acoustic agglomeration on smoke alarms can be subtle and sometimes difficult to identify. Examination of soot agglomeration may require macro- or microscopic magnification. The identification of acoustic soot agglomeration on smoke alarms may also require specialized knowledge, training, experience, and expertise. It is recommended that investigators who lack such expertise and experience seek professional assistance from fire analysts more knowledgeable in this area.

An unpowered (non-functioning) smoke alarm after exposure to a sooty atmosphere.

Close-up of the external “horn” (sound) outlet of the unpowered smoke alarm displayed in Figure 6.2.10.3.1(a) after exposure to a sooty atmosphere, showing no acoustic soot agglomeration.

A duplicate powered (functioning) smoke alarm after exposure to the same sooty atmosphere as the smoke alarm in Figures 6.2.10.3.1(a) and (b), displaying typical acoustic soot agglomeration.

Close-up of the external “horn” (sound) outlet of the powered smoke alarm displayed in Figure 6.2.10.3.1(c) after exposure to a sooty atmosphere, showing acoustic soot agglomeration.

For more information on research into Acoustic Soot Agglomeration on smoke alarms see the following references: Munger, J., “Residential Smoke Alarms: Their Effect on the Reduction of America’s Fire Death and Injury Rate,” Ph.D. dissertation, Columbia Southern University, 1999. Worrell, C. L., Roby, R. J., Streit L., and Torero, J. L., “Enhanced Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors,” Fire Technology, 37, 343-362, (USA: Kluwer Academic Publishing, 2001). Worrell, C.L., Lynch, J.A., Jommas, G., Roby, R.J., Streit, L., and Torero, J.L., “Enhanced Soot Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors,” Fire Technology, 39, 309-346, 2003. Kennedy, Patrick M., Kennedy, Kathryn C., and Gorbett, Gregory E., “A Fire Analysis Tool – Revisited: Acoustic Soot Agglomeration in Residential Smoke Alarms,” InterFlam 2004 Proceedings, InterScience Communications, London, 2004. Mealy, C.L., and Gottuk, D.T., “Full-Scale Validation Tests of a Forensic Methodology to Determine Smoke Alarm

Printed on 9/18/2009 83 Report on Proposals – November 2010 NFPA 921 Response,” ISFI 2008 Proceedings, International Symposium on Fire Investigation Science and Technology, NAFI, Sarasota, FL, 2008. are essentially symmetrical visible vibration patterns on basically flat surfaces representing the nodal regions where the surface of a vibrating body is free or relatively free from vibratory motion. Originally discovered by Robert Hooke in 1680, rediscovered by German physicist Ernst Chladni, and first published in his 1787 book, ("Discoveries in the Theory of Sound"). The photos in Figures 6.2.10.3.1 (a), (b), (c), and (d) are from laboratory research tests reported in: Kennedy, P.M., Kennedy, K.C., and Gorbett, G.E., “A Fire Analysis Tool – Revisited: Acoustic Soot Agglomeration in Residential Smoke Alarms,” InterFlam 2004 Proceedings, InterScience Communications, London, 2004. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. Since the issuance of the 2001 edition of NFPA 921 the use of acoustic soot agglomeration as a soot pattern analysis tool has become de rigueur in cases where the operation of a single or multiple station smoke alarm is in question. Several principal and alternate committee members and “friends of the committee” have participated in the underlining scientific research and “peer reviewed” publication of this issue. The users of NFPA 921 should be aware of the basics of this relatively new investigative tool.

Revise text to read as follows: 6.2.10.3* Enhanced Soot Deposition (Acoustic Soot Agglomeration) on Smoke Alarms In many cases, the nature of soot deposition on certain surfaces of typical single or multiple station smoke alarms can show that the smoke alarm sounded or did not sound during a fire. Enhanced Soot Deposition (Acoustic Soot Agglomeration) is a phenomenon whereby the soot particulate in smoke forms identifiable patterns on such surfaces of the smoke alarm as: the internal and external surfaces of the smoke alarm cover near the edges of the “horn” (sound) outlet(s); and the edges of and “horn” sound outlet(s) of the interior “horn” enclosures if present. ; and surfaces of the “horn” disks themselves. (see Figures 6.2.10.3.1 (a), (b), (c), and (d)*) 6.2.10.3.1* Acoustic waves in the smoky atmosphere and mechanical vibrations of the surfaces of the smoke alarm itself, both caused by the high frequency vibrations (~4000 hz) of the activated smoke alarm “horn” disk, cause the soot particles to adhere to each other (agglomerate) in the atmosphere and be deposited on the surfaces of the smoke alarm in identifiable patterns (Chladni figures*). (see Figures 6.2.10.3.1 (a), (b), (c), and (d)*) 6.2.10.3.2 The absence of such acoustic soot agglomeration on a smoke alarm may be indicative of a smoke alarm’s failure to sound during a fire event depending on the nature of the burning fuel and its smoke, the existence of high percentages of smoke obscuration in the atmosphere, and the amount of time that the smoke alarm was exposed to the smoke. 6.2.10.3.31 Scene investigators should be cognizant of the importance of smoke alarms which may bear physical evidence of alarm activation, and consider more detailed documentation, examination, and collection of such evidence. 6.2.10.3.42 Enhanced soot deposition Acoustic soot agglomeration evidence can be delicate and easily disturbed or wiped away by careless handling or evidence packaging of the smoke alarm(s) in question. Care should be taken not to disturb any suspected agglomerated soot deposits. 6.2.10.3.53 Evidence of enhanced soot deposition acoustic agglomeration on smoke alarms can be subtle and sometimes difficult to identify. Examination of soot agglomeration may require macro- or microscopic magnification. The identification of acoustic soot agglomeration on smoke alarms may also require specialized knowledge, training, experience, and expertise. It is recommended that investigators who lack such expertise and experience seek professional assistance from fire analysts more knowledgeable in this area.

Printed on 9/18/2009 84 Report on Proposals – November 2010 NFPA 921

FIGURE 6.2.10.3.1 (a) An unpowered (non-functioning) smoke alarm after exposure to a sooty atmosphere. (not shown, change in text only)

FIGURE 6.2.10.3.1 (b) Close-up of the external “horn” (sound) outlet of the unpowered smoke alarm displayed in Figure 6.2.10.3.1(a) after exposure to a sooty atmosphere, showing no enhanced soot deposition acoustic soot agglomeration. (not shown, change in text only)

FIGURE 6.2.10.3.1 (c) A duplicate powered (functioning) smoke alarm after exposure to the same sooty atmosphere as the smoke alarm in Figures 6.2.10.3.1(a) and (b), displaying typical enhanced soot deposition acoustic soot agglomeration. (not shown, change in text only)

FIGURE 6.2.10.3.1 (d) Close-up of the external “horn” (sound) outlet of the powered smoke alarm displayed in Figure 6.2.10.3.1(c) after exposure to a sooty atmosphere, showing enhanced soot deposition acoustic soot agglomeration. (not shown, change in text only)

ANNEX A A.6.2.10.3 For more information on research into Acoustic Soot Agglomeration on smoke alarms see the following references:

Munger, J., “Residential Smoke Alarms: Their Effect on the Reduction of America’s Fire Death and Injury Rate,” Ph.D. dissertation, Columbia Southern University, 1999. Worrell, C. L., Roby, R. J., Streit L., and Torero, J. L., “Enhanced Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors,” Fire Technology, 37, 343-362, (USA: Kluwer Academic Publishing, 2001).

Worrell, C.L., Lynch, J.A., Jommas, G., Roby, R.J., Streit, L., and Torero, J.L., “Enhanced Soot Deposition, Acoustic Agglomeration, and Chladni Figures in Smoke Detectors,” Fire Technology, 39, 309-346, 2003.

Kennedy, Patrick M., Kennedy, Kathryn C., and Gorbett, Gregory E., “A Fire Analysis Tool – Revisited: Acoustic Soot Agglomeration in Residential Smoke Alarms,” InterFlam 2004 Proceedings, InterScience Communications, London, 2004. Phelan, Patrick. An Investigation of Enhanced Soot Deposition on Smoke Alarm Horns. M. S. Thesis, Worcester Polytechnic Institute. 2004 [new reference insterted]

Mealy, C.L., and Gottuk, D.T., “Full-Scale Validation Tests of a Forensic Methodology to Determine Smoke Alarm Response,” ISFI 2008 Proceedings, International Symposium on Fire Investigation Science and Technology, NAFI, Sarasota, FL, 2008.

A.6.2.10.3.1 Chladni figures are essentially symmetrical visible vibration patterns on basically flat surfaces representing the nodal regions where the surface of a vibrating body is free or relatively free from vibratory motion. Originally discovered by Robert Hooke in 1680, rediscovered by German physicist Ernst Chladni, and first published in his 1787 book, Entdeckungen über die Theorie des Klanges ("Discoveries in the Theory of Sound").

The photos in Figures 6.2.10.3.1 (a), (b), (c), and (d) are from laboratory research tests reported in: Kennedy, P.M., Kennedy, K.C., and Gorbett, G.E., “A Fire Analysis Tool – Revisited: Acoustic Soot Agglomeration in Residential Smoke Alarms,” InterFlam 2004 Proceedings, InterScience Communications, London, 2004.

Throughout, the term “acoustic soot agglomeration” was replaced with “enhanced soot deposition” to more accurately reflect the use of the terms in the literature. 6.2.10.3 “or did not sound” has been added to reflect that this analysis methodology can be used to positively identify alarms that sounded and did not sound. The phrase “…surfaces of the ‘horn’ disks themselves” to more accurately reflect where soot deposition patterns are observed and to be consistent with the literature. 6.2.10.3.1 and 6.2.10.3.2 were deleted as the text was partly redundant and the complexity of the topic is better presented in the cited references and not in the text of this document. The annex material to 6.2.10.3.1 was deleted along with the section. 6.2.10.3.5 The last two sentences were deleted as the text was not necessary. Printed on 9/18/2009 85 Report on Proposals – November 2010 NFPA 921 Annex A: The Munger reference was deleted as it is a difficult reference to obtain and does not add to the use or understanding of enhanced soot deposition analyses. A reference to the thesis by Phelan was added as it provides information that addresses the use and understanding of enhanced soot deposition analyses.

Printed on 9/18/2009 86 Patrick Kennedy Proposal PAGE 5 New Sections 6.2.10.3 et seq. Acoustic Soot Agglomeration on Smoke Alarms

FIGURE 6.2.10.3.1(c) A duplicate powered (functioning) smoke alarm after exposure to the same sooty atmosphere as the smoke alarm in Figures 6.2.10.3.1(a) and (b), displaying typical acoustic soot agglomeration.

Patrick Kennedy Proposal PAGE 4 New Sections 6.2.10.3 et seq. Acoustic Soot Agglomeration on Smoke Alarms

FIGURE 6.2.10.3.1(b) Close-up of the external “horn” (sound) outlet of the unpowered smoke alarm displayed in Figure 6.2.10.3.1(a) after exposure to a sooty atmosphere, showing no acoustic soot agglomeration.

Patrick Kennedy Proposal PAGE 3 New Sections 6.2.10.3 et seq. Acoustic Soot Agglomeration on Smoke Alarms

FIGURE 6.2.10.3.1(a) An unpowered (non-functioning) smoke alarm after exposure to a sooty atmosphere.

Patrick Kennedy Proposal PAGE 6 New Sections 6.2.10.3 et seq. Acoustic Soot Agglomeration on Smoke Alarms

FIGURE 6.2.10.3.1(d) Close-up of the external “horn” (sound) outlet of the powered smoke alarm displayed in Figure 6.2.10.3.1(c) after exposure to a sooty atmosphere, showing acoustic soot agglomeration.

Report on Proposals – November 2010 NFPA 921 ______921-80 Log #113

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: Oily substances, which do not mix with water, float and create diffraction interference patterns on the surface of water. The phenomenon that creates “rainbow” patterns in a thin film of one transparent liquid on another liquid (such as oil on water) is due to interference, not diffraction. Diffraction is the dispersive effect on light caused by light passing near the edge of an opaque object (paraphrased definition from ). Interference is the interaction between two waves of the same frequency . The rainbow pattern seen on oil sheens is caused when the light reflecting from the two oil interfaces (air-oil and oil-water) at odd harmonic one-quarter light wavelength oil film thicknesses (1/4, 3/4, 5/4, etc.) interferes with one another causing destructive interference cancelling light of a specific wavelength and leaving the remaining light “coloured.” The varying oil film thickness cancels different wavelengths (colours) at different locations, causing the rainbow effect in the original white light (or light and dark stripes if originally illuminated with monochromatic light). The same effect is seen in a soap bubble in air. The misunderstanding may arise because diffraction gratings create spectra (rainbows) through a combination of diffraction (through many parallel transparent and opaque lines on the diffraction grating) and interference of the resultant diffracted light.

Printed on 9/18/2009 87 Report on Proposals – November 2010 NFPA 921 ______921-81 Log #99

______Bob Eugene, Underwriters Laboratories Inc. Revise text to read as follows: 6.3.3.1.2.3 The ability of the surface to withstand the passage of heat over time is called its finish rating. The finish rating of a surface material only represents the performance of the material in a specific laboratory test (e.g., as shown in ANSI/UL 263, Standard for Safety Fire Tests of Building Construction and Materials) and not necessarily the actual performance of the material in a real fire. Knowledge of the concept can be of value to an investigator's overall fire spread analysis. Update standards titles to indicate ANSI approvals.

Printed on 9/18/2009 88 Report on Proposals – November 2010 NFPA 921 ______921-82 Log #92

______Ryan M. Cox, Kodiak Enterprises, Inc. Revise text to read as follows:

6.3.7.12 Saddle Burns

***Insert 921_L92_ Figure 6.3.7.12 here***

6.3.7.12.1 Saddle burns are distinctive D- or saddle-shaped patterns that are sometimes found on the top edges of floor joists. Saddle burns display deep charring, and the fire patterns are highly localized and gently curved, as seen in Figure 6.3.7.12. 6.3.7.12.2 They can be caused by fire burning downward through the floor above the affected joists, as may be seen in post-flashover conditions. They can be created by radiant heat from a burning material in close proximity to the floor, including piles of smoldering charred materials and materials that may melt and burn on the floor [e.g., polyurethane foam]. Ventilation caused by floor openings may also contribute to the development of these patterns. 6.3.7.12.3 Saddle burns can also be created by burning in the joist spaces below the floor membrane and breaching the joists at the top edge where the joist abuts the floor boards. As the fire progresses, it may burn through the floor boards above the joist leaving the distinctive-shaped damage to the joists that survive. 6.3.7.12.4 The presence of saddle burns does not indicate that an ignitable liquid was used. If ignitable liquids are suspected to have been the reason for the fire damage, then laboratory confirmation is necessary.

The manner in which the existing text reads supports the incorrect belief that ignitable liquids are the likely explanation for the presence of saddle burns. No published research exists to establish that saddle burns result "often" by the burning of ignitable liquids. Field experiments indicate a burning pool of ignitable liquids more likely will not result in the creation of saddle burns. The pool of liquid won't last long enough to create the saddle burn patterns described in this section. The new text reflects a correction to that misconception and eliminates a figure that lacks adequate explanation as to the how the saddle burns were created. That existing image, Figure 6.3.7.12 originally submitted by Dennis W. Smith, depicts a room where widespread saddle burns exist. The room did not go to flashover and the burns were caused by a camp fire that had been set in the middle of the room and allowed to burn until the floor boards were penetrated. The new image depicts saddle burns on floor joists where the floor above was both burned away and still existing.

The photographs submitted is less clear than in the one currently in the document and D-patterns are an undefined new term. The research is unpublished.

Printed on 9/18/2009 89

Report on Proposals – November 2010 NFPA 921 ______921-83 Log #134

______Robert Toth, IRIS Fire Investigations, Inc. Revise text as follows: Flame, heat, and smoke produce patterns as a result of fire growth, and fire spread, and heat. Movement patterns are produced by the growth, spread, and the flow of products of combustion away from an initial heat source. Suggestion is for clarity.

Printed on 9/18/2009 90 Report on Proposals – November 2010 NFPA 921 ______921-84 Log #126

______Kevin Crawford, Thornton, CO Add new text as follows: Most fire patterns will exhibit a combination of movement and intensity patterns described above. The fire investigator will need to define and distinguish the difference between the two types of patterns in order to determine the correct area or point of origin. Failure to distinguish the difference may lead the investigator to an incorrect area or point of origin. The investigator should be aware of the impact each type of pattern has on the other. Rarely will movement and intensity patterns be individualized and in most fires both will be present and must be identified properly by the investigator in order to properly identify the true area of origin. As the fire moves it may encounter new fuel packages which will burn with greater intensity than the area the fire moved from and thus could lead the investigator to wrongfully claim the new fuel package area the area of origin.

Revise text to read as follows: 6.4.1.3 Combination of Patterns. Most fire patterns will exhibit a combination of movement and intensity patterns described above. The fire investigator will need to define and distinguish the difference between the two types of patterns in order to determine the correct area or point of origin. Failure to distinguish the difference may lead the investigator to an incorrect area or point of origin. The investigator should be aware of the impact each type of pattern has on the other. 6.4.1.3 Combination of Patterns. Fire patterns may exhibit a combination of effects. The investigator should be aware of the influence each type of pattern may have on the other and the sequence of their production. Failure to consider these factors may lead the investigator to erroneous conclusions regarding fire dynamics. Structural and editorial changes to the proposed text better communicate the concept presented by the submitter.

Printed on 9/18/2009 91 Report on Proposals – November 2010 NFPA 921 ______921-85 Log #127

______Kevin Crawford, Thornton, CO Revise text as follows: … If necessary or possible, the investigator should verify the original approved drawings, the actual as-built condition, and the current building condition. This verification can be accomplished by requesting the original building plans from the local building department or the original architect, by an examination of the fire scene … similar houses or buildings … Building department and fire department inspectors are typically the last step in the verification process prior to occupancy of a home or other building. The inspectors would therefore be the last known valid approval for appropriate construction. Changes made after the inspections could very likely be non-code compliant. The original fire protection systems would have been designed (if they ever existed) for the original building.

Printed on 9/18/2009 92 Report on Proposals – November 2010 NFPA 921 ______921-86 Log #128

______Kevin Crawford, Thornton, CO Add new text as follows: When the investigator is comparing the original plans, the as-built plans, and the current construction careful attention should be given to the location of current walls and the current electrical wiring construction. Multiple times changes are made by new occupants of a building, commercial and residential. Wall reconfiguration and wiring changes/additions are the most often changes made by an occupant without gaining required construction permits. Changes made after the last inspections could very likely be non-code compliant. Multiple changes need to be accounted for in anticipation of assignment of responsibility.

Revise text to read as follows: 7.2.2.6.1 Common Construction Changes. When the investigator is comparing the original plans, the as-built plans, and the current construction, careful attention should be given to the location of current walls and the current electrical wiring construction as these are often changed without required permits. The Committee added the additional material, as reflected in the submitter’s substantiation.

Printed on 9/18/2009 93 Report on Proposals – November 2010 NFPA 921 ______921-87 Log #129

______Kevin Crawford, Thornton, CO Revise text as follows: … such as a steel partition. More intense burning may be masked by a material with a high thermal conductivity. Define for the fire investigator why knowing the thermal conductivity of a material is important to consider.

The additional wording does not reflect all the ideas that precede it. The comment may serve to limit the understanding of the effect of thermal conductivity.

Printed on 9/18/2009 94 Report on Proposals – November 2010 NFPA 921 ______921-88 Log #130

______Kevin Crawford, Thornton, CO Revise text as follows: A manufactured home is … connected to the required utilities. (See NFPA 501, “Standard on Manufactured Housing”) In the U.S. since…. Whenever possible to substantiate the NFPA codes they should reference internally as well as externally.

Printed on 9/18/2009 95 Report on Proposals – November 2010 NFPA 921 ______921-89 Log #29

______Michael McGuire, EFI Global Add new text to read as follows: This section needs some discussion of possible locations of an open neutral. Locations such as: XFMR neutral, panel board neutral, utility splices, etc. should be mentioned.

Figure 8.5.2 actually shows an open ground not neutral. Compare to Figure 8.3.2.1(a). The only difference between the two is a break in the grounding conductor.

Submitter provides no text.

Printed on 9/18/2009 96 Report on Proposals – November 2010 NFPA 921 ______921-90 Log #132

______Kevin Crawford, Thornton, CO Revise text as follows: Depending on the receptacle style, line hot and neutral wires…Some outlets have push-in terminals for the line hot and neutral conductors… The term ‘line’ is not one of the terms defined previously. 8.3.2.1.2 defines Changing the term here from ‘line’ to ‘hot’ maintains consistency in the document.

Printed on 9/18/2009 97 Report on Proposals – November 2010 NFPA 921 ______921-91 Log #133

______Kevin Crawford, Thornton, CO Revise text as follows: … the hot conductor (commonly usually black or red but may be any another color such as red, but necessarily not except green, white, gray, or bare) should be connected… The positive wording “necessarily not” could be confused with the allowable wording “not necessarily” and thus construed to mean white, green, or bare are acceptable as the hot conductor. This change also maintains consistency with the wording in 8.7.5.1.2 and NFPA 70-310.12

Printed on 9/18/2009 98 Report on Proposals – November 2010 NFPA 921 ______921-92 Log #131

______Kevin Crawford, Thornton, CO Add new text as follows: If a nail is misdriven through the wire insulation and makes contact with the only the hot conductor and an ungrounded metal substrate (such as construction flashing) the metal substrate may become energized with the potential of the hot conductor. Other subsequent remote contacts with the metal substrate may complete the circuit. Most occasions in which the circuit is completed the overcurrent protection device will activate and open the circuit stopping any subsequent heating. If the connection between the metal substrate and the ground is weak the connection may heat and over time cause ignition to surrounding ignitable material. A misdriven staple will not likely carry sufficient current before melting to create the remote heating. This is the confirmed cause in one fire and suspected cause in a second in the same building complex. 8.11.8 does not make mention of a nail or staple contacting only the hot conductor and a metal substrate such as flashing or wire mesh. A weak or loose connection between the metal substrate and any ground point will act very similar to the loose connection described in 8.10.4 causing that weak or loose ground to heat resulting in thermal damage and charring of materials adjacent to the loose connection.

The submitter provides no technical basis for proposed new text.

Printed on 9/18/2009 99 Report on Proposals – November 2010 NFPA 921 ______921-93 Log #124

______Kevin Crawford, Thornton, CO Add new text as follows: Due to factors such as corrosion and earth settlement and shifting the investigator should not take the conditions of bonding or ground for granted. Conditions such as those listed can greatly affect the original state of the ground. Specific electrical testing should be conducted to confirm the bonding or grounding conditions if the area has a history of ground movement or the investigator sees any such indications of ground settlement. In regions where soils move and settle or where the construction of buildings has settled the ground or bond may easily be broken or otherwise not properly grounded or bonded.

Revise text to read as follows:: 8.12.5.2.3.1 Due to factors such as corrosion and earth settlement or and shifting, the investigator should not take the conditions of bonding or ground for granted. Conditions such as those listed can greatly affect the original state of the ground path. Specific electrical testing should be conducted to confirm the bonding or grounding conditions. if the area has a history of ground movement or the investigator sees any such indications of ground settlement. Delete proposed text and insert a second sentence into 8.12.5.2.3 to read: Many factors such as corrosion and earth settlement or shifting can greatly affect the original state of the ground path.

The committee believes these examples point out some factors that can affect the ground path and other concepts are already covered in existing text.

Printed on 9/18/2009 100 Report on Proposals – November 2010 NFPA 921 ______921-94 Log #63

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add the phrase “and explosions” after the word “fire” in the 3rd sentence. The paragraph to read: “They can also be fuel sources for fires and explosions in these structures.” These gases can fuel both fires and explosions.

Printed on 9/18/2009 101 Report on Proposals – November 2010 NFPA 921 ______921-95 Log #64

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add citation at the end of the paragraph: ( ) A Citation is needed here.

Printed on 9/18/2009 102 Report on Proposals – November 2010 NFPA 921 ______921-96 Log #86

______David M. Smith, Associated Fire Consultants Revise text to read as follows: 9.2.4.1 Specialized chemical detectors called stain tubes can be used in the field, and gas chromatography can be used, on other than natural gas samples, as a lab test for more accurate results. The proposed text is accurate and resolves the conflict present within 9.2.4.3. "Laboratory testing of gas samples is not generally adequate to determine the effective level of odorant in a natural gas sample.

Printed on 9/18/2009 103 Report on Proposals – November 2010 NFPA 921 ______921-97 Log #19

______James Mazerat, Unified Investigations Add new text as follows: The accuracy of a proposed hypothesis, which states that the failure in the detection of an odorant used to supply a warning of fugitive gases was primarily due to a lack of odorant, must include specific research into a person involved ability to detect odors due to the person’s age, health and exposure to chemicals. All or any of these conditions can compromise the accuracy and the ability of a person’s process to detect and identify odors. All indications suggest that these physical conditions, attributed directly to the person’s lack of physical ability to detect and identify specific odors, and can contribute to an increase fire related safety hazard for the individuals using either Natural or LP gas. This information direct the investigator to not just rely on the testing of the odorant to reach a conclusion as to why the gas was not detected but also to consider the human factors.

The Committee does not believe the proposed text adds to the existing text. This is a complex issue and research references would be required to substantiate a general statement of this nature.

Printed on 9/18/2009 104 Report on Proposals – November 2010 NFPA 921 ______921-98 Log #21

______James Mazerat, Unified Investigations Add new text as follows: When evaluating the operation of detector used to detector propane leaks or attempting to locate the source of ignition it is important that the investigator be aware of the difference between a gas leaks versus gas escaping from an unlit open burner. Pure propane vapors from a leaking pipe or gas fitting is heavier than air and will build up their heaviest concentration at the leak and if undisturbed, will float down until they mix with air. Gas from an open burner will dissipate into the air. When mixed with air, the gas becomes only marginally heavier than air and will expand outward. If a gas burner is left on, the area around the discharge will be considerable and may be in the ignitable range. This condition, of the gas not settling, will exist for an extended period of time. Eventually the higher concentration of gas will settle to lower levels. Depending on the location of available sources of ignition this can cause a delay in both detection and ignition. There is a difference in how the gas will react base on the flow being a laminar or turbulent flow. Many investigators are under the belief that there is no affect of the weight of the LP gas where it is discharged through an open pipe or the burner on the stove. Testing conducted by manufacture of LP gas detectors and provided in the safety pamphlets indicates this hypothesis is not supported through the testing conducted by these companies. The user of the product the results of the testing which indicates there is a difference caused by the discharge of this gas, be it through an open pipe or a burner on a stove. The results of their testing are important in assisting the investigator in determining the source of the point of discharge of the gas.

The submitter seems to imply that propane escaping from an unlit burner is within the flammable range while the propane from a leak must be diluted to the flammable range. This is scientifically incorrect. The submitter is referred to the American Gas Association, Fundamentals of Gas Combustion; document XH0373, pages 20 and 21.

Printed on 9/18/2009 105 Report on Proposals – November 2010 NFPA 921 ______921-99 Log #88

______David M. Smith, Associated Fire Consultants Revise text to read as follows: 9.3.2 Pipelines used to distribute natural gas in centralized grid systems for use by residential and business customers are called or . Normal operating pressures in distribution main pipelines vary widely among gas utility companies in different geological areas. Pressures in distribution main pipelines seldom exceed 1035 kPa (150 psi) in high-pressure systems and are typically 414 kPa or less (60 psi or less). Rural distribution main systems which must deliver gas to more distant customers are necessarily at higher pressure than urban systems. A Main is a type of Distribution line. The proposed text revision resolves the conflict present between the existing text and the definitions of "Distribution Line" and "Main" within 49 CFR 192.3, stating: means a pipeline other than a gathering or transmission line. means a distribution line that serves as a common source of supply for more than one service line.

Editorial: the following text was not marked as new text: A Main is a type of Distribution line.

Printed on 9/18/2009 106 Report on Proposals – November 2010 NFPA 921 ______921-100 Log #87

______David M. Smith, Associated Fire Consultants New text to read as follows: 9.3.3 A service Line is a type of distribution Line. The proposed addition of text clarifies the relationship of Service Lines and Main Lines to Distribution Lines as reflected in 49 CFR 192.3.

Printed on 9/18/2009 107 Report on Proposals – November 2010 NFPA 921 ______921-101 Log #89

______David M. Smith, Associated Fire Consultants Delete text to read as follows: 9.3.4.1 Depending on local rules, gas meters may be considered to be part of the gas utility company's service line or the property of the gas customer. The existing text is inaccurate and in conflict with 49 CFR 192.3 indicating: means a distribution line that transports gas from a common source of supply to an individual customer, to two adjacent or adjoining residential or small commercial customers, or to multiple residential or small commercial customers served through a meter header or manifold. A service line ends at the outlet of the customer meter or at the connection to a customer's piping, whichever is further downstream, or at the connection to customer piping if there is no meter.

Printed on 9/18/2009 108 Report on Proposals – November 2010 NFPA 921 ______921-102 Log #65

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Change paragraph title to: “9.9 Investigating Fuel Gas Systems Incidents” Add additional text and figures so that the text reads as on the attached pages:

The investigation of building fuel gas incidents can be an extremely complicated, technical, scientific, and potentially dangerous task requiring specialized knowledge, training and experience. Investigators faced with the requirement to investigate a fuel gas incident scene that exceeds the resources available or is beyond their knowledge or expertise should secure the scene to preserve evidence and endeavor to obtain technical expertise and adequate resources to accomplish the scene investigation in a safe and correct manner. Such an analysis should be a systematic detailed examination of the fuel gas system. Each component of the system should be evaluated to determine whether, and to what extent, it operated, or failed, and to what extent it contributed to the fire or explosion. Measurements and diagrams necessary to an adequate analysis of a fuel gas system include details of the structure involved; the fuel gas delivery piping and equipment including piping materials, lengths, and sizes; as well as valves, connectors and fittings. These measurements and diagrams should include all of the piping system and components from the utilization equipment and appliances back to and including the fuel gas source (i.e. tank, cylinder, or main). Notations should be made of the various pressures and flow rates; obvious breaks in piping, and the positions and settings (open, closed) of valves and controls Diagrams can be made to an appropriate approximate scale or may be schematic or isometric in nature. ( )

Example of a scaled fuel gas piping diagram.

Example of a scaled isometric fuel gas piping diagram.

Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The section is about Investigating Fuel Gas Systems Incidents, not all just systems. Additional text and figures are needed to assist the reader with methods of investigating such incidents.

Note: The figures may need to be redrawn for clarity.

Printed on 9/18/2009 109

Report on Proposals – November 2010 NFPA 921 ______921-103 Log #20

______James Mazerat, Unified Investigations Add new text as follows: The LP-Gas being heavier than air with vapor density of about 1.5 for propane and 2.0 for butane, also tend to pocket within a structure, through at low levels. If these products are escaping from an open burner, where they are being mixed with air there will be a difference in the buoyancy. This difference can allow the gas to stay suspended at higher level for long periods of time. However, in the pure form of the product, the buoyant nature of their products of combustion when ignited prevents them from producing similar pocketing burn patterns as natural gas. Consideration must be give as to how the gas entered the atmosphere. The greater the turbulence at the point of entry the more mixture with the air and the longer the gas will remain suspended at higher levels, similar to natural gas. This is to better clarify information about LPG leaks and what the investigator can be expected see has taken place as to the location of sources of ignition and damage from pockets of burning gas at higher than expected levels. In cases where the gas came from unlit burners it would not be unusual to see damage patterns well above floor level. Substantiation of this condition is the results of the testing done by the manufacturers of the detectors used to detect leaking LPG and the companies using these detectors, such as Beaver Motor Coaches, Safe T Alert, a division of MTI Industries, CCI Control, manufacturer of LP gas detectors, and the warring pamphlets supplied by these companies.

The committee believes that the proposal is inappropriate for the paragraph cited and these issues are covered in existing text. See Sections 9.9, 9.9.3, 9.2.2.2, and 21.8.

Printed on 9/18/2009 110 Report on Proposals – November 2010 NFPA 921 ______921-104 Log #66

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add citation to the end of paragraph as follows: ( ), and Add Figure and caption after paragraph as seen on attached page.

***Insert Artwork Here***

Figure 9.9.4.2 Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. This figure will assist the reader in following the directions in the paragraph.

Insert new 9.9.7 with subsequent paragraphs being renumbered: Collection of Gas Piping When collecting gas piping, steps should be taken to maintain evidentiary value. Screw junctions, unions, tees, or elbows should not be unscrewed or tightened in order to isolate a section. Doing so may destroy evidence of previously existing poor connections. Longitudinal witness marks should be placed on every joint and cut site to ensure accurate reconstruction of the spatial relationship of the piping. (See figure 9.9.7) Caption is supposed to say Figure 9.9.7 9.9.4.1.2 A method of intrusive, non destructive marking and cutting of fuel gas pipes in a manner that the relationships of the severed cut ends will be recorded. See diagram provided for proposed changes. Witness mark is to be inserted into every drawing in this section.

Committee believes this modified text is best placed in a new section addressing evidence collection. This figure will assist the reader in following the directions in the paragraph.

Printed on 9/18/2009 111

3. Proposal

A A

FIGURE 9.9.4.2.

Report on Proposals – November 2010 NFPA 921 ______921-105 Log #67

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add citation at the end of the paragraph: ( ) and Add Photo and caption as shown on attached page

***Insert Artwork Here***

Figure 9.9.5.1 Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. This figure will assist the reader in understanding the paragraph.

Printed on 9/18/2009 112

FIGURE 9.9.5.1 Bubble test of leaking fuel gas piping “T” fitting.

Report on Proposals – November 2010 NFPA 921 ______921-106 Log #68

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Add wording to paragraph, including citation to new photo. Add new photo and caption as displayed on the attached pages: If regulators or other gas appliance and service components have not been severely damaged by fire, they can be tested to see whether they are functioning correctly. These tests can be conducted with a variety of gases, including air, natural gas, propane, or butane). With the use of proper laboratory or field equipment, both lockup and flow pressures, as well as normal or leak flow rates, can be determined. In such tests, the resultant data must be adjusted from the test medium gas to the gases for which the devices were designed. These adjustments are based on the relative vapor densities of the gases.

***Insert Artwork Here***

Example of field equipment for testing flow rate (five gauges on left) and line pressure (digital manometer on right) Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. Both non-flammable and actual fuel gases themselves are commonly used for pressure and flow testing. These additions will assist the reader in understanding the paragraph.

Revise text to read as follows: 9.9.6 Testing Flow Rates and Pressures. If regulators or other gas appliance and service components have not been severely damaged by fire, they can be tested to see whether they are functioning correctly. These tests can be conducted with a variety of non-flammable and flammable gases, including air, nitrogen, helium, or the actual fuel gases for the system (i.e. natural gas, propane, or butane). When flammable gases are used, be sure to eliminate all ignition sources. With the use of proper laboratory or field equipment, both lockup and flow pressures, as well as normal or leak flow rates, can be determined. In such tests, the resultant data must be adjusted from the test medium gas to the gases for which the test devices were designed. These adjustments are based on the relative vapor densities of the gases. (see Figure 9.9.6)

***Insert Figure Here*** FIGURE 9.9.6 Example of field equipment for testing flow rate (five gauges meters on left) and line pressure (digital manometer on right) Added text clarifies the content and safety.

Printed on 9/18/2009 113

FIGURE 9.9.6 Example of field equipment for testing flow rate (five gauges on left) and line pressure (digital manometer on right) Report on Proposals – November 2010 NFPA 921 ______921-107 Log #69

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add citation for new figures, ( ), and new figures and captions at the end of the paragraph, as on the attached page.

***Insert Artwork Here***

Figure 9.9.7.1.1(a)

***Insert Artwork Here***

Figure 9.9.7.1.1(b) Figures will help the reader understand the paragraph.

Source: The U. S. Department of Transportation's (DOT) Pipeline and Hazardous Material Safety Administration (PHMSA), Office of Pipeline Safety (OPS)) [government publication not copyrighted]

Insert the missing captions and changes as follows:

Figure 9.9.7.1.1 (a) Leaking Gas following migrating along the sewer line into the home, after leaking at the service tee. Natural gas can migrate in this manner. (source: The U. S. Department of Transportation (DOT) Pipeline Hazardous Material Safety Administration (PHMSA), Office of Pipeline Safety (OPS)

Figure 9.9.7.1.1(b) (not shown, change in text only)

An example of how a gas leak can get into a sewer system. (source: The U. S. Department of Transportation (DOT) Pipeline Hazardous Material Safety Administration (PHMSA), Office of Pipeline Safety (OPS)

Edits to figures: Add an arrow showing source of leak and insert a bell joint on the sewer line above (in proximity) the hole (Kennedy to provide new figures)

Edited text clarifies the content.

Printed on 9/18/2009 115

Figure 9.9.7.1.1 (a)

Figure 9.9.7.1.1 (b)

Report on Proposals – November 2010 NFPA 921 ______921-108 Log #90

______David M. Smith, Associated Fire Consultants Delete text to read as follows: 9.9.7.2(B) A decrease in pressure in the system, which increases gas flow rates, easily remedies this problem. The existing text implies that decreasing pressure in a gas system is "easily accomplished" by a utility. this assumption is inaccurate as that action may require extensive manpower, specialized engineering software and equipment (including portable gas tanks to supplement the system). A decrease in pressure within a system leads to customer outages of those furthest from the high-pressure tap. Note: Supporting material is available for review at NFPA Headquarters.

The word easily was supposed to be a strike through instead of underline 9.9.7.2(B) A decrease in pressure in the system, which increases gas flow rates, easily remedies this problem. Delete the last three sentences of existing text 9.9.7.2(B).

The additional removal of wording clarifies and corrects the paragraph.

Printed on 9/18/2009 116

Report on Proposals – November 2010 NFPA 921 ______921-109 Log #120

______George A. Codding, Louisville Fire Dept. New text to read as follows: The person in lawful control of the property can grant the investigator permission or consent to enter and remain on the property. This is a voluntary act on the part of the responsible person and can be withdrawn at any time by that person. When consent is granted, the investigator should document it. One effective method is to have the person in lawful control sign a written consent form. The investigator may choose to make enquiries to ensure that the person giving consent has lawful control of the property. For example, if a tenant has rights to control leased property under a rental agreement, the property owner (landlord) may not have the immediate right to access that property, and may therefore lack the power to consent. The section correctly states that consent may be given by a person in lawful control of property. However, investigators are well advised to make simple inquiries to assure that the consenting person has the legal power to grant consent. The proposed language reminds the investigator to consider the status of the consenting person, to help avoid a common pitfall that could void a search. The landlord/tenant example is discussed in 365 U.S. 610, 81 S.Ct. 776 (1961), where the court held that a landlord did not have the authority to consent to law enforcement agents’ entry onto leased premises.

Make an editorial change as follows: 11.3.3.1 Consent. The person in lawful control of the property can grant the investigator permission or consent to enter and remain on the property. This is a voluntary act on the part of the responsible person and can be withdrawn at any time by that person. When consent is granted, the investigator should document it. One effective method is to have the person in lawful control sign a written consent form. The investigator may choose to make einquiries to ensure that the person giving consent has lawful control of the property. For example, if a tenant has rights to control leased property under a rental agreement, the property owner (landlord) may not have the immediate right to access that property, and may therefore lack the power to consent.

Printed on 9/18/2009 117 Report on Proposals – November 2010 NFPA 921 ______921-110 Log #122

______George A. Codding, Louisville Fire Dept. Revise text to read as follows: 11.3.3.3.1 The purpose of an administrative search warrant is generally to allow those charged with the responsibility, by ordinance or statute, to investigate the origin and cause of a fire and to fulfill their obligation according to the law. An administrative search warrant may be obtained from a court of competent jurisdiction upon a showing that consent has not been granted or has been denied. Unlike a criminal search warrant, the administrative warrant need not be supported by "probable cause" that a crime has been committed; instead, probable cause is based on a showing that the proposed It is not issued on the traditional showing of “probable cause,” as is the criminal search warrant, although it is still necessary to demonstrate that the search is reasonable. The search should be justified by showing of justified by a reasonable governmental interest, and supported by a statute, ordinance, or regulation. If a valid public interest justifies the instruction, then valid and reasonable probable cause has been demonstrated. For an administrative search warrant to issue, the requested search must be supported by a valid statute, ordinance, or regulation. E.g. 387 U.S. 523, 538-39, 87 S.Ct.1727 (1967); 436 U.S. 307, 323, 98 S.Ct. 1816 (1978). Although the regulation need not expressly provide for the issuance of an administrative warrant, it must provide for governmental inspection and/or entry to advance legitimate governmental needs under enumerated circumstances. Although the first sentence of this section alludes to this important prerequisite, it should be spelled out since it is a necessary foundation for an administrative warrant. The proposed language also may provide a clearer statement of the requirements for a warrant, and clarifies the probable cause concept (although traditional criminal probable cause is not the legal standard for the issuance of an administrative warrant, nonetheless the Fourth Amendment does say that “probable cause” must exist for a search to be valid).

Revise text to read as follows: 11.3.3.3.1 The purpose of an administrative search warrant is generally to allow those charged with the responsibility, by ordinance or statute, to investigate the origin and cause of a fire and to fulfill their obligation according to the law. An administrative search warrant may be obtained from a court of competent jurisdiction upon a showing that consent has not been granted or has been denied. Unlike a criminal search warrant, the administrative warrant need not be supported by "probable cause" that a crime has been committed; Instead, probable cause is based on a showing that the proposed It is not issued on the traditional showing of “probable cause,” as is the criminal search warrant, although it is still necessary to demonstrate that the search is reasonable. The search should be justified by showing of justified by a reasonable governmental interest, and supported by a statute, ordinance, or regulation. If a valid public interest justifies the intrusion instruction, then valid and reasonable probable cause has been demonstrated. Editorial: instruction is intrusion in the existing text. Based on submitter’s substantiation, current text is accurate however additional text accepted by the committee clarifies the issue.

Printed on 9/18/2009 118 Report on Proposals – November 2010 NFPA 921 ______921-111 Log #121

______George A. Codding, Louisville Fire Dept. Revise text to read as follows: In light of the criminal charges that can be made as a result of a fire, the government investigator should ascertain whether they are required to advise the person being questioned of his or her “Miranda rights” and if so, when and how to advise of those rights. The person being questioned should be advised of the following if the interrogation is conducted in a custodial setting. by an investigator who represents a governmental agency or who is acting at the request of government investigators. This part of the chapter discusses some legal standards that apply to all investigators, and some that only apply to government investigators. The Miranda custodial interrogation legal analysis only applies to governmental investigators 384 U.S. 436 at p. 444), and undoubtedly to those acting at their behest. Some potential confusion could be avoided by stating this explicitly.

Revise text to read as follows: 11.3.4.1 In light of the criminal charges that can be made as a result of a fire, the government investigator should ascertain whether they are required to advise the person being questioned of his or her “Miranda rights” and if so, when and how to advise of those rights. The person being questioned should be advised of the following if the interrogation is conducted in a custodial setting. by an investigator who represents a governmental agency or who is acting at the request of government investigators.

The deleted word “government” limits the responsibility to only government investigators when it applies to all investigators.

Printed on 9/18/2009 119 Report on Proposals – November 2010 NFPA 921 ______921-112 Log #70

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Delete “by Persons Other Than Public Authorities” from the title of the paragraph. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep a pace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The text of this section applies to all fire investigators in general. NFPA 921 is designed and intended for all fire investigators. The issue to which this section applies, the unfair limitation of full access to the evidentiary value of items of physical evidence by subsequent investigators, is largely necessary because of the abuses of public sector, without apparent regard for the rights of other interested parties. Public authorities are equally liable for compliance with the legal standards of this section, compliance with the cited ASTM Forensic Standards, spoliation or misconduct with reference to the handling of evidence as any fire investigator. The current text does not even mention public authorities, why they may not be held to the same high moral, ethical, and legal standards as the private sector, or in what circumstances they will not be sanctioned to evidentiary nonfeasance or malfeasance. NFPA 921 should not be an apologist for the unprofessional, inappropriate activities of any one sector of its audience.

Change the title as submitter proposed. Insert in 11.3.5.7 after the word testing and before the sentence starting with Guidance. Making this the third and fourth sentence in that section. This section is not intended to apply to evidence collected as part of a criminal investigation. Once the evidence is no longer required for a criminal investigation it should be appropriately released.

The committee believes that the change of title accompanied the exception is appropriate.

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______George A. Codding, Louisville Fire Dept. Revise text to read as follows: Between the time an investigation is concluded and the time the matter comes to trial, there may be legal proceedings in which information and documents are exchanged between parties, testimony is taken, and admissions are requested. These proceedings can be categorized as "discovery." They serve to assist the parties to prepare their cases, to understand the evidence and facts possessed by the other parties, and to evaluate their cases for potential settlement when appropriate. to determine whether a case should go to trial, and if so, what objects, documents, facts, or opinions will be allowed as evidence. Many of these proceedings can be categorized as “discovery.” These proceedings occur primarily in civil cases, but may be available in criminal cases in some jurisdictions. While discovery is governed by legal rules, there is usually not a judge involved in this part of the litigation, unless the parties are unable to resolve a particular issue. Other pre-trial issues may involve a judge or magistrate who may issue advance rulings on what objects, documents, facts, or opinions will be allowed at evidence at trial. A majority of the sections·under this heading discuss the discovery process: Therefore, the introduction section should emphasize discovery and set it apart from pre-trial motions practice. As currently stated, the section suggests that pretrial motions (the determination of what will be allowed as evidence) are "discovery" and are not presided over by a judge. In fact, a judge or magistrate is typically involved in the determination of pre-trial motions. This proposed language gives a more accurate description of the goals of discovery, which occurs between the parties without the involvement of the judge, and eliminates confusing language that blends discovery with pre-trial motions practice.

Editorial change in last sentence as follows: 11.4.1 Introduction. Between the time an investigation is concluded and the time the matter comes to trial, there may be legal proceedings in which information and documents are exchanged between parties, testimony is taken, and admissions are requested. These proceedings can be categorized as "discovery." They serve to assist the parties to prepare their cases, to understand the evidence and facts possessed by the other parties, and to evaluate their cases for potential settlement when appropriate. to determine whether a case should go to trial, and if so, what objects, documents, facts, or opinions will be allowed as evidence. Many of these proceedings can be categorized as “discovery.” These proceedings occur primarily in civil cases, but may be available in criminal cases in some jurisdictions. While discovery is governed by legal rules, there is usually not a judge involved in this part of the litigation, unless the parties are unable to resolve a particular issue. Other pre-trial issues may involve a judge or magistrate who may issue advance rulings on what objects, documents, facts, or opinions will be allowed as evidence at trial.

Printed on 9/18/2009 121 Report on Proposals – November 2010 NFPA 921 ______921-114 Log #23

______Joseph E. Boisseau, City of Colonial Heights Fire & EMS Revise text as follows: I recommend that Chapter 12 Safety be moved to Chapter 3 of 921. Safety is an important part of the job and often overlooked. In order to conduct any fire or explosive scene we must know the safety aspects first.

Manual of style as dictated by NFPA will not allow moving to Chapter 3 since this is reserved for definitions.

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______Ronald L. Hopkins, Eastern Kentucky University

Fire scenes, by their nature, are dangerous places. Fire investigators have a duty to themselves and to others such as other investigators, equipment operators, laborers, property owners who may be endangered at fire scenes during the investigation. This chapter will provide the investigator with some basic recommendations concerning a variety of safety issues, including personal protective equipment (PPE). It should be noted, however, that the investigator should be aware of and follow the requirements of safety-related laws (OSHA, federal, or state) or those policies and procedures established by their agency, company, or organization. Additionally, a first aid kit should be present at all fire scenes and the location of the nearest hospital/trauma center should be identified prior to beginning the scene examination.

Fire scenes, by their nature, are dangerous places. Fire investigators have a duty to themselves and to others (such as other investigators, equipment operators, laborers, property owners, attorney’s) who may be endangered at fire scenes during the investigative process. This chapter will provide the investigator with some basic recommendations concerning a variety of safety issues, including personal protective equipment (PPE). It should be noted, however, that the investigator should be aware of and follow the requirements of safety-related laws (OSHA: federal or state) or those policies and procedures established by their agency, company, or organization. For additional information concerning safety requirements or training, see appropriate local, state, or federal occupational safety and health regulations and Munday, J. W. Safety at Scenes of Fire and Related Incidents. London: Fire Protection Association, 1994. Donahue, M. “Safety and Health Guidelines for Fire and Explosion Investigators,” Stillwater, OK: Fire Protection Publications, International Fire Service Training Association, Oklahoma State University, 2002. The fireground atmosphere encountered by fire and explosion investigators as part of their normal work routine changes rapidly with time, may contain a combination of multiple respiratory hazards, and is often (IDLH). The inhalation of harmful dusts, toxic gases, and vapors at fire and explosion scenes is a common hazard to investigators who typically arrive to initiate their investigation after fire suppression and overhaul operations are completed. Many researchers have assessed the extent to which firefighters are exposed to hazardous substances during extinguishment activities. These studies set the foundation upon which better protective standards for fire investigators can be developed and present issues related to short-term and long-term health effects. Examples of such studies are described in A – C. In 1998, the Phoenix (Arizona) Fire Department conducted a comprehensive air monitoring study designed to characterize firefighter exposures during overhaul operations. The study concluded that numerous concentrations of toxic air contaminants were present during fire overhaul that exceeded occupational permissible exposure limits (PELs). The researchers found that without the use of respiratory protection, firefighters were exposed to these irritants, chemical asphyxiants and carcinogens. A National Fire Protection Association study tallied an average of 4,585 injuries per year related to smoke inhalation, gas inhalation, and respiratory distress in firefighters between 1996 and 2006. In 2006, researchers from the University of Cincinnati, College of Medicine compiled data from over 32 studies that investigated the propensity of firefighters to develop cancer and found that firefighters had probable cancer risks for multiple myeloma, non-Hodgkin’s lymphoma, and prostate and testicular cancers. Although limited, some research has attempted to quantify the hazards present during the investigation of fires. The National Institute for Occupational Safety and Health (NIOSH) in conjunction with the Alcohol, Tobacco, and Firearms Fire Investigation Division recognized the hazards of overhaul operations from fire investigators sifting through debris in a 1998 health hazard evaluation report, and in 2004, published the results of study regarding fire scene uniform contaminations. The 1998 study quantified compounds present at fire scenes post-fire extinguishment. Although in low concentrations, compounds detected included; dusts, aliphatic hydrocarbons, acetone, acetic acid, ethyl acetate, isopropanol, styrene, benzene, toluene, xylene, furfural, phenol, and naphthalene. PAHs with carcinogenic potential included benz(a)anthracene, benzo(b)fluoranthene, and benzo(a)pyrene. While all of the previous compounds were found at levels, below NIOSH recommended exposure limits, formaldehyde was found in concentrations nearly twice as high as its limit of 0.1 ppm.

Printed on 9/18/2009 123 Report on Proposals – November 2010 NFPA 921 The 2004 study quantified the hazards presented to investigators and their families due to contamination of their clothing during fire scene investigations. Researchers found a potential for contamination of other clothing washed with the soiled uniforms. Based on the report findings, they researchers recommended that protective clothing should be worn during fire scene investigations, and to reduce the potential for carrying contaminants home, investigators should use disposable coveralls, or the use of a professional laundry service. . All public and private sector employers have a responsibility to provide a “safe” workplace and to protect their employees from recognized hazards, as required under the of the Occupational Safety and Health (OSH) Act of 1970. Investigators and their employers are expected to comply with all OSHA regulations, standards, and practices applicable to the tasks and activities conducted at their workplace, which most often will be at fire and explosion scenes. The key to compliance with occupational safety and health regulations and the foundation of an organization’s standard operating procedures, policies and employee training programs is a comprehensive written . OSHA has identified five critical elements that have consistently proven successful in helping organizations reduce the incidence of occupational injuries, illnesses, and fatalities and that are necessary to develop and implement an effective fire investigator occupational safety and health program. . Organizations must have a clearly articulated written safety and health policy statement that is understood by all personnel. It is critical that understand the priority of safety and health protection in relation to other organizational values. Identifying potential hazards at a fire or explosion scene requires an active, ongoing examination and analysis of work processes, practices, procedures, equipment, and working conditions. Identifying hazards not only helps to determine the appropriate level of personal protective clothing and equipment (PPE) needed to adequately protect investigators, but it also can be used to identify appropriate training and education needs. This is based on the determination that a potential hazard exists at scene. Hazards are either eliminated or managed by the implementation of SOPs and work practices that outline effective engineering controls and PPE. This process provides for the systematic identification, evaluation, prevention, and control of general workplace hazards and less obvious hazards that may arise during on-site activities. An effective training and education program addresses the safety and health responsibilities of all personnel throughout the organization, including supervisors. Agencies should consider integrating some aspect of safety and health training and education into all organizational training and education activities to reinforce the importance of safety. Management and employees must make a serious commitment to sustain the organization’s safety and health program and make it a key priority. Without this level of commitment, the safety and health program is doomed for failure. Organizations should reach out and continually look for new and improved practices, methods, programs, technology, and equipment specifically tailored to the duties and responsibilities of investigators. An effective includes provisions for the systematic identification, evaluation, and prevention or control of general workplace hazards and less obvious hazards that may arise during on-site activities. Investigators should refer to NFPA 1500 – S for specific guidance on developing an effective risk management / health and safety program for their organization.

Add the following to Annex C as they are the sources for 12.1 Bolstad-Johnson, Dawn M., et. al, , Phoenix Fire Department / University of Arizona Prevention Center / Arizona State University, 1998. Grant, C., “Respiratory Exposure Study for Fire Fighters And Other Emergency Responders”, The Fire Protection Research Foundation, National Fire Protection Association, Quincy, MA, December 2007. LeMasters, G., Genaidy, A., Succop, P., et al, “Cancer Risk Among Firefighters: A Review and Meta-Analysis of 32 Studies”, , Volume 48, Number 11, November 2006, pp. 1189-1202. Kinnes, G., Hine, G., Health Hazard Evaluation Report 96-0171-2692, Bureau of Alcohol, Tobacco, and Firearms, Washington, D.C, May 1998. Snyder, E., Health Hazard Evaluation Report 2004-0368-3030, Bureau of Alcohol, Tobacco, Firearms and Explosives, Austin, TX, January 2007. This material was developed as a part of the Safety Committee Task Group work and it provides the user with valuable information and resources concerning occupational health research and better states the need to utilize existing laws concerning safety and the workplace and establish a management system for their safety and health Printed on 9/18/2009 124 Report on Proposals – November 2010 NFPA 921 program.

Revise text to read as follows: 12.1* General. Fire scenes, by their nature, are dangerous places. Fire investigators have an obligation duty to themselves and perhaps to others (such as other investigators, equipment operators, laborers, property owners, attorney’s) who may be endangered at fire scenes during the investigative process. This chapter will provide the investigator with some basic recommendations concerning a variety of safety issues, including personal protective equipment (PPE). It should be noted, however, that the investigator should be aware of and follow the applicable requirements of safety-related laws (OSHA: federal or state) or those policies and procedures established by their agency, company, or organization. A.12.1 For additional information concerning safety requirements or training, see appropriate local, state, or federal occupational safety and health regulations and Munday, J. W. Safety at Scenes of Fire and Related Incidents. London: Fire Protection Association, 1994. Donahue, M. “Safety and Health Guidelines for Fire and Explosion Investigators,” Stillwater, OK: Fire Protection Publications, International Fire Service Training Association, Oklahoma State University, 2002. 12.1.1* General Injury/Health Statistics. The fireground atmosphere encountered by fire and explosion investigators as part of their normal work routine changes rapidly with time, may contain a combination of multiple respiratory hazards, and is often can be Immediately Dangerous to Life and Health (IDLH). The inhalation of harmful dusts, toxic gases, and vapors at fire and explosion scenes is a common hazard to investigators who typically arrive to initiate their investigation after fire suppression and overhaul operations are completed. A 12.1.1 NTIS Publication number PB-94-195047, May 1994 12.1.1.21* Many researchers have assessed the extent to which firefighters are exposed to hazardous substances during extinguishment activities. These studies set the foundation upon which better protective standards for fire investigators can be developed and present issues related to short-term and long-term health effects. A.12.1.1.21 Examples of such studies are described in A – C. (A) In 1998, the Phoenix (Arizona) Fire Department conducted a comprehensive air monitoring study designed to characterize firefighter exposures during overhaul operations. The study concluded that numerous concentrations of toxic air contaminants were present during fire overhaul that exceeded occupational permissible exposure limits (PELs). The researchers found that without the use of respiratory protection, firefighters were exposed to these irritants, chemical asphyxiants and carcinogens. (B) A National Fire Protection Association study tallied an average of 4,585 injuries per year related to smoke inhalation, gas inhalation, and respiratory distress in firefighters between 1996 and 2006. (C) In 2006, researchers from the University of Cincinnati, College of Medicine compiled data from over 32 studies that investigated the propensity of firefighters to develop cancer and found that firefighters had probable cancer risks for multiple myeloma, non-Hodgkin’s lymphoma, and prostate and testicular cancers. 12.1.1.32 Although limited, some research has attempted to quantify the hazards present during the investigation of fires. The National Institute for Occupational Safety and Health (NIOSH) in conjunction with the Bureau of Alcohol, Tobacco, and Firearms and Explosives Fire Investigation Division recognized the hazards of overhaul operations from fire investigators sifting through debris in a 1998 health hazard evaluation report, and in 20047, published the results of a study regarding contamination of clothing exposed at fire scenes uniform contaminations. 12.1.1.32.1 The 1998 study quantified compounds present at fire scenes post-fire extinguishment. Although in low concentrations, compounds detected included; dusts, aliphatic hydrocarbons, acetone, acetic acid, ethyl acetate, isopropanol, styrene, benzene, toluene, xylene, furfural, phenol, and naphthalene. Polycyclic Aromatic Hydrocarbons (PAHs) with carcinogenic potential included benz(a)anthracene, benzo(b)fluoranthene, and benzo(a)pyrene. While all of the previous compounds were found at levels, below NIOSH recommended exposure limits, formaldehyde was found in concentrations nearly twice as high as its limit of 0.1 ppm. 12.1.1.32.2 The 2004 study quantified the hazards presented to investigators and their families due to contamination of their clothing during fire scene investigations. Researchers found a potential for contamination of other clothing washed with the soiled uniforms. Based on the report findings, they researchers recommended that protective clothing should be worn during fire scene investigations, and to reduce the potential for carrying contaminants home, investigators should use disposable coveralls, or the use of a specialty professional laundry service for this purpose. 12.1.2 Health and Safety Programs. All public and private sector employers have a responsibility to provide a “safe” workplace and to protect their employees from recognized hazards, as required under the General Duty Clause of the Occupational Safety and Health Administration (OSHA) Act of 1970. Investigators and their employers are expected to comply with all OSHA regulations, standards, and practices applicable to the tasks and activities conducted at their workplace, which most often will be at fire and explosion scenes. The key to compliance with occupational safety and health regulations and the foundation of an organization’s standard operating procedures, policies and employee Printed on 9/18/2009 125 Report on Proposals – November 2010 NFPA 921 training programs is a comprehensive written Occupational Safety and Health Program. 12.1.2.1 OSHA has identified five critical elements that have consistently proven successful in helping organizations reduce the incidence of occupational injuries, illnesses, and fatalities and that are necessary to develop and implement an effective fire investigator occupational safety and health program. 12.1.2.1.1 Management commitment and employee participation. Organizations must have a clearly articulated written safety and health policy statement that is understood by all personnel. It is critical that everyone understand the priority of safety and health protection in relation to other organizational values. 12.1.2.1.12 Hazard and risk assessment. Identifying potential hazards at a fire or explosion scene requires an active, ongoing examination and analysis of work processes, practices, procedures, equipment, and working conditions. Identifying hazards not only helps to determine the appropriate level of personal protective clothing and equipment (PPE) needed to adequately protect investigators, but it also can be used to identify appropriate training and education needs. 12.1.2.1.13 Hazard prevention and control. This is based on the determination that a potential hazard always exists at every scene. Hazards are either eliminated or managed by the implementation of SOPs and work practices that outline effective engineering controls and PPE. This process provides for the systematic identification, evaluation, prevention, and control of general workplace hazards and less obvious hazards that may arise during on-site activities. 12.1.2.1.14 Safety and health training and education. An effective training and education program addresses the safety and health responsibilities of all personnel throughout the organization, including supervisors. Agencies should consider integrating some aspect of safety and health training and education into all organizational training and education activities to reinforce the importance of safety. 12.1.2.1.15 Long-term commitment. Management and employees must make a serious commitment to sustain the organization’s safety and health program and make it a key priority. Without this level of commitment, the safety and health program is doomed for failure. Organizations should reach out and continually look for new and improved practices, methods, programs, technology, and equipment specifically tailored to the duties and responsibilities of investigators. 12.1.2.2 An effective Fire Investigator Occupational Safety and Health Program includes provisions for the systematic identification, evaluation, and prevention or control of general workplace hazards and less obvious hazards that may arise during on-site activities. Investigators should refer to NFPA 1500 – Standard on Fire Department Occupational Safety and Health Program for specific guidance on developing an effective risk management / health and safety program for their organization. Proposal 2 of 3 for Section 12.1: Renumber remaining sections Proposal 3 of 3 for Section 12.1: Add the following to Annex C as they are the sources for 12.1 Bolstad-Johnson, Dawn M., et. al, Characterization of Firefighter Exposures During Fire Overhaul, Phoenix Fire Department / University of Arizona Prevention Center / Arizona State University, 1998. Grant, C., “Respiratory Exposure Study for Fire Fighters And Other Emergency Responders”, The Fire Protection Research Foundation, National Fire Protection Association, Quincy, MA, December 2007. LeMasters, G., Genaidy, A., Succop, P., et al, “Cancer Risk Among Firefighters: A Review and Meta-Analysis of 32 Studies”, Journal of Occupational and Environmental Medicine, Volume 48, Number 11, November 2006, pp. 1189-1202. Kinnes, G., Hine, G., Health Hazard Evaluation Report 96-0171-2692, Bureau of Alcohol, Tobacco, and Firearms, Washington, D.C, May 1998. Snyder, E., Health Hazard Evaluation Report 2004-0368-3030, Bureau of Alcohol, Tobacco, Firearms and Explosives, Austin, TX, January 2007.

Changes better clarify the information provided. Paragraph numbering was corrected

Printed on 9/18/2009 126 Report on Proposals – November 2010 NFPA 921 ______921-116 Log #136

______Ronald L. Hopkins, Eastern Kentucky University Proposal Create New 12.2 and title it General Fire Scene Hazards, then move existing text as indicated to this section, re-number, and add or delete text as indicated. 12.1.4 The investigator should remain aware of the general and particular dangers of the scene under investigation. The investigator should keep in mind the potential for serious injury at any time and should not become complacent or take unnecessary risks. The need for this awareness is especially important when the structural stability of the scene is unknown or when the investigation requires that the investigator be working above or below ground level. 12.1.1 Fire scene examinations should not be undertaken alone. A minimum of two individuals should be present to ensure that assistance is at hand if an investigator should become trapped or injured. If the fire scene is investigated by one investigator, a clear communications protocol needs to be established between the site investigator and an off-site contact person. An estimated completion time should be established, and periodic contacts between the scene investigator and off-site contact person should be made at regular intervals. If it is impossible for the investigator to be accompanied, he or she should at least notify a responsible person of where the investigator will be and of when he or she can reasonably be expected to return. 12.1.6 12.1.6.1 12.2.2.1 It is common for investigators to put in long periods of strenuous personal labor during an incident scene investigation. This labor may result in fatigue, which can adversely influence an investigator’s physical coordination, strength, or judgment to recognize or respond to hazardous conditions or situations. Keep in mind that the use of heavy safety clothing and respiratory protection will further increase fatigue. 12.1.6.2 12.2.2.2 Periodic rest, fluid replacement, and nourishment should be provided in a safe atmosphere, remote from but convenient to the fire scene. Sanitation facilities that include a restroom and washing station are necessary on large or major incidents. The hazard to the fire investigator is not just through aspiration and absorption but also through ingestion, so it is essential that eating and drinking occur out of the scene after removal of contaminated gear and the washing of face and hands. Whenever the investigator has to work above or below grade levels they should be aware of the special hazards that may be present. 12.2.5 Standing Water. 12.2.5.1 12.2.3.1 Standing water in basements can pose a variety of dangers to the investigator. Puddles of water in the presence of energized electrical systems can be lethal if the investigator should touch an energized wire, ungrounded appliance, or other piece of equipment while standing in a puddle water. 12.2.5.2 12.2.3.2 Pools of water that may appear to be only inches deep may in fact be well over the investigator’s head. Pools of water may also conceal hidden danger such as holes or dangerous objects that may trip or otherwise injure the investigator. 12.2.3.3 Air quality of basement or underground areas may require atmospheric testing. The testing should determine the oxygen concentration or evaluate other potential atmospheric conditions that are suspected. 12.2.3.4 When working above grade, the investigator should consider the need for appropriate fall protection equipment. Requirements of the OSHA (State or Federal) regulations for fall protection and fall protection trigger heights should be consulted and followed. 12.2.3.5 When working from any aerial platform the investigator should determine if that platform or piece of equipment has been designed (labeled) for use by people. Equipment not designated for use by people should not be used. 12.2.4 Working around Mechanized Equipment. The utilization of heavy and mechanized equipment at the fire or explosion scene present unique issues and concerns for both those investigators that are present and the overall scene safety. 12.2.4.1 When mechanized equipment is in use the area should be isolated by barricades to prevent entry into that area or if investigators are required to be in that area they should wear appropriate high visibility vests or clothing and a safety monitor that will communicate with the operator and worn investigators of changing hazards or conditions should be present. 12.2.4.2 The swing areas of cranes and the path that will be taken to remove debris should be identified and barricaded to prevent entry and potential injury. No one should work under a load that is being moved by a crane.

12.2.6.1 12.2.5.1 Fire and explosion scenes always generate the interest of bystanders. Their safety, as well as the

Printed on 9/18/2009 127 Report on Proposals – November 2010 NFPA 921 security of the scene and its evidence, should be addressed by the investigator. 12.2.6.2 12.2.5.2 The investigation scene should be secured from entry by curious bystanders. This security may be accomplished by merely roping off the area and posting “Keep Out” signs and barricade tape, or it may require the assistance of police officers, fire service personnel, or other persons serving as guards. Any unauthorized individuals found within the fire investigation scene area should be identified and their identity noted; then they should be required to leave escorted off of the site to prevent potential injury.

12.2.1.1 12.2.6.1 If the investigator is going to enter parts of the structure before the fire is completely extinguished, he or she the investigator should receive permission from the fire ground commander. The investigator should coordinate his or her activities with the fire suppression personnel and keep the fire ground commander advised of the areas into which he or she will be entering and working. The investigator should not move into other areas of the structure without informing the fire ground commander. The investigator should not enter a burning structure unless accompanied by fire suppression personnel, and unless appropriately trained to do so. 12.2.1.2 12.2.6.2 When conducting an investigation in a structure soon after the fire is believed to be extinguished, the investigator should be mindful of the possibility of a rekindle. The investigator should be alert for continued burning or a rekindle and should remain aware at all times of the fastest or safest means of egress. The controlling investigator at a fire or explosion scene should at a minimum have a First Aid Kit, access to local emergency notification numbers, and the location of emergency medical care in the event that an emergency arises during the investigative process. The controlling investigator at a fire or explosion scene should have an established emergency evacuation signal and meeting place identified for other investigators that may be working on the scene. The type of signal and evacuation location should be discussed during the first safety meeting and at other times new or different investigators arrive at the scene. The information included in this proposal was developed as a part of the Safety Task Group work. Much of the material included in this proposed section was already included in the existing document and represents a change in the overall chapter organization and includes some new items including working around mechanized equipment and below and above grade.

Revise text to read as follows: 12.1.4 12.2 General Fire Scene Safety. The investigator should remain aware of the general and particular dangers of the scene under investigation. The investigator should keep in mind the potential for serious injury at any time and should not become complacent or take unnecessary risks. The need for this awareness is especially important when the structural stability of the scene is unknown or when the investigation requires that the investigator be working above or below ground level. 12.1.1 12.2.1 Investigating the Scene Alone. Fire scene examinations should not be undertaken alone. A minimum of two individuals should be present to ensure that assistance is at hand if an investigator should become trapped or injured. If the fire scene is investigated by one investigator, a clear communications protocol needs to be established between the site investigator and an off-site contact person. An estimated completion time should be established, and periodic contacts between the scene investigator and off-site contact person should be made at regular intervals. If it is impossible for the investigator to be accompanied, he or she should at least notify a responsible person of where the investigator will be and of when he or she can reasonably be expected to return. 12.1.6 12.2.2 Investigator Fatigue. 12.1.6.1 12.2.2.1 It is common for investigators to put in long periods of strenuous personal labor during an incident scene investigation. This labor may result in fatigue, which can adversely influence an investigator’s physical coordination, strength, or judgment to recognize or respond to hazardous conditions or situations. Keep in mind that the use of heavy safety clothing and respiratory protection will further increase fatigue. 12.1.6.2 12.2.2.2 Periodic rest, fluid replacement, and nourishment should be obtained provided in a safe atmosphere, remote from but convenient to the fire scene. Sanitation facilities that include a restroom and washing station are necessary on large or major incidents. The hazard to the fire investigator is not just through aspiration and absorption but also through ingestion, so it is essential that eating and drinking occur out of the scene after removal of contaminated gear and the washing of face and hands. 12.2.3 Working Above or Below Grade Levels. Whenever the investigators has to work above or below grade levels they should be aware of the special hazards that may be present. 12.2.5 Standing Water. 12.2.5.1 12.2.3.1 Standing water in basements can pose a variety of dangers to the investigator. Puddles of water in the presence of energized electrical systems can be lethal if the investigator should touch an energized wire, ungrounded appliance, or other piece of equipment while standing in a puddle water. Printed on 9/18/2009 128 Report on Proposals – November 2010 NFPA 921 12.2.5.2 12.2.3.2 Pools of water that may appear to be only inches deep may in fact be well over the investigator’s head. Pools of water may also conceal hidden danger such as holes or dangerous objects that may trip or otherwise injure the investigator. 12.2.3.3 Air quality of basement or underground areas may require atmospheric testing. The testing should determine the oxygen concentration or evaluate other potential atmospheric conditions that are suspected. 12.2.3.4 When working above grade, the investigator should consider the need for appropriate fall protection equipment. Requirements of the OSHA (State or Federal) regulations for fall protection and fall protection trigger heights should be consulted and followed. 12.2.3.5 When working from any aerial platform the investigator should determine if that platform or piece of equipment has been designed (labeled) for use by people. Equipment not designated for use by people should not be used. 12.2.4 Working around Mechanized Equipment. The utilization of heavy and mechanized equipment at the fire or explosion scene present unique issues and concerns for both those investigators that are present and the overall scene safety. 12.2.4.1 When mechanized equipment is in use, the area should be isolated by barricades to prevent entry into that area or if investigators are required to be in that area, they should wear appropriate high visibility vests or clothing, and a safety monitor that will communicate with the operator and worn warn investigators of changing hazards or conditions should be present. 12.2.4.2 The swing areas of cranes and the path that will be taken to remove debris should be identified and barricaded to prevent entry and potential injury. No one should work under a load that is being moved by a crane. 12.2.6 12.2.5 Safety of Bystanders. 12.2.6.1 12.2.5.1 Fire and explosion scenes often always generate the interest of bystanders. Their safety, as well as the security of the scene and its evidence, should be addressed by the investigator. 12.2.6.2 12.2.5.2 The investigation scene should be secured from entry by curious bystanders. This security may be accomplished by merely roping off the area and posting “Keep Out” signs and barricade tape, or it may require the assistance of police officers, fire service personnel, or other persons serving as guards. Any unauthorized individuals found within the fire investigation scene area should be identified and their identity noted; then they should be required to leave escorted off of the site to prevent potential injury. 12.2.1 12.2.6 Status of Suppression. 12.2.1.1 12.2.6.1 If the investigator is going to enter parts of the structure before the fire is completely extinguished, he or she the investigator should receive permission from the fire ground commander. The investigator should coordinate his or her activities with the fire suppression personnel and keep the fire ground commander advised of the areas into which he or she will be entering and working. The investigator should not move into other areas of the structure without informing the fire ground commander. The investigator should not enter a burning structure unless accompanied by fire suppression personnel, and unless appropriately trained to do so. 12.2.1.2 12.2.6.2 When conducting an investigation in a structure soon after the fire is believed to be extinguished, the investigator should be mindful of the possibility of a rekindle. The investigator should be alert for continued burning or a rekindle and should remain aware at all times of the fastest or safest means of egress. 12.2.7 First Aid Kit and Emergency Notification Numbers. The controlling entity investigator at a fire or explosion scene should at a minimum have a First Aid Kit, access to local emergency notification numbers, and the location of emergency medical care in the event that an emergency arises during the investigative process. 12.2.8 Emergency Notification Signal. The controlling entity investigator at a fire or explosion scene should have an established emergency eV ACuation signal and meeting place identified for other investigators that may be working on the scene. The type of signal and eV ACuation location should be discussed during the first safety meeting and at other times when new or different investigators arrive at the scene.

Changes better clarify the information provided.

Printed on 9/18/2009 129 Report on Proposals – November 2010 NFPA 921 ______921-117 Log #24

______Joseph E. Boisseau, City of Colonial Heights Fire & EMS Revise text as follows: 12.2.5.3 – Foam can pose a hazard to any fire scene and the investigators. Suppression foam is used by fire departments in both Class A and Class B fires. The foam can hide holes in the floor, tripping hazards, debris, sharp objects, tools, and various other items left in the fire scene. The foams can make walking surfaces slippery causing falls. The investigator should determine if foam has been used and if it remains in the scene prior to entering. If foam has been used, then it is recommended that the foam be allowed to dissipate or the foam be washed out of the scene prior to making entry. Several fire departments are now using Class A foam for residential and commercial fires to prevent rekindles. Recent studies by the ATF show that the foam has very little effect on the detection of accelerants, but they point out that foam poses a safety risk to the investigator. I have seen this safety concern personally on fire scenes both residential and woods fires.

Revise text to read as follows: 12.2.3.2.1 12.2.5.3 – Foam can pose a hazard to any fire scene and the investigators.Suppression foam is used by fire departments in both Class A and Class B fires. Foam can pose a hazard to any fire scene and the investigators. The foam can hide holes in the floor, tripping hazards, debris, sharp objects, tools, and various other items left in the fire scene. The foams can make walking surfaces slippery causing falls. The investigator should determine if foam has been used and if it remains in the scene prior to entering. If foam has been used, then it is recommended that the foam be allowed to dissipate, or the foam be carefully washed out of the scene prior to making entry so as to minimize the possibility of altering the scene or destroying evidence. The committee believes the intent of the submitter was to make this a new 12.2.5.3 paragraph. Due to revision of Chapter 12, this paragraph is being inserted 12.2.3.2.1.

Printed on 9/18/2009 130 Report on Proposals – November 2010 NFPA 921 ______921-118 Log #137

______Ronald L. Hopkins, Eastern Kentucky University Proposal Create New 12.3 and title it Fire Scene Hazards, then move existing text as indicated to this section, re-number, and add or delete text as indicated. 12.1.4 The investigator should remain aware of the general and particular dangers of the scene under investigation. The investigator should keep in mind the potential for serious injury at any time and should not become complacent or take unnecessary risks. The need for this awareness is especially important when the structural stability of the scene is unknown or when the investigation requires that the investigator be working above or below ground level. Even in cases where the fire investigator believes the structure to be stable, caution should always be taken as visual observations of the stability of the structure are not always consistent with the actual stability of the building. Heat and/or suppression activities can cause the structural components of the building to fail or weaken. It is recommended that investigators work in teams of two or more. By working in teams, the investigators can assist each other and held ensure each other’s safety. Whereas working alone is not recommended, when instances arise that necessitate the investigators working alone, information as to where, when and for how long the investigator is working at the scene should be provided to someone in case of an accident or mishap. . Physical hazards, such as slip, trip, and fall hazards, holes in floors, sharp surfaces, broken glass, and other such hazards, can cause a physical hazard to the investigator. Investigator fatigue and the use of Personal Protective Equipment increase the potential for physical injury while investigating the fire or explosion scene. During the use of tools; hand, portable power tools, ladders (step, specialty, extension) care should be taken to observe all safety requirements and operational guidelines to lessen the potential of injury. The use of flashlights, portable lighting (Intrinsically safe, if required) will reduce the potential of a slip or fall. Additionally identification, marking and covering holes as well as other items that can pose a physical hazard will reduce the potential injury. Standing water and wet or slippery surfaces should be appropriately marked and barricaded to prevent investigators from entering the area. 12.2.2 By their nature, most structures that have been involved in fires or explosions are structurally weakened. Roofs, ceilings, partitions, load-bearing walls, and floors may have been compromised by the fire or explosion. 12.3.2.1Heat affects various building components in different ways, some of which may not be visible to the naked eye. Caution should always be taken to assess the stability of the structure prior to entering and throughout the processing of the scene. If the scene processing takes more than one day, stability assessments should be conducted numerous times as the effects of the fire damage to the building may change throughout scene processing. Weather can also become a mitigating factor in the stability of the building necessitating constant reassessments throughout the entire scene processing. 12.2.2.1 12.3.2.2 The investigator’s task requires that he or she enter these structures and often requires that he or she perform tasks of debris removal that may dislodge or further weaken these already unsound structures. Before entering such structures or beginning debris removal, the investigator should make a careful assessment of the stability and safety of the structure. If necessary, the investigator should seek the help of qualified structural experts to assess the need for the removal of dangerously weakened construction or should make provisions for shoring up load-bearing walls, floors, ceilings, or roofs. Electrical hazards at the investigation scene can come from the building's electrical utility service, emergency or standby power, or those tools and equipment the investigator brings on to the scene. The electrical service should be disconnected or the appropriate circuits isolated. 12.2.4 12.3.3.1 Electrical Hazards. Although the fire investigators may arrive on the scene hours or even days later, they should recognize potential hazards in order to avoid injury or even death. Serious injury or death can result from electric shocks or burns. Investigators as well as fire officers should learn to protect themselves from the dangers of electricity while conducting fire scene examinations. The risk is particularly high during an examination of the scene immediately following the fire. When conditions warrant, the investigator should ensure that the power to the building or to the area affected has been disconnected prior to entering the hazardous area. The investigator should also recognize that buildings may have several utility feeds and should ensure that all feeds are disconnected prior to entering the hazardous area. The fire investigator should not disconnect the building’s electric power but should ensure that the authorized utility does so. 12.2.4.112.3.3.2* When electrical service has been interrupted and the power supply has been disconnected, a tag or lock should be attached to the meter, indicating that power has been shut off. If more than one person or group is

Printed on 9/18/2009 131 Report on Proposals – November 2010 NFPA 921 investigating the scene, each person or group should attach their own tab or lock on the requisite meter. This precludes the meter from being inadvertently switched to the “on” position by a person or group leaving the area while a second person or group is still processing the scene. In considering potential electrical hazards, always assume that danger is present. The investigator should personally verify that the power has been disconnected. This verification can be accomplished with the use of a voltmeter. Some meters allow the accurate measuring of volts, ohms, and resistance. Other devices are designed simply to indicate the presence of alternating current. These pencil-sized products give an audible or visual alarm when the device tip is placed on the wire (bare or jacketed). When utilizing voltage-testing equipment, it is imperative that the testing device be rated for the voltage supplied to the structure under investigation. Utilization of equipment that is not rated properly exposes the investigator to electrocutions and puts other investigators in the area of the testing at great risk. If any doubt exists as to whether the equipment is energized, the local electric utility should be called for verification. A.12.2.4.1 12.3.3.2 For additional information, see the following: “Who sets the rules for electrical testing and safety?” originally published by Fluke Corporation and cited from the Cole-Parmer Technical Library (http://www.coleparmer.com/techinfo/pring.asp?htmlfile=fluke_electricalsafety.htm&=293 accessed December 9, 2006. Fire Fighter Fatality Investigation Report F99-28 — CDC/NIOSH, as accessed at http://www.cdc.gov/niosh/fire/reports/face9928.html on December 9, 2006. NJ Face Investigation Report 04-NJ-059, dated October 4, 2005. 12.2.4.2 12.3.3.3 The investigator may be working at fire scenes that have been equipped with temporary wiring. The investigator should be aware that temporary wiring for lighting or power arrangements is often not properly installed, grounded, or insulated and, therefore, may be unsafe. 12.2.4.3 12.3.3.4 The investigator should consider the following electrical hazards shown in 12.2.4.3 12.3.3.4(A) through 12.2.4.3 12.3.3.4(L) when examining the fire scene. (A) All wires should be considered energized or “hot,” even when the meter has been removed or disconnected. (B) When approaching a fire scene, the investigator should be alert to fallen electrical wires on the street; on the ground; or in contact with a metal fence, guard rail, or other conductive material, including water. (C) The investigator should look out for antennas that have fallen on existing power lines, for metal siding that has become energized, and for underground wiring. (D) The investigator should use caution when using or operating ladders or when elevating equipment in the vicinity of overhead electric lines. (E) It should be noted that building services are capable of delivering high amperage and that short circuiting can result in an intense electrical flash, with the possibility of serious physical injury and burns. (F) Rubber footwear should not be depended on as an insulator. (G) A flooded basement should not be entered if the electrical system is energized. Energized electrical equipment should not be turned off manually while standing in water. (H) Operation of any electrical switch or non-explosion proof equipment in the area that might cause an explosion if flammable gas or vapors are suspected of being present should be avoided. (See 12.2.7.) When electric power must be shut off, it should be done at a point remote from the explosive atmosphere. (I) Lines of communication and close cooperation with the utility company should be established. Power company personnel possess the expertise and equipment necessary to deal with electrical emergencies. (J) The investigator should locate and avoid underground electric supply cables before digging or excavating on the fire scene. (K) The investigator should be aware of multiple electrical services that may not be disconnected, extension cords from neighboring buildings, and similar installations. (L) A meter always should be used to determine whether the electricity is off. 12.2.7.1 Fires and explosions often generate toxic or noxious gases. The presence of hazardous materials in the structure is certain. Homes contain chemicals in the kitchen, bath, and garage that can create great risk to the investigator if he or she is exposed to them. Commercial and business structures are generally more organized in the storage of hazardous materials, but the investigator cannot assume that the risk is less in such structures. Many buildings built prior to 1975 will contain asbestos. The investigator should be aware of the possibility that he or she could become exposed to dangerous atmospheres during the course of an investigation. 12.2.7.2 12.3.4.1 In addition, it is not uncommon for atmospheres with insufficient oxygen to be present within a structure that has been exposed to fire or explosion. Fire scene atmospheres may contain ignitible gas, vapors, and liquids as well as low oxygen concentrations. The atmosphere should be tested using appropriate equipment to determine whether such hazards or conditions exist before working in or introducing ignition sources into the area. Such ignition sources may include electrical arcs from flashlights, radios, cameras and their flashes, and smoking materials. 12.3.4.2 The investigator should be aware that the atmosphere may change while processing a scene. As the Printed on 9/18/2009 132 Report on Proposals – November 2010 NFPA 921 investigator moves objects during the excavation of the scene, may allow pockets of gases to escape or may unintentionally rupture a container or pipe. Due to this, constant attention should be made as to the atmosphere that the investigator is working in. 12.3.4.3 Chemicals that are normally present at the scene or those that are a result of the incident should be considered. In commercial occupancies, the investigator may wish to obtain copies of Material Safety Data Sheets (MSDS) to determine the hazards of those products. The identification of chemical hazards that may be present as a result of the incident is more difficult. There are many reference documents the investigator may use to determine the hazards of suspected chemicals present at the investigation scene, including the National Institute of Safety and Health (NIOSH) Pocket Guide to Chemical Hazards. 12.3.4.4 Gas Utilities that serve the structure or the industrial process should be identified and shut off at the meter and locked out or tagged out. If complete isolation of the building cannot be accomplished, the investigator should insure that the area of the building or industrial process being excavated and examined be isolated from any connected gas utilities. 12.3.4.5 The presences of chemicals such as Pesticides should also be considered in both residential and commercial occupancies. If they are properly contained they generally will not pose a threat. However, if the container is broken prior to or while processing the scene the investigator will need to take appropriate precautions such as avoiding the area or utilizing appropriate personal protective equipment. Sources of biological hazards include bacteria, viruses, insects, plants, birds, animals, and humans. These sources can cause a variety of health effects ranging from skin irritation and allergies to infections (e.g., tuberculosis, communicable diseases), cancer, etc. Some of these hazards may not be recognized without specialized assistance. 12.3.5.1 There are common sources of biological hazards found in residential and commercial occupancies and they include decomposing food, garbage, animals that did not survive the fire, and broken or damaged waste water pipes and systems. The investigator should not open refrigerators or freezers without considering the condition of the food, especially if the electrical service has been off for several days. 12.3.5.2 If the investigator is required to work around biological hazards, appropriate Personal Protective Equipment should be worn and upon completion of the work, appropriate decontamination and disposal should occur. The use of disposable outer garments is helpful as they can provide excellent protection and limit the need for decontamination of garments worn under them. Machinery and equipment present on the scene may have stored energy. Prior to working around machinery and equipment, the investigator will need to determine if they are at zero mechanical state or if they are still operational or functional. For specialized machinery or equipment, the investigator may need to seek the assistance of the property owner or other technical resource to assist in controlling the stored energy. Sources of energy other than electrical include air and hydraulic. There are many hazards present at fire scenes. In addition to the ones previously listed, there are some hazards specific to the particular occupancy. These hazards may fall within the categories previously described or may be in addition to the ones listed or in some instances need to be re-stated. 12.3.7.1 Radiological Hazards that may be found in Doctors or Dentist Offices and some industrial occupancies. Doctors or Dentist Offices frequently have small amounts of radiological hazards found in X Ray machines. If the investigator believes that the machines were compromised as a result of the fire, then appropriate isolation, protection, and decontamination will need to be completed if exposure has or may have occurred. 12.2.3 The investigator should determine the status of all utilities (i.e., electric, gas, and water) within the structure under investigation. Determine before entering if electric lines are energized (primary, secondary, or temporary electrical service), if fuel gas lines are charged, or if water mains and lines are operative. Determining the status of all utilities is necessary to prevent the possibility of electrical shock or inadvertent release of fuel gases or water during the course of the investigation. Using mechanized equipment during the fire scene processing, brings additional dangers to the scene. Care should be taken while processing the scene during mechanized equipment usage. The investigator should be aware of the movement of equipment and materials and recognize that the operator of that equipment may not be aware that the investigator may be in danger. They will be focused on the operational task and not on the location of those that may be in the area. 12.2.5.1 12.3.7.4 Standing Water. Standing water can pose a variety of dangers to the investigator. Puddles of water in the presence of energized electrical systems can be lethal if the investigator should touch an energized wire while standing in a puddle. 12.2.5.2 12.3.7.4.1 Pools of water that may appear to be only inches deep may in fact be well over the investigator’s head. Pools of water may also conceal hidden danger such as holes or dangerous objects that may trip or otherwise injure the investigator. 12.2.2.2 12.3.7.4.2 The investigator should also be especially mindful of hidden holes in floors or of other dangers that Printed on 9/18/2009 133 Report on Proposals – November 2010 NFPA 921 may be hidden by standing water or loosely stacked debris. The investigator should keep in mind that the presence of pooled extinguishment water or of weather-related factors — such as the weight of rain water, high winds, snow, and ice — can affect the ability of structures to remain sound. For example, a badly damaged structure may only continue to stand until the ice melts. The proposed material follows the outline that was developed by the Safety Chapter Task Group and is the result of work completed by a number of the task group members. The proposed material incorporates existing text as well as new text that is intended to provide the investigator with important information and assistance in the recognition and controlling methodologies for hazards that can be expected on the fire and explosion scene. This information also emphasizes that the investigator should look for site specific hazards and find methodologies for the control of those hazards.

Revise text to read as follows: 12.1.4 12.3 Fire Scene Hazards. The investigator should remain aware of the general and particular dangers of the scene under investigation. The investigator should keep in mind the potential for serious injury at any time and should not become complacent or take unnecessary risks. The need for this awareness is especially important when the structural stability of the scene is unknown or when the investigation requires that the investigator be working above or below ground level. Even in cases where the fire investigator believes the structure to be stable, caution should always be taken as visual observations of the stability of the structure are not always consistent with the actual stability of the building. Heat and/or suppression activities can cause the structural components of the building to fail or weaken. It is recommended that investigators work in teams of two or more. By working in teams, the investigators can assist each other and held help ensure each other’s safety. Whereas working alone is not recommended, when instances arise that necessitate the an investigators working alone, information as to where, when and for how long the investigator is working at the scene should be provided to someone in case of an accident or mishap. 12.3.1 Physical Hazards. Physical hazards, such as Slip, trip, and fall hazards, holes in floors, sharp surfaces, broken glass, and other such hazards, can cause a physical hazard injury to the investigator. Investigator fatigue and the use of Ppersonal Pprotective Eequipment increases the potential for physical injury while investigating the fire or explosion scene. During the use of tools; When using hand, portable power tools, and ladders, (step, specialty, extension) care should be taken to observe all safety requirements and operational guidelines to lessen the potential of injury. The use of flashlights, or portable lighting (intrinsically safe, if required) will reduce the potential of a slip or fall. Additionally identification, marking and covering holes as well as other items that can pose a physical hazard will reduce the potential injury. Standing water and wet or slippery surfaces should be appropriately marked and barricaded to prevent investigators from entering the area. 12.2.2 12.3.2 Structural Stability Hazards. By their nature, most structures that have been involved in fires or explosions are structurally weakened. Roofs, ceilings, partitions, load-bearing walls, and floors may have been compromised by the fire or explosion. 12.3.2.1Heat affects various building components in different ways, some of which may not be visible to the naked eye. Caution should always be taken to assess the stability of the structure prior to entering and throughout the processing of the scene. If the scene processing takes more than one day, stability assessments may need to should be conducted numerous times as the effects of the fire damage to the building may change throughout scene processing. Weather conditions can affect can also become a mitigating factor in the stability of the building necessitating constant reassessments throughout the entire scene processing. 12.2.2.1 12.3.2.2 The investigator’s task requires that he or she enter these structures and often requires that he or she perform tasks of debris removal that may dislodge or further weaken these already unsound structures. Before entering such structures or beginning debris removal, the investigator should make a careful assessment of the stability and safety of the structure. If necessary, the investigator should seek the help of qualified structural experts to assess the need for the removal of dangerously weakened construction or should make provisions for shoring up load-bearing walls, floors, ceilings, or roofs. 12.1.2.1.3 12.3.3 Electrical Hazards. Electrical hazards at the investigation scene can come from the building's electrical utility service, emergency or standby power, or those tools and equipment the investigator brings on to the scene. The electrical service should be disconnected or the appropriate circuits isolated. 12.2.4 12.3.3.1 Electrical Hazards. Although the fire investigators may arrive on the scene hours or even days later, they should recognize potential hazards in order to avoid injury or even death. Serious injury or death can result from electric shocks or burns. Investigators as well as fire officers should learn to protect themselves from the dangers of electricity while conducting fire scene examinations. The risk is particularly high during an examination of the scene immediately following the fire. When conditions warrant, the investigator should ensure that the power to the building or to the area affected has been disconnected prior to entering the hazardous area. The investigator should also recognize that buildings may have several utility feeds and should ensure that all feeds are disconnected prior to entering the Printed on 9/18/2009 134 Report on Proposals – November 2010 NFPA 921 hazardous area. The fire investigator should not disconnect the building’s electric power but should ensure that the authorized utility does so. 12.2.4.112.3.3.2* Lockout / Tagout (LOTO). When electrical service has been interrupted and the power supply has been disconnected, a warning tag or lock should be attached to the appropriate disconnect meter, indicating that power has been shut off. If more than one person or group is investigating the scene, each person or group should attach their own warning tag or lock on the requisite appropriate disconnect meter. This may precludes the disconnect meter from being inadvertently switched to the “on” position by a person or group leaving the area while a second person or group is still processing the scene. In considering potential electrical hazards, always assume that danger is present. The investigator should personally verify that the power has been disconnected. This verification can be accomplished with the use of a voltmeter. Some meters allow the accurate measuring of volts, ohms, and resistance. Other devices are designed simply to indicate the presence of alternating current. These pencil-sized products give an audible or visual alarm when the device tip is placed on the wire (bare or jacketed). When utilizing voltage-testing equipment, it is imperative that the testing device be rated for the voltage supplied to the structure under investigation. Utilization of equipment that is not properly rated properly exposes the investigator to electrocutions and puts other investigators in the area of the testing at great risk. If any doubt exists as to whether the equipment is energized, the local electric utility should be called for verification. A.12.2.4.1 12.3.3.2 For additional information, see the following: “Who sets the rules for electrical testing and safety?” originally published by Fluke Corporation and cited from the Cole-Parmer Technical Library (http://www.coleparmer.com/techinfo/pring.asp?htmlfile=fluke_electricalsafety.htm&=293 accessed December 9, 2006. Fire Fighter Fatality Investigation Report F99-28 — CDC/NIOSH, as accessed at http://www.cdc.gov/niosh/fire/reports/face9928.html on December 9, 2006. NJ Face FACE Investigation Report 04-NJ-059, dated October 4, 2005. 12.2.4.2 12.3.3.3 The investigator may be working at a fire scenes that have has been equipped with temporary wiring. The investigator should be aware that temporary wiring for lighting or power arrangements is often not properly installed, grounded, or insulated and, therefore, may be unsafe. 12.2.4.3 12.3.3.4 The investigator should consider the following electrical hazards shown in 12.2.4.3 12.3.3.4(A) through 12.2.4.3 12.3.3.4(L) when examining the fire scene. (A) All wires should be considered energized or “hot,” even when the meter has been removed or disconnected. (B) When approaching a fire scene, the investigator should be alert to fallen electrical wires on the street; on the ground; or in contact with a metal fence, guard rail, or other conductive material, including water. (C) The investigator should look out for antennas that have fallen on existing power lines, for metal siding that has become energized, and for underground wiring. (D) The investigator should use caution when using or operating ladders or when elevating equipment in the vicinity of overhead electric lines. (E) It should be noted that building services are capable of delivering high amperage and that short circuiting can result in an intense electrical flash, with the possibility of serious physical injury and burns. (F) Rubber footwear should not be depended on as an insulator. (G) A flooded basement should not be entered if the electrical system is energized. Energized electrical equipment should not be turned off manually while standing in water. (H) Operation of any electrical switch or non-explosion proof equipment in the area that might cause an explosion if flammable gas or vapors are suspected of being present should be avoided. (See 12.2.7.) When electric power must be shut off, it should be done at a point remote from the explosive atmosphere. (I) Lines of communication and close cooperation with the utility company should be established. Power company personnel possess the expertise and equipment necessary to deal with electrical emergencies. (J) The investigator should locate and avoid underground electric supply cables before digging or excavating on the fire scene. (K) The investigator should be aware of multiple electrical services that may not be disconnected, extension cords from neighboring buildings, and similar installations. (L) A meter always should be used to determine whether the electricity is off. 12.3.4 Chemical Hazards. 12.2.7.1 Fires and explosions often generate toxic or noxious gases. The presence of hazardous materials in the structure is certain. Homes contain chemicals in the kitchen, bath, and garage that can create great risk to the investigator if he or she is exposed to them. Commercial and business structures are generally more organized in the storage of hazardous materials, but the investigator cannot assume that the risk is less in such structures. Many buildings built prior to 1975 will contain asbestos. The investigator should be aware of the possibility that he or she could become exposed to dangerous atmospheres during the course of an investigation. 12.2.7.2 12.3.4.1 In addition, it is not uncommon for atmospheres with insufficient oxygen to be present within a Printed on 9/18/2009 135 Report on Proposals – November 2010 NFPA 921 structure that has been exposed to fire or explosion. Fire scene atmospheres may contain ignitible gases, vapors, and liquids as well as low oxygen concentrations. The atmosphere should be tested using appropriate equipment to determine whether such hazards or conditions exist before working in or introducing ignition sources into the area. Such ignition sources may include electrical arcs from flashlights, radios, cameras and their flashes, and smoking materials. 12.3.4.2 The investigator should be aware that the atmosphere may change while processing a scene. As the investigator moves objects during the excavation of the scene, may allow pockets of gases to escape or may unintentionally rupture a container or pipe. Due to this, constant attention should be made as to the atmosphere that the investigator is working in. pockets of gases may escape or containers and pipes may be ruptured. Therefore, the atmosphere may need to be monitored. 12.3.4.3 Chemicals that are normally present at the scene or those that are a result of the incident should be considered. In commercial occupancies, the investigator may wish to obtain copies of Material Safety Data Sheets (MSDS) to determine the hazards of those products. The identification of chemical hazards that may be present as a result of the incident is more difficult. There are many reference documents the investigator may use to determine the hazards of suspected chemicals present at the investigation scene, including the National Institute of Safety and Health (NIOSH) Pocket Guide to Chemical Hazards. 12.3.4.4 Gas Uutilities that serve the structure or the industrial process should be identified and shut off at the meter and locked out. or tagged out. If complete isolation of the building cannot be accomplished, the investigator should iensure that the area of the building or industrial process being excavated and examined be isolated from any connected gas utilities. 12.3.4.5 The presences of chemicals such as Ppesticides should also be considered in both residential and commercial occupancies. If they are properly contained, they generally will not pose a threat. However, if the container is broken prior to or while processing the scene, the investigator will need to take appropriate precautions such as avoiding the area or utilizing appropriate personal protective equipment. 12.3.5 Biological Hazards. Sources of biological hazards include blood, body fluids, and human remains. , bacteria, viruses, insects, plants, birds, animals, and humans. These sources can cause a variety of health effects ranging from skin irritation and allergies to infections (e.g., tuberculosis, communicable diseases), cancer, etc. Some of these hazards may not be recognized without specialized assistance. 12.3.5.1 There are common sources of biological hazards found in residential and commercial occupancies and they include decomposing food, garbage, animals that did not survive the fire, and broken or damaged waste water pipes and systems. The investigator should not open refrigerators or freezers without considering the condition of the food, especially if the electrical service has been off for several days. 12.3.5.2 If the investigator is required to work around biological hazards, appropriate Ppersonal Pprotective Eequipment should be worn and upon completion of the work, appropriate decontamination and disposal should occur. The use of disposable outer garments is helpful as they can provide excellent protection and limit the need for decontamination of garments worn under them. 12.3.6 Mechanical Hazards. Machinery and equipment present on the scene may have stored energy. Prior to working around machinery and equipment, the investigator will need to determine if they are at zero mechanical state or if they are still operational or functional. For specialized machinery or equipment, the investigator may need to seek the assistance of the property owner or other technical resource to assist in controlling the stored energy. Sources of energy other than electrical include air and hydraulic. 12.3.7 Miscellaneous Hazards. There are many hazards present at fire scenes. In addition to the ones hazards previously listed, there are some hazards specific to the particular occupancy. These hazards may fall within the categories previously described or may be in addition to the ones listed or in some instances need to be re-stated. 12.3.7.1 Radiological Hazards. Radiological Hazards that may be found in medical Doctors or Dentists Ooffices and some industrial occupancies. Medical Doctors or Dentist Ooffices frequently may contain have small amounts of radiological radioactive materials. hazards found in X-ray machines. If the investigator believes that the machines were compromised as a result of the fire, then appropriate isolation, protection, and decontamination will need to be completed if exposure has or may have occurred. 12.2.3 12.3.7.2 Utilities. The investigator should determine the status of all utilities (i.e., electric, gas, and water) within the structure under investigation. Determine before entering if electric lines are energized (primary, secondary, or temporary electrical service), if fuel gas lines are charged, or if water mains and lines are operative. Determining the status of all utilities is necessary to prevent the possibility of electrical shock or inadvertent release of fuel gases or water during the course of the investigation. 12.3.7.3 Mechanized Equipment Hazards Caught Between Struck By. Using mechanized equipment during the fire scene processing, brings additional dangers to the scene. Care should be taken while processing the scene during mechanized equipment usage. The investigator should be aware of the movement of equipment and materials and recognize that the operator of that equipment may not be aware that the investigator may be in danger. They will can be Printed on 9/18/2009 136 Report on Proposals – November 2010 NFPA 921 focused on the operational task and not on the location of those that may be in the area. 12.2.5.1 12.3.7.4 Standing Water. Standing water can pose a variety of dangers to the investigator. Puddles of water in the presence of energized electrical systems can be lethal if the investigator should touch an energized wire while standing in a puddle. 12.2.5.2 12.3.7.4.1 Pools of water that may appear to be only inches deep may in fact be well over the investigator’s head. Pools of water may also conceal hidden danger such as holes or dangerous objects that may trip or otherwise injure the investigator. 12.2.2.2 12.3.7.4.2 The investigator should also be especially mindful of hidden holes in floors or of other dangers that may be hidden by standing water or loosely stacked debris. The investigator should keep in mind that the presence of pooled extinguishment water or of weather-related factors — such as the weight of rain water, high winds, snow, and ice — can affect the ability of structures to remain sound. For example, a badly damaged structure may only continue to stand until the ice melts.

The revised text removes redundancy and improves clarity. Reference 12.3.7.4 through 12.3.7.4.2: See committee action on 921-116 (Log #136).

Printed on 9/18/2009 137 Report on Proposals – November 2010 NFPA 921 ______921-119 Log #138

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.4 and title it Safety Plans, then move existing text as indicated to this section, re-number, and add or delete text as indicated. There could be a number of safety plans that the controlling investigator may be required to develop as a part of the investigative process. The complexity of the plans and the topics included will vary depending on the hazards identified on the scene. Other factors including the number of investigators and support personnel, severity of the hazards present, the use of specialized personal protective equipment (PPE), use of mechanized equipment, government and organizational policies and procedures will need to be considered. One of the first tasks that should be completed before a fire or explosion investigation is begun is a Hazard and Risk Assessment. Thereby the investigator will be able to determine the hazards present and control those hazards by engineering or administrative control or through the selection and use of appropriate personal protective equipment (PPE). Hazard and Risk Assessments are comprised of three different actions, as shown in 12.1.2.1 12.4.1 through 12.1.2.3.3 12.4.1.3.

****Insert Artwork Here**** (921-L138/F2010/Rop/Rec - Risk Assessment chart)

The example form below is useful in documenting the Hazard and Risk Assessment. 12.1.2.1 To simplify the process of hazard identification and to allow a more systematic and complete identification process, the investigator may use a classification system of the hazards. It should be remembered that classification of hazards is not the most important action. The most important aspect of this process is to identify the presence of the hazard. Physical hazards, such as slip, trip, and fall hazards, or sharp surfaces, broken glass, and other such hazards, can cause a physical hazard to the investigator. Many structural hazards are easily identified without the need to have specialized technical assistance, but in complex scenes or heavily damaged scenes the investigator may want to consider the assistance of a structural engineer. Electrical hazards at the investigation scene can come from the building's electrical utility service, emergency or standby power, or those tools and equipment the investigator brings on to the scene. The electrical service should be disconnected or the appropriate circuits isolated. Chemicals that are normally present at the scene or those that are a result of the incident should be considered. In commercial occupancies, the investigator may wish to obtain copies of Material Safety Data Sheets (MSDS) to determine the hazards of those products. The identification of chemical hazards that may be present as a result of the incident is more difficult. There are many reference documents the investigator may use to determine the hazards of suspected chemicals present at the investigation scene, including the National Institute of Safety and Health (NIOSH) Pocket Guide to Chemical Hazards. Sources of biological hazards include bacteria, viruses, insects, plants, birds, animals, and humans. These sources can cause a variety of health effects ranging from skin irritation and allergies to infections (e.g., tuberculosis, communicable diseases), cancer, etc. Some of these hazards may not be recognized without specialized assistance. Machinery and equipment present on the scene may have stored energy. Prior to working around machinery and equipment, the investigator will need to determine if they are at zero mechanical state or if they are still operational or functional. For specialized machinery or equipment, the investigator may need to seek the assistance of the property owner or other technical resource to assist in controlling the stored energy. Depending on the specific hazard identified, the determination of the risks associated with the hazard could vary from simple qualitative assessments to complex quantitative assessments. Also, as a part of this analysis, the investigator will determine the likelihood that they will come in contact with that hazard. As an example, for a chemical (even if it is a chemical hazard) contained in a drum or other containment device, the risk is minimal. Given that example, a control mechanism may be to isolate the area where the container is in order to prevent damage and potential release. Table 12.4.1 below provides guidance on selecting the level of risk a hazard may pose.

Printed on 9/18/2009 138 Report on Proposals – November 2010 NFPA 921

****Insert Table 12.4.1 here****

Following the determination of the risk level, this level should be compared to a suitable benchmark or acceptance criteria. In some cases, the acceptance criteria has been established by regulators (OSHA). To control a hazard, the investigator can utilize several methodologies that include engineering controls, administrative controls, or the selection and use of appropriate PPE. Engineering controls can be as simple as placing appropriate shoring to reinforce damaged structural elements or the demolition of those areas after they are properly documented. Or, they can be very complex solutions that will require a structural engineer to evaluate, design corrective measures, and manage the installation of the corrective measures. Administrative controls can include the isolation of an area by the use of signs or barrier tape, by briefing of those that will be working in the area of the hazards and cautioning them that they are not to enter within the isolated area, by obtaining specialized resources that have expertise dealing with the hazard present, or by a combination of methodologies. The use of PPE is generally considered the least effective of the control measures. However, due to the conditions that the investigator may encounter at the scene and the duration of the work, PPE can be a suitable control mechanism. Care will need to be taken to determine the hazard present to ensure that the PPE selected is acceptable for the hazard present and that the user of the PPE is trained and capable to use it. After the Hazard and Risk Assessment process has been completed, specialized safety plans may need to be developed. The specific plan needed will be based on the hazards present, OSHA (Federal or State) requirements, and agency or organization requirements. The depth and complexity of the required plans will be dependent on the type of hazard and the risk that it poses, the number of investigators and ancillary people that will be working on the scene, and outside contractors that may be hired to assist with debris removal. If there are no hazards present that require a site specific safety program, then one does not need to be developed. A few examples of site specific safety plans could be needed to be developed are listed below, it should be noted that the listing is not all inclusive. The controlling investigator will need to determine the plans that are applicable and the other investigators may also need to have a program that is compatible for those employees they have working on the scene. Hazard Communication Site Plan would include identification of and the location of hazardous materials, location of Material Safety Data Sheets, how exposure to the chemicals would be provided, any labeling or identification of the materials, and how that information would be transmitted to those that could be exposed.

OSHA Publication 3186-06N, (2003). Also available as a 521 KB PDF, 29 pages. Provides a model hazardous communication program with an easy-to-use format to tailor to the specific requirements of your establishment. If the investigative process would include working within confined spaces as defined by OSHA 1910.146, than that standard would need to be reviewed and a site program developed. If there are no confined spaces or if investigators would not be working within a confined space, then a program does not have to be written. Depending on the complexity of the scene a formal organizational structure may need to be established for managing the safety component. For small scenes, with very limited safety concerns the safety component may be management in an informal manner only requiring the assessment of the scene and the development of a plan to control those hazards. For scenes of “Complex Investigations” safety will be a major function that will have to be assigned as a specific organizational function with direct input into the management of that investigation. Figure 12.3.3, is an example of how the safety function may be completed at a complex investigation.

****Insert Figure 12.3.3 Here**** (921-L138/F2010/Rop/Rec)

General safety meetings are conducted two or three times a workday. They can be conducted more frequently as need arises, times that the investigator or person managing the safety task should consider is at the start of the day and after lunch prior to the start of work. Printed on 9/18/2009 139 Report on Proposals – November 2010 NFPA 921 There may be a need to organize a special safety briefing just prior to a specific task or to remind those doing a specialized task as a part of the investigative process of key safety concerns and controls. A safety de-briefing may need to be completed at the end of the workday and at other times that there is a need. The end of the day general meeting can be used to remind those on scene of the requirements for the next day, or discuss safety issues that arose during the day. 12.4.4.3 Issues that are brought up by other investigators relative to safety related concerns should be addressed by the controlling investigator or team and the results provided to all investigators and teams operating at the scene as soon as the issue has been resolved. The proposal follows the outline prepared by the Safety Chapter Task group and includes information previously not included in the document and the section on Hazard and Risk Assessment relocated mostly intact from the 2008 edition. The proposed material provides essential information for the investigator responsible for the development of site specific plans and the management of those plans.

Create a new section 12.4 and title it Safety Plans, then move existing text as indicated to this section, renumber, and add or delete text as indicated. 12.4 Safety Plans. There could be a number of safety plans that the controlling investigator entity may be required to develop as a part of the investigative process. The complexity of the plans and the topics included will vary depending on the hazards and risks identified on the scene. Other factors may need to be considered including the number of investigators and support personnel, severity of the hazards and risks present, the use of specialized personal protective equipment (PPE), use of mechanized equipment, government and organizational policies and procedures. will need to be considered. 12.4.1* Hazard and Risk Assessment. One of the first tasks that should be completed before a fire or explosion scene investigation is begun is a Hazard and Risk Assessment. Thereby t The investigator will be able to determine the hazards present and control those hazards by engineering or administrative control or through the selection and use of appropriate personal protective equipment (PPE). Hazard and Risk Assessments are comprised of three different actions, as shown in 12.1.2.1 12.4.1 through 12.1.2.3.3 12.4.1.3.

****Insert Artwork Here****

(921-L138/F2010/Rop/Rec - Risk Assessment chart)

A. 12.4.1 The example form below is useful in documenting the Hazard and Risk Assessment. 12.1.2.1 12.4.1.1 Identify the Hazards. To simplify the process of hazard identification and to allow a more systematic and complete identification process, the investigator may can use a classification system of the hazards. It should be remembered that classification of hazards is not the most important action. The most important aspect of this process is to identify the presence of the hazard. 12.4.1.1 Identify the Hazards. The hazard and risk assessment process begins with the identification of hazards. To simplify the hazard identification process and to allow for more systematic and complete identification, hazards can be grouped by type. 12.1.2.1.1 12.4.1.1.1 Physical Hazards. Physical hazards, such as slip, trip, and fall hazards, or sharp surfaces, broken glass, and other such hazards, can cause a physical hazard to the investigator. 12.1.2.1.2 12.4.1.1.2 Structural Hazards. Many structural hazards are easily identified without the need to have specialized technical assistance, but in complex scenes or heavily damaged scenes the investigator may want to consider the assistance of a structural engineer. 12.1.2.1.3 12.4.1.1.3 Electrical Hazards. Electrical hazards at the investigation scene can come from the building's electrical utility service, emergency or standby power, or those tools and equipment the investigator brings on to the scene. The electrical service should be disconnected or the appropriate circuits isolated. 12.1.2.1.4 12.4.1.1.4 Chemical Hazards. Chemicals that are normally present at the scene or those that are a result of the incident should be considered. In commercial occupancies, the investigator may wish to obtain copies of Material Safety Data Sheets (MSDS) to determine the hazards of those products. The identification of chemical hazards that may be present as a result of the incident is more difficult. There are many reference documents the investigator may use to determine the hazards of suspected chemicals present at the investigation scene, including the National Institute of Safety and Health (NIOSH) Pocket Guide to Chemical Hazards. 12.1.2.1.5 12.4.1.1.5 Biological Hazards. Sources of biological hazards include blood, body fluids, and human remains. , bacteria, viruses, insects, plants, birds, animals, and humans. These sources can cause a variety of health effects ranging from skin irritation and allergies to infections (e.g., tuberculosis, communicable diseases), cancer, etc. Some of Printed on 9/18/2009 140 Report on Proposals – November 2010 NFPA 921 these hazards may not be recognized without specialized assistance. 12.1.2.1.6 12.4.1.1.26 Mechanical Hazards. Machinery and equipment present on the scene may have stored energy. Prior to working around machinery and equipment, the investigator will need to determine if they are at zero mechanical state or if they are still operational or functional. For specialized machinery or equipment, the investigator may need to seek the assistance of the property owner or other technical resource to assist in controlling the stored energy. 12.1.2.2 12.4.1.2 Determine the Risk of the Hazard. Depending on the specific hazard identified, the determination of the risks associated with the hazard could vary from simple qualitative assessments to complex quantitative assessments. Also, as a part of this analysis, the investigator will determine the likelihood that they will come in contact with that hazard. As an example, for a chemical (even if it is a chemical hazard) contained in a sealed drum or other containment device, the risk is minimal. Given that example, a control mechanism may be to isolate the area where the container is in order to prevent damage and potential release. Table 12.4.1 below provides guidance on selecting the level of risk a hazard may pose.

****Insert Table 12.4.1 here****

12.1.2.3 12.4.1.3 Control the Hazard. Following the determination of the risk level, this level should be compared to a suitable benchmark or acceptance criteria. In some cases, the acceptance criteria has been established by regulators (OSHA). To control a hazard, the investigator can utilize several methodologies that include engineering controls, administrative controls, or the selection and use of appropriate PPE. 12.1.2.3.1 12.4.1.3.1 Engineering Controls. Engineering controls can be as simple as placing appropriate shoring to reinforce damaged structural elements or the demolition of those areas after they are properly documented. Or, they can be very complex solutions that will require a structural engineer to evaluate, design corrective measures, and manage the installation of the corrective measures. 12.1.2.3.2 12.4.1.3.2 Administrative Controls. Administrative controls can include the isolation of an area by the use of signs or barrier tape, by briefing of those that will be working in the area of the hazards and cautioning them that they are not to enter within the isolated area, by obtaining specialized resources that have expertise dealing with the hazard present, or by a combination of methodologies. 12.1.2.3.3 12.4.1.3.3 The use of PPE is generally considered the least effective of the control measures. However, due to the conditions that the investigator may encounter at the scene and the duration of the work, PPE can be a suitable control mechanism. Care will need to be taken to determine the hazard present to ensure that the PPE selected is acceptable for the hazard present and that the user of the PPE is trained and capable to use it.

The specific plan needed will be based on the hazards present, OSHA (Federal or State) requirements, and agency or organization requirements. The depth and complexity of the required plans will be dependent on the type of hazard and the risk that it poses, the number of investigators and ancillary people that will be working on the scene, and outside contractors that may be hired to assist with debris removal. If there are no hazards present that require a site specific safety program, then one does not need to be developed. A few examples of site specific safety plans could be needed to be developed are listed below, it should be noted that the listing is not all inclusive. The controlling investigator entity will need to determine the plans that are applicable, such as those listed below. and the oOther investigators may also need to have a compatible program that is compatible for those for their employees. they have working on the scene. 12.4.2.1* Hazard Communication Site Plan (HazCom Plan). Hazard Communication Site The HazCom Plan would includes the identification of and the location of hazardous materials, location of Material Safety Data Sheets, how exposure to the chemicals would be provided may occur, any and labeling or identification of the materials., and how that information would be transmitted to those that could be exposed. The HazCom plan also requires training and documentation of such training. A.12.4.2.1 OSHA Model Plans and Programs for the OSHA Bloodborne Pathogens and Hazard Communications Standards. OSHA Publication 3186-06N, (2003). Also available as a 521 KB PDF, 29 pages. Provides a model hazardous communication program with an easy-to-use format to tailor to the specific requirements of your establishment. 12.4.2.2 Confined Space Program. If the investigative process would include working within If the investigation requires entry into a confined space as defined by OSHA 1910.146, then a site program should be developed. Any persons not entering the confined space will not require training. than that standard would need to be reviewed and a site program developed. If there are no confined spaces or if investigators would not be working within a confined space, then a program does not have to be written. 12.4.3 Management of Plans and Site Safety. Depending on the complexity of the scene a formal organizational Printed on 9/18/2009 141 Report on Proposals – November 2010 NFPA 921 structure may need to be established for managing the safety component. For small scenes, with very limited safety concerns the safety component may be management in an informal manner only requiring the assessment of the scene and the development of a plan to control those hazards. For scenes of “Complex Investigations” safety will be a major function that will may have to be assigned as a specific organizational function with direct input into the management of that investigation. Figure 12.3.3, is an example of how the safety function may be completed at a complex investigation.

****Insert Figure 12.3.3 Here****

(921-L138/F2010/Rop/Rec)

12.4.4 3 Safety Meetings and Briefings. General safety meetings are conducted two or three times a workday. They can be conducted more frequently as need arises, times that the investigator or person managing the safety task should consider is at the start of the day and after lunch prior to the start of work. General safety meetings should be conducted as frequently as needed, often two or three times a day. A special safety meeting may be required prior to beginning a new phase or a new task. A safety de-briefing can also be used at the end of the special tasks or at the end of the investigation. 12.4.4.1 Special Safety Briefings. There may be a need to organize a special safety briefing just prior to a specific task or to remind those doing a specialized task as a part of the investigative process of key safety concerns and controls. 12.4.4.2 Safety De-Briefings. A safety de-briefing may need to be completed at the end of the workday and at other times that there is a need. The end of the day general meeting can be used to remind those on scene of the requirements for the next day, or discuss safety issues that arose during the day. 12.4.4.3 Issues that are brought up by other investigators relative to safety related concerns should be addressed by the controlling investigator or team and the results provided to all investigators and teams operating at the scene as soon as the issue has been resolved. ul

Committee believes that the modification of the wording better explains the concept of this section. The committee believes that those sections that were deleted were unnecessary.

Printed on 9/18/2009 142

Table 12.4.1 Rating Impact Probability

High Disabling injury Repetitive Event Loss of body part, Greater than 50% of occurring or Fatality Has happened frequently in similar situations Medium Medical Aid Infrequent event Injury 10‐50% chance of occurring Low First Aid Injury Unlikely event Less than 10% chance of occurring Has never been observed but is still felt to be possible

921/L138/R/F2010/ROP

Report on Proposals – November 2010 NFPA 921 ______921-120 Log #139

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.5 and title it Chemical and Contaminate Exposure and add text as indicated. A part of the process of determining the type and level of Personal Protective Equipment (PPE) the investigator should understand some basic terminology associated with the exposure to chemicals and substances they may encounter on the fire and explosion scene.

Local effects occur at the site of the contact, for example an acid or caustic burn, or contamination by dusts or some liquids. Systemic effects occur at a site that could be distant from the entry point of the substance, ultimately acting on a target organ or organ systems.

Inhalation is the most common route of entry for toxins in the workplace. Inhalation is also the most rapid and efficient route of exposure, immediately introducing toxic chemicals into the respiratory tissues and bloodstream. For this reason it is considered the most important and potentially most serious method of exposure. This route can cause both local and systemic effects. Skin absorption occurs when the chemical passes directly through the skin. The primary function of the skin is to act as a barrier against the entry of foreign materials into the body. This barrier, which is effective against many chemicals, it does allow some toxic materials to readily pass through. Usually the presence of cuts and scrapes will greatly increase the absorption rate. Absorption through the mucous membrane is more effective than thorough the skin. Absorption can lead to local and systemic effects. Generally health hazards from ingestion are of a lesser concern. The toxicity of chemicals via the gastrointestinal tract is usually of a lower order. The entry of toxic materials through ingestion usually occurs due to contamination of food, drinks, and smoking. This contamination is most often associated with poor or no decontamination, food and beverages in the work place. Care taken to wash hands, arms, and face as well as the decontamination of clothing will limit the potential of ingesting a hazard. Also, moving to a place away from the potential contaminated area to eat or take rest breaks will assist in preventing cross contamination. Chemicals can enter the body when the skin is broken by an object, and the object is contaminated. Simple items such as a paper cut, if the paper is contaminated can in fact cause problems. The contamination can be great if the injury occurs around chemicals. Even small wounds should be treated to prevent contamination. Whenever possible the proper protective clothing should be worn to lessen the potential of injury and contamination. Chemicals can be absorbed directly through the eyes. In some instances, the chemical cannot be detected, only the symptoms of the toxic effects can be noticed. In other situations the chemical on contact causes an adverse affect. (Acids and Caustics)

. Acute exposures typically refer to a one time high level of exposure of over a short period of time. This type of exposure is usually associated with inhalation of high concentrations or from direct skin contact by splash or immersion. The symptoms and effects are usually immediately apparent. However, in some situations the symptoms can be delayed until the chemical reaches the target organ and can cause reversible and irreversible effects. Chronic exposures typically refer to repetitive or continuous low level exposures over a long period of time (weeks to years). The inhalation concentrations are usually low and direct skin contact is with substances that have a low potential for skin absorption. The symptoms and effects are usually delayed, in some instances 20-30 years. The effects can be reversible or irreversible. Repeated exposure either over a short period of time or longer periods, may allow the chemical exposure to add to the original dosage. Carbon Monoxide is an example of a material that the exposure dosage is cumulative. However, in this case over time, the Carbon Monoxide is removed from the body. Lead, however is cumulative and is not cleansed by the body through bodily functions. Some chemical exposure will require that there be a time span between exposure and onset of symptoms. This is called the latency period, carcinogens are examples of products that have a latency period. This work follows the outline of the Safety Chapter Task group and provides information for fire investigators in the selection of PPE which will be addressed in the next section. Also, based upon the toxicology references that were cited in 12.1 indicates that many of the investigators that have been exposed did not think about

Printed on 9/18/2009 143 Report on Proposals – November 2010 NFPA 921 the potential exposure route.

Create a new section 12.5 and title it Chemical and Contaminate Exposure and add text as indicated. As part of the process of determining the type and level of Personal Protective Equipment (PPE) the investigator should understand some basic terminology associated with the exposure to chemicals and substances they may encounter on the fire and explosion scene.

Systemic effects occur at a site that could be distant from the entry point of the substance, ultimately acting on a target organ or organ systems.

Inhalation is the most common route of entry for toxins. in the workplace. Inhalation is also the most rapid and efficient route of exposure, immediately introducing toxic chemicals into the respiratory tissues and bloodstream. For this reason it is considered the most important and potentially most serious method of exposure. This route can cause both local and systemic effects. Skin Surface absorption occurs when the chemical passes directly through the skin. The primary function of the skin is to act as a barrier against the entry of foreign materials into the body. This barrier, while which is effective against many chemicals, it does allow some toxic materials to readily pass through. Usually the presence of cuts and scrapes will greatly increase the absorption rate. Chemicals can be absorbed directly through the eyes. In some instances, the chemical cannot be detected, only the symptoms of the toxic effects can be noticed. Absorption occurs more readily through the mucous membrane is more effective than thorough the skin. Absorption can lead to local and systemic effects. Generally health hazards from ingestion are of a lesser concern. The toxicity of chemicals via the gastrointestinal tract is usually of a lower order. The entry of toxic materials through ingestion usually occurs due to contamination of food, drinks, and smoking. This type of exposure contamination is most often associated with poor or no decontamination. , or ingesting food and beverages. in the work place. Care taken to wash hands, arms, and face as well as the decontamination of clothing will limit the potential of ingesting a hazard. Also, moving to a place away from the potential contaminated area to eat or take rest breaks will assist in preventing cross exposure contamination. Chemicals can enter the body when the skin is broken penetrated by a contaminated object. , and the object is contaminated. Minor lacerations Simple items such as a paper cut, if the paper is contaminated, can in fact cause problems. The contamination can be great severe if the injury occurs around chemicals. Even small wounds should be treated to prevent contamination. Whenever possible the proper protective clothing should be worn to lessen the potential of injury and contamination. 12.5.3.5 Ocular. Chemicals can be absorbed directly through the eyes. In some instances, the chemical cannot be detected, only the symptoms of the toxic effects can be noticed. In other situations the chemical on contact causes an adverse affect. (Acids and Caustics)

Acute exposures typically refer to a one time high level of exposure of over a short period of time. This type of exposure is usually associated with inhalation of high concentrations or from direct skin contact by splash or immersion. The symptoms and effects are usually immediately apparent. However, in some situations the symptoms can be delayed until the chemical reaches the a target organ. and Effects can cause be reversible and or irreversible effects. Chronic exposures typically refer to repetitive or continuous low level exposures over a long period of time (weeks to years). In this type of exposure the inhalation concentrations are usually low or and direct skin contact involve is with substances that have a low potential for skin absorption. The symptoms and effects are usually delayed, in some instances 20-30 years. The effects can be reversible or irreversible. Repeated exposure either over a short period of time or longer periods, may allow the chemical exposure to add to the original dosage. Carbon Monoxide is an example of a material that the exposure dosage is cumulative. However, in this case over time, the Carbon Monoxide is removed from the body. Lead, however is cumulative and is not cleansed by the body through bodily functions. Some chemical exposures will not cause symptoms until some time after exposure. require that there be a time span between exposure and onset of symptoms. This is called the latency period., cCarcinogens are examples of products that have a latency period.

The committee believes changes in the proposed text improves the clarity of the discussion.

Printed on 9/18/2009 144 Report on Proposals – November 2010 NFPA 921

Printed on 9/18/2009 145 Report on Proposals – November 2010 NFPA 921 ______921-121 Log #140

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.6 and title it Personal Protective Equipment, then move existing text as indicated to this section, renumber, and add or delete text as indicated.

12.1.2.3.3 The use of PPE is generally considered the least effective of the control measures. However, due to the conditions that the investigator may encounter at the scene and the duration of the work, PPE can be a suitable control mechanism. Care will need to be taken to determine the hazard present to ensure that the PPE selected is acceptable for the hazard present, and that the user of the PPE is trained and capable to use it., the user understands the limitations of the equipment, the user understands the need for effective personal decontamination after using the equipment, and that the user knows how to inspect and clean the equipment. Proper personal protective equipment (PPE), including safety shoes or boots with a protective mid-puncture resistant sole and steel toe, gloves, safety helmet, eye protection, and protective clothing, should be worn at all times while investigating the scene. The type of protective clothing will depend on the type and level of hazards present. When there is a potential for injuries from falling objects or potential cuts or scrapes from sharp objects, fire-fighting turnout gear or similar clothing that provides most of this type of protection and may be the best choice. When an investigator is dealing with a potential exposure of toxic substances and debris, disposable coveralls as required by some safety-related regulations may be necessary. In high hazard atmospheres, may be required. Whenever PPE is worn to provide protection from a hazardous environment, the wearer must be trained in the proper donning, doffing, limitations, use, and decontamination of such equipment to assure that it is properly worn and functioning. Whenever PPE is worn to provide protection from a hazardous environment, it should be properly decontaminated or disposed of in order to avoid subsequent exposure to residues. The investigator should be trained in the proper methodology to complete personal decontamination and the proper method of decontamination or disposal of PPE worn in order to avoid subsequent exposure to residues still in the clothing and gear. The effort required to decontaminate clothing can be reduced through the use of outer disposable garments such as Tyvek® coveralls and latex booties over footware. Even when choosing to wear standard cloth coveralls or fire-fighting turnout gear, consideration should be given to the safe handling of the clothing so as not to create additional exposure. Investigators should decontaminate all potentially contaminated personal protective clothing and equipment (PPE) prior to leaving the scene to limit the potential for contaminating their vehicles, offices and residences (or change their clothes to avoid spreading contamination to “clean” areas away from the scene). If investigators opt to wash their clothing at home, contaminated clothing should not be washed with other “clean” clothing to avoid the potential for cross-contamination. Investigators should also consider using a commercial laundry service on a regular basis to ensure the greatest probability that their protective clothing does not contain potentially harmful contaminants that may lead to short and long-term health effects. In those situations where these measures are not utilized or practical, investigators should employ a basic decontamination process that consists of scrubbing and rinsing contaminated gear and equipment with soap (detergent) and water. This process should be implemented in accordance with any specific manufacturer’s recommendations for their respective equipment such as respirators. For specific guidance in decontamination of turnout gear, , should be consulted. For incidents where hazardous materials are confirmed to be present, decontamination procedures may be obtained from . In addition to occupational laws and regulations there are standards that are promulgated in relation to the various components of firefighting PPE. This gear is listed in the National Fire Protection Association standard; NFPA 1971. This standard provides minimum requirements for the following components: Turnout Coat Turnout Pants Helmet with eye shield

Printed on 9/18/2009 146 Report on Proposals – November 2010 NFPA 921 Firefighting type gloves Firefighting type boots In addition to the National Fire Protection Association standards which may be adopted, there are mandatory regulations as to the use of PPE. These mandatory requirements come in the form of OSHA standards one of which covers mandates for PPE: OSHA 29, CFR 1910.132 to 1910. 139. The scene itself will dictate which level of protection will be required. Table 12.5.1.5 provides examples of PPE and the part of the body protected by that equipment.

****Insert Table Here**** (921-L140_Tb12.5.2_R.doc)

A.12.1.3.1 A. For additional information concerning the use of respiratory protection Personal Protective Equipment, see 29 CFR 1910.134 “Respiratory Protection” SubPart I, Personal Protective Equipment, 29CFR 1926 SubPart E, Personal Protective Equipment, and NFPA 1500, Standard on Fire Department Occupational Safety and Health Program,, 2002 edition (see Section 7.8)., Respiratory Protection for Fire and Emergency Services, 1st Edition, IFSTA, NFPA 472 Standard for Competence of Responders to Hazardous Materials/Weapons of Mass Destruction Incidents, NFPA 1404Standard for Fire Service Respiratory Protection Training, NFPA 1851Standard on Selection, Care, and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting, NFPA 1852 Standard on Selection, Care, and Maintenance of Open-Circuit Self-Contained Breathing Apparatus (SCBA), NFPA 1981 Standard on Open-Circuit Self-Contained Breathing Apparatus (SCBA) for Emergency Services, NFPA 1992 Standard on Liquid Splash-Protective Ensembles and Clothing for Hazardous Materials Emergencies, NFPA 1994 Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents 2007 Edition and Safety and Health Guidelines for the Fire and Explosion Investigator, Donahue, IFSTA. . Not all forms of eye protection are the same. The smaller flip down shields installed on fire helmets only provide limited protection and are not recommended by themselves. Larger flip down shields covering the entire face are available and provide better protection from splashing liquids. Safety glasses should be worn with the side shields to provide adequate protection, goggles will afford the best protection from liquid splashes. 12.6.2.1.1 Short of wearing a full facepiece from an air purifying respirator (APR) or self contained breathing apparatus (SCBA), goggles are a good option for protection. They should fit snugly against the face to provide optimum protection. There are two options for goggles, vented and non-vented. Vented goggles will give protection from flying objects. They will also breathe, potentially preventing fogging of the lenses. However, if the atmosphere contains dust, or should the investigators actions create dust in the atmosphere, they should be wearing the non vented variety which will give more protection from dust and small minute particles. These goggles should be treated with a non fogging chemical to keep the lenses clear in most circumstances. 12.6.2.1.2 The best protection for both the eyes and face is the full facepiece filter mask or SCBA. Because they may tend to fog up like the goggles, it is a good practice to use an anti-fog agent on the interior. This will help assure the wearer has full vision while walking around a hazardous location. 12.6.2.1.3.There may be a further concern for safety when using specialized tools and equipment. When using lasers there needs to be added protection for the eyes in the use of specific filters to prevent damage to the eyes. In the instances where it is necessary for cutting or welding to remove or to shore up structural elements, it will be necessary to wear the heavier eye protection to prevent burning of the eyes from the arc’s these devices can produce. The best protection from falling objects or from impact of the head with obstacles, such as low beams, is the firefighting helmet. However, there is a drawback from using firefighting helmets for long periods of time because of the weight, there is a sufficient strain on the neck that can cause additional fatigue. 15.6.2.2.1 Hard Hat. Should there be limited exposure of falling objects or a less likely impact from objects on the scene the investigator may want to consider wearing a lighter hardhat. One without a brim will also be an advantage when using photographic equipment, but without the brim deflection of lightweight objects may be limited. Otherwise the hard hat may have to be removed each time the investigator puts the camera to the eye to take a photograph as hardhats do not provide the protection required when worn backwards. 15.6.2.2 Head protection should be washed and decontaminated after use, inspected prior to use, replaced if damaged due to impact or UV deterioration, and no glues or solvents used that do not meet the manufactures recommendations. Footwear must protect the wearer as well as be comfortable. To not be comfortable may create other medical complications such as blisters or sores which will limit the productivity of the wearer. The footwear must match the scene being searched. If the scene is still laden with water then the investigator should be wearing Printed on 9/18/2009 147 Report on Proposals – November 2010 NFPA 921 boots that are water resistant with an outer surface such as rubber to prevent absorption of contaminates. When the scene is dry with no contaminates the investigator may choose to wear lighter work boots. 12.6.2.3.1 When walking through debris there is always a risk of nails or other sharp objects penetrating the sole of the boot. In these situations the boots should be puncture resistant. This can be done with steel soles or composite materials that will resist such punctures. Some boots even offer sidewall protection from puncture in the form of materials that are soft and flexible. In addition the footwear must be steel toe to meet OSHA regulations but more important protect the wearer from falling objects. The proper selection of gloves that provide puncture protection or protection from biological or chemical contamination should also be considered. When conducting scene excavation or debris removal, puncture-resistant fire-fighting gloves or lighter leather gloves should be selected. Firefighter type gloves will offer more protection but little dexterity of the fingers. The lighter leather gloves will provide the dexterity, but lowers the puncture resistance of the glove and can be punctured from sharp objects in the fire debris and as such caution should be exercised. Additional protection from the leaching of toxic substances should be provided by wearing latex (or similar) gloves underneath the leather gloves., Depending on the situation the investigator may want to consider wearing latex or nitrile gloves under the leather or other glove to increase the level of protection. or t The investigator may also need to select specialty, such as chemical resistant gloves, that would be more appropriate for the hazard present. Wearing multiple layers of gloves can be an advantage when using camera equipment or other tools or instruments. The outer layer can be quickly removed when using equipment preventing cross contamination and then donned when returning to other tasks. Hearing protection may also be necessary depending on the noise levels that may be caused by the use of heavy equipment and other tools. Hearing protection can range from ear plugs, canal caps, and headsets (standard to electronic) The type or level of protection will be dependent on the maximum sound being projected from the equipment and the noise reduction capability of the hearing protection selected. While a concern when wearing hearing protection is the reduction of the ability to hear sounds that could be warnings of other hazards from cracking of building components to normal conversation. A solution may be the use of hearing protection that enables normal sounds such as voices to come through but still reduces loud or high pitched noise. This can be in the form of ear muffs with electronic filters that takes out the loud sound but electronically allows other sounds like voices to come through. 12.1.3.1* 12.6.2.6 Respiratory Protection. Appropriate respiratory protection is necessary at most fire scenes. Immediately following fire extinguishment and during overhaul, there may be combustible gases and smoke, low oxygen concentrations, toxic or carcinogenic airborne particles, and high heat conditions present. In these atmospheres, the investigator should utilize the appropriate level of respiratory protection. Respiratory protection that could be worn includes Air Purifying Respirators (APR), Powered Air Purifying Respirators (PAPR), Self Contained Breathing Apparatus (SCBA), Supplied Air Respirators, or combination SCBA and Supplied Air Respirators in combination with and other Personal Protective Equipment( PPE). 12.6.2.6.1 Air Purifying Respirators and Powered Air Purifying Respirators. The use of that are appropriate and should recognize that air-purifying respirators should not be utilized is not permitted in atmospheres where the oxygen level is below 19.5 percent or Immediately Dangerous to Life and Health (IDLH) atmospheres conditions are present. Oxygen Deficient or IDLH Atmospheres will require the use of Positive Pressure Self Contained Breathing Apparatus, Closed Circuit Breathing Apparatus, Airline Supplied Respirators with an escape cylinder or Combination SCBA and Airline Supplied. 12.6.2.6.2 The act of disturbing the fire debris can create dust and release organic vapors, which should be considered hazardous, and the investigator should be wearing a filter mask and an air purifying respirator with appropriate cartridges. The decision to wear a full-face respirator versus a half-face respirator will be up to the investigator and the employer and the type selected depends on the hazards present at the scene. In the respirator selection process, consideration should be given to eye protection, as many toxic substances can be absorbed through the sclera. If a half-face respirator is selected, then wearing a pair of vented goggles will provide protection from this type of hazard absorption of hazards through the sclera of the eye. 12.6.2.6.3 If Regardless of the type of respiratory protection is worn, the investigator or other individual on the scene required to wear respiratory protection equipment will need to be properly trained, medically and physically fit, and have been properly fit tested when required for the particular respiratory protection being worn. Additional guidance concerning respirators and the responsibilities of the employer and employee are contained in Occupational Safety and Health Administration (OSHA) Regulation 29 CFR, Section 1910.134 (Respiratory Protection). The proposed material follows the outline developed by the Safety Chapter Task Group and represents combined efforts of the task group members and greatly enhances the information provided to the investigator. The information contained also follows recognized OSHA requirements and other national standards. This section serves as a quick reference of the options available to protect the investigator during the investigation process. Printed on 9/18/2009 148 Report on Proposals – November 2010 NFPA 921

Renumber the table to 12.6.2 Create a new section 12.6 and title it Personal Protective Equipment, then move existing text as indicated to this section, renumber, and add or delete text as indicated. 12.6 Personal Protective Equipment (PPE). 12.1.2.3.3 The use of PPE is generally considered the least effective of the control measures. However, due to the conditions that the investigator may encounter at the scene and the duration of the work, PPE can be a suitable control mechanism. Care will need to be taken to determine the hazard present to ensure that the PPE selected is acceptable for the hazard present, and that the user of the PPE is trained and capable of to use using it., the user understands the limitations of the equipment, the user understands the need for effective personal decontamination after using the equipment, and that the user knows how to inspect and clean the equipment. Proper personal protective equipment (PPE), including safety shoes or boots with a protective mid-puncture resistant sole and steel toe, gloves, safety helmet, eye protection, and protective clothing, should be worn at all times while investigating the scene. The type of protective clothing will depend on the type and level of hazards present. When there is a potential for injuries from falling objects or potential cuts or scrapes from sharp objects, fire-fighting turnout gear or similar clothing that provides most of this type of protection and may be the best choice. When an investigator is dealing with a potential exposure of toxic substances and debris, disposable coveralls as required by some safety-related regulations may be necessary. In high hazard atmospheres, hazardous environmental suits may be required. Whenever PPE is worn to provide protection from a hazardous environment, the wearer must be trained in the proper donning, doffing, limitations, use, and decontamination of such equipment to assure that it is properly worn and functioning. Whenever PPE is worn to provide protection from a hazardous environment, it should be properly decontaminated or disposed of in order to avoid subsequent exposure to residues. The investigator should be trained in the proper methodology to complete personal decontamination and the proper method of decontamination or disposal of PPE worn in order to avoid subsequent exposure to residues still in the clothing and gear. The effort required to decontaminate clothing can be reduced through the use of outer disposable garments such as Tyvek® coveralls and latex booties over footware. Even when choosing to wear standard cloth coveralls or fire-fighting turnout gear, consideration should be given to the safe handling of the clothing so as not to create additional exposure. Investigators should decontaminate all potentially contaminated personal protective clothing and equipment (PPE) prior to leaving the scene to limit the potential for contaminating their vehicles, offices and residences (or change their clothes to avoid spreading contamination to “clean” areas away from the scene). If investigators opt to wash their clothing at home, contaminated clothing should not be washed with other “clean” clothing to avoid the potential for cross-contamination. Investigators should also consider using a commercial specialty laundry service on a regular basis to ensure the greatest probability that their protective clothing does not contain potentially harmful contaminants that may lead to short and long-term health effects. In those situations where these measures are not utilized or practical, investigators should employ a basic decontamination process that consists of scrubbing and rinsing contaminated gear and equipment with soap (detergent) and water. This process should be implemented in accordance with any specific manufacturer’s recommendations for their respective equipment such as respirators.

For incidents where hazardous materials are confirmed to be present, decontamination procedures may be obtained from NFPA Supplement 10, Guidelines for Decontamination of Fire Fighters and Their Equipment Following Hazardous Materials Incidents. 12.6.1.5 National Standards In addition to occupational laws and regulations there are standards that are promulgated in relation to the various components of firefighting PPE. This gear is listed in the National Fire Protection Association standard; NFPA 1971. This standard provides minimum requirements for the following components: Turnout Coat Turnout Pants Helmet with eye shield Firefighting type gloves Firefighting type boots

In addition to the National Fire Protection Association standards which may be adopted, there are mandatory Printed on 9/18/2009 149 Report on Proposals – November 2010 NFPA 921 regulations as to the use of PPE. These mandatory requirements come in the form of OSHA standards one of which covers mandates for PPE: OSHA 29, CFR 1910.132 to 1910. 139. The scene itself will dictate which level of protection will be required. Table 12.5.1.56.2 provides examples of PPE and the part of the body protected by that equipment.

****Insert Table Here****

(921-L140_Tb12.5.2 Tb 12.6.2_R.doc)

A.12.1.3.1 In addition to occupational laws and regulations there are standards that are promulgated in relation to the various components of firefighting PPE. This gear is listed in the National Fire Protection Association standard; NFPA 1971. This standard provides minimum requirements for the following components: Turnout Coat Turnout Pants Helmet with eye shield Firefighting type gloves Firefighting type boots In addition to the National Fire Protection Association standards which may be adopted, there are mandatory regulations as to the use of PPE. These mandatory requirements come in the form of OSHA standards one of which covers mandates for PPE: OSHA 29, CFR 1910.132 to 1910. 139. The scene itself will dictate which level of protection will be required. For additional information concerning the use of respiratory protection Personal Protective Equipment, see 29 CFR 1910.134 “Respiratory Protection” SubPart I, Personal Protective Equipment, 29CFR 1926 SubPart E, Personal Protective Equipment, and NFPA 1500, Standard on Fire Department Occupational Safety and Health Program,, 2002 edition (see Section 7.8)., Respiratory Protection for Fire and Emergency Services, 1st Edition, IFSTA, NFPA 472 Standard for Competence of Responders to Hazardous Materials/Weapons of Mass Destruction Incidents, NFPA 1404Standard for Fire Service Respiratory Protection Training, NFPA 1851Standard on Selection, Care, and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting, NFPA 1852 Standard on Selection, Care, and Maintenance of Open-Circuit Self-Contained Breathing Apparatus (SCBA), NFPA 1981 Standard on Open-Circuit Self-Contained Breathing Apparatus (SCBA) for Emergency Services, NFPA 1992 Standard on Liquid Splash-Protective Ensembles and Clothing for Hazardous Materials Emergencies, NFPA 1994 Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents 2007 Edition and Safety and Health Guidelines for the Fire and Explosion Investigator, Donahue, IFSTA. 12.6.2.1 Eye Protection. Not all forms of eye protection are the same. The smaller flip down shields installed on fire helmets only provide limited protection and are not recommended by themselves. Larger flip down shields covering the entire face are available and provide better protection from splashing liquids. Safety glasses should be worn with the side shields to provide adequate protection, goggles will afford the best protection from liquid splashes. 12.6.2.1.1 Short of wearing a full facepiece from an air purifying respirator (APR) or self contained breathing apparatus (SCBA), goggles are a good option for protection. They should fit snugly against the face to provide optimum protection. There are two options for goggles, vented and non-vented. Vented goggles will give protection from flying objects. They will also breathe, potentially preventing fogging of the lenses. However, if the atmosphere contains dust, or should the investigators actions create dust in the atmosphere, they should be wearing the non vented variety which will give more protection from dust and small minute particles. These goggles should be treated with a non fogging chemical to keep the lenses clear in most circumstances. 12.6.2.1.2 The best protection for both the eyes and face is the full facepiece filter mask or SCBA. Because they may tend to fog up like the goggles, it is a good practice to use an anti-fog agent on the interior. This will help assure the wearer has full vision while walking around a hazardous location. 12.6.2.1.3.There may be a further concern for safety when using specialized tools and equipment. When using lasers there needs to be added protection for the eyes in the use of specific filters to prevent damage to the eyes. In the instances where it is necessary for cutting or welding to remove or to shore up structural elements, it will be necessary to wear the heavier eye protection to prevent burning of the eyes from the arc’s these devices can produce. 12.6.2.2 Head protection. The best protection from falling objects or from impact of the head with obstacles, such as low beams, is the firefighting helmet. However, there is a drawback from using firefighting helmets for long periods of time because of the weight, there is a sufficient strain on the neck that can cause additional fatigue. 12.6.2.2.1 Hard Hat. Should there be limited exposure of falling objects or a less likely impact from objects on the Printed on 9/18/2009 150 Report on Proposals – November 2010 NFPA 921 scene the investigator may want to consider wearing a lighter hardhat. One without a brim will also be an advantage when using photographic equipment, but without the brim deflection of lightweight objects may be limited. Otherwise the hard hat may have to be removed each time the investigator puts the camera to the eye to take a photograph as hardhats do not provide the protection required when worn backwards. 12.6.2.2 Head protection should be washed and decontaminated after use, inspected prior to use, replaced if damaged due to impact or UV deterioration, and no glues or solvents used that do not meet the manufactures recommendations. 12.6.2.3 Foot Protection. Footwear must protect the wearer as well as be comfortable. To not be comfortable may create other medical complications such as blisters or sores which will limit the productivity of the wearer. The footwear must match the scene being searched. If the scene is still laden with water then the investigator should be wearing boots that are water resistant with an outer surface such as rubber to prevent absorption of contaminates. When the scene is dry with no contaminates the investigator may choose to wear lighter work boots. 12.6.2.3.1 When walking through debris there is always a risk of nails or other sharp objects penetrating the sole of the boot. In these situations the boots should be puncture resistant. This can be done with steel soles or composite materials that will resist such punctures. Some boots even offer sidewall protection from puncture in the form of materials that are soft and flexible. In addition the footwear must be steel toe to meet OSHA regulations but more important protect the wearer from falling objects. 12.1.3.2 12.6.2.4 Hand Protection. The proper selection of gloves that provide puncture protection or protection from biological or chemical contamination should also be considered. When conducting scene excavation or debris removal, puncture-resistant fire-fighting gloves or lighter leather gloves should be selected. Firefighter type gloves will offer more protection but little dexterity of the fingers. The lighter leather gloves will provide the dexterity, but lowers the puncture resistance of the glove and can be punctured from sharp objects in the fire debris and as such caution should be exercised. Additional protection from the leaching of toxic substances should be provided by wearing latex (or similar) gloves underneath the leather gloves., Depending on the situation the investigator may want to consider wearing latex or nitrile gloves under the leather or other glove to increase the level of protection. or t The investigator may also need to select specialty, such as chemical resistant gloves, that would be more appropriate for the hazard present. Wearing multiple layers of gloves can be an advantage when using camera equipment or other tools or instruments. The outer layer can be quickly removed when using equipment preventing cross contamination and then donned when returning to other tasks. 12.6.2.5 Hearing Protection. Hearing protection may also be necessary depending on the noise levels that may be caused by the use of heavy equipment and other tools. Hearing protection can range from ear plugs, canal caps, and headsets (standard to electronic) The type or level of protection will be dependent on the maximum sound being projected from the equipment and the noise reduction capability of the hearing protection selected. While a concern when wearing hearing protection is the reduction of the ability to hear sounds that could be warnings of other hazards from cracking of building components to normal conversation. A solution may be the use of hearing protection that enables normal sounds such as voices to come through but still reduces loud or high pitched noise. This can be in the form of ear muffs with electronic filters that takes out the loud sound but electronically allows other sounds like voices to come through. 12.1.3.1* 12.6.2.6 Respiratory Protection. Appropriate respiratory protection is necessary at most fire scenes. Immediately following fire extinguishment and during overhaul, there may be combustible gases and smoke, low oxygen concentrations, toxic or carcinogenic airborne particles, and high heat conditions present. In these atmospheres, the investigator should utilize the appropriate level of respiratory protection. Respiratory protection that could be worn includes Air Purifying Respirators (APR), Powered Air Purifying Respirators (PAPR), Self Contained Breathing Apparatus (SCBA), Supplied Air Respirators, or combination SCBA and Supplied Air Respirators in combination with and other Personal Protective Equipment( PPE). 12.6.2.6.1 Air Purifying Respirators and Powered Air Purifying Respirators. The use of that are appropriate and should recognize that air-purifying respirators should not be utilized is not permitted in atmospheres where the oxygen level is below 19.5 percent or Immediately Dangerous to Life and Health (IDLH) atmospheres conditions are present. Oxygen Deficient or IDLH Atmospheres will require the use of Positive Pressure Self Contained Breathing Apparatus, Closed Circuit Breathing Apparatus, Airline Supplied Respirators with an escape cylinder or Combination SCBA and Airline Supplied. 12.6.2.6.2 The act of disturbing the fire debris can create dust and release organic vapors, which should be considered hazardous, and the investigator should be wearing a filter mask and an air purifying respirator with appropriate cartridges. The decision to wear a full-face respirator versus a half-face respirator will be up to the investigator and the employer and the type selected depends on the hazards present at the scene. In the respirator selection process, consideration should be given to eye protection, as many toxic substances can be absorbed through the sclera. If a half-face respirator is selected, then wearing a pair of vented goggles will provide protection from this type of hazard absorption of hazards through the sclera of the eye. Printed on 9/18/2009 151 Report on Proposals – November 2010 NFPA 921 12.6.2.6.3 If Regardless of the type of respiratory protection is worn, the investigator or other individual on the scene required to wear respiratory protection equipment will need to be properly trained, medically and physically fit, and have been properly fit tested when required for the particular respiratory protection being worn. Additional guidance concerning respirators and the responsibilities of the employer and employee are contained in Occupational Safety and Health Administration (OSHA) Regulation 29 CFR, Section 1910.134 (Respiratory Protection).

The material listed in the appendix item 12.6.2 covers in much greater detail the appropriate examples of personal protection equipment. The text as modified better clarifies the subject.

Printed on 9/18/2009 152 Table 12.5.2 Body Example of PPE Eye Safety Glasses, Goggles, UV, Welding and Laser Face Face Shield Head Hard Hat, Helmet Feet Safety Shoes, Boots Hands and Arms Gloves Body Vests, Aprons, Chemical Suits Hearing Earplugs, Canal Caps and Earmuffs Respiratory APR, PAPR, SCBA, Air Supplied

Report on Proposals – November 2010 NFPA 921 ______921-122 Log #141

______Ronald L. Hopkins, Eastern Kentucky University Create New 12.7 and title it Emergency Action Plans and include the text proposed below. There may be a number of potential emergency situations that could occur while processing a fire or explosion scene. Proper action by those on the scene will lessen the potential impact of those emergencies. Contained in the General Industry OSHA Standards 1910.38, there is a requirement to develop and implement an emergency action plan for emergencies. While that standard does reference what is needed for a fire emergency, there is application for other emergencies to be included. Emergency action plans for two investigators processing the scene may be simple and communicated verbally to each other. On large or complex scenes where there will be a number of investigators present and they may be working in various areas of the building or site, a more formalized set of Emergency Action Plans may need to be developed. The following plan examples are intended to provide the investigator with some basic information that should be included in the Emergency Action Plans. In the event that the scene will need to be evacuated because of a change in structural conditions, accidental release of a hazardous material, severe weather, or some other unexpected condition an emergency action plan should be developed and implemented. Included in the evacuation plan would be a method of notification, routes of escape, location for gathering, and methodology to account for all people that were working at the scene. This plan can formal and written or discussed by all present during the investigation process. This information should be communicated to additional investigators or groups as they arrive on scene. As with the emergency evacuation plan, this plan can be written or simply communicated to participants during a safety meeting. The medical emergency plan should include locations of hospitals or other emergency facilities, emergency phone numbers for the local emergency medical system (EMS), the location of the first aid kit that is kept on scene, and notification of appropriate management controlling the scene. There may be additional items included as dictated by the condition or location of the scene. . As with the other plans previously discussed, the severe weather plan will only need to be considered if there is a potential for severe weather (Thunderstorms, Tornados, Wind, Snow, Cold). While it may seem common sense, when conditions could change rapidly, it is advantageous to have organized and discussed the methodology of notification and where the meeting place is located. Assuming that the original fire has been extinguished, there are still situations that may occur on the fire or explosion scene during the investigative process that may cause a fire. The use of mechanized equipment, portable tools, cutting and welding equipment can all be possible ignition sources. Additional sources of fuels other than ordinary combustibles would include hazardous materials and the building utilities. Included in the Fire Emergency Plan would be the phone number and location of the nearest fire department, notification of others that are working on the scene, evacuation routes and meeting places, and a methodology for the accounting of personnel. This information should be communicated to all individuals that will be working on the scene regardless of their responsibilities. . There may be a need to develop additional emergency action plans based on issues identified that are specific to the scene. If additional plans are needed, then the controlling investigation team would be responsible for the development of the plans and the communication of the plan information to all others that would be working at the scene. The material proposed follows the outline developed by the Safety Chapter Task Group and is intended to provide the investigator with baseline information that should be included in the fire or explosion scene Emergency Action Planning Process. It should be noted that there is no requirement to have a formal written plan, but rather to at least address the items during the planning process for working a fire or explosion scene. There is also guidance in this section for those that may be in involved in complex investigation where a more formal methodology of the development and implementation of Emergency Action Plans. The requirement to include this information in the workplace can be found in the OSHA Documents 1910.38.

Create New 12.7 and title it Emergency Action Plans and include the text proposed below. There may be A number of potential emergency situations that could can occur while processing a fire or explosion scene. Proper action by those on the scene will lessen the potential impact of those emergencies. Contained in the General Industry OSHA Standards 1910.38, there is a requirement to develop and implement an emergency action plan for emergencies. While that standard does reference what is needed for a fire emergency, there is application for other emergencies to be included. An eEmergency action plans for two investigators

Printed on 9/18/2009 153 Report on Proposals – November 2010 NFPA 921 processing the scene may be simple and communicated verbally to each other. On large or complex scenes where there will be a number of investigators present and they may be working in various different areas of the building or site, a more formalized set of emergency action plans may need to be developed. The following plan examples are intended to provide the investigator with some basic information that should be included in the emergency action plans. In the event that the scene will need to be evacuated because of a change in structural conditions, accidental release of a hazardous material, severe weather, or some other unexpected condition an emergency action evacuation plan should be developed and implemented. Included in tThe evacuation plan would be should include a method of notification, routes of escape, location for gathering, and methodology to account for all people that were working at the scene. This plan can be formal and written or discussed by all present during the investigation process. This information should be communicated to additional investigators or groups as they arrive on scene. As with the emergency evacuation plan, tThis plan can be written or simply communicated to participants during a safety meeting. The medical emergency plan should include locations of hospitals or other emergency facilities, emergency phone numbers for the local emergency medical system (EMS), the location of the first aid kit that is kept on scene, and notification of appropriate management controlling the scene. There may be additional items included as dictated by the condition or location of the scene. As with the other plans previously discussed, the severe weather plan will only need to be considered if there is a potential for severe weather. (Thunderstorms, Tornados, Wind, Snow, Cold). While it may seem common sense, wWhen conditions could change rapidly, it is advantageous to have organized and discussed the methodology of notification and where the meeting place is located. Assuming that the original fire has been extinguished, there are still situations that may occur on the fire or explosion scene during the investigative process that may cause a fire. The use of mechanized equipment, portable tools, cutting and welding equipment can all be possible ignition sources. Additional sources of fuels other than ordinary combustibles would include hazardous materials and the building utilities. Included in the fire emergency plan would be the phone number and location of the nearest fire department, notification of others that are working on the scene, evacuation routes and meeting places, and a methodology for the accounting of personnel. This information should be communicated to all individuals that will be working on the scene regardless of their responsibilities. There may be a need to develop additional emergency action plans based on issues identified that are specific to the scene. If additional plans are needed, then the controlling investigation team entity would be responsible for the development of the plans and the communication of the plan information to all others that would be working at the scene.

The Committee believes that the changes reflect improvements in the information imparted by the submitter.

Printed on 9/18/2009 154 Report on Proposals – November 2010 NFPA 921 ______921-123 Log #142

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.8 and title it Post Scene Activities and add the following text to that section. There are a number of safety related items that are completed after processing a fire or explosion scene. Some of the items such as medical evaluations are an ongoing safety related program. Decontamination of people, personal protective equipment, clothing, tools, and equipment used on scene must be completed in a manner that will not cause cross contamination or exposure to others. Part of this process has been discussed previously in the safety chapter, but it is important to include mention of this important action when the work required to process the scene is completed. The amount and level of decontamination efforts has to be commensurate with the hazards identified and the level of contamination exposed. In some instances, a simple washing of the person, tools, clothing and equipment is sufficient in other situations, a more formal manner of decontamination and disposal may be required. The process should be established prior to starting the scene process. Exposure to health hazards during the processing of the fire or explosion scene should be noted on the appropriate medical related documents. If the investigator was exposed to health hazards during the investigation additional medical screening may be required. Reporting of exposure and additional medical screening should be done in accordance with the employer’s procedures and policies. This material follows the outline developed by the Safety Chapter Task Group and is intended to bring additional attention to the investigation concerning the need for appropriate decontamination as well as the need to keep medical records updated and if required as a result of exposure to health hazards the need to be appropriately screened to determine the effects of the exposure.

Create a new section 12.8 and title it Post Scene Activities and add the following text to that section. There are a number of safety related items that are may need to be completed after processing a fire or explosion scene. Some of the items such as medical evaluations are an ongoing safety related program. Two such activities are described below. Decontamination of people, personal protective equipment, clothing, tools, and equipment used on scene must be completed in a manner that willThe amount and level of decontamination efforts has to should be commensurate with the hazards identified and the level of contamination exposed ex not cause cross contamination or exposure to others. Part of this process has been discussed previously in the safety chapter, but it is important to include mention of this important action when the work required to process the scene is completed. The amount and level of decontamination efforts has to should be commensurate with the hazards identified and the level of contamination exposed exposure. In some instances, a simple washing of the person, tools, clothing and equipment is sufficient in other situations, a more formal manner of decontamination and disposal may be required. The process should be established prior to starting the scene process. Exposure to health hazards during the processing of the fire or explosion scene should be noted on the appropriate medical related documents. If the investigator was exposed to health hazards during the investigation, additional medical screening may be required. Reporting of exposure and additional medical screening should be done in accordance with the employer’s agency procedures and policies. The investigator should be aware that governmental reporting and documenting requirements may also apply. (See OSHA 29 CFR 1910.120.)

The Committee believes changes to the text improves clarity. Further, it believes alerting the investigator to governmental requirements in this area is worthwhile.

Printed on 9/18/2009 155 Report on Proposals – November 2010 NFPA 921 ______921-124 Log #143

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.9 and title it Off -Scene Investigation Activities, then move existing text as indicated to this section, renumber, and add or delete text as indicated. 12.4 12.4.1 12.9.1 Safety considerations also extend to ancillary fire investigation activities not directly related to the fire or explosion scene examination. Such ancillary investigation activities include physical evidence handling and storage, laboratory examinations and testing, and live fire or explosion recreations and demonstrations. The basic safety precautions dealing with use of safety clothing and equipment, and the proper storage and prominent labeling of hazardous materials evidence, thermal, inhalation, and electrical dangers of fire and explosion recreations or demonstrations should be followed. The investigator may have to conduct witness interviews away from the fire scene in locations that are not totally controlled by the investigator. In that case the investigator should be aware of surroundings and other actions that could cause harm to the investigator. Environmental hazards may include dogs or other dangerous animals, armed witness, gang activities in the neighborhood or any other situation that may put the investigator at risk. 12.4.2 12.9.3 Valuable safety information for those conducting ancillary fire investigation not directly related to the fire or explosion scene examination or witness interviews may be found in NFPA 30, Flammable and Combustible Liquids Code, NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, NFPA 1403, Standard on Live Fire Training Evolutions, and NFPA 1500, Standard on Fire Department Occupational Safety and Health Program. Additional information may also be obtained by the appropriate government agency regulations such as Occupational Safety and Health Administration (OSHA) documents, Environmental Protection Agency (EPA) documents, state and local regulations, and documents written by other standards-making organizations such as the Compressed Gas Association (CGA), American Petroleum Institute (API), American Society of Testing and Materials (ASTM), American National Standards Institute (ANSI), and others that may impact the investigation activities. The information included in this proposal follows the outline developed by the Safety Chapter Task Group and also reflects the concern of the investigative community for an awareness of environmental hazards while working off of the fire scene. This section incorporates both existing and proposed new text.

Create a new section 12.9 and title it Off -Scene Investigation Activities, then move existing text as indicated to this section, renumber, and add or delete text as indicated. 12.4 12.4.1 12.9.1 Safety considerations also extend to ancillary fire investigation activities not directly related to the fire or explosion scene examination. Such ancillary investigation activities include physical evidence handling and storage, laboratory examinations and testing, and live fire or explosion recreations and demonstrations. The basic safety precautions dealing with use of safety clothing and equipment, and the proper storage and prominent labeling of hazardous materials evidence, thermal, inhalation, and electrical dangers of fire and explosion recreations or demonstrations should be included in evidence storage, examination, and testing protocols followed. The investigator may have to conduct witness interviews away from the fire scene in locations that are not totally controlled by the investigator. In that case the investigator should be aware of surroundings and other actions that could cause harm to the investigator. Environmental Hazards may include dogs or other dangerous animals, an armed witness, gang activities in the neighborhood or any other situation that may put the investigator at risk. 12.4.2 12.9.3 Valuable safety information for those conducting ancillary fire investigation not directly related to the fire or explosion scene examination or witness interviews may be found in NFPA 30, Flammable and Combustible Liquids Code, NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, NFPA 1403, Standard on Live Fire Training Evolutions, and NFPA 1500, Standard on Fire Department Occupational Safety and Health Program. Additional information may also be obtained by the appropriate government agency regulations such as Occupational Safety and Health Administration (OSHA) documents, Environmental Protection Agency (EPA) documents, state and local regulations, and documents written by other standards-making organizations such as the Compressed Gas Association (CGA), American Petroleum Institute (API), American Society of Testing and Materials (ASTM), American National Standards Institute (ANSI), and others that may impact the investigation activities.

Printed on 9/18/2009 156 Report on Proposals – November 2010 NFPA 921 Even though much of 12.9.3 is existing text, the committee believes the information in 12.9.3 does not relate to this section of the chapter.

Printed on 9/18/2009 157 Report on Proposals – November 2010 NFPA 921 ______921-125 Log #144

______Ronald L. Hopkins, Eastern Kentucky University Create a new section 12.10 and title it Scenes that may involve a Terroristic Event, Hazardous Materials Incident, or Drug Lab, then move existing text as indicated to this section, re-number, and add or delete text as indicated.

12.3 Fire is an event that can result from a criminal act. The initial incendiary device that created the fire or explosion may not be the only device left at the scene by the perpetrator. A secondary incendiary or explosive device may be left at the scene with the intent to harm fire, rescue, or investigative personnel. Of further concern are the chemicals used in the device that may leave a residue, creating an additional exposure. 12.3.1 The potential endangerment from a secondary incendiary or explosive device is remote compared to other hazards created at the scene from the initial device. However, the investigator should always be wary of any unusual packages or containers at the crime scene. If there is reason to believe that such a device may exist, it is necessary to contact the appropriate authorities to have specialists “sweep” the area. Close cooperation between investigative personnel and the explosive ordnance disposal (EOD) specialists can preclude the unnecessary destruction of the crime scene. 12.3.2 If the incendiary or explosive device is rendered safe by the appropriate personnel, care should be taken when handling the rendered device or any residue from the device. Exposure to the chemical residue could endanger the investigator. Appropriate protective clothing and breathing apparatus should be worn while in the process of collecting such evidence. 12.3.3 There is a potential for a terrorist to release biological or radiological particulates as a part of his or her terrorist act. Usually the emergency response personnel will be aware of such an act while mitigating the emergency incident. If there is any suspicion that either type of hazardous substance has been released, the scene must be rendered safe prior to the entry of investigative personnel. If this rendering is not possible and the investigation is to go forward, only those investigative personnel trained to work in such atmospheres should be allowed to enter the scene. Completing an investigation at the scene of a Drug Lab can expose the investigator to hazardous chemicals. The investigator should take appropriate actions to prevent contamination, including the use of appropriate personal protective equipment and insure that appropriate decontamination is completed and that the scene is isolated to prevent exposure to others. 12.3.4 Many of the tools and equipment used in the process of conducting an investigation may be rendered unsafe after being used in hazardous atmospheres. The necessary procedures, equipment, tools, and supplies to render your equipment safe should be in place prior to undertaking the investigation. Precautions should also be in place to dispose of the tools safely should they be incapable of being rendered safe. The material included in this proposal follows the outline developed by the Safety Chapter task group and reflects the task groups concern for investigator safety while working on specialized scenes. The proposal incorporates both new and existing text.

Create a new section 12.10 and title it Scenes that may involve a Terroristic Event, Hazardous Materials Incident, or Drug Lab, then move existing text as indicated to this section, renumber, and add or delete text as indicated. Scenes that may involve a Terroristic Event, Hazardous Materials Incident, or Drug Lab 12.3 Fire is an event that can result from a criminal act. The initial incendiary device that created the fire or explosion may not be the only device left at the scene by the perpetrator. A secondary incendiary or explosive device may be left at the scene with the intent to harm fire, rescue, or investigative personnel. Of further concern are the chemicals used in the device that may leave a residue, creating an additional exposure. 12.3.1 The potential endangerment from a secondary incendiary or explosive device is remote compared to other hazards created at the scene from the initial device. However, the investigator should always be wary of any unusual packages or containers at the crime scene. If there is reason to believe that such a device may exist, it is necessary to contact the appropriate authorities to have specialists “sweep” the area. Close cooperation between investigative personnel and the explosive ordnance disposal (EOD) specialists can preclude the unnecessary

Printed on 9/18/2009 158 Report on Proposals – November 2010 NFPA 921 destruction of the crime scene. 12.3.2 If the incendiary or explosive device is rendered safe by the appropriate personnel, care should be taken when handling the rendered device or any residue from the device. Exposure to the chemical residue could endanger the investigator. Appropriate protective clothing and breathing apparatus should be worn while in the process of collecting such evidence. 12.3.3 There is a potential for a terrorist to release biological or radiological particulates as a part of his or her terrorist act. Usually the emergency response personnel will be aware of such an act while mitigating the emergency incident. If there is any suspicion that either type of hazardous substance has been released, the scene must be rendered safe prior to the entry of investigative personnel. If this rendering is not possible and the investigation is to go forward, only those investigative personnel trained to work in such atmospheres should be allowed to enter the scene. Completing an investigation at the scene of a Ddrug Llab can expose the investigator to hazardous chemicals. The investigator should take appropriate actions to prevent contamination, including the use of appropriate personal protective equipment and i ensure that appropriate decontamination is completed and that the scene is isolated to prevent exposure to others. 12.3.4 Many of the tools and equipment used in the process of conducting an investigation may be rendered unsafe after being used in hazardous atmospheres. The necessary procedures, equipment, tools, and supplies to render your equipment safe should be in place prior to undertaking the investigation. Precautions should also be in place to dispose of the tools safely should they be incapable of being rendered safe.

Committee believes the title change and minor modifications to the text clarifies the discussion.

Printed on 9/18/2009 159 Report on Proposals – November 2010 NFPA 921 ______921-126 Log #71

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add new paragraph: Every year NFPA sponsors or co-sponsors fire investigation training programs in various cities and countries including: The National Fire, Arson, and Explosion Investigation Training Program; The National Advanced Fire, Arson, and Explosion Investigation Program; The National Vehicle Fire Investigation Training Program; The National Seminar of Fire Analysis Litigation; NFPA two-day seminars on NFPA 921; the InterFlam International Fire Engineering Conference, and the International Symposium on Fire Investigation Science and Technology (ISFI). Chapter 13 is Sources of Information. One of the greatest sources of information to fire investigators is NFPA’s continuing training programs, seminars, and educational sessions at the NFPA annual meetings. This is particularly true with NFPA’s sponsored and co-sponsored fire investigation programs which focus on NFPA 921. Every year, more than five hundred fire investigation professionals avail themselves of these important learning opportunities. This information should be brought to the attention of NFPA 921’s audience.

Add new paragraph: 13.6.1.3 13.6.1.2 Every year NFPA sponsors or co-sponsors fire investigation training programs in various cities and countries. including: The National Fire, Arson, and Explosion Investigation Training Program; The National Advanced Fire, Arson, and Explosion Investigation Program; The National Vehicle Fire Investigation Training Program; The National Seminar of Fire Analysis Litigation; NFPA two-day seminars on NFPA 921; the InterFlam International Fire Engineering Conference, and the International Symposium on Fire Investigation Science and Technology (ISFI).

This modified text is more consistent with existing text with respect to the existing training opportunities.

Printed on 9/18/2009 160 Report on Proposals – November 2010 NFPA 921 ______921-127 Log #72

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Add “and vehicle fire investigators” at the end of the second sentence. The sentence should read: “Each year, the board certifies fire and explosion investigators, and fire investigation instructors, and vehicle fire investigators. NAFI offers three certifications, fire and explosion investigator, fire investigation instructor, and vehicle fire investigator. “Vehicle fire investigator” is currently missing from the list in this section.

Printed on 9/18/2009 161 Report on Proposals – November 2010 NFPA 921 ______921-128 Log #155

______Melvin Robin, ATF New text to read as follows: “Sometimes sequence of photographs taken by investigators does not represent the exact sequence in which the fire scene investigation was undertaken. Investigators should be prepared to articulate the disparity between the sequence of the investigative steps and the sequence of photographs.” “Investigators should prepare, when applicable, a photograph log detailing the directional view of the photograph, item photographed, photograph number, and any other additional pertinent information. The photograph log can be used in conjunction with the photograph diagram. The photograph log should include a header which details the identity of the photographer, the address or location of the scene, type of camera used, investigation number, and date.” Problem--Sequence of photographs, if not matching sequence of investigation, does not necessarily imply faulty investigation. Problem--No photograph address specific explanation of a photograph log, although sample of photograph log is provided for in read of document.

Add the following text to the end of current 15.2.4.1.1 Deviations from the general photography sequence described in this section does not necessarily indicate faulty investigative methodology.

The language the committee drafted more clearly expresses the concepts the submitter addressed in the first paragraph. The second paragraph is rejected because it is not clear to the committee what the submitter requests and in any event appears to be addressed already in paragraphs 15.2.4.4, 15.2.4.4.1 and 15.2.4.4.2.

Printed on 9/18/2009 162 Report on Proposals – November 2010 NFPA 921 ______921-129 Log #159

______Melvin Robin, ATF New text to read as follows: “Investigators should use and initial photograph to document the address or other identifiers on the side of the structure even if they are not part of the fire scene. This will assist investigators in later court proceedings in testifying that a series of photographs are related to a particular fire investigation.” Investigators should be cautioned to photograph building identifiers

The language submitted is confusing and the subject matter is already addressed in paragraph 15.2.6.4 and 15.2.4.4.1.

Printed on 9/18/2009 163 Report on Proposals – November 2010 NFPA 921 ______921-130 Log #114

______Michael A. Learmonth, Giffin Koerth Forensic Engineering Revise text to read as follows: Drawings and sketches should include the name of the drawer, the source of the data (if different than the drawer) and the date of creation, unless that is obvious from the context such as in the middle of dated, personal field notes. The accuracy and credibility of drawings and sketches are dependant on the source and timing of its creation which should be easily determined from the document itself. All drafting classes teach that the drafter, source of the drawing information and date of creation should be included.

This material is already covered in section 15.4.4.

Printed on 9/18/2009 164 Report on Proposals – November 2010 NFPA 921 ______921-131 Log #152

______Melvin Robin, ATF New text to read as follows: “Investigators should ensure that their sponsoring organization has the appropriate documented standards and procedures for the collection and preservation of evidence. Investigators primary guidance in collecting evidence will come from their organization’s own Standard Operating Procedures.” Investigators should also be beholden to their own SOPs.

The committee believes that the existing text is adequate.

Printed on 9/18/2009 165 Report on Proposals – November 2010 NFPA 921 ______921-132 Log #73

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Once collected at the scene, physical evidence is usually often examined and tested, frequently in a laboratory or other testing facility. Physical evidence may be examined and tested to identify its chemical composition; to establish its physical properties; to determine its conformity or lack of conformity to certain legal or industry standards; to establish its operation, inoperation, or malfunction; to determine its design sufficiency or deficiency, or other issues that will provide the fire investigator with an opportunity to understand and determine the origin of a fire, the specific cause of a fire, the contributing factors to a fire’s spread, or the responsibility for a fire. The investigator should consult with the laboratory or other testing facility to determine what specific services are provided and what limitations are in effect. The purpose of such examinations is to gather as much evidentiary value as possible from such physical evidence. All inspections, examinations, and testing of evidence, whether at the scene or elsewhere, particularly intrusive or destructive inspections, should be properly documented and conducted in accordance with the appropriate ASTM forensic standards when applicable.

ASTM Standard E 860 - ; ASTM Standard E 1492 - ; and ASTM E 1459, .

is defined as the inspection, examination, or testing of evidence without any permanent change to the evidentiary value of the evidence. Nondestructive evidence inspections are conducted in order that interested parties can view, measure, make notes, diagrams, photographs, and make other visual observations of the evidence in a nondestructive manner and without permanently changing the evidentiary value of the items or artifacts. If these inspections do not involve destructive elements, all interested parties need not be present for such nondestructive inspections. ( ) These inspections commonly include photography, x-ray, and diagramming; physical measurement of the size, weight, or density of the artifacts, (i.e. depth of char and depth of calcination measurements), and testing of such properties as electrical resistance and continuity, or ferromagnetism (nature of a metal). is defined as the nondestructive inspection, examination, or testing of evidence involving insignificant physical changes to evidence without any permanent change to the evidentiary value of the evidence. On many occasions the effective inspection and examination of evidence first requires that unimportant portions of, or attachments to, an evidence item must be removed or altered in order to gain access to the important evidentiary information. Common intrusive procedures include the opening or removal of an artifact’s cover, outer case, or door; the cutting away or cleaning off of charred or melted material or debris which is obstructing access to an area or information of interest; or the cutting of electrical wires or piping between connections for more efficient examination, collection, or testing ( )). Such intrusive procedures, though they may in fact change the unimportant portions of the evidence; do not effectively alter the overall evidentiary value of the item.

Intrusive inspection procedures should be well documented by notes, photographs, diagrams, etc., before, during and after alteration. is defined as the inspection, examination, or testing of evidence in which the evidence will be consumed or significant permanent change to the evidentiary value of the evidence can be reasonably expected. Common destructive inspection procedures include ignition temperature and

Printed on 9/18/2009 166 Report on Proposals – November 2010 NFPA 921 flammability characteristics testing, metallurgical testing, chemical testing, and preparation of samples for such testing. In many cases, the impact of such destructive inspections can be mitigated by the collection and distribution of “split” samples to interested parties. Prior to any destructive inspection of evidence, all interested parties should be notified, protocols should be developed and distributed, and testing facilities should be decided upon. Each of the interested parties may decide to have its own expert view or participate in the inspections.

Destructive inspection procedures should be well documented by notes, photographs, diagrams, etc., before, during and after alteration. Forensic inspection protocols are written documents detailing the procedures which will be undertaken during the forensic inspection, examination, or testing of physical evidence. They form a general outline of the tasks to be accomplished, the manner and order of the tasks, any specific test standards to be utilized, and the general nature of information being sought. Effective forensic inspection protocols have provisions for modifying their provisions or procedures as new or different information is acquired during the inspection. ( )

The inspection, examination, or testing of evidence in which the evidence will be consumed or significant permanent change to the evidentiary value of the evidence can be reasonably expected.

The nondestructive inspection, examination, or testing of evidence involving insignificant physical changes to evidence without any permanent change to the evidentiary value of the evidence. ( )

The inspection, examination, or testing of evidence without any permanent change to the evidentiary value of the evidence. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. For many years now current common practice involving the inspection of physical evidence in the fire investigation profession has classified these types of inspections by the nature of any changes to the evidentiary value necessitated by those inspections, examinations, or testing. The definitions of what changes or destroys the evidentiary value of materials or artifacts and what does not, have frequently been misinterpreted by unsophisticated or inexperienced investigators who do not have an authoritative, peer-reviewed, context by which the difference between non-destructive, intrusive, or destructive inspections can be judged. This has produced many unnecessary and dilatory arguments of evidence inspection protocols. This proposal merely elucidates the practical definitions of such inspections which have been in use by the forensic investigation profession for years. NFPA 921-2008 contains thirteen (13) current references to “destructive” or “non-destructive” evidence alterations, examinations, and testing in six separate chapters, (Legal, Documentation, Physical Evidence; Appliances, Vehicles, and Complex Investigations). Nowhere in the document are these terms or intrusive examinations defined.

The Committee believes that the material in the proposal is covered in section 11.3.5.6.1. Printed on 9/18/2009 167 Report on Proposals – November 2010 NFPA 921

Printed on 9/18/2009 168 Report on Proposals – November 2010 NFPA 921 ______921-133 Log #47

______Michael Fox, Chemical Accident Reconstruction Services, Inc.

such tests should be performed and carried out by procedures that have been standardized by some recognized group.

While standard tests are recommended and preferred, it is recognized that not every situation in need of testing falls precisely into a previously developed standard test category. In those instances the fire investigator may need to develop “Specialized Tests.” For example, the fire investigator may need to determine if the presence of chemical X in a fire scenario enhances or reduces the probability or severity of a specific fire. When Specialized Tests are needed, they should be performed within the scientific principles of experimental tests. Every step of the Specialized Test should be documented such that any other competent investigator could reproduce the experiment and obtain the same results within experimental error. Whenever possible, the Specialized Test to evaluate some unknown should change only one variable at a time. If more than one variable is changed at a time, it may not be possible to determine the effect or cause of any single variable. Control samples should be included to form a basis for comparison. In such evaluations, the amounts of materials used in the experiment should be weighed and/or measured. Key steps in the experiment should be photographed and/or videotaped. Data considered, such as temperatures and/or radiant heat fluxes and other significant parameters should be recorded and documented. The design and results of a Specialized Test should assist the investigator in reaching a scientific and valid conclusion. For example (but not limited to) the presence of X chemical caused the fire to burn faster and hotter, supported by time-temperature profiles of comparative fires with and without chemical X. Most fire investigators recognize the need for Specialized Tests that do not fall readily into a well-established test procedure. For example, how does a fire investigator determine the temperature at which an aerosol spray paint will explode and then cause or contribute to a fire? Or, how does a fire investigator determine if an additive contributes to the flammability of a unique mixture of fuels? Fire Investigators are faced with answering such questions all the time. If fire investigators were not involved in legal testimony, then perhaps the lack of flexibility in NFPA 921 test methods would not be a serious problem. However, over the years the courts have pretty well adopted NFPA 921 as “the legal standard” for fire investigation. In that context the lack of flexibility to develop Specialized Tests can be a serious barrier for any fire investigator. Attorneys use NFPA 921 as much as fire investigators do, and attorneys have been known to challenge Specialized Tests as “non-standard” and hence “unreliable” tests that do not meet the rules of evidence. This is true regardless of how well constructed, controlled and documented and scientific a Specialized Test might be. The mere fact that a Specialized Test is not specifically listed by a paragraph number within NFPA 921 is sufficient ammunition for a skillful attorney to raise a Daubert type challenge. While suggestive text is being offered for a new section of NFPA 921 that will allow Specialized Testing, it is fully expected that the large pool of talent within the NFPA will help craft a paragraph that will offer flexibility to the fire investigator to develop Specialized Tests when needed, but at the same time require the Specialized Tests to meet rigorous scientific methodologies and protocols. In other words, the language of the Section 16.10.1.3 would assure that any Specialized Tests would be reliable, professional and acceptable to both the scientific community and the courts, but not open the door to junk science.

Proposal #1 – Revised text – Section 16.10.1 Whenever possible, such tests should be performed and carried out by procedures that have been standardized by some recognized group. Proposal #2 – New Section 16.10.1.3 – Proposed Text While standard tests are recommended and preferred, it is recognized that not every situation in need of testing falls precisely into a previously developed standard test category. In those instances the fire investigator may need to develop “Specialized Tests.” For example, the fire investigator may need to determine if the presence of chemical X in a fire scenario enhances or reduces the probability or severity of a specific fire. When Specialized Tests are needed, they should be performed within the scientific principles of experimental tests. Every step of the Specialized Test should be documented such that any other competent investigator could reproduce the experiment and obtain the same results within experimental error.

Printed on 9/18/2009 169 Report on Proposals – November 2010 NFPA 921 Whenever possible, The Specialized Test to evaluate some unknown should change only one variable at a time. If more than one variable is changed at a time, it may not be possible to determine the effect or cause. of any single variable. Control samples should be included to form a basis for comparison. In such evaluations, the amounts of materials used in the experiment should be weighed and/or measured. Key steps in the experiment should be photographed and/or videotaped. Data considered, such as temperatures and/or radiant heat fluxes and other significant parameters should be recorded and documented. The design and results of a Specialized Test should assist the investigator in reaching a scientific and valid conclusion. For example (but not limited to) the presence of X chemical caused the fire to burn faster and hotter, supported by time-temperature profiles of comparative fires with and without chemical X. The committee believes the text as modified is more clear.

Printed on 9/18/2009 170 Report on Proposals – November 2010 NFPA 921 ______921-134 Log #74

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Replace the second and third sentences with: The is defined as: a structure, part of a structure, or general geographic location within a fire scene, in which the “ of a fire or explosion is reasonably believed to be located. The is defined as: the smallest location which a fire investigator can define, within an “area of origin,” in which a heat source, source of oxygen, and a fuel interacted with each other and a fire or explosion began. . Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep apace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. The current definitions of Origin, Area of Origin, and Point of Origin are inexact, confusing and do not conform to how the terms are actually used in the field. This proposal sets a new, simple, and understandable definition for Point of Origin. The definitions in this paragraph do not even correspond to definitions elsewhere in the document (section 3.3).

Replace the second sentences with: The area of origin is defined as: a structure, part of a structure, or general geographic location within a fire scene, in which the “point of origin” of a fire or explosion is reasonably believed to be located. The point of origin is defined as: the smallest location which a fire investigator can define, within an “area of origin,” in which a heat source, source of oxygen, and a fuel interacted with each other and a fire or explosion began.

See committee action on 921-13 (Log #52) and 921-30 (Log #58).

Printed on 9/18/2009 171 Report on Proposals – November 2010 NFPA 921 ______921-135 Log #44

______Hal C. Lyson, Fire Cause Analysis Revise text to read as follows: 17.4 Analyze the Data. The scientific method requires that all data collected that bears upon the origin be analyzed. This is to make it consistent with the change that is a proposal to 18.4 where the data that is analyzed is related to the origin analyses, and not data that may not be related to origin.

Revise text to read as follows: The scientific method requires that all data collected related to that bears upon the origin be analyzed. The Committee believes the text as modified more accurately describes the concept.

Printed on 9/18/2009 172 Report on Proposals – November 2010 NFPA 921 ______921-136 Log #35

______Hal C. Lyson, Fire Cause Analysis Revise text as follows: The investigator should not assume that the fire at the origin burned the longest and therefore fire patterns showing the greatest damage must be at the area of origin. The origin may be at the area greatest damage or the base of pattern such as the base of a “V” pattern. This is more likely in pre-flashover or pre-full room involved fires. However, greater damage in one place than in another may be the result of differences in thermal exposure due to differences in fuel loading, the location of the fuel package in the compartment, increased ventilation, or fire-fighting tactics. For similar reasons, a fire investigator should consider these factors when there is a possibility of multiple origins. The 2008 document does not come out and say that the origin may be at the area of greatest damage or the base of a “V” pattern. It provides good discussion on why it may not be the origin but not that it can be the origin and why the investigator needs to look at other places. There is discussion on pattern generation in the patterns chapter and the science chapter, but not this conclusion.

Revise text to read as follows: 17.4.1.3 Pattern Generation. The investigator should not assume that the fire at the origin burned the longest and therefore fire patterns showing the greatest damage must be at the area of origin. The origin may be at the area of greatest damage or at the base of a pattern, such as the base of a “V” pattern. This is more likely in compartments that have not become fully involved. pre-flashover or pre-full room involved fires. However, Greater damage in one place than in another may be the result of differences in thermal exposure due to differences in fuel loading, the location of the fuel package in the compartment, increased ventilation, or fire-fighting tactics. For similar reasons, a fire investigator should consider these factors when there is a possibility of multiple origins. The committee is accepting the submitter’s proposal but correcting some typographical errors and making sentences easier to understand.

Printed on 9/18/2009 173 Report on Proposals – November 2010 NFPA 921 ______921-137 Log #156

______Melvin Robin, ATF New and revise text to read as follows: Remove figure 17.4.3.2 Repeated in 17.4.3.2(b)

One figure shows how the instrument was constructed while the other shows how the instrument was used.

Printed on 9/18/2009 174 Report on Proposals – November 2010 NFPA 921 ______921-138 Log #158

______Melvin Robin, ATF Delete text to read as follows: Take out figure 17.4.3.2, Repetitive of 17.4.3.2(b)

See committee action on 921-137 (Log #156).

Printed on 9/18/2009 175 Report on Proposals – November 2010 NFPA 921 ______921-139 Log #118

______Daniel L. Churchward, Kodiak Enterprises, Inc. Revise text to read as follows: Change existing text in 17.4.5.3.1 to read: ... Arcing can create highly localized damage where the temperatures exceed the melting point of the conductor metal. Arcing can create complementary damage to adjacent conductors or grounded surfaces .... Neither of these statements are correct in their present form because neither of them are absolutes. Fire-induced damaged to un-energized stranded copper conductors can create visually similar damage to conductors as that created by arcing.

Printed on 9/18/2009 176 Report on Proposals – November 2010 NFPA 921 ______921-140 Log #117

______Daniel L. Churchward, Kodiak Enterprises, Inc. New text to read as follows: 17.4.5.7 Arc Survey Limitations As previously discussed, arc surveys can identify areas where the fire had damaged energized electrical conductors early in the fire's development. Likewise, the spatial relationship of arc sites can identify a specific space where the fire occurred before electrical energy to that space was cut off. Both of these investigative tools can be helpful in the origin determination. However, the accuracy of the effort is directly dependent upon the investigation correctly identifying arc damage on the wires. Fire damage to copper conductors can mimic arc damage and visual inspection at the site may not be sufficient to validate arc sites. If the analysis of the circuits incorrectly identifies damage on the conductors as arcing, hypotheses formed from the analyses will be based on flawed data and will, most likely, be challenged. The investigator may want to collect each perceived arc site for evaluation and verification to rebut any challenge to the investigation's hypotheses. Field experiments have produced examples of damage on un-energized stranded copper conductors that have been incorrectly identified as arc sites. The consequence of this raises the question of accuracy in all arc surveys especially when the survey is based solely on a field examination of the wiring. By warning the reader of limitations to arc surveys, and by suggesting an off-site evaluation of proposed arc sites, the reader is cautioned to consider taking steps at the scene to resolve future disputes that may arise.

Revise text to read as follows: 17.4.5.7 Arc Survey Limitations As previously discussed, Arc surveys can identify areas where the fire had damaged energized electrical conductors early in the fire's development. Likewise, the spatial relationship of arc sites can identify a specific space where the fire occurred before electrical energy to that space was cut off. Both of these investigative tools can be helpful in the origin determination. However, The accuracy of the effort, however, is directly dependent upon the investigation investigator correctly identifying arc damage on the wires. Fire damage to copper conductors can mimic arc damage, and visual inspection at the fire scene site may not be sufficient to correctly identify validate arc sites. If the analysis of the circuits incorrectly identifies damage on the conductors as arcing, hypotheses formed from the analyses will be based on flawed data and will be incorrect., most likely, be challenged. The investigator may want to collect each perceived arc site for more detailed evaluation and verification. to rebut any challenge to the investigation's hypotheses. The committee believes the text, as modified, more accurately describes the concept.

Printed on 9/18/2009 177 Report on Proposals – November 2010 NFPA 921 ______921-141 Log #CP10

______Technical Committee on Fire Investigations, Replace existing chapter 18 with the following: Chapter 18 Fire Cause Determination 18.1 Introduction. This chapter recommends a methodology to follow in determining the cause of a fire. Fire cause determination is the process of identifying the first fuel ignited, the ignition source, the oxidizing agent, and the circumstances that resulted in the fire. Fire cause determination generally follows origin determination (see Origin Determination Chapter). Generally a fire cause determination can be considered reliable only if the origin has been correctly determined. 18.1.1 Fire Cause Factors. The determination of the cause of a fire requires the identification of those factors that were necessary for the fire to have occurred. Those factors include the presence of a competent ignition source, the type and form of the first fuel ignited, and the circumstances, such as failures or human actions, that allowed the factors to come together and start the fire. Device or appliance failures can involve, for example, a high temperature thermostat that fails to operate. The device may have failed due to a design defect. Human contributions to a fire can include a failure to monitor a cooking pot on the stove, failure to connect electrical wiring tightly resulting in a high resistance connection, or intentional acts. For example, consider a fire that starts when a blanket is ignited by an incandescent lamp in a closet. The various factors include having a lamp hanging down too close to the shelf, putting combustibles too close to the lamp, and leaving the lamp on while not using the closet. The absence of any one of those factors would have prevented the fire. The function of the investigator is to identify those factors that contribute to the fire. 18.1.2 First Fuel Ignited. The first fuel ignited is that which first sustains combustion beyond the ignition source. For example, the wood of the match would not be the first fuel ignited, but paper, ignitable liquid, or draperies would be, if the match were used to ignite them. 18.1.3 Ignition Source. The ignition source will be at or near the point of origin at the time of ignition, although in some circumstances, such as the ignition of flammable vapors, the two may not appear to coincide. Sometimes the source of ignition will remain at the point of origin in recognizable form, whereas other times the source may be altered, destroyed, consumed, moved or removed. Nevertheless, the source should be identified in order for the cause to be proven. There are however occasions when there is no physical evidence of the ignition source, but an ignition sequence can be hypothesized based on other data. 18.1.4 Oxidant. Generally the oxidant is the oxygen in the earth’s atmosphere. Medical oxygen, such as that stored in cylinders or produced by oxygen concentrators, and certain chemical compounds may support or enhance combustion reactions (see Oxidizing Agents in the Basic Fire Science Chapter). 18.1.5 Ignition Sequence. A fuel by itself or an ignition source by itself does not create a fire. Fire results from the combination of fuel, an oxidant, and an ignition source. The investigator’s description of events, including the ignition sequence, (the factors that allowed the ignition source, fuel and oxidant to react) can help establish the fire cause. 18.2 Overall Methodology. The overall methodology for determining the cause of the fire is the scientific method as described in the Basic Methodology Chapter . This methodology includes recognizing and defining the problem to be solved, collecting data, analyzing the data, developing a hypothesis or hypotheses, and most importantly, testing the hypothesis or hypotheses. In order to use the scientific method, the investigator must develop at least one hypothesis based on the data available at the time. These initial hypotheses should be considered “working hypotheses,” which upon testing may be discarded, revised, or expanded in detail as new data is collected during the investigation and new analyses are applied. This process is repeated as new information becomes available. (See Figure 18.2)

***Insert Figure 18.2 Here*** FIGURE 18.2 An Example of Applying the Scientific Method to Cause Determination

18.2.1 Consideration of Data In some instances, a single item, such as an irrefutable article of physical evidence or a credible eyewitness to the ignition, or a video recording, may be the basis for a determination of cause. In most cases, however, no single item is sufficient in itself to allow determination of the fire cause. The investigator should use all available resources to develop fire cause hypotheses and to determine which hypotheses fit all of the credible data available. When an apparently plausible hypothesis fails to fit some item of data, the investigator should try to reconcile the two and determine whether the hypothesis or the data is erroneous. 18.2.2 Sequence of Activities. The various activities required to determine the cause using the scientific method (data collection, analysis, hypothesis development, and hypothesis testing) occur continuously. Likewise, recording the scene,

Printed on 9/18/2009 178 Report on Proposals – November 2010 NFPA 921 note taking, photography, evidence identification, witness interviews, origin investigation, failure analysis, and other data collection activities may be performed simultaneously with these efforts. Investigators should refer to the other sections of this guide that deal with these specific activities. Similarly, investigators need to remain aware of potential spoliation and scene contamination issues and should refer to the Chapters on Legal Considerations and Physical Evidence. 18.2.3 Point and Area of Origin. In some cases, it will be impossible to determine the point of origin of a fire within the area of origin. Where a single point cannot be identified, it can still be valuable for many purposes to identify the area(s) of origin. In such instances, the investigator should be able to provide reliable explanations for the area of origin with the supporting evidence for each option. In some situations, the extent of the damage may reduce the ability to specifically identify the point of origin, without removing the ability to put forward credible origin and cause hypotheses. 18.3 Data Collection for Fire Cause Determination. Data collection processes for cause determination includes identification of fuel packages, ignition sources, oxidizers and circumstances. Data should be collected to identify all potential fuels, ignition sources, and oxidants within the area or areas of origin. Data may also need to be collected from outside the area of origin. Examples of this would be unburned fuel samples or exemplar ignition sources located in other areas. Data on the circumstances bringing the fuel, ignition sources, and oxidizer together may come from many different sources. If available, a review of pre-fire documentation of possible areas of origin can be of value. 18.3.1 Identify Fuels in the Area of Origin. The investigator should identify the fuels present in the area of origin at the time of ignition. One of these fuels will be the first fuel ignited. The type, quantity, and specific location of structural and content fuels should be identified. 18.3.1.1 Identifying the initial fuel is necessary for evaluating the competency of potential ignition sources and understanding the events that caused the fire. Sometimes a portion of the first ignited fuel will survive the fire, but often it does not. The initial fuel must be capable of being ignited within the limitations of the ignition source. The components in most buildings are not susceptible to ignition by heat sources having low energy, low temperature, or short duration. For example, flooring, structural lumber, wood cabinets, and carpeting do not ignite unless they are exposed to a substantial heat source. The investigator should identify easily ignited items that, once ignited, could provide the heat source to damage or involve these harder-to-ignite items. (See Basic Fire Science chapter, Fuel Load). 18.3.1.2 The initial fuel could be part of a device that malfunctions or fails. Examples include insulation on a wire that is heated to its ignition temperature by excessive current, or the plastic housing on an overheating coffee maker. 18.3.1.3 The initial fuel might be something too close to a heat-producing device. Examples are clothing against an incandescent lamp or a radiant heater, wood framing too close to a wood stove or fireplace, or combustibles too close to an engine exhaust manifold or catalytic converter. 18.3.1.4 Certain fuels produce residues not typically found after a fire. These residues differ from construction and contents materials that are normally present in the area of origin. Examples include residues of ignitable liquids or pyrotechnic materials, such as flares. 18.3.1.5 Gases, vapors, and combustible dusts can be the initial fuel and can cause confusion about the location of the point of origin, because the point of ignition can be some distance away from where sustained fire starts in the structure or furnishings. Also, flash fire may occur with sustained burning of light density materials, such as curtains, that are located away from the initial vapor-fuel source. 18.3.1.6 Information should be sought from persons having knowledge (such as occupants) about recent activities in the area of origin and what fuel items should or should not have been present. Information should also be obtained about the construction of the structure in the origin area. Construction details could include information about the floor, ceiling and wall coverings, type of doors, type of windows or other information necessary for the analysis. The age of construction materials and attachment methodologies may be relevant. This information could reveal the initial fuel for the fire. This information would also be helpful to an investigator to prevent overlooking secondary and subsequent fuels that were present in the origin area that would contribute to fire growth. The investigator should refer to the chapters on Basic Fire Science, Fire Patterns, Building Systems, and Sources of Information when analyzing an origin area for the initial fuel. 18.3.2 Identify Source and Form of the Heat of Ignition. The investigator should identify and document all heat-producing items in the area of origin. Heat producing items include devices, appliances, equipment, and self-heating and reactive materials. The investigator should also identify devices or equipment that are not normally heat producing, but may produce enough heat for ignition through misuse or malfunction. 18.3.2.1 Potential sources of ignition for gases, vapors, or dusts include open flames, arcs from motors and switches, electric igniters, standing pilots or flames in gas appliances, hot surfaces, and static electricity. 18.3.3 Identify Items and Activities in Area of Origin. Information should be obtained from owners and occupants about recent activities in the area of origin and what appliances, equipment, or heat-producing devices, were present. This information is especially important when potential ignition sources are not identifiable post-fire. The information would also be helpful in alerting an investigator to small or easily overlooked items when examining the area of origin. When electrical energy sources are considered as potential ignition sources, the investigator should refer to the chapters on Printed on 9/18/2009 179 Report on Proposals – November 2010 NFPA 921 Electricity and Appliances. Information on purchase, such as new or used, how and when they were used, repair history, and problems should also be gathered. 18.3.4* Identify the Oxidant. The most common oxidant (oxidizer or oxidizing agent) within a fire is the oxygen in earth’s atmosphere and no special documentation is required. However, other oxidants, as described below, should be identified and documented when they are in or near the area of origin. A.18.3.4 ASTM G145-08, Standard Guide for Studying Fire Incidents in Oxygen Systems and NFPA 430, Code for the Storage of Liquid and Solid Oxidizers. 18.3.4.1 Sometimes oxygen exists at greater than the normal atmospheric concentration, such as in hyperbaric chambers, oxygen tents, or around oxygen generation and storage equipment. 18.3.4.2 Some chemicals other than molecular oxygen are classified as oxidants. Certain common chemicals, such as pool sanitizers, may also act as oxidants. 18.3.4.3 Some chemical mixtures, such as solid rocket fuel, contain an oxidizer as well as a fuel and require no external oxidizing source. 18.3.5 Identify Ignition Sequence Data. The investigator should develop data that can be used to analyze the events that brought the fuel and ignition source together (ignition sequence). This information on the conditions surrounding the coincidence of fuel, ignition source and oxidizer may be available through observations, witness accounts, or weather data. Time lines can be useful in organizing and analyzing this data. (See Chapter on Failure Analysis and Analytical Tools.) Additional data collection may be necessary in order to determine the circumstances that brought the fuel, ignition source and oxidizer together. Data collection may continue even after the fire scene has been processed and could require specialized laboratory equipment. Such additional data may result in modification or rejection of previously developed hypotheses or reconsideration of previous rejected hypotheses. 18.4 Analyze the Data. The scientific method requires that all data collected that bears upon the fire cause be analyzed. Analyzing the data requires the examination and interpretation of each component of data collected that bears upon the fire cause. This is an essential step that must take place before the formation of any hypotheses. The purpose of the analysis is to attribute specific meaning to the results of the examination and interpretation process, which will ultimately play a role in hypothesis development and testing. The identification, gathering, and cataloging of data does not equate to data analysis. Analysis of the data is based on the knowledge, training, experience, and expertise of the individual doing the analysis. If the investigator lacks the knowledge to properly attribute meaning to a piece of data, then assistance should be sought from someone with the necessary knowledge. Understanding the meaning of the data will enable the investigator to form hypotheses based on the evidence, rather than on speculation or subjective belief. 18.4.1 Fuel Analysis. Fuel analysis is the process of identifying the first (initial) fuel item or package that sustains combustion beyond the ignition source and identifying subsequent target fuels beyond the initial fuel. 18.4.1.1 Geometry and Orientation. An understanding of the geometry and orientation of the fuel is important in determining if the fuel was the first material ignited. The physical configuration of the fuel plays a significant role in its ability to be ignited. A nongaseous fuel with a high surface-to-mass ratio is much more readily ignitable than a fuel with a low surface-to-mass ratio. Examples of high surface-to-mass fuels include dusts, fibers, and paper. As the surface-to-mass ratio increases, the heat energy or time required to ignite the fuel decreases. Gases and vapors are fully dispersed (in effect, an extremely high surface-to-mass ratio) and can be ignited by a low heat energy source instantly. 18.4.1.2 Ignition Temperature. The fuel must be capable of being ignited by the hypothesized ignition source. The ignition temperature of the fuel should be understood. It is important to understand the difference between piloted ignition and autoignition temperatures. The components in most buildings are not susceptible to ignition by heat sources of low energy, low temperature, or short duration. For example, flooring, structural lumber, wood cabinets, and carpeting do not ignite unless they are exposed to a substantial heat source. 18.4.1.3 Quantity of Fuel. The first material ignited may not result in fire growth and spread if a sufficient quantity of the fuel does not exist. For example, if the lighter fluid used to start a charcoal fire is consumed before enough heat is transferred to the briquettes, the fire goes out. The investigator should conduct an analysis of the quantity of fuels (primary, secondary, tertiary, etc.) to determine that it is sufficient to explain the resulting fire. 18.4.2 Ignition Source Analysis. The investigator should evaluate the potential ignition sources in the area of origin to determine if they are competent. A competent ignition source will have sufficient energy and be capable of transferring that energy to the fuel long enough to raise the fuel to its ignition temperature. 18.4.2.1 Heating of the potential fuel will occur by the energy that reaches it. Each fuel reacts differently to the energy that impacts on it based upon its thermal and physical properties. Energy can be reflected, transmitted, or dispersed through the material, with only the absorbed energy causing the fuel temperature to rise. 18.4.2.2 Flammable gases or liquid vapors, such as those from gasoline, may travel a considerable distance from their original point of release before reaching a competent ignition source. Only under specific conditions will ignition take place, the most important condition being concentration within the flammable limits and an ignition source of sufficient Printed on 9/18/2009 180 Report on Proposals – November 2010 NFPA 921 energy located in the flammable mixture. 18.4.3 Oxidant. The oxidant is usually the oxygen in the atmosphere. In some cases alternate or additional oxidants may have been present and the investigator should consider this and the role of such conditions in ignition and spread. 18.4.3.1 If the existence of an oxidant other than atmospheric oxygen is suspected based upon the presence of residue, that residue should be collected and analyzed in a laboratory. Typically the oxidant does not survive in its original form, but may leave characteristic residues. 18.4.4 Ignition Sequence. 18.4.4.1 The ignition sequence of a fire event is defined as the succession of events and conditions that allow the source of ignition, the fuel, and the oxidant to interact in the appropriate quantities and circumstance for combustion to begin. Simply identifying a fuel or an ignition source by itself does not and cannot describe how a fire came to be. Fire results from the interaction of fuel, an oxidant, and an ignition source. Therefore, the investigator should be cautious about deciding on a cause of a fire just because a readily ignitable fuel, potential ignition source, or any other of an ignition sequence’s elements is identified. The sequence of events that allow the source of ignition, the fuel, and the oxidant to interact in the appropriate quantities and circumstances for combustion to begin, is essential in establishing the cause. 18.4.4.2 Analyzing the ignition sequence requires determining events and conditions that occurred or were logically necessary to have occurred, in order for the fire to have begun. Additionally, in describing an ignition sequence, the order in which those events occurred should be determined. 18.4.4.2.1 In each fire investigation, the various contributing factors to ignition should be investigated and included in the ultimate explanation of the ignition sequence. These factors should include: 1) How and sequentially when the first fuel ignited came to be present in the appropriate shape, phase, configuration, and condition to be capable of being ignited(a competent fuel); 2) How and sequentially when the oxidant came to be present in the right form and quantity to interact with the first fuel ignited and ignition source and allow the combustion reaction; 3) How and sequentially when the competent ignition source came to be present and interact with the fuel; 4) How and sequentially when the competent ignition source transferred its heat energy to the fuel, causing ignition; 5) How and sequentially when any acts, omissions, outside agencies or conditions brought the fuel, oxidant, and competent ignition source together at the time and place for ignition to occur; 6) How the first fuel subsequently ignited any secondary, tertiary, and successive fuels which resulted in any fire spread. 18.4.4.3 There are times when there is no physical evidence of the ignition source found at the origin, but where an ignition sequence can logically be inferred using other data. Any determination of fire cause should be based on evidence rather than on the absence of evidence; however, there are limited circumstances when the ignition source cannot be identified, but the ignition sequence can logically be inferred. This inference may be arrived at through the testing of alternate hypotheses involving potential ignition sequences, provided that the conclusion regarding the remaining ignition sequence is consistent with all known facts (see Basic Methodology Chapter). The following are examples of situations that lend themselves to formulating an ignition scenario when the ignition source is not found during the examination of the fire scene. The list is not exclusive and the fire investigator is cautioned not to hypothesize an ignition sequence without data that logically supports the hypothesis. A. Diffuse fuel explosions and flash fires B. When an ignitable liquid residue (confirmed by laboratory analysis) is found at one or more locations within the fire scene and its presence at that location(s) does not have an innocent explanation. (See Incendiary Fires chapter) C. When there are multiple fires (See Incendiary Fires chapter) D. When trailers are observed. (See Incendiary Fires chapter) E. The fire was observed or recorded at or near the time of inception or before it spread to a secondary fuel. 18.5 Developing a Cause Hypothesis. The investigator should use the scientific method (see the Basic Methodology Chapter) as the method for data gathering, hypothesis development, and hypothesis testing regarding the consideration of potential ignition sequences. This process of consideration actually involves the development and testing of alternate hypotheses. In this case, a separate hypothesis is developed considering each individual competent ignition source at the origin as a potential ignition source. Systematic evaluation (hypothesis testing) is then conducted with the elimination of those hypotheses that are not supportable (or refuted) by the facts discovered through further examination. The investigator is cautioned not to eliminate a potential ignition source merely because there is no obvious evidence for it. For example, the investigator should not eliminate the electric heater because there is no arcing in the wires or because the contacts are not stuck. There may be other methods by which the heater could have been the ignition source other than a system failure, such as combustible materials being stored too close to it. Potential ignition sources should be eliminated from consideration only if there is reliable evidence that they could not be the ignition source for the fire. For example, an electric heater can easily be eliminated from consideration if it was not energized. Printed on 9/18/2009 181 Report on Proposals – November 2010 NFPA 921 18.5.1 Devices present at the point/area of origin which are either heat-producing, or are capable of heat production when they sustain a fault or failure (e.g., electrical devices of various kinds) should always be placed on the list of hypotheses, even if, for some reason, they are easy to eliminate. 18.5.2 The investigator should carefully consider potential ignition sources which do not correspond to a physical device that can be recovered. Such potential ignition sources include open flames where the device does not remain (e.g., a cigarette lighter was used, but not left at the scene) and static electricity discharges (including lightning). Given the lack of a physical device, other evidence is needed to establish the presence or absence of an ignition source. 18.5.3 For each potential ignition source in the area of origin, it must be established that there existed a fuel or fuels, in an appropriate form and configuration, for which the potential ignition source could be considered a competent ignition source. A cause hypothesis can be developed even in the absence of being able to state specifically which of these fuels was the first ignited. 18.5.4 There may be multiple competent ignition sources in the area of origin with a known first fuel. A cause hypothesis can be developed in the absence of being able to state specifically which of these competent ignition sources ignited the known first fuel. Where propane leaks into a cellar, the standing pilot on either the water heater or the furnace may have been the ignition source, however post-fire it may not be possible to definitively determine which of the two ignited the gas. 18.6 Testing the Cause Hypothesis. Each of the alternate hypotheses that were developed must then be tested using the Scientific Method. If all of the hypotheses developed, except one, are successfully eliminated, then the cause of the fire is identified. If two or more hypotheses remain that cannot be eliminated, then the cause is Undetermined. 18.6.1 Use of the Scientific Method dictates that any hypothesis formed from analysis of the data collected in an investigation must stand the test of careful and serious challenge, by the investigator testing the hypothesis or by examination by others. (see the Basic Methodology Chapter) [See Daubert v. Merrell Dow Pharmaceuticals, Inc. 509 U.S. 579, 113 S. Ct. 2786 (1993).] 18.6.2 Testing of the hypothesis is done by the principle of deductive reasoning, in which the investigator compares the hypothesis to all the known facts as well as the body of scientific knowledge associated with the phenomena relevant to the specific incident. Ultimately, the cause determination is arrived at through the testing of cause hypotheses. 18.6.3 In testing a cause hypothesis, the following questions should be answered: 1) Is the hypothesized ignition source a competent ignition source for the first fuel ignited? 2) Is the required time for ignition consistent with the time line associated with the cause hypothesis and facts of the incident? 3) What were the circumstances that brought the ignition source in contact with the first fuel ignited? 4) What, if any, were the failure modes required for ignition to occur? 18.6.4 Means of Hypothesis Testing. When testing a hypothesis, the investigator should attempt to disprove, rather than to confirm, the hypothesis. If the hypothesis cannot be disproved, then it may be accepted as either possible or probable. Hypothesis testing may include: any application of fundamental principles of science, physical experiments or testing, cognitive experiments, analytical techniques and tools, and systems analysis. 18.6.4.1 Scientific Literature. The use of the scientific literature is an important means to develop information that can be used in hypothesis testing. A review of the literature may include descriptions of experiments and testing that can also be applied to the investigator’s specific case. “Gateways” to the scientific literature can include Internet databases, technical libraries, textbooks and handbooks. The validity of the information in the literature should be considered by the investigator. 18.6.4.2 Fundamental Principles of Science. A cause hypothesis is disproved if it violates the fundamental laws of physics or thermodynamics. Water does not burn – a hypothesis positing the ignition of water would be wrong. 18.6.4.3 Physical Experiments or Testing. Experiments can be conducted to test the hypothesized cause. Care must be exercised in developing an experimental protocol that will produce reliable and applicable results for the specific fire or explosion incident. For more information, see Section on Fire Testing in the Chapter on Failure Analysis and Analytical Tools. 18.6.4.4 Cognitive Experiments. In a cognitive experiment, one sets up a premise and tests it against the data. An example of a cognitive experiment is, “If it were posited that the door was open during the fire and the hinges were found with mirror image patterns, then the hypothesis would be disproved.” For more information see the Chapter on Basic Methodology. 18.6.4.5 Time Lines. In the context of testing a cause hypothesis, the time frame may be a discriminator for determining if an ignition scenario is consistent with the available data as it related to time frames. 18.6.4.6 Fault Trees. Fault trees can be used to test the possibility of a hypothesized fire cause. Fault trees are developed by breaking down an event into causal component parts. These components are then placed in a logical sequence of events or conditions necessary to produce the event. If the conditions or sequence are not present then the hypothesis is disproved. Printed on 9/18/2009 182 Report on Proposals – November 2010 NFPA 921 18.6.4.7 Additional analytical techniques and tools in the Chapter on Failure Analysis and Analytical Tools can be helpful in hypothesis testing. 18.6.5 Process of Elimination. The process of determining the ignition source for a fire, by eliminating all potential ignition sources and then claiming such methodology is proof of an ignition source in which there is no physical evidence of its existence, violates the Scientific Method. Any hypothesis formulated for the causal factors, e.g. first fuel, ignition source and ignition sequence, must be based on facts. Those facts are derived from evidence, observations, calculations, experiments and the laws of science. Subjective or speculative information cannot be included in the analysis. 18.6.5.1 In the circumstance where all possible fire cause hypotheses have been eliminated and the investigator is left with no hypothesis that is evidenced by the facts of the investigation, the only choice for the investigator is to opine that the fire cause, or specific causal factors, remains undetermined. It is improper to base hypotheses on the absence of any supportive evidence. That is, it is improper to opine a specific ignition source that has no evidence to support it even though all other hypothesized sources were eliminated. 18.6.5.2* Rendering an opinion in the absence of any evidence of fire cause, or if there is only ambiguous evidence to support it, is known as “negative corpus” and does not follow the scientific method. The process of eliminating all other fire causes and thereby determining that the fire cause classification must be incendiary, accidental, or natural does not conform to the scientific method, is inappropriate and should not be done. In such a case, the only appropriate fire cause classification is undetermined. A.18.6.5.2 For more information, see the following: Smith, Dennis W., “The Pitfalls, Perils and Reasoning Fallacies of Determining the Fire Cause in the Absence of Proof: The Negative Corpus Methodology,” ISFI Proceedings 2006, International Symposium on Fire Investigation Science and Technology, National Association of Fire Investigators, Sarasota, FL, 2006, pp. 313-325; and, The National Fire Investigator, Spring 2007, NAFI, p.4-11 18.6.5.3 The investigator should remember that the cause of a fire is defined as “the circumstances, conditions, or agencies that bring together a fuel, ignition source, and oxidizer (such as air or oxygen) resulting in a fire or a combustion explosion.” (See the Definitions Chapter, Fire Cause) The identification of an ignition source and a first fuel is not sufficient to determine a cause. Determining a fire cause and ignition sequence requires that any proposed hypothesis include consideration of the relationship between the competency of the ignition source and the first fuel ignited. Do the proposed ignition source and first fuel ignited have complementary ignition characteristics (minimum ignition energy and temperature, heat release rate, specific heat, thermal inertia, heat transfer mechanism, etc.)? 18.6.5.4* “Negative Corpus.” Negative Corpus methodology is defined as the inappropriate use of the process of elimination to determine that a fire cause is classified as incendiary. Negative corpus methodology causes un-testable hypotheses to be generated, and often results in incorrect determinations of the ignition source and first fuel ignited. A.18.6.5.4 For more information, see the following: Smith, Dennis W., “The Pitfalls, Perils and Reasoning Fallacies of Determining the Fire Cause in the Absence of Proof: The Negative Corpus Methodology,” ISFI Proceedings 2006, International Symposium on Fire Investigation Science and Technology, National Association of Fire Investigators, Sarasota, FL, 2006, pp. 313-325; and, The National Fire Investigator, Spring 2007, NAFI, p.4-11 18.7 Selecting the Final Hypothesis. Once the hypotheses regarding the “Cause” of the fire have been tested, the investigator should review the entire process, to ensure that all credible data are accounted for and all credible alternate cause hypotheses have been considered and eliminated. When using the scientific method, the failure to consider alternate hypotheses is a serious error. A critical question to be answered by fire investigators is, “Are there any other cause hypotheses that are consistent with the data?” The investigator should document the facts that support the cause determination to the exclusion of all other reasonable causes. 18.7.1 Establishing the Cause. Although cause is common terminology, the investigator should describe it in terms of the competent ignition source providing enough heat to ignite the first fuel, and the circumstances of how they came together. The fuels involved after the first fuel should be noted, this may be especially true when the first fuel is part of the source, such as an appliance. In such a case the subsequent fuels may be the combustibles that are located near the appliance where the fire originated. 18.7.2 Inconsistent Data. It is unusual for all data items to be totally consistent with the selected hypothesis. Each piece of data should be analyzed for its reliability and value. Not all data in an analysis has the same value. Frequently, some analysis or witness statement will provide data that appears to be inconsistent. Contradictory data should be recognized and resolved. Incomplete data may make this difficult or impossible. If resolution is not possible, then the cause hypothesis should be re-evaluated. 18.7.3 Safety Devices and Features. Safety devices and features are often engineered and built to prevent fires from occurring or becoming a hostile fire. The cause determination will need to account for the actions of safety devices. 18.7.4 Undetermined Fire Cause. The final opinion is only as good as the quality of the data used in reaching that opinion. If the level of certainty of the opinion is only “possible” or “suspected,” the fire cause is unresolved and should be classified as “undetermined”. This decision as to the level of certainty in data collected in the investigation or of any Printed on 9/18/2009 183 Report on Proposals – November 2010 NFPA 921 hypothesis drawn from an analysis of the data rests with the investigator. Committee Action: Accept Committee Substantiation: The technical committee accepted the work of the task group on cause. This chapter was rewritten to discuss cause determination following the sequence of the scientific method. The chapter is now formatted like the origin determination chapter. The committee also feels that the discussion of negative corpus is important. changes to process of elimination and negative corpus more clearly discusses these topics.

The technical committee accepted the work of the task group on cause. This chapter was rewritten to discuss cause determination following the sequence of the scientific method. The chapter is now formatted like the origin determination chapter. The committee also feels that the discussion of negative corpus is important.

Printed on 9/18/2009 184

Includes File 921 CP#10

Report on Proposals – November 2010 NFPA 921 ______921-142 Log #96

______Joseph Carey, Robinson & Cole LLP New text to read as follows:

***See Include 921_L96_R.pdf*** During the last cycle, chapter 17 was rewritten to allow the reader to conduct the origin aspect of the investigation following the steps of the scientific method. Chapter 18 should also be reorganized to allow the read to follow the scientific method step-by-step when engaged in the fire cause portion of the investigation. In addition to reorganizing chapter 18, the text should be revised, certain sections removed and relocated to other chapters.

The committee rejects this public proposal in favor of the committee’s rewrite of Chapter 18.

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Report on Proposals – November 2010 NFPA 921 ______921-143 Log #145

______Daniel L. Churchward, Kodiak Enterprises, Inc.

18.2 Process of Elimination The process of determining the ignition source for a fire, or the cause for a fire, by eliminating all identified ignition sources and then claiming such methodology is proof of an ignition source in which there is no physical evidence of its existence, violates the Scientific Method. Any hypothesis formulated for the causal factors, e.g. first fuel, ignition source and ignition sequence, must be based on facts. Those facts are derived from observations and experiments. Subjective or speculative information cannot be included in the analysis. 18.2.1 During the analysis of an investigation, it is common that several hypotheses may develop which could be possible, explanations for the fire cause. These possibilities exist because they have some fact in support of them and they can reasonably be expected to have occurred during the time leading up to the fire's inception. Each of these possible: hypotheses can be analyzed in light of all known facts and this process of elimination may leave one possibility for consideration. Depending on the data available, that remaining hypothesis may be deemed the most likely, or, "probable", fire cause hypothesis as long as it is consistent with all known facts and scientific principles. If more than one possible hypotheses remains, and neither is deemed probable[more likely than the other], the cause is undetermined. 18.2.2 In the circumstance where all possible hypotheses have been eliminated and the investigator is left with no hypothesis that is evidenced by the facts of the investigation, the only choice for the investigator is to opine that the fire cause, or specific causal factors, remains undetermined. It is improper to base hypotheses on the absence of any supportive evidence. That is, it is improper to opine a specific ignition source that has no evidence to support it even though all other hypothesized sources were eliminated. 18.2.3 In the instance, where one, or more, causal factors is unknown - for instance the ignition source - the investigator may still have sufficient evidence associated with the first fuel or the ignition sequence to formulate a defensible hypothesis. An example of such circumstances is where a propane cloud, leaking from a burst pipe, is ignited by an unknown ignition source. There may be sufficient evidence for the cause to be identified without knowing what ignited the propane. Likewise, if an abnormal fuel source, such as gasoline, is identified in laboratory samples taken from a fire scene location where gasoline was not supposed to be present, the presence of that gasoline may be sufficient for the investigator to determine the fire cause without knowing what the ignition source for the gasoline had been. However, rendering an opinion in the absence of any evidence, or in the presence of ambiguous evidence to support it, is known as negative corpus and does not follow the scientific method. The past editions of the document have not addressed the common practice of determining the cause for a fire, or in specific instances the ignition source, by the "elimination of all other ignition sources" or "the elimination of all other: known causes." This practice commonly results in the determination of a cause with no factual evidence to support it, a practice otherwise known as "negative corpus." This practice is technically improper and needs to be addressed in this document.

The committee rejects this public proposal in favor of the committee’s rewrite of Chapter 18.

Printed on 9/18/2009 186 Report on Proposals – November 2010 NFPA 921 ______921-144 Log #94

______Joseph Carey, Robinson & Cole LLP Delete and add new text to read as follows: Delete sections 18.6 - 18.6.2 18.6 Opinions. When forming opinions from hypotheses about fires or explosions, the investigator should set standards for the level of certainty in those opinions. The following lists two levels of confidence that have significance with respect to opinions: (1) Probable. This level of certainty corresponds to being more likely true than not. At this level of certainty, the likelihood of the hypothesis being true is greater than 50 percent. (2) Possible. At this level of certainty, the hypothesis can be demonstrated to be feasible but cannot be declared probable. If two or more hypotheses are equally likely, then the level of certainty must be "possible." 18.6.1 Use of the scientific method dictates that any hypothesis formed from an analysis of the data collected in an investigation must stand the challenge of reasonable examination, by the investigator testing his hypothesis or by the examination of others. (See Chapter 4.) [See Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993).] 18.8.2 Ultimately, the decision as to the level of certainty in data collected in the investigation or of any hypothesis drawn from an analysis of the data rests with the investigator. The final opinion is only as good as the quality of the data used in reaching that opinion. If the level of certainty of the opinion is only "feasible" or "suspected," the cause shoud be listed asundetermined. Only when the level of certainty is considered feasible can a fire cause be classified as accidental, incendiary, or natural. Insert the following text and renumber existing section 4.5 Reporting Procedure, as 4.6. Many courts have set a threshold of certainty for the investigator to be able to render opinions, such as "proven to an acceptable level of certainty", "a reasonable degree of scientific and engineering certainty", or "reasonable degree of certainty within my profession". While these terms of art are important for the specific jurisdiction or court in which they apply, defining these terms in those contexts is beyond the scope of this document. The following sections briefly discuss the applicability of these topics. The level of certainty describes how strongly someone holds an opinion. Someone may hold any opinion to a higher or lower level of certainty. That level is determined by assessing the investigator's confidence in the data. in the analysis of that data, and testing of hypotheses formed. That level of certainty may determine the practical application of the opinion, especially in legal proceedings. The investigator should know the level of certainty that is required to meet the burden for providing expert testimony. For example, when a cause cannot be identified with the legally required level of certainty, the investigator can state that the fire is undetermined and then list the possible causes with support for each cause hypothesis. The investigator may then suggest other data collection or research that may result in a final cause hypothesis. These activities may include forensic examination of the suspect appliance, interviews of witnesses, fire testing, or research. While the level of certainty comes from the data and analysis, certain entities, such as courts, may sometimes look for particular words to accompany the reported opinions. Two distinctive words used in most courts are and

(1) Probable. This level of certainty corresponds to being more likely true than not. At this level of certainty, the likelihood of the hypothesis being true is greater than 50 percent. (2) Possible. At this level of certainty, the hypothesis can be demonstrated to be feasible but cannot be declared probable. If two or more hypotheses are equally likely, then the level of certainty must be "possible." If the level of certainty of an opinion is merely "suspected," the opinion does not qualify as an expert opinion. If the level of certainty is only "possible," the opinion should be specifically expressed as "possible," Only when the level of certainty is considered "probable" should an opinion be expressed with reasonable certainty. The section on Opinions is currently located in chapter 18. Opinions do not apply only to cause determination, they apply to all aspects of the investigation and therefore should be treated in chapter 4, Basic Methodology. I propose deleting the existing section 18.6 and placing the revised text on opinions in chapter 4 at 4.5. The current section 4.5 Reporting Procedures should then be renumbered at 4.6.

The committee rejects this public proposal in favor of the committee’s rewrite of Chapter 18.

Printed on 9/18/2009 187 Report on Proposals – November 2010 NFPA 921

Printed on 9/18/2009 188 Report on Proposals – November 2010 NFPA 921 ______921-145 Log #93

______Dennis W. Smith, Kodiak Enterprises, Inc. New text to read as follows: *18.7 "Negative Corpus." Negative Corpus refers to a process of inferring an ignition source or a fire cause in the absence of physical evidence of the ignition source. The Negative Corpus methodology utilizes a process, referred to as a process of elimination, to determine or conclude a fire cause, or to classify a fire cause as either incendiary or accidental. The "elimination of all accidental causes" or "the elimination of all other causes" to reach a conclusion regarding some other ignition source or fire cause is a finding that cannot be justified scientifically using logical reasoning by way of the Scientific Method and should be avoided. *A.18.7 For more information, see: Smith, Dennis W. "The Pitfalls, Perils and Reasoning Fallacies of Determining the Fire Cause in the Absence of Proof: The Negative Corpus Methodology," ISFI Proceedings 2006, International Symposium on Fire Investigation Science and Technology, National Association of Fire Investigators, Sarasota, FL, 2006, p. 313; and, The National Fire Investigator, Spring 2007, NAFI, p.4-11 Vaughn, Lewis, The Power of Critical Thinking, Effective Reasoning About Extraordinary Claims, 2nd ed. Oxford University Press, New York/Oxford, 2008 Darner, Edward, T. Attacking Faulty Reasoning. A Practical Guide to Fallacy-Free Thinking, 4th ed., WadsworthJThomson Learning, Belmont, CA, 2001 Kahane, Howard and Cavender, Nancy, Logic and Contemporary Rhetoric, The Use of Reason in Everyday Life, 9th ed. Wadsworth-Thomson Learning, Belmont, CA, 2002 A.J. Burger, The Ethics of Belief, Dry Bones Press, Sagan, Carl, The demon-Haunted World, Science As A Candle in the Dark, Ballantine Books, New York, 1996 *18.7.1 The Negative Corpus Methodology relies on a reasoning fallacy referred to as the The appeal to ignorance is arguing that an absence, or lack, of evidence proves something. However, the absence of evidence proves nothing. Fundamentally, the absence of evidence provides no reason to believe any claim or allegation. A lack of evidence simply reveals the claimant is ignorant and reveals what the claimant does not know about something, as opposed to what is known. *A.18.7.1 Occasionally, an investigator may incorrectly believe, or even allege that their claim must be true because it hasn't been shown to be false. However, the inability to refute a claim is not the same thing as proving it true. For example, someone asserting that their hypothesis regarding a fire cause must be correct because the opposing side has not, or cannot (e.g. due to the lack of evidence preservation or scene documentation) make any "counter-claim" or refute their claim. Some investigators use this method to claim some unfound, alleged open-flame ignition device (e.g. a lighter removed from the origin, or an unfound match) was the ignition source for the fire, but for which admittedly, there is no evidence. In this circumstance, the only method available to refute the claim is to find evidence of the ignition source. Investigators sometimes claim that an open flame was the ignition source for the fire, even when no physical evidence of the device producing the open flame exists. Then, in the absence of evidence, the investigator alleges the ignition source was determined by eliminating all other known ignition sources. The proof, they indirectly allege, is in fact, the absence of proof. Similarly, an investigator may allege the presence of an ignitable liquid in the absence of any affirmative evidence (e.g. positive laboratory test), instead relying on the interpretation of ambiguous fire patterns. In this circumstance, an allegation for the presence of an ignitable liquid could never be refuted even when conclusive evidence of a fire cause were identified. However, the inability to refute a claim is not the same thing a proving the claim true. If an issue could be proven with a lack of evidence, almost anything could be proven. Assume that a claim, or a hypothesis, is made stating, "Ghosts exist because there is no proof they don't." Due to the negative framing of the claim, the only method possible to refute the claim or test this hypothesis, is to prove that ghosts do exist. Allegations are occasionally made in fire investigation with reference to candles, cigarettes or a human act. The allegation is framed such that, "It's my opinion that the ignition source came from an open flame." The reason supporting the claim, whether stated or not, is "because other known ignition sources (in the area of origin) have been eliminated." By restating the claim, the investigator is actually alleging, "This fire is from an open flame, because there is no proof the ignition source is from something else." Once again, as with the allegation of ghosts previously given, the only way to disprove this hypothesis is to find evidence of what is the ignition source, completely discounting the fact that in many fires the ignition source is never found or identified. *18.7.2 The appeal to ignorance is sometimes referred to as the "shifting burden of proof" The responsibility for providing proof for a claim rests with the person making the claim. The burden of proof principle requires that the person

Printed on 9/18/2009 189 Report on Proposals – November 2010 NFPA 921 making an allegation or claim must provide evidence to support their claim. However, the person asserting an argument based on the absence of evidence, such as a Negative Corpus argument, places the burden of proof on the wrong side, in effect, asking the opposing side to find positive evidence in order to refute I the claim. When relying on the Negative Corpus Methodology (the appeal to ignorance), instead of providing positive evidence of the claim, the claimant does the opposite and asserts and relies on the absence of evidence to support their claim. This means the opposing party must provide the evidence that the claim is not true, clearly putting the challenging party on the wrong side. In essence, the opposing or challenging party must do all the work to prove the claim false, notwithstanding the fact that refuting a negative assertion is generally impossible. *18.7.2 An example of the "shifting burden of proof" has occurred is when an investigator claims that some unfound or unproven ignition source is the cause of the fire, and attempts to support this position because the opposing investigator cannot find evidence of or "prove" some another ignition source; therefore, the ignition source being proffered is the only alternative. The error in this line of reasoning occurs because the claimant incorrectly believes or asserts that the elimination of one hypothesis proves some alternate or remaining hypothesis. This is not true. For example, if an investigator asserts that the ignition source for the fire was a device that he did not find, is no longer available or no longer exists, the only apparent method available to refute the claim is to find evidence of the alleged device, or some other ignition source. The demand for the challenging expert to find evidence of an ignition source in this circumstance is unfair because the claimant is asking for, in many cases, the impossible - to find something that is unrecognizable or may no longer exists (e.g. the real ignition source, if the origin was incorrectly identified, or in instances where potential ignition sources were not adequately documented or preserved). In essence, the claimant has attempted to force the opposing side to do the work and find positive evidence that the claimant failed to find or identify. A negative hypothesis is framed in a manner that makes incapable of being tested or falsified. Any hypothesis that is incapable of being tested, or falsified, is an invalid hypothesis. It is the responsibility of the claimant to provide the evidence and the reasons for a claim to be accepted. The investigator who challenges the claim is under no obligation to prove the claim wrong in event of weak or non-existent evidence. No claim should ever be accepted without good reasons and good evidence. The Negative Corpus methodology relies upon un-testable hypotheses, and often results in incorrect determinations regarding the ignition source and the fire cause. 18.7.3 The Negative Corpus methodology is also occasionally improperly relied upon to infer the ignition source of fires classified as "accidental." Incidents alleging candles, cigarettes, equipment and appliances as an ignition source are occasionally alleged even when no physical evidence of the item or a failure can be identified. Allegations of product failures are improper when no physical evidence or remains of the item, equipment or appliance exist. Before it can be concluded that a particular appliance has caused a fire, it should be first be established how the appliance or equipment generated sufficient heat energy to result in ignition. (See §24.1.1. How the Appliance Generated Heat) 18.7.4 The Negative Corpus methodology or any process like it, utilizes an inappropriate methodology by which the results, opinions or conclusions cannot be relied upon to be valid or reliable, and thus should be avoided. The concept of determining a fire cause in the absence of proof has long standing in the fire investigation community, but it one that has no scientific or logical basis supporting a conclusion derived from such a process. Further, this process, often referred to as "negative corpus" or "the negative corpus methodology" is a methodology in conflict and opposed to the tenets of the of scientific method which is the accepted and required methodology for fire investigation according the NFPA 1033, Standard for Professional Qualifications for Fire Investigator 2009 ed., 4.1.2. Lastly, the negative corpus methodology or any process like it cannot be expected to yield valid and reliable conclusions.

The committee rejects this public proposal in favor of the committee’s rewrite of Chapter 18.

Printed on 9/18/2009 190 Report on Proposals – November 2010 NFPA 921 ______921-146 Log #CP4

______Technical Committee on Fire Investigations, The Committee is revising Chapter 21 Explosions and its associated Annex material to read as follows: Chapter 21 Explosions 21.1* General. 21.1.1 Historically, the term explosion has been difficult to define precisely. The evidence that indicates an explosion occurred includes damage or change brought about by blast overpressure as an integral element, producing physical effects on structures, equipment and other objects. 21.1.2 This effect can result from the confinement of the blast overpressure or the impact of an unconfined pressure or shock wave on an object, such as a person or structure. Overpressure is the pressure generated or released in excess of the surrounding ambient pressure. (See Section 21.11 Outdoor Vapor Cloud Explosions.) 21.1.3 Explosion Definition. For fire and explosion investigations, an explosion is the sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gas(es) under pressure. These gases then do mechanical work, such as defeating their confining vessel or moving, changing, or shattering nearby materials. 21.1.3.1 Hydrostatic Vessel Failure. The failure and bursting of a tank or vessel from hydrostatic pressure of a non-compressible fluid such as water is not an explosion, because the pressure is not created by gas. Explosions are gas dynamic. 21.1.3.2 Flash Fires. A flash fire is a fire that spreads rapidly through a diffuse fuel, such as dust, gas, or the vapors of an ignitible liquid, without the production of damaging pressure. The ignition of diffuse fuels does not necessarily always cause explosions. Whether an explosion occurs depends on the location and concentration of diffuse fuels and on the geometry, venting, and strength of the confining structure or vessel, if present, and the presence of obstacles. 21.1.4 Although an explosion is almost always accompanied by the production of a loud noise, the noise itself is not an essential element in the definition of an explosion. The generation and violent escape of gases are the primary criteria of an explosion. 21.1.5 The ignition of a flammable vapor–air mixture within a can, which bursts the can or even only pops off the lid, is considered an explosion. The ignition of the same mixture in an open field, while it is a deflagration, may not be an explosion as defined in this document, even though there may be the release of gas under pressure. 21.1.6 In applying this chapter, the investigator should keep in mind that there are numerous factors that control the effects of explosions and the nature of the damage produced. These factors include the type, quantity, and configuration of the fuel, the size and shape of the containment vessel or structure, obstacles located within the structure, the type and strength of the materials of construction of the containment vessel or structure, and the type and amount of venting present. (See Section 21.5.) 21.1.7 Sections of this chapter present explosion analysis techniques and terms that have been developed primarily from the analysis of explosions involving diffuse fuel sources, such as ignitable gases, dusts, and the vapors from ignitable liquids in buildings as described in the Building Systems Chapter Section on Types of Construction. The scope of this chapter covers all structures in general. However, many of the aids developed covering structural damage are most appropriate for residential and commercial frame structures, e.g. high/low order damage. The reader is cautioned that application of these principles to structures of other construction types may require additional research and/or guidance from other references on explosion effects. The analysis of explosions involving condensed-phase (solid or liquid) explosives, particularly detonating (high) explosives, will also require specialized knowledge that goes beyond the scope of this text. 21.1.8 The investigation of explosion events can be an extremely complicated, technical, scientific, and potentially dangerous task. Investigators faced with the requirement to investigate an explosion scene that exceeds the resources available or is beyond their knowledge or expertise, the investigator should secure the scene to preserve evidence and endeavor to obtain technical expertise and adequate resources to accomplish the scene investigation in a safe and correct manner. 21.2* Types of Explosions. There are two major types of explosions with which investigators are routinely involved: mechanical and chemical, with several subtypes within these types. These types are differentiated by the source or mechanism by which the blast overpressure is produced. 21.2.1 Mechanical Explosions. A mechanical explosion is the rupture of a closed container, cylinder, tank, boiler, or

Printed on 9/18/2009 191 Report on Proposals – November 2010 NFPA 921 similar storage vessel resulting in the release of pressurized gas or vapor. The pressure within the confining container, structure, or vessel is not due to a chemical reaction or change in chemical composition of the substances in the container. 21.2.2* BLEVEs. The boiling liquid expanding vapor explosion (BLEVE) is the type of mechanical explosion that will be encountered most frequently by the fire investigator. These are explosions involving vessels that contain liquids under pressure at temperatures above their atmospheric boiling points. The liquid need not be flammable. BLEVEs are a subtype of mechanical explosions but are so common that they are treated here as a separate explosion type. A BLEVE can occur in vessels as small as disposable lighters or aerosol cans and as large as tank cars or industrial storage tanks. While the initiating event can be caused by a vessel failure, the explosion and overpressure associated with a BLEVE is due to expansion of pressurized gas or vapor in the ullage (vapor space) combined with the rapidly boiling liquid liberating vapor. 21.2.2.1 A BLEVE frequently occurs when the temperature of the liquid and vapor within a confining tank or vessel is raised by an exposure fire to the point where the increasing internal pressure can no longer be contained and the vessel explodes. (See Figure 21.2.2.1.) This rupture of the confining vessel subjects the pressurized liquid to a sudden drop in pressure and allows it to vaporize almost instantaneously contributing to the overpressure and explosion. If the contents are ignitable, there is almost always a fire. If the contents are noncombustible, there can still be a BLEVE, but no ignition of the vapors. Ignition usually occurs either from the original external heat that caused the BLEVE or from some electrical or friction source created by the blast or fragments of the vessel.

FIGURE 21.2.2.1 An LP-Gas Cylinder That Suffered a BLEVE as a Result of Exposure to an External Fire. (Existing Figure 21.2.2.1)

21.2.2.2 A BLEVE may also result from a reduction in the strength of a container as a result of mechanical damage or localized heating above the liquid level. This rupture of the confining vessel subjects the pressurized liquid to a sudden drop in pressure and allows it to vaporize almost instantaneously, contributing to the overpressure and explosion. A common example of a BLEVE not involving an ignitable liquid is the bursting of a steam boiler. The source of overpressure is the steam created by the sudden vaporization of the water. This overpressure and explosion can catastrophically fail the boiler. No chemical, combustion, or nuclear reaction is necessary. This contributes to the energy source, overpressure, and explosion. The chemical nature of the steam (H2O) is not changed. 21.2.2.3 BLEVEs may also result from mechanical damage, overfilling, runaway reaction, overheating vapor-space explosion, and mechanical failure. See Figure 21.2.2.3, which shows the extent of possible damage from a BLEVE.

FIGURE 21.2.2.3 A Railroad Tank Car of Butadiene that Suffered a BLEVE as a Result of Heating Created by an Internal Chemical Reaction. (Existing Figure 21.2.2.3)

21.2.3* Chemical Explosions. 21.2.3.1 In chemical explosions, the generation of the overpressure is the result of exothermic reactions wherein the fundamental chemical nature of the fuel is changed. Chemical reactions of the type involved in an explosion usually propagate in a reaction front away from the point of initiation. 21.2.3.1.1 Combustion Explosions. The most common of the chemical explosions are those caused by the burning of combustible hydrocarbon fuels. These are combustion explosions and are frequently characterized by the presence of a fuel with air as an oxidizer. A combustion explosion may also involve dusts. In combustion explosions, overpressures are caused by the rapid volume production of heated combustion products as the fuel burns. Because these events are likely to be encountered by the fire investigator, combustion explosions are considered here as a separate explosion type. 21.2.3.1.2 Chemical explosions can involve solid combustibles or explosive mixtures of fuel and oxidizer, but more common to the fire investigator will be reactions involving gases, vapors, or dusts mixed with air. Such combustion reactions are called propagation reactions because they occur progressively through the reactant (fuel), with a definable flame front or reaction zone separating the reacted and unreacted fuel. 21.2.3.1.3. Combustion explosions are classified as either deflagrations or detonations, depending on the velocity of the flame front propagation through the fuel air mixture. This should not be confused with the flame speed, which is the speed of the flame propagation relative to a fixed point. The regimes of propagating flame fronts are more accurately described by three categories: a slow deflagration, a fast deflagration, and a detonation. (See Figure’s 21.2.3.1.3(a) (b) and (c) ) 21.2.3.1.3.1. Slow deflagrations are combustion reactions in which the velocity of the reaction zone (flame front) relative to the unreacted fuel-air medium is less than the speed of sound and its associated flame speed relative to a fixed observer is also less than the speed of sound in the unreacted mixture. The pressures across in front and behind Printed on 9/18/2009 192 Report on Proposals – November 2010 NFPA 921 the flame front are essentially the same. Due to the subsonic nature of a slow deflagration and the fact that pressure within a room equilibrates at the speed of sound, the resulting overpressures throughout the confining vessel will experience a similar pressure-time history.

***Insert Figure 21.2.3.1.3(a) Here*** FIGURE 21.2.3.1.3(a) The CFD-simulation shows flame front/velocities in m/s (upper) and pressure in psig (lower) at two monitoring points for a typical slow deflagration. The overpressures both behind and ahead of the flame are essentially the same for the duration of the flame front propagation.

21.2.3.1.3.2. Fast deflagrations are combustion reactions in which the velocity of the reaction zone (flame front) relative to the unreacted fuel medium is less than the speed of sound, however, flame speeds associated with fast deflagrations are higher than the speed of sound in the unreacted mixture. Fast deflagrations are the result of significant flame acceleration due to highly reactive fuels (i.e. hydrogen, acetylene, ethylene) or significant turbulence generation from the geometry of the confining vessel or congestion. Congestion is a term used to describe the abundance of obstacles in the path of the flame front. Highly reactive fuels or significant congestion can result in flame accelerations creating high gas velocities ahead of the flame and a shock wave in front of the flame front. This results in significant local overpressures (much greater than ideal slow deflagrations) and can result in similar damage as detonations. The turbulence generated flame accelerations are the driving mechanisms for maintaining a fast deflagration, and if removed, the fast deflagration will transition back to a slow deflagration.

***Insert Figure 21.2.3.1.3(b) Here*** FIGURE 21.2.3.1.3(b) CFD-simulations of pressure in psi (upper) and flame/velocity in m/s (lower) for a typical fast deflagration. High flow velocities and precompression of the unburned gas are observed ahead of the flame, which is propagating faster than the speed to an observer in a fixed reference frame. Observed overpressures in the region of the flame are typically 2 to 15 times higher than ambient pressure, or can even be higher due to wave reflections. [Simulations result in smoothing of the shock front. Actual shock fronts will be even sharper].

21.2.3.1.3.3. Detonations are combustion reactions in which the velocity of the reaction zone relative to the unreacted flammables is faster than the speed of sound. Detonations are reaction zones that are autoignited by the shock waves ahead of the flame. Unlike fast deflagrations, detonations are self-sustaining processes and do not require other driving mechanisms. To initiate a detonation a very strong release of energy is required (i.e, deflagration to detonation transition (DDT) or the detonation of explosives).

***Insert Figure 21.2.3.1.3(c) Here*** FIGURE 21.2.3.1.3(c) CFD-simulations of a typical pressure in psi (upper) and flame/velocity in m/s (lower) for a detonation flame. Overpressures greater than 16 times the ambient pressure are typically observed the flame front, which can propagate at typical speeds of 1500-2000 m/s. There is no region of overpressure ahead of the flame. [Simulations result in smoothing of the shock front and small velocities ahead of the flame due to the run-up period. Actual shock fronts will be even sharper and the velocities ahead of the front will no longer be present when it is fully developed].

21.2.3.1.4 Several subtypes of combustion explosions can be classified according to the types of fuels involved. The most common of these fuels are as follows: (1) Flammable gases (2) Vapors of ignitable (flammable and combustible) liquids (3) Combustible dusts (4) Smoke and flammable products of incomplete combustion (backdraft explosions) (5) Aerosols 21.2.4 Electrical Explosions. High-energy electrical arcs may generate sufficient heat to cause an explosion. The rapid heating of the surrounding gases results in a mechanical explosion that may or may not cause a fire. The clap of thunder accompanying a lightning bolt is an example of an electrical explosion effect. High-energy electrical arcs require high voltage and are not covered in this chapter. 21.2.5 Nuclear Explosions. In nuclear explosions, the high pressure is created by the enormous quantities of heat produced by the fusion or fission of the nuclei of atoms. The investigation of nuclear explosions is not covered by this document. 21.3 Characterization of Explosion Damage. For descriptive and investigative purposes, it can be helpful to characterize incidents, particularly in structures, on the Printed on 9/18/2009 193 Report on Proposals – November 2010 NFPA 921 basis of the type of damage noted. The terms high-order damage and low-order damage have been used by the fire investigation community to characterize explosion damage. Use of the terms high-order damage and low-order damage is recommended to reduce confusion with similar terms used to describe the energy release from explosives. (See Section 21.12.) The differences in damage are a function of the blast load applied to surfaces (rate of pressure rise, peak pressure, and impulse, achieved in the incident) and the strength of the confining or restricting structure, or vessel, rather than the maximum pressures being reached. It should be recognized that the use of the terms low-order damage and high-order damage may not always be appropriate, and a site may contain evidence spanning both categories. 21.3.1 Low-Order Damage. Low-order damage is characterized by walls bulged out or laid down, virtually intact, next to the structure. Roofs may be lifted slightly and returned to their approximate original position. Windows may be dislodged, sometimes without glass being broken. Debris produced is generally large and is moved short distances. Low-order damage is produced when the blast load is sufficient to fail structural connections of large surfaces, such as walls or roof, but insufficient to break up larger surfaces and accelerate debris to significant velocities. (See Figure 21.3.1.)

FIGURE 21.3.1 Low-Order Damage in a Dwelling. (Existing Figure 21.3.1)

21.3.2* High-Order Damage. High-order damage is characterized by shattering of the structure, producing small debris pieces. Walls, roofs, and structural members are broken apart with some members splintered or shattered, and with the building completely demolished. Debris is thrown considerable distances, possibly hundreds of feet. High-order damage is the result of relatively high blast loads. (See Figures 21.3.2. (a-c))

FIGURE 21.3.2(a) High-Order Damage of a Four-Bedroom Single Story House without ensuing fire. (Old Figure 21.3.2, with new Title and number)

***Insert Figure 21.3.2(b) Here*** FIGURE 21.3.2(b) High-Order Damage of a three-Bedroom House with ensuing fire.

***Insert Figure 21.3.2(c) Here*** FIGURE 21.3.2(c) High-Order Damage remains of a Commercial Structure.

21.4 Effects of Explosions. An explosion is a gas dynamic phenomenon that, under ideal theoretical circumstances, will manifest itself as an expanding spherical heat and pressure wave front. The heat, overpressure, and pressure waves produce the damage characteristic of explosions. The effects of explosions can be observed in five major groups: blast overpressure and wave effect, dynamic drag loads, projected fragment effect, thermal effect, and seismic effect (ground shock). 21.4.1 Blast Overpressure and Wave Effect. 21.4.1.1 General. Certain explosions produce significant volumes of gases. As these gases are generated, the pressure in the confining vessel increases and can significantly damage the containing vessel. In addition, the expanding gases and the displaced air moved by the gases produce a pressure front that is primarily responsible for the damage and injuries associated with explosions. (See figure 21.4.1.1)

***Insert Figure 21.4.1.1 Here*** FIGURE 21.4.1.1 Illustration of pressure fronts in psi (upper) and flame front/velocities in m/s (lower) from a vented ethylene/air explosion just after initial venting 132 msec after ignition (left) and 142 msec after ignition (right).

21.4.1.1.2 For smaller cylindrical objects, such as pipes, supports or lamp posts, damage is largely due to the dynamic drag loads induced by the displaced gases (explosion wind) flowing past the object. The effects of the explosion wind can even be greater after the blast wave and peak overpressures have passed the object (See figures 4.1.1.2(a) and 4.1.1.2(b))

***Insert Figure 21.4.1.1.2(a) Here*** FIGURE 21.4.1.1.2(a) Lamp Post Damage due to Dynamic Drag Loads Imparted by the Displaced Gases (Explosion Wind) at Flixborough, England.

***Insert Figure 21.4.1.1.2(b) Here*** FIGURE 21.4.1.1.2(b) Illustration of flame front/velocities in m/s (upper) and dynamic pressure/drag in kPa (lower) from a vented ethylene/air explosion 142 msec after ignition (left) and 190 msec after ignition when the blast wave as already Printed on 9/18/2009 194 Report on Proposals – November 2010 NFPA 921 passed (right).

21.4.1.1.3 The blast pressure front occurs in two distinct phases, based on the direction of the forces in relation to the point of origin of the explosion. These are the positive pressure phase and the negative pressure phase. 21.4.1.1.4 A typical pressure history from an idealized detonation, measured at a point away from the point of detonation, is shown in Figure 21.4.1.1.4 and consists of positive and negative phases. The area under the pressure–time curve is called the impulse of the explosion.

***Insert Figure 21.4.1.1.4 Here*** FIGURE 21.4.1.1.4 Typical Pressure History from an Idealized Detonation, Measured at a Point Away from the Point of Detonation. (Existing Figure 21.4.1.1.2)

21.4.1.2 Positive Pressure Phase. The positive pressure phase is that portion of the blast pressure front in which the expanding gases are moving away from the point of origin. The positive pressure phase is more powerful than the negative pressure phase and is responsible for the majority of pressure damage. This damage can include weakening of the structure such that the structure can be further damaged by the negative pressure phase. 21.4.1.3 Negative Pressure Phase. 21.4.1.3.1 As the extremely rapid expansion of the positive pressure phase of the explosion moves outward from the origin of the explosion, it displaces, compresses, and heats the ambient surrounding air. A low air pressure condition (relative to ambient) is created at the epicenter or origin. Due to the negative pressure condition (relative to ambient), air rushes back to the area of the origin to equilibrate this low-pressure condition. 21.4.1.3.2 The negative pressure phase can cause secondary damage and move items of physical evidence toward the point of origin. Movement of debris during the negative pressure phase may conceal the point of origin. The negative pressure phase is usually of considerably less power than the positive pressure phase but may be of sufficient strength to cause collapse of structural features already weakened by the positive pressure phase. The negative pressure phase may be difficult to detect by witnesses or by post-blast examination in diffuse-phase (gas/vapor) explosions. 21.4.1.4 Shape of Blast Wave (Front). The shape of the blast front from an idealized explosion would be spherical. It would expand evenly in all directions from the epicenter. In the real world, confinement, obstruction, ignition position, cloud shape or concentration distribution at the source of the blast pressure wave changes and modifies the direction, shape, and force of the front. (See Figures 21.4.1.4(a) and (b))

***Insert Figure 21.4.1.4(a) Here*** Figure 21.4.1.4 (a) Idealized Propagating Flame and Pressure Fronts (After Harris (1983) p.3)

***Insert Figure 21.4.1.4(b) Here*** Figure 21.4.1.4 (b) Idealized Representation of a Flame Front in a Cuboid Vessel (From Harris, 1983)

21.4.1.4.1 Venting of the confining vessel or structure may cause damage outside of the vessel or structure. The most damage can be expected to be in the path of the venting as a result of the blast wave and expelled hot products. For example, the blast pressure front in a room may travel through a doorway and damage items or materials directly in line with the doorway in the adjacent room. The same relative effect may be seen directly in line with the structural seam of a tank or drum that fails before the sidewalls. As the blast wave travels radially from the venting source, damage can also be observed at locations not in line with the vent (See figure 21.4.1.1.1) 21.4.1.4.2 The blast pressure front may also be reflected off solid obstacles and redirected, resulting in a substantial increase or possible decrease in pressure, depending on the characteristics of the obstacle struck. 21.4.1.4.3 After propagating reactions have consumed their available fuel, the force of the expanding blast pressure front decreases with the increase in distance from the epicenter of the explosion. (See Figure 21.4.1.4.3)

***Insert Figure 21.4.1.4.3 Here*** Figure 21.4.1.4.3 Typical Overpressure History at Locations Distant from Center of Explosion.

21.4.1.5 Rate of Pressure Rise versus Maximum Pressure. The type of damage caused by the blast pressure front of Printed on 9/18/2009 195 Report on Proposals – November 2010 NFPA 921 an explosion is dependent not only on the total amount of energy generated but also, and often to a larger degree, on the rate of energy release and the resulting rate of pressure rise. 21.4.1.5.1 Relatively slow rates of pressure rise will produce the pushing or bulging type of damage effects seen in low-order damage. The weaker parts of the confining structure or vessel, such as windows or structural seams, will rupture first; thereby venting the blast pressure wave and reducing the total damage effects of the explosion. 21.4.1.5.2 In explosions of structures where the rate of pressure rise is very rapid, faster than the structure can respond to it, there will be more shattering of the confining vessel or container, and debris will be thrown great distances, as the venting effects are not allowed sufficient time to develop. This is characteristic of high-order damage. 21.4.1.5.3 Where the rate of pressure rise is less rapid, but faster than the structure can respond to it, the venting effect will have an important impact on the maximum pressure developed. See NFPA 68, Standard on Explosion Protection by Deflagration Venting, for equations, data, and guidance on calculating the theoretical effect of venting on pressure during a deflagration. Such calculations assume a structure or vessel that can sustain such a high pressure. The maximum theoretical pressure that can be developed by a slow deflagration can, under some circumstances, be as high as 7 to 9 times higher than the initial pressure. These pressures however are achieved in testing vessels which do not allow the pressure wave to vent, and so are not readily transferred to actual conditions encountered at an explosion scene. Under certain conditions with fuels of high reactivity (hydrogen, acetylene, ethylene), turbulence generated by the geometry of the confining vessel, or high congestion within the structure, local pressures due to fast deflagrations can exceed 7 times the initial pressure due to dynamic effects such as pressure focusing, reflections and pre-compression. Specialized experiments or Computational Fluid Dynamics (CFD) tools can be used to analyze such effects. 21.4.1.5.4 In commonly encountered situations, such as fugitive gas explosions in residential or commercial buildings, the maximum pressure will be limited to a level slightly higher than the pressure that major elements of the building enclosure (e.g., walls, roof, and large windows) can sustain without rupture (minimum failure pressure). In a well-built residence, this pressure will seldom exceed 21 kPa (3 psi). 21.4.2 Shrapnel Effect (Projectiles). 21.4.2.1 When the containers, structures, or vessels that contain or restrict the blast overpressures are ruptured, they are often broken into pieces or fragments that may be thrown over great distances with great force. These fragments are also called missiles, shrapnel, debris, or projectiles. They can cause great damage and personal injury, often far from the source of the explosion. In addition, fragments can sever electric utility lines, fuel gas or other flammable fuel lines, or storage containers, thereby adding to the size and intensity of post-explosion fires or causing additional explosions. 21.4.2.2 The distance to which missiles can be propelled outward from an explosion depends greatly on their initial direction, velocity, mass, and aerodynamic characteristics. An idealized diagram for missile trajectories is shown in Figure 21.4.2.2 for several different initial directions. The actual distances that missiles can travel depend greatly on aerodynamic conditions, obstructions and occurrences of ricochet impacts. As illustrated in Figure 21.4.2.2, the investigator should be mindful that the total distance of travel through the air for a missile, may not be represented by the actual linear distance from the missile’s original location.

FIGURE 21.4.2.2 Idealized Missile Trajectories for Several Initial Flight Directions. (Existing Figure 21.4.2.2)

21.4.3 Thermal Effect. Combustion explosions release quantities of energy that heat combustion gases and ambient air to high temperatures. This heat can ignite nearby thermally thin, and low thermal inertia combustibles or can cause burn injuries to anyone nearby. (See Basic fire Science Chapter Section on Heat Transfer) These secondary fires increase the damage and injury from the explosion and complicate the investigation process. In some cases the fire may actually occur as the primary event; it may be difficult to determine which occurred first, the fire or the explosion. 21.4.3.1 All chemical explosions liberate heat because of the chemical changes in the fuel that occur. The thermal damage (See Section on effective temperatures in fire Patterns Chapter) depends on the nature of the fuel as well as the duration of the high temperatures. 21.4.3.2* Fireballs and firebrands are possible thermal effects of explosions, particularly BLEVEs involving liquefied gas. Fireballs are the momentary ball of flame present during or after the explosive event. As the outer envelope of the gas cloud burns, it lifts and forms the fireball. As fireballs rise they produce mushroom clouds, in which violent convection currents can form. A fireball may produce high-intensity, short-duration thermal radiation. Fireballs can be the result of momentum driven forces such as a BLEVE or burst vessel, or from buoyancy driven forces resulting from a combusting vapor cloud. Firebrands are hot or burning fragments propelled from the explosion. All these effects may serve to initiate fires away from the center of the explosion. A 21.4.3.2 For additional information on Fireballs See: Lees’ Loss Prevention in the Process Industries, 16.15 Fireballs, Babrauskas, Vytenis, Ignition Handbook, p.524-527 21.4.4 Seismic Effect (Ground Shock). Printed on 9/18/2009 196 Report on Proposals – November 2010 NFPA 921 For ground shock to occur, the explosion must transmit significant energy into the ground, causing soil motion. Or as damaged portions of large structures are knocked to the ground, localized kinetic energy can be transmitted into the ground. These ground motion effects, usually negligible for small explosions and diffuse fuel explosions, can sometimes produce additional damage to structures, underground utility services, pipelines, tanks, and cables. 21.5 Factors Controlling Explosion Effects. Factors that can control the effects of explosions include the type and configuration of the fuel; nature, size, volume, and shape of any containment vessel or object affected; level of congestion and obstacles within the vessel; location and magnitude of ignition source; venting of the containment vessel; relative maximum pressure; and rate of pressure rise. The nature of these factors and their various combinations in any one explosion incident can produce a wide variety of physical effects with which the investigator will be confronted. Various phenomena affect the characteristics of a blast pressure front as it travels away from the source. 21.5.1 Fuel The nature of the fuel, whether it is a dust, gas, vapor or aerosol of a flammable or combustible liquid, or explosive, will have a profound impact upon the effects that the explosion will produce. Airborne fuels produce remarkably different effects that those from explosives or pyrotechnics. (See the Fuels Section, of Basic Fire Science Chapter) 21.5.2 Turbulence. Turbulence within a fuel–air mixture increases the flame speed and, therefore, greatly increases the rate of combustion and the rate of pressure rise. Turbulence can produce rates of pressure rise with relatively small amounts of fuel that can result in high-order damage even though the mixture was above or below stoichiometric conditions. The shape, size, and location of obstacles within the confining vessel can have a profound effect on the severity of the explosion by affecting the nature of turbulence. Congestion from an abundance of obstacles in the path of the combustion wave has been shown to increase turbulence and greatly increase the severity of the explosion, mainly due to increasing the flame speed of the mixture involved. Other mixing and turbulence sources, such as fans and forced-air ventilation, may increase the explosion effects. (See Figure 21.8.2.1.7) 21.5.3* Nature of Confining Space. The nature of containment— its size, shape, construction, volume, materials, design, and internal obstacles — will also greatly change the effects of the explosion. For example, a specific percentage by volume of natural gas mixed with air will produce a different rate-of–pressure rise if it is contained in a 28.3 m3 (1000 ft3) room than if it is contained in a 283.2 m3 (10,000 ft3) room at the time of ignition (ref. NFPA 68). This variation in effects is true even though the maximum overpressure achieved will be essentially the same. 21.5.3.1 A long, narrow corridor filled with a combustible vapor–air mixture, when ignited at one end, will be very different in its pressure distribution, rate of pressure rise, and its effects on the structure than if the same volume of fuel–air were ignited in a cubical compartment. 21.5.3.2 During the explosion, turbulence caused by obstructions within the containment vessel can increase the damage effects. This turbulence can be caused by solid obstructions, such as columns or posts, machinery, pipes, racks, etc., which increase flame speed, and thus increase the rate of pressure rise. 21.5.4* Location and Magnitude of Ignition Source. The highest rate of pressure rise will occur if the ignition source is in the center of an uncongested, cubic confining structure. The closer the ignition source is to the walls of such a confining vessel or structure, the sooner the flame front will reach the wall and extinguish causing a reduction in the flame surface and reaction zone. This results in the loss of energy and a corresponding lower rate of pressure rise and a less violent explosion. (See figure 21.5.4 for experimental test results)

***Insert Figure Here*** FIGURE 21.5.4 Laboratory Test Results for Varying Ignition Source Positions* (10.15% Methane/Air Mixture, 0.28m3 Spherical Vessel)

21.5.4.1 In commonly encountered structures, which include areas of high aspect ratio, semi-confinement, venting or partial congestion, the location of the ignition source is very important to the development of the overpressure (maximum pressure and rate of pressure rise) and the corresponding damage level and distribution. Specialized experiments or Computational Fluid Dynamics (CFD) tools can be used to analyze such incidents. 21.5.4.2 The energy of the ignition source generally has a minimal effect on the course of an explosion, but unusually large ignition sources (e.g., blasting caps or explosive devices) can significantly increase the speed of pressure development and, in some instances, can cause a deflagration to transition into a detonation. 21.5.5 Venting. With diffuse fuel (i.e. gas, vapor, or dust) explosions, the venting of the containment vessel will also have a profound effect on the nature of explosion damage. For example, it may be possible to cause a length of steel pipe to burst in the center if it is sufficiently long, in spite of the fact that it may be open at both ends. The number, size, and location of doors and windows in a room may determine whether the room experiences complete destruction, merely a slight movement of the walls and ceiling, or no damage to walls and ceiling. 21.5.5.1 Venting of a confining vessel or structure may also cause damage outside of the vessel or structure. The Printed on 9/18/2009 197 Report on Proposals – November 2010 NFPA 921 most damage can be expected in the path of venting as a result of the blast wave and expelled hot products. For example, the blast pressure front in a room may travel through a doorway and may damage items or materials directly in line with the doorway in the adjacent room. The same relative effect may be seen directly in line with the structural seam of a tank or drum that fails before the sidewalls. As the blast wave travels radially from the venting source, damage can also be observed at locations not in line with the vent. 21.5.5.2 With detonations, venting effects are considerably less than deflagrations, as the high speeds of the blast pressure fronts are too fast for any venting to effectively relieve the peak pressures. 21.5.6 Blast Pressure Wave (Blast Pressure Front) Modification by Reflection. As a blast pressure front encounters objects in its path, the blast pressure front may amplify due to its reflection. This reflection will cause the overpressure to increase with the amplification, depending on the angle of incidence and the incident overpressure. This is further exacerbated in corners where pressure may be locally focused due to the reflections. 21.5.7 Blast Pressure Front Modification by Refraction and Blast Focusing. At times a lack of homogeneity in the affected atmosphere can cause anomalies in the behavior of the expected blast pressure front. When a blast pressure front encounters a layer of air at a significantly different temperature or density, it may cause the blast pressure front to bend, or refract. This occurs because the speed of sound is proportional to the square root of temperature, and thereby the density, of the air. A low-level temperature inversion can cause an initially hemispherical blast front to refract and to focus on the ground around the center of the explosion. Severe weather-related wind shear can cause focusing in the downwind direction. 21.6 Seated Explosions. 21.6.1 General. The seat of an explosion is defined as the crater or concentrated area of great damage, frequently roughly circular or spheroid in shape. The seat of an explosion may not always be located at the point of initiation (epicenter). Material may be thrown out of the crater. This material is called ejecta and may range from larger pieces of shattered debris to fine dust. The presence of a seat indicates the explosion of a concentrated fuel source in contact with or in close proximity to the seat. (See Figure 21.6.1.)

***Insert Figure 21.6.1 Here*** FIGURE 21.6.1 An 3’ diameter explosion seat from an explosive detonated on the ground. Soil ejecta can be seen in the lower right quadrant of the photo.

21.6.1.1 These seats can be of any size, depending on the size and strength of the explosive material involved. They typically range in size from a few centimeters (inches) to 7.6 m (25 ft) in diameter. They display an easily recognizable crater of pulverized soil, floors, or walls located at the center of otherwise less damaged areas. Seated explosions are generally characterized by high pressure and rapid rates of pressure rise. 21.6.1.2 Only specific types or configurations of explosive fuels can produce seated explosions. These include explosives, steam boilers, tightly confined gaseous fuels or liquid fuel vapors, and BLEVEs occurring in relatively small containers, such as cans or barrels. 21.6.1.3 In general, it is accepted that reaction velocities should exceed the speed of sound (detonations) to produce seated explosions, unless the damage is produced by shrapnel (projectiles) from a failing vessel. Each of these explosions involves a rapid release of energy from a containment vessel, resulting in a pressure wave that decays with distance. 21.6.2 Explosives. Explosions fueled by many explosives are often most easily identified by their highly centralized epicenters, or seats. High explosives especially produce such high-velocity, positive pressure phases at detonation that they often shatter their immediate surroundings and produce craters or highly localized areas of great damage. However, if an explosion occurs where the explosive material is not in contact with a surface (suspended or at some distance above ground), a crater may not be present and the investigator would have to consider just the area of greatest damage and the types of fuels that may be present to make a determination. 21.6.3 Boiler and Pressure Vessels. A boiler explosion often creates a seated explosion because of its high energy, rapid rate of pressure release, and confined area of origin. Boiler and pressure vessel explosions will exhibit effects similar to explosives, though with lesser localized overpressure near the source. 21.6.4 Confined Fuel Gas and Liquid Vapor. Fuel gases or ignitible liquid vapors when confined to such small vessels as cylinders, small tanks, barrels, or other containers can also produce seated explosions. 21.6.5 BLEVE. A boiling liquid expanding vapor explosion will produce a seated explosion if the confining vessel (e.g., a cylinder, drum, or tank) is of a small size and if the rate of pressure release when the vessel fails is rapid enough (mechanical explosion). 21.7 Non-seated Explosions. Non-seated explosions occur most often when the fuels are dispersed or diffused at the time of the explosion because Printed on 9/18/2009 198 Report on Proposals – November 2010 NFPA 921 the rates of pressure rise are moderate and because the explosive velocities are subsonic. It should be kept in mind that even detonations of diffuse fuels and condensed phase explosives may produce non-seated explosion damage under certain conditions, such as an elevated explosion. 21.7.1 Fuel Gases. Fuel Gases, such as commercial natural gas and liquefied petroleum (LP) gases, most often produce non-seated explosions. This is because these gases often are confined in large vessels, such as individual rooms or structures, and their deflagration speeds are subsonic. 21.7.2 Pooled Flammable/Combustible Liquids. Explosions from the ignition of vapors of pooled flammable or combustible liquids are typically non-seated explosions. The large areas that they cover and from which they evolve their ignitable vapors, and their subsonic explosive speeds preclude the production of small, concentrated, high-damage seats. 21.7.3* Dusts. Dust explosions most often occur in confined areas of relatively wide dispersal, such as grain elevators, materials-processing plants, and coal mines, where combustible dust can accumulate in sufficient quantity to support a propagating reaction. These large areas of origin preclude the production of pronounced seats. 21.7.4 Backdraft (Smoke Explosion). Backdrafts involve a widely diffused volume of particulate matter and combustible gases. Their explosive velocities are subsonic, thereby precluding the production of pronounced seats. 21.8 Gas/Vapor Combustion Explosions. The most commonly encountered explosions are those involving gases or vapors, especially fuel gases or the vapors of ignitible liquids. Table 21.8 (a) provides some useful properties of common flammable gases. NFPA 68, Standard on Explosion Protection by Deflagration Venting, provides a more complete introduction to the fundamentals of these explosions. Table 21.8(a) lists only single values of lower and upper limits, those limits do in fact change with temperature. Figure 21.8(b) shows how the flammable limits might vary with temperature.

Table 21.8(a) Combustion Properties of Common Flammable Gases (Existing Table 21.8 from NFPA 921-2008)

***Insert Figure 21.8(b) Here*** Figure 21.8(b) Chart demonstrating the effect of temperature on the Flammable/Explosive range of gases (GexCon - Gas Explosion Handbook, Figure 4.5)

21.8.1* Ignition of Gases and Vapors. Gaseous fuel–air mixtures are the most easily ignitible fuels capable of causing an explosion. Minimum ignition temperatures in the 370°C to 590°C (700°F to 1100°F) range are common, and they can be even lower for heavier hydrocarbons, such as n-heptane at 215°C (419°F). Minimum ignition energies of some selected fuels are shown in Table 21.8.1. While Table 21.8.1 shows single values, minimum ignition energy varies with fuel/air ratio as shown in Figure 21.8.1 for methane.

Table 21.8.1 Minimum Ignition Energies of Selected Fuels* ***Insert Table Here*** * Glassman, I (1996), Combustion, 3rd ed., San Diego: Academic Press

Figure 21.8.1 An Experimental comparison of the minimum ignition energy of methane as a function of percentage of methane in the air (GexCon - Gas Explosion Handbook, Figure 4.4) 21.8.2 Interpretation of Explosion Damage. The explosion damage to structures (low-order and high-order) is related to a number of factors. These include the fuel-to-air ratio, vapor density of the fuel, turbulence effects, volume of the confining space, location and magnitude of the ignition source, venting, and the characteristic strength of the structure. 21.8.2.1* Fuel-to-Air Ratio. The nature of damage to the confining structure can be an indicator of the fuel–air mixture at the time of ignition. 21.8.2.1.1 Adiabatic flame temperatures are related to the concentration of fuel as illustrated in Figure 21.8.2.1.1 The theoretical peak pressure of a fuel is largely related to its adiabatic flame temperatures, and to a lesser extent the net mole production/consumption in the reaction.

***Insert Figure 21.8.2.1.1 Here*** FIGURE 21.8.2.1.1 Adiabatic flame temperature for initial conditions 1 atm. and 25° C. (GexCon - Gas Explosion Handbook, Figure 4.7)

21.8.2.1.2 It is not necessary for an entire volume to be occupied by a ignitable mixture of fuel and air for there to be an explosion. Relatively small volumes of ignitable mixtures capable of causing damage may result from gases or vapors collecting in a given area and being ignited before having migrated to all areas of a room or confining vessel. Depending upon the fuel’s properties and the geometry of the confining structure, an explosion or flash fire may result. Printed on 9/18/2009 199 Report on Proposals – November 2010 NFPA 921 The absence of explosion damage does not preclude the presence of an ignitable fuel/air mixture. 21.8.2.1.3 Explosions that occur in mixtures at or near the lower explosive limit (LEL) or upper explosive limit (UEL) of a gas or vapor produce less violent explosions than those near the optimum concentration (i.e., usually just slightly rich of stoichiometric). This is because the less-than-optimum ratio of fuel and air results in lower flame speeds, lower rates of pressure rise, and lower maximum pressure. In general, these explosions tend to push and heave at the confining structure, producing low-order damage. However, there are cases when stratified levels of fuel rich mixtures are pushed out a vent opening and mix with the ambient air, creating flammable mixtures and potentially strong explosions. 21.8.2.1.4* Laminar Burning Velocity. In laminar flame propagation, the flame propagation rate relative to the unburned gas is termed the laminar burning velocity, SL. The burning velocity is the rate of flame propagation relative to the velocity of the unburned gas ahead of it. The fundamental burning velocity is the burning velocity for laminar flame under stated conditions of composition, temperature, and pressure of the unburned gas. Fundamental burning velocity is an inherent characteristic of a combustible and is a fixed value, whereas actual flame speed can vary widely, depending on the existing parameters of temperature, pressure, confining volume and configuration, combustible concentration, and turbulence. The laminar burning velocity is the velocity component that is normal to the flame surface and is determined experimentally by a wide variety of techniques including: (1) Bunsen flames: ratio of the volume flow rate, divided by the actual flame front area, (2) flat flame burners, (3) spherically propagating flames and (4) counterflow flame configurations. This is often not the velocity which is of actual interest to the investigator. (See Table 21.8.2.1.4)

***Insert Table Here*** TABLE 21.8.2.1.4: TYPICAL COMBUSTION PROPERTIES OF COMMON GASEOUS FUELS*

21.8.2.1.4.1 The laminar burning velocity is the velocity at which a flame reaction front moves into the unburned mixture as it chemically transforms the fuel and oxidant into combustion products. It is only a fraction of the flame speed. The flame speed is the product of the velocity of the flame front caused by the volume expansion of the combustion products due to the increase in temperature and any increase in the number of moles and any flow velocity due to motion of the gas mixture prior to ignition. The burning velocity of the flame front can be calculated from the fundamental burning velocity, which is reported in NFPA 68, Standard on Explosion Protection by Deflagration Venting, at standardized conditions of temperature, pressure, and composition of unburned gas. As pressure and turbulence increase substantially during an explosion, the fundamental burning velocity will increase, further accelerating the rate of pressure increase. NFPA 68 lists data on the various materials. 21.8.2.1.5 Expansion Ratio. The expansion ratio is the post-ignition rate of expansion of a fuel/air mixture’s products of combustion behind the expanding flame front. The expanding products of combustion propel the unreacted fuel/air mixture ahead of the flame front. Expansion ratio is generally a specific value for each fuel at a defined temperature, pressure and fuel/air concentration. The density ratio, , is the expansion ratio for the mixture, where ρu is the density of unburned gas, and ρb is the density of burned gas. If the chemical composition of the fuel and the oxidizer are known, the expansion ratio can be computed for stoichiometric combustion under ideal conditions. The expansion ratio is highest in fuel/air mixtures slightly above the stochiometric concentration. This expansion ratio is directly proportional to the volume and temperature of the products of combustion. For most commonly encountered gaseous fuels the expansion factors are between 7 and 8. (See Table 21.8.2.1.4) 21.8.2.1.6 Laminar Flame Speed. The laminar flame speed is the local speed of a freely propagating flame relative to a fixed point without the effect of turbulence in the fuel/air mixture. (See section 28.8.2.1.7.) It is the product of the burning velocity and the expansion ration of the flame front and is given by: . For hydrocarbon-air mixtures one may say that the higher the laminar flame speed, the more reactive is the mixture. This means that the flame can propagate fast through a cloud and thereby cause flame acceleration and pressure build-up. The maximum laminar flame speeds for methane and propane are 3.5 m/sec (11.5 ft/sec) and 4 m/sec (13.1 ft/sec), respectively. For certain mixture concentrations instabilities can occur causing the flame to wrinkle and increase the flame surface. This can further increase the laminar flame speed higher than reported above. (See Figure 21.8.2.1.6)

***Insert Figure 21.8.2.1.6 Here*** FIGURE 21.8.2.1.6 Expanding Spherical H2/O2/N2 flame front at 3 atm. Left-Wrinkled Equivalence Ratio 0.7, Right-Non-wrinkled Equivalence Ratio 2.25. (Tse et al., Proc. Combust. Inst.28, pp.1793–1800, 2000)

Burning Velocity, (SL) x Expansion Ratio, (E) = Laminar Flame Speed, (Sb) For Methane: 1.47 ft./sec. x 7.4 = 10.87 ft./sec.

Printed on 9/18/2009 200 Report on Proposals – November 2010 NFPA 921 21.8.2.1.7 Turbulent flame speed. Explosions will rarely involve laminar (non-turbulent) combustion. Turbulence greatly increases flame speed and the turbulent flame speed will generally be the flame speed which is relevant to a real explosion. It is difficult to compute the turbulent flame speed for an accidental explosion, since local flow conditions have to be known, including factors such as obstructions and their congestion, which increase the turbulent flame speed. However, it is worthy to note that turbulent flame speeds can be higher than the speed of sound in the unreacted mixture (i.e., fast deflagrations). (See Figure 2.8.2.1.7)

***Insert Figure 21.8.2.1.7 Here*** FIGURE 21.8.2.1.7 Influence of obstacle arrangement on flame propagation in ethylene-air mixtures in a vessel (van Wingerden et al., 1991)

21.8.2.1.8 Explosions of mixtures near the LEL do not tend to produce large quantities of post-explosion fire, as nearly all of the available fuel is consumed during the explosive propagation. 21.8.2.1.9 Explosions of mixtures near the UEL tend to produce post-explosion fires because of the fuel-rich mixtures. The delayed combustion of the remaining fuel produces the post-explosion fire. Often, a portion of the mixture over the UEL has fuel that does not burn until it is mixed with air during the explosion’s venting phase or negative pressure phase, thereby producing the characteristic post-explosion fire or secondary explosion. 21.8.2.1.10 When optimum (i.e., most violent) explosions occur; it is almost always at mixtures near or just above the stoichiometric mixture (i.e., slightly fuel rich). This is the optimum mixture. These mixtures produce the most efficient combustion and, therefore, the highest flame speeds, rates of pressure rise, maximum pressures, and consequently the most damage. Post-explosion fires and secondary explosions can occur if there are pockets of overly rich mixtures that further mix with air (oxygen) resulting in mixtures within the flammable/explosive range and subsequent burning. Hydrogen and certain other fuels, however, can produce explosions for a much larger range of concentrations away from stoichiometry. Furthermore, explosions can also result from structures with a high level of congestion, even when mixture well away from stoichiometric conditions. 21.8.2.2* Specific Gravity (air) (Vapor Density). The specific gravity (air) (vapor density) of the gas or vapor fuel can have a marked effect on the nature of the explosion damage to the confining structure, such as dwellings and other buildings. While air movement from both natural and forced convection is the dominant mechanism for moving gases in a structure, the specific gravity (air) (vapor density) can affect the movement of a gas or vapor as it escapes from its container or delivery system. 21.8.2.2.1 Fugitive gas from a natural gas leak in the first story of a multistory structure, if it is not ignited promptly, may be manifested in an explosion with an epicenter in an upper story. The natural gas, being lighter than air, will initially rise through natural openings and may even migrate inside walls. However, as natural gas mixes with air to a flammable mixture, the mixture is essentially the same density as air, and continued migration is governed largely by air movement and diffusion. The gas will continue to disperse in the structure until an ignition source is encountered. However, eventually in the absence of a continuing leak, any gas will be diluted and will dissipate. 21.8.2.2.2 Fugitive gas from an LP-Gas leak, if it is not ignited promptly, can travel away from the source and, due to its initial density, will tend to migrate downward over time. However, as LP-gas mixes with air to a flammable mixture, the mixture is essentially the same density as air, and continued migration is governed by air movement and diffusion. During the leak and for some time thereafter, the gas may be at a higher concentration in low area. However, in the absence of a continuing leak, any gas will be diluted and eventually will dissipate. 21.8.2.2.3 Ignition of the gas will occur only if the concentration is within the flammable/explosive limits and in contact with a competent ignition source 21.8.2.2.4 Whether lighter- or heavier-than-air gases are involved, there may be evidence of the passage of flame where the fuel–air layer was. Scorching and blistering of paintwork and thermally thin materials (e.g. lampshades) are indicators of this phenomenon. The operation of heating and air-conditioning systems, temperature gradients, and the effects of wind on a building can cause mixing and movement that can reduce the effects of vapor density. Vapor density effects are greatest in still-air conditions. 21.8.2.2.5* Full-scale testing of the distribution of flammable gas concentrations from turbulent jets into rooms has shown that near stoichiometric concentrations of gas will develop between the location of the leak and either the ceiling for lighter-than-air gases or the floor for heavier-than-air gases. It was also reported that a heavier-than-air gas that leaked at floor level will create a greater concentration at floor level and that the gas will slowly diffuse upward. A similar but inverse relationship is true for a lighter-than-air gas leaked at ceiling height. In both cases this testing indicated the gas/air mixtures would become fairly homogeneous and that for turbulent jets the previous general belief was incorrect that lighter-than-air gas leaks would fill a compartment from the top down. However, for low momentum leaks in still air, Printed on 9/18/2009 201 Report on Proposals – November 2010 NFPA 921 lighter-than-air gas leaks will fill a compartment from the top down (see figure 21.8.2.2.5). Ventilation, both natural and mechanical, can change the movement and mixing of the gas and can result in gas spreading to adjacent rooms.

***Insert Figure 21.8.2.2.5 Here*** FIGURE 21.8.2.2.5 The plot is showing percent methane in air for a natural gas release involving a high momentum turbulent jet (right) and low momentum jet (left) due to flow impingement or partial confinement. Each leak is approximately 100 ft3/hr and the room is approximately 5300 ft3.

21.8.2.2.6* The specific gravity (air) (vapor density) of the fuel is not necessarily indicated by the relative elevation of the structural explosion damage above floor level. It was once widely thought that if the walls of a particular structure were blown out at floor level, the gaseous fuel would be heavier than air, and, conversely, if the walls were blown out at ceiling level, the fuel would be lighter than air. Since explosive pressure within a room equilibrates at the speed of sound, a wall will experience a similar pressure-time history across its entire height, unless significant flame acceleration occurs due to very reactive fuels (i.e. hydrogen, acetylene, ethylene) or significant turbulence generation from the structure geometry and congestion. The level of the explosion damage within a conventional room is a function of the construction strength of the wall headers and bottom plates, the least resistive giving way first. 21.8.2.2.7 Specific Gravity (air) (Vapor Density) of Ignitable Gaseous Mixtures The specific gravity (air) (vapor density) of a gases or vapors in their 100% undiluted states can be considerably different than when they are mixed with air to a mixture within their flammable/explosive ranges. Ignitable mixtures of gases and vapors are a combination of the fuel components and air. In general, these ignitable mixtures are predominantly air, being 85% to 99% air (notable exceptions include hydrogen, acetylene, ethylene). The specific gravity (air) (vapor density) of most ignitable mixtures are much closer to the actual specific gravity (air) (vapor density) of air (1.0) than to the specific gravity (air) (vapor density) of the 100% undiluted fuel components which are commonly referenced in fire and explosion investigation texts. The calculations for determining the actual specific gravity (air) (vapor density) of a given fuel/air mixture at the minimum ignitable mixture are accomplished by a mixing equation as follows:

For a given gaseous fuel mixture: ***Insert Equation Here***

Where: is the specific gravity (air) (vapor density) of the fuel/air mixture

Printed on 9/18/2009 202

INCLUDES FILE 921 CP#4

Chapter 21 Explosions

1. Figure 21.2.2.1 An LP-Gas Cylinder That Suffered a BLEVE as a Result of Exposure to an External Fire. (Existing Figure 21.2.2.1)

2. Figure 21.2.2.3 A Railroad Tank Car of Butadiene that Suffered a BLEVE as a Result of Heating Created by an Internal Chemical Reaction. (Existing Figure 21.2.2.3.)

3. Figure 21.2.3.1.3(a)

FIGURE 21.2.3.1.3(a) The CFD-simulation shows flame front/velocities in m/s (upper) and pressure in psig (lower) at two monitoring points for a typical slow deflagration. The overpressures both behind and ahead of the flame are essentially the same for the duration of the flame front propagation. (New Figure) 4. Figure 21.2.3.1.3(b)

FIGURE 21.2.3.1.3(b) CFD-simulations of pressure in psi (upper) and flame/velocity in m/s (lower) for a typical fast deflagration. High flow velocities and precompression of the unburned gas are observed ahead of the flame, which is propagating faster than the speed to an observer in a fixed reference frame. Observed overpressures in the region of the flame are typically 2 to 15 times higher than ambient pressure, or can even be higher due to wave reflections. [Simulations result in smoothing of the shock front. Actual shock fronts will be even sharper]. (New Figure) 5. Figure 21.2.3.2.3(c)

FIGURE 21.2.3.1.3(c) CFD-simulations of a typical pressure in psi (upper) and flame/velocity in m/s (lower) for a detonation flame. Overpressures greater than 16 times the ambient pressure are typically observed the flame front, which can propagate at typical speeds of 1500-2000 m/s. There is no region of overpressure ahead of the flame. [Simulations result in smoothing of the shock front and small velocities ahead of the flame due to the run-up period. Actual shock fronts will be even sharper and the velocities ahead of the front will no longer be present when it is fully developed]. (New Figure) 6. Figure 21.3.1 Low-Order Damage in a Dwelling. (Existing Figure 21.3.1) 7. Figure 21.3.2.(a) High-Order Damage of a Four-Bedroom Single Story House without ensuing fire. (Old Figure 21.3.2. with new Title and number) 8. Figure 21.3.2(b) High Order Damage of a three-Bedroom House with ensuing fire.

FIGURE 21.3.2(b) High-Order Damage of a three-Bedroom House with ensuing

fire.

(New Figure) 9. Figure 21.3.2 (c ) High-Order Damage remains of a Commercial Structure.

FIGURE 21.3.2(c) High-Order Damage remains of a Commercial Structure.

(New Figure)

10. Figure 21.4.1.1 Illustration of pressure fronts inpsi (upper and flame front/velocities in m/s (lower from a vented ethylene/air explosion just after initial venting 132 msec after ignition (left and 142 msec after ignition (right).

FIGURE 21.4.1.1 Illustration of pressure fronts in psi (upper) and flame front/velocities in m/s (lower) from a vented ethylene/air explosion just after initial venting 132 msec after ignition (left) and 142 msec after ignition (right). 11. Figure 21.4.1.1.2 (a) Lamp Post Damage due to Dynamic Drag Loads Imparted by the Displaced Gases (Explosion Wind) at Flixborough, England.

FIGURE 21.4.1.1.2(a) Lamp Post Damage due to Dynamic Drag Loads Imparted by the Displaced Gases (Explosion Wind) at Flixborough, England. 12. Figure 21.4.1.1.2(b) Illustration of flame front/velocities in m/s (upper) and dynamic pressure/drag in kPA (lower) from a vented ethylene/air explosion 142 msec after ignition (left ) and 190 msec after ignition when the blast wave has already passed (right).

FIGURE 21.4.1.1.2(b) Illustration of flame front/velocities in m/s (upper) and dynamic pressure/drag in kPa (lower) from a vented ethylene/air explosion 142 msec after ignition (left) and 190 msec after ignition when the blast wave has already passed (right). 13. Figure 21.4.1.1.4 Typical Pressure History from an Idealized Detonation. Measured at a Point Away from the Point of Detonation.

FIGURE 21.4.1.1.4 Typical Pressure History from an Idealized Detonation, Measured at a Point Away from the Point of Detonation.

(Existing Figure 21.4.1.1.2)

14. Figure 21.4.1.4(a) Idealized Propagating Flame and Pressure Fronts

Figure 21.4.1.4 (a) Idealized Propagating Flame and Pressure Fronts

(After Harris (1983) p.3)

(New Figure)

15. Figure 21.4.1.4(b) Idealized Representation of a Flame Front in a Cuboid Vessel

Figure 21.4.1.4 (b) Idealized Representation of a Flame Front in a Cuboid Vessel (From Harris, 1983) (New Figure) 16. Figure 21.4.1.4.3 Typical Overpressure History at Locations Distant From Center of Explosion.

Figure 21.4.1.4.3. Typical Overpressure History at Locations Distant from Center of Explosion.

(New Figure) 17. Figure 21.4.2.2 Idealized Missile Trajectories for Several Initial Flight Directions. (Existing Figure 21.4.2.2) 18. Figure 21.5.4 Laboratory Test Results for Varying Ignition Source Positions

Figure 21.5.4 Laboratory Test Results for Varying Ignition Source Positions*

(10.15% Methane/Air Mixture, 0.28m3 Spherical Vessel)

Maximum Time to Maximum Rate of Maximum Spark Pressure Pressure Rise Pressure Position (p.s.i.a.) (p.s.i./sec.) (sec.)

Center 117 4960 0.095 Bottom 113 1870 0.133 Side 109 1750 0.147 Top 108 1620 0.148

*Reported by Harris (1983) (New Figure) 19. Figure 21.6.1 An 3’ diameter explosion seat from an explosive detonated on the ground. Soil ejecta can be seen in the lower right quadrant of the photo.

Figure 21.6.1 An ~3’ diameter explosion seat from an explosive detonated on the ground. Soil ejecta can be seen in the lower right quadrant of the photo.

(New Figure)

20. Table 21.8 Combustion Properties of Common Flammable Gases (Existing Table 21.8)

21. Figure w1.8 Chart demonstrating the effect of temperature on the Flammable/Explosive range of gases.

Figure 21.8 Chart demonstrating the effect of temperature on the Flammable/Explosive range of gases (GexCon - Gas Explosion Handbook, Figure 4.5)

(New Figure)

22. Table 21.8.1 Minimum Ignition Energies of Selected Fuels

Table 21.8.1 Minimum Ignition Energies of Selected Fuels*

Minimum

Ignition

Gas/Vapor Energy

(mJ)

Acetylene 0.020

Benzene 0.225

Butane 0.260

Ethane 0.240

Heptane 0.240

Hexane 0.248

Hydrogen 0.018 Methane 0.280

Methanol 0.140

Methyl ethyl ketone 0.280

Pentane 0.220

Propane 0.250

* Glassman, I (1996), Combustion, 3rd ed., San Diego: Academic Press

(New Table)

23. Figure 21.8.1 An Experimental comparision of the minimum ignition energy of methane as a function of percentage of methane in the air

Figure 21.8.1 An Experimental comparison of the minimum ignition energy of methane as a function of percentage of methane in the air

(GexCon - Gas Explosion Handbook, Figure 4.4)

(New Figure) 24. Figure 21.8.2.1.1 Adiabatic flame temperature for initial conditions 1 atm. And 25◦ C

Figure 21.8.2.1.1 Adiabatic flame temperature for initial conditions 1 atm. and 25° C.

(GexCon - Gas Explosion Handbook, Figure 4.7)

(New Figure)

25. Table 21.8.2.1.4 Typical Combustion Properties of Common Gaseous Fuels

% Gas at % Gas at Maximum Adiabatic Expansion Max.

Maximum Laminar Stochiometric flame Ratio** Laminar Burning Burning temperature Gas Ratio Flame Velocity Velocity ° kelvin (T /T ) Speed (Optimum m/sec. f i (°F.) m/sec. Mixture) (Ft./Sec.)

(Ft./Sec.)

Acetylene 7.7 9.3 1.58 2598 9.0 14.2

(5.18) (4217) (46.6) Benzene 2.7 3.3 0.62 2287 7.9 4.9

(2.03) (3657) (16.08)

Butane 3.1 3.5 0.50 2168 7.5 3.7

(1.64) (3443) (12.13)

Ethane 5.6 6.3 0.53 2168 7.5 4.0

(1.74) (3443) (13.12)

Heptane 1.9 2.3 0.53 2196 7.6 4.0

(1.71) (3493) (13.12)

Hexane 2.2 2.5 0.53 2221 7.7 4.0

(1.71) (3538) (13.12)

Hydrogen 30.0 54 3.5 2318 8.0 28.0

(11.48) (3713) (91.86)

Methane 9.5 10.0 0.45 2148 7.4 3.5

(1.48) (3407) (11.48)

Pentane 2.6 2.9 0.52 2232 7.7 4.0

(1.71) (3558) (13.12)

Propane 4.0 4.5 0.52 2198 7.6 4.0 (1.71) (3497) (13.12)

*after Harris (1983)

** The actual Expansion Ratio is given by u/b the density of the reactants (u) divided by the density of the products (b), or equivalently in near constant pressure conditions (Tf/Ti)(Nb/Nu), the product of the ratio of absolute flame temperature (Tf) to absolute initial gas temperature (Ti) and the ratio of the number of moles of the products (Nb) to the number of moles of the reactants (Nu). Harris assumes the number of moles of the products (Nb) is equal to the number of moles of the reactants (Nu) and computes the expansion ratio based on the absolute temperature ratio alone. As such, the values in the table will be slightly different than actual values.

26. 21.8.2.1.6 Expanding Spherical H2/02/N2 flame front at 3 atm. Left-Wrinkled Equivalence Ratio 0.7, Right-Non-wrinkled Equivalence Ratio 2.25

Figure 21.8.2.1.6 Expanding Spherical H2/O2/N2 flame front at 3 atm. Left-Wrinkled Equivalence Ratio 0.7, Right-Non-wrinkled Equivalence Ratio 2.25.

(Tse et al., Proc. Combust. Inst.28, pp.1793–1800, 2000) (New Figure) 27. Influence of obstacle arrangement on flame propagation in ethylene-air mixtures in a vessel

Figure 21.8.2.1.7 Influence of obstacle arrangement on flame propagation in ethylene-air mixtures in a vessel (van Wingerden et al., 1991)

28. 21.8.2.2.5 The plot is showing percent methane in air for a natural gas release involving a high momentum turbulent jet (right and a low momentum jet (left) due to flow impingement or partial confinement. Each leak is approximately 100ft³/hr and the room is approximately 5300 ft³

Figure 21.8.2.2.5 The plot is showing percent methane in air for a natural gas release involving a high momentum turbulent jet (right) and low momentum jet (left) due to flow impingement or partial confinement. Each leak is approximately 100 ft3/hr and the room is approximately 5300 ft3. (New Figure) 29. New formula

For a given gaseous fuel mixture: VDm = VDf (Cf) + (100 - Cf)

100

Where: VDm is the specific gravity (air) (vapor density) of the fuel/air mixture

VDf is the specific gravity (air) (vapor density) of the gaseous fuel component,

and

Cf is the concentration by volume percentage of the fuel within the fuel/air

mixture.

(New Formula)

30. Figure 21.14.4.1.4 A simple Debris Field Diagram from a dwelling gas explosion

Figure 21.14.4.1.4 A simple Debris Field Diagram from a dwelling gas explosion

(New Figure)

31. Table 21.14.4.1.5(a) Human Injury Criteria (Includes Injury from Flying Glass and Direct Overpressure Effects) (Existing Table 21.13.4.1.4(a) ) 32. Table 21.14.4.1.5(b) Property Damage Criteria (Existing Table 21.13.4.1.4(b) ) 33. Figure 21.15 Diagram Showing Displacement of Wall, Doors, and Windows Due to Explosion. (Existing Table 21.14 ) Report on Proposals – November 2010 NFPA 921 ______921-147 Log #151

______Melvin Robin, ATF New text to read as follows: (4) Fire Bombs, commonly called Molotov cocktails (which leave evidence in the form of the ignitable chemicals, or compounds used within them, the broken container broken or intact containers, and wicks, comprised of paper, cloth or any other combustible material. Molotov Cocktails may be intact when recovered, therefore the container should be clarified as being broken or intact. And we should identified any combustible material which could be used as a wick.

Revise text to read as follows: (4) Fire Bombs, commonly called Molotov cocktails (which leave evidence in the form of the ignitable chemicals, or compounds used within them, the broken container broken or intact containers and wicks). comprised of paper, cloth or any other combustible material.

The addition of examples of wicks adds nothing to the document.

Printed on 9/18/2009 203 Report on Proposals – November 2010 NFPA 921 ______921-148 Log #160

______Melvin Robin, ATF New and revise text to read as follows: Add as an example at end of paragraph: “Vandalism & graffiti; prior fire activity at location or prior criminal activity at location or neighborhood” Potential indicators may include a range of items not listed in the document.

The proposed text is inappropriate if placed as requested. The idea may be appropriately placed as a subsection of 22.3, however, it lacks sufficient verbiage as standalone text. There is no indication by the submitter as to which text to revise.

Printed on 9/18/2009 204 Report on Proposals – November 2010 NFPA 921 ______921-149 Log #77

______Stuart A. Sklar, Fabian, Sklar and King, P.C. Delete text to read as follows: Delete 22.4.6 There is no validated basis for this section. The statements contained therein are unreliable, and serve no useful purpose.

The current text is valid as “other evidentiary factors.” The fact that a property owner has experience prior incendiary fires at other owned properties may even be admissible in trial.

Printed on 9/18/2009 205 Report on Proposals – November 2010 NFPA 921 ______921-150 Log #78

______Stuart A. Sklar, Fabian, Sklar and King, P.C. Delete text to read as follows: Delete 22.4.8.2 This section does not appear to belong in the Incendiary Fire chapter in a list of "Other Evidentiary Factors". This section deals with "natural conditions" and seems to have nothing to do with incendiary fires.

Committee believes that the language is accurate and appropriately placed in the text.

Printed on 9/18/2009 206 Report on Proposals – November 2010 NFPA 921 ______921-151 Log #CP6

______Technical Committee on Fire Investigations,

***Include-921-LCP6*** The chapter was reorganized to follow the format of other chapters within the document. In its rewritten form, the chapter now presents the reader with basic knowledge associated with fire related deaths and injuries, and then provides details to the reader regarding the implementation of this knowledge in the field. In addition to reorganization, new text was added to the document. This new text reflects the current state-of-the-art in fire related death and injury investigation, which was absent in the previous editions of the text. The chapter first appeared in the 1998 edition of NFPA 921 and has not undergone any major revisions since its first appearance. Science and technology has become more advanced since the original authoring of the document, and the use of pathological and toxicological data in fire investigation has also become more frequent. As such, the newly revised document has focused on educating the fire investigator on the importance of collecting pathological and toxicological data in the process of performing their investigation.

Printed on 9/18/2009 207 INCLUDES FILE NFPA 921 CP #6

Chapter 23 Fire and Explosion Deaths and Injuries

1. Figure 23.2.5.1 Old Figure 23.7.2.4

2. Figure 23.5.5.1 Old Figure 23.2.2.2

3. Figure 23.5.7 Old Figure 23.2.4.2

4. Figure 23.8.1.3 Old Figure 23.7.2.2.1

5. Figure 23.8.1.4 Old Figure 23.7.2.2.2

6. Figure 23.10.8.2.1

23.10.8.2.1 The CFK equation is represented as

HbCOA  PIBV t CO CO  e b BtAV HbCOA 0 CO  PIBV CO

where



 ,OC 2 / HbOMPA 2  ,OC PIP  49 2 O2 PI 0208.0304.148  PI O2 CO M  218

HBO2 22.0  HbCO t

HbCO t  tCOHb  0022.0%

1 CO  VAPLDLB 33.0 DLCO 35 2  eVO

2  RMVVO  0309.0274.22/ PL  713

A E  132933.0 fVV f  0165.0exp RMV  3293.2 and

HbO2  mL of O 2 mLper of blood

HbCO t  mL of CO mLper of blood at time tof

HbCO 0  mL of CO/mL blood at the beginning theof exposure

M  ratio theof ofaffinity blood toCOfor that Ofor 2 P  average partial pressure of oxygen lungin s,capillarie mmHg ,OC 2  V CO  rate of endogenous CO ,production mL/min

DLCO  diffusivit theofy lung CO,for *mL/min mmHg PL  barometric pressure theminus vapor pressure of water at body temperature, mmHg

Vb  blood volume, mL (74 mL/kg body weigh t)

PI CO  partial pressure of CO inhaledin air, mmHg

VA  alveolar ventilation rate, mL/min t  exposure duration, min e  7182.2 RMV  respritory minutevolume

7. Figure 23.6.10 Old Figure Delete

8. A.23.6.1 Old Figure A.23.7.1.4 Report on Proposals – November 2010 NFPA 921 ______921-152 Log #CP7

______Technical Committee on Fire Investigations, The Committee is revising Chapter 25 Vehicle Fires and adding a section on Agricultural Equipment to read as follows and then renumber existing material: Agricultural Equipment and Implements 25.14 Introduction. This section refers to the investigation of fires involving self-propelled agricultural equipment and drawn farm implements. Self-propelled agricultural equipment is any type of equipment powered by an internal combustion engine and does not have to be pushed or pulled by other equipment. Drawn farm implements must be connected to a tractor or similar equipment and pulled or pushed to accomplish its designed task. Common functions performed by implements include soil cultivation, planting, fertilizing, spraying, irrigation, and harvesting. Implements generally use hydraulic lifts or may require connection to a tractor’s power take-off (PTO) for operation. Many implements require hydraulic power for on-board hydraulic drives or electrical power for lights, electronic controls, and sensing equipment. Included in the discussion will be the classification and description of the various types of equipment likely to be encountered, unique features, and special hazards associated with each type. 25.14.1 Agricultural Equipment Investigation Safety. In addition to the guidance set forth in the Safety Chapter, the following hazards may be encountered when performing a post-fire investigation. 25.14.1.1 Due to the nature of construction and use of agricultural equipment, an investigator may encounter particulate from burned composite materials (e.g. fiberglass), and burned or decaying vegetation. Sharp edges from re-solidified glass or metals may cause penetrating injuries or lacerations. The sheer size and bulk of agricultural equipment creates an overhead environment with potential impact hazards which can cause head or eye injury. Investigations may require working at elevations with little or no platform or support, and slippery and/or uneven surfaces posing slip or fall hazards. Ladders or other specialized equipment may be necessary for working on the upper regions of this equipment. These hazards may require the use of additional safety equipment or procedures as outlined in the Safety Chapter. 25.14.1.2 Hazardous materials such as fuels, herbicides, pesticides, and other agricultural chemicals may be found in various tanks or containers located on the unit. The potentially large capacities of storage tanks (fuel, hydraulic fluid, water, chemicals) may result in large spills or pools of liquid. Chemicals may also be present in powder or granular form. Soil surrounding the involved equipment may be contaminated by these products. Exposure to these materials may result in safety concerns such as inhalation injuries, chemical burns, irritations, slips, or falls. These hazards may require the use of additional safety equipment or procedures as outlined in the Safety Chapter. 25.14.1.3 The post-fire condition or location of the agricultural equipment may be unstable. Efforts similar to those outlined previously in this chapter should be employed to stabilize the equipment prior to initiating an examination, as required. Mechanical parts or components may fall, pinch, slide, shear, rupture, collapse, or release pressurized liquids or gases. Efforts should be made to identify and secure these potential hazards prior to conducting an investigation. 25.14.1.4 Agricultural equipment fires generally occur in agricultural fields, roadways, or equipment sheds. Burned equipment in fields may pose additional hazards including uneven ground, loose soil, water, mud, snow, plants, snakes and insects. Burned agricultural equipment may provide hiding places for reptiles or rodents. Agricultural equipment fires in structures may pose additional hazards such as collapse, exposure to chemicals, collapse of stacked or stored contents, or sharp or pointed tools or implements. 25.14.2 Equipment Classification and Description. For specifications of a particular make or model of equipment, refer to the manufacturer’s information for that particular piece of equipment. 25.14.2.1 Farm Tractors. Tractors are used for pulling or pushing machinery or trailers, lifting, carrying, loading, plowing, tilling, disking, harrowing, planting, and similar tasks. Most tractors currently in use on farms today are equipped with gasoline or diesel engines. Tractors may be conventional “in-line” tractors or articulated tractors that hinge in the middle. Engines are typically located forward of the operator’s station. Tractors may have manual transmissions, hydrostatic drive transmissions, or electronically assisted hydraulic transmissions. Tractors may have two or four wheel drive. Tractors may have disc or drum brakes. 25.14.2.1.1 Power Take Off (PTO). Tractors are equipped with a PTO which consists of a splined shaft attachment off of the tractor’s transmission. A shaft is attached from the tractor to an implement to provide rotary power. PTO’s can be mounted at the front, middle, or rear of the tractor. 25.14.2.1.2 Hydraulic Components. Tractors may be equipped with hydraulically powered attachments. A series of hydraulic pumps, valves, and hoses, are required for operation.

Printed on 9/18/2009 208 Report on Proposals – November 2010 NFPA 921 25.14.2.2 Combines. Combines are used to harvest corn, soybeans, wheat and other grain crops. There are three separate functions that a combine performs during the harvesting process. First a cutting unit, generally referred to as a “header”, cuts the crop to be harvested. The crop is then picked up and carried through a threshing mechanism, which separates and removes the unwanted material (residue). The remaining crop is then fed through a cleaning system and into a hopper or tank. When the hopper is full, the crop is mechanically off-loaded into a mobile transport trailer or truck. Most combines currently in use on farms today are equipped with turbo-charged diesel engines. Engines are generally transverse mounted high and to the rear of the grain tank. On some older units, engines can be found to the right side of the operator’s station, forward of the grain tank. Combines are generally equipped with hydrostatic drive transmissions. The front wheels on a combine are the drive wheels while the rear wheels steer. Hydraulic drive motors may be used to provide all-wheel-drive on newer equipment. (See Figure 25.14.22)

***Insert Figure 25.14.2.2 Here*** Figure 25.14.2.2 Combine terminology.

25.14.2.2.1 Headers. There are various header configurations to match the crop to be harvested. Headers are attached to the front of the combine through a latching system that allows for changing and adjustment. Hydraulic and electrical connections are also made to the header for its operation. 25.14.2.2.2 Threshing/Crop Cleaning System. Once the crop is cut, it is carried up to a system of cylinders and plates to separate the residue from the crop. The crop then travels through a series of sieves and fan-driven air to further clean the crop. The residue is carried on a separate series of plates to the back of the combine where it may be chopped into fine pieces. A mechanical spreader may be used at the rear of the combine to scatter the residue on the ground behind the unit as it moves through the field. 25.14.2.2.3 Unloading System. After the crop is cleaned, it is fed into a hopper or grain tank. Sensors in the tank provide indication to the operator when the tank is full. An auger system moves the harvested crop through a chute and discharges it into an “attending trailer”. 25.14.2.3 Forage Harvesters. Forage harvesters (also known as a silage harvester, forager or chopper) are similar equipment that harvests field crops to make silage. Silage is grass, corn, or other plants that have been chopped into small pieces, compacted, and then allowed to partially ferment to provide feed for livestock. Haylage is a similar process but uses dry hay. Forage harvesters utilize special cutting heads that cut the plants and then feeds them into a series of rotating processing drums, which utilize steel knives to chop the plant material into small pieces (silage). The silage is then fed into an accelerator device similar to a rotating fan, which forcefully pushes the silage up and out of a discharge chute and into an “attending trailer”. Most forage harvesters currently in use on farms today are equipped with turbo-charged diesel engines. Engines are generally mounted in-line at the rear of the harvester. Forage harvesters are generally equipped with electronically assisted hydraulic transmissions. The front wheels on a harvester are the drive wheels while the rear wheels steer. Harvesters may be equipped with four wheel drive. 25.14.2.4 Cotton Pickers. Cotton pickers harvest cotton using attachments called row units or picking drums. Rows of barbed spindles rotate at high speed to remove the cotton from the plant. The cotton is removed from the spindles by a counter-rotating doffer and blown upward into a large steel basket mounted at the rear of the unit. Once the basket is full, the picker is designed to dump the harvested cotton into a detached steel box with a hydraulic compactor arm called a module builder. Evolving cotton picker designs take the harvested cotton, form it into a round or square bale, wrap it, and eject the bale much like a hay baler (see below). Most cotton pickers currently in use are equipped with turbo-charged diesel engines. Engines are generally transverse mounted below and to the rear of the operator’s station, near the center of the unit. Cotton pickers are generally equipped with hydrostatic drive transmissions. The front wheels on a cotton picker are the drive wheels while the rear wheels steer and provide some drive assistance. Cotton pickers are generally equipped with disc, drum brakes or sealed wet-brakes.

***Insert Figure 25.14.2.4.1(a) Here*** Figure 25.14.2.4.1(a) Elevation view of internal components of a row unit.

***Insert Figure 25.14.2.4.1(b) Here*** Figure 25.14.2.4.1 (b) Schematic of a row unit.

25.14.2.4.1 Row Units. Row Units are attached to a header at the front of the cotton picker. The harvesting and separation process takes place in the row units. The individual units are attached to the header in such a way as to allow easy adjustment. Hydraulic, electrical, and water connections are made to the row units. The mechanical operations of the units are usually PTO driven. The electrical connections are for fine adjustment of the row units and operation sensors. Each row unit contains a series of vertical drums mounted with a plurality of moistened tapered Printed on 9/18/2009 209 Report on Proposals – November 2010 NFPA 921 spindles that pull the cotton from the bolls. As the spindles pass by rubberized “doffer” lugs, the cotton is scrubbed from the spindles. The liberated cotton is then collected at the back of the row unit where forced air is used to blow the cotton out of the unit, up a plastic chute attached to each row unit, and into the basket, which is located immediately to the rear of the operator’s station, over the rear portion of the equipment. 25.14.2.4.2 Moistener System. Unique to cotton pickers is the moistening system, which consists of a water tank, a pump, and distribution system. Depending on the design, the tank may be located either inside the frame, under the basket, at the rear of the unit or immediately behind the operator’s station and in front of the basket. The moistener system keeps the spindles moist during operation for more efficient picking of the cotton as it passes through the row unit. 25.14.2.4.3 Hydraulic System. Hydraulic systems operate the row units, drive wheels, braking, steering, and basket lift systems. System components include a large capacity reservoir, pump, manifold valve assembly, hoses, and couplings. 25.14.2.4.4 Lubrication System. Cotton Pickers also contain a separate lubrication system for the row units. This lubrication system consists of a non-metallic lubricant reservoir, a lubrication pump, control box, hoses and couplings. Oil-base lubricant provides an additional fuel load in the picking units in the event of a fire. 25.14.2.5 Sprayers. Sprayers may be self-propelled tractors fitted with solution tanks, booms, and a solution dispensing system specifically designed for chemical solution applications to row crops. Most sprayers have similar characteristics to farm tractors. The primary difference between the two is that sprayers are elevated for adequate ground clearance above maturing crops. Most sprayers are not equipped with PTO attachments. Sprayers may also be found as attachments to standard tractors. 25.14.2.6 Windrowers, Floaters, Spreaders, Fertilizer Applicators. Each of these pieces of equipment is designed for a specific agricultural function with physical characteristics similar to sprayers. Each piece of equipment may also be found as attachments to standard tractors. 25.14.2.7 Baling Equipment. A baler is used to compress a cut and raked crop (such as hay, straw, corn plants, or peanut plants) into round or square bales, which are bound with twine, wire, or synthetic wrap. 25.14.2.7.1 Round Balers. Round balers produce "round" or "rolled" bales of hay or silage. The crop is rolled inside the baler using a series of rubberized belts and fixed rollers. When the bale reaches a determined size, it is bound and discharged from the rear. 25.14.2.7.1.1 Baling Chamber. The baling chamber is located in the center of the unit. The chamber contains a series of rotating rubberized belts, mounted side by side, and routed around a series of fixed and floating rollers, which generate the roll or bale. Additional crop material is added to the outside of the roll. Once the roll is complete, the operator prepares the roll and it is discharged. 25.14.2.7.1.2 Gate. A hydraulic gate is located at the rear of the baler. When opened, a bale is discharged, then closed, and the formation of a new bale begins. Some models are equipped with a hydraulically operated bale ejector or ramp. 25.14.2.7.2 Square Balers. A knife cuts the hay where it enters the chamber from the pickup. The mechanical plunger then rams the hay rearwards, compressing it into thin wafers or sections that form the bale. A measuring device measures the appropriate length of the bale and triggers the twine tying mechanism. As the next bale is formed, the finished bale is driven out of the rear of the baling chamber. Some square balers are equipped to hydraulically eject bales out of a chute and into a towed trailer. 25.14.2.7.3 Pickups. Pickups use a series of tines to pick up crop material that has been piled in rows and is located underneath the front of the baler. The pickup, which is driven by a chain and sprocket attached to the main drive sprocket gather the crop material and feed it into the baling chamber. 25.14.2.7.4 Chain Drive Systems. These systems have a series of chains, sprockets, and idler tension pulleys that are used to drive the pickup and the belt and roller system. These components can be found behind lift-up or swing out door panels, or behind bolted inspection panels, which provide access to fixed roller mounting points. The chain drive system is powered through a gear box on the baler by shaft attachment to the tractor’s PTO. 25.14.2.7.5 Hydraulic System. Hydraulic pressure is supplied to the baler by the tractor via hydraulic line connections. On board equipment includes hydraulic lines, valves, and connectors. 25.14.2.7.6 Electrical System. Electrical circuits on the baler operate lights and sensors powered and protected by the tractor’s electrical system. 25.14.3 Unique Safety Concerns. 25.14.3.1 Fluid Capacities. All fluid capacities tend to be larger on agricultural equipment. Diesel fuel capacities can be several hundred gallons to allow for uninterrupted operation over many hours. Large quantities of combustible liquids may be released prior to or during a fire, which can increase the rate and intensity of the fire. This can potentially obscure fire patterns produced in the early stages of the fire. The fuel tank construction may be non-metallic and its location may be elevated. The construction material of the liquid tank may also contribute to the overall fuel load. 25.14.3.2 Internal Equipment. Due to the construction of this type of equipment, specialized tools or assistance may be Printed on 9/18/2009 210 Report on Proposals – November 2010 NFPA 921 necessary in order to access internal areas. The investigator may seek assistance from persons who have experience with the specific make and model of equipment in order to complete the investigation while maintaining preservation of the evidence. Refer to the Legal Considerations Chapter for detailed information regarding spoliation of evidence, notification of interested parties, and recommended procedures for destructive testing before any dismantling of the machinery. 25.14.3.3* Overhead Electrical Hazards. The normal height of agricultural equipment may exceed the height of standard-sized vehicles, such as semi trucks. Operational heights may also be greater due to dumping or other reasonably foreseeable operations. Agricultural fields crossed by or bordered by overhead high voltage electrical lines may pose an additional hazard, since these energized lines might be contacted by the agricultural equipment during normal operations. In the event that agricultural equipment has made contact with high voltage electrical lines, the investigator should take all necessary precautions to ensure that the electrical conductor (lines) have been properly de-energized, tested and grounded by qualified electric utility personnel prior to approaching the equipment for investigation. A safety perimeter of at least ten feet as required by OSHA should be established away from the affected equipment and enforced by the investigator until the electrical lines have been properly de-energized, tested and grounded by qualified electric utility personnel. 25.14.3.4 Elevated Basket. Cotton picker fires may occur in the harvested cotton collected in the basket. A typical action for the operator is to attempt to dump the cotton from the basket and move the picker away from the burning cotton. If the operator is unable to complete this action, the basket may be elevated from its normal position on the frame. The picker may be unstable because of this condition or the basket itself may need to be secured before an investigation can be initiated. In some cases, the basket may have fallen to the side of the picker, hindering the investigation of the hydraulic system. Special assistance or equipment may be necessary to gain safe access to the areas underneath the basket. 25.14.3.5 Gate Failure. On round balers, failure of the gate’s hydraulic system may result in severe crushing or entrapment hazards. Care should be taken to secure the gate if open. 25.14.3.6 Hydraulic Bale Ejector. Bale ejectors may be found as an option on certain makes of square hay balers. These ejectors are hydraulically powered and controlled by electrical sensors/switches for operation. The hydraulic system is self contained and pre-charged. The hydraulic pump is driven by the tractor’s PTO. Springs may be used to assist in the ejection process. Because the system is hydraulically driven, the ejector is not a safety concern, post fire, unless the unit is placed into operation. 25.14.4 Unique Fire Cause Concerns. 25.14.4.1 Scrapping. Scrapping is the common practice of a secondary harvest of previously picked cotton fields in which scrap cotton, still attached to the boll, is harvested. During this harvest, the plant has been dead for some time and is generally very dry. In this dry condition, water is not needed to assist with spindle cleaning as it is during the primary harvest. The water pump is taken off line to protect the pump from cavitation, over-heating, and warping of the seals. During this operation, excessive amounts of crop residue can collect within the row unit causing friction with the rotating mechanical components or jammed crop residue can force these mechanical components out of alignment, resulting in metal-to-metal contact between spindles or the metal housing components of the row unit. Hot slag generated from this contact may ignite collected cotton dust or fine crop residue and be blown into the basket, igniting the harvested cotton.

***Insert Figure 25.14.4.2 Here*** Figure 25.14.4.2 Collected foreign combustible material on a cotton picker.

25.14.4.2 Foreign Combustible Materials. The collection and build-up of foreign combustible materials may occur in various locations on agricultural equipment. These materials include combustible vegetative debris or residue, which may collect in or around exhaust system components and turbochargers. It may also collect in air filters, clogging the filter and causing higher than normal operating temperatures. Vegetative debris or residue may also collect in and around belts, chains, sprockets, rotating shafts, and other moving parts, leading to ignition by frictional heating. The presence of foreign combustible materials may become increasingly important as a fire risk with increased engine component operating temperatures necessitated by changes in emissions requirements. 25.14.4.3 Maintenance. Agricultural equipment requires routine maintenance as outlined in the Equipment Operators’ Manual. If the pre-determined maintenance schedule is not followed, an increase in the potential for fire may result. The type of crop to be harvested, environmental conditions at the time of harvest, and the time available to the farmer to complete the harvest all impact the farmer’s ability to maintain and adhere to an acceptable and appropriate service and maintenance schedule. Interviews conducted with the equipment owner and/or operator(s) and a review of maintenance records (if available) are helpful to establishing any relevance of the involved equipment’s maintenance history to the origin or cause of the fire. Printed on 9/18/2009 211 Report on Proposals – November 2010 NFPA 921 25.14.5 Fuels. Many of the fuels that are found on agricultural equipment are similar to those found in automobiles and trucks. Please refer to the Fuels in Vehicles section of this chapter for detailed information on the various fuels. Agricultural equipment carries larger quantities of various ignitable liquids to: a) allow the equipment operator to cover more ground over a longer period of time between refueling stops; b) provide adequate lubrication for moving and rotating components; or c) provide adequate hydraulic fluid quantities to maintain pressure for multiple, simultaneous functions. 25.14.5.1 Diesel Fuel. Diesel fuel is the primary ignitable liquid used for agricultural equipment engines. 25.14.5.2 Biodiesel. Biodiesel is an alternative fuel, produced from, renewable resources for use in common diesel engines. Biodiesel itself contains no petroleum, but can be blended at any level with petroleum to create a biodiesel blend. Agricultural equipment may be designed to run on biodiesel fuels. Suitable blends contain a range of 2%-20% biodiesel and 80% to 98% petroleum diesel. B20 (20% biodiesel and 80% petroleum) has similar performance characteristics to No. 2 diesel fuel. B100 (100% biodiesel) generates slightly lower energy production than petroleum diesel (118,170 BTU/gal. vs. 129,050 BTU/gal.) and has a higher flash point than petroleum diesel (100-170ºC vs. 60-80ºC). (Footnote: Biodiesel Handling and Use Guidelines, Third Edition. September 2006. US Dept. of Energy) Biodiesel is lighter than water, insoluble, slightly heavier than air, and mildly volatile. If a biodiesel blend is suspected of being used, the same safety precautions should be taken as those for diesel fuel. The investigator should be aware of the possibility of self-heating when the bio diesel fuel has been in contact with rags or similar materials. 25.14.5.3 Plastics. Plastics may be found as trim, covers, or enclosures of most agricultural equipment, particularly those with enclosed cabs. Most of the rigid plastics are used for engine enclosures and wheel covers, and in the operator’s station for trim panels, control panels, knobs, buttons, etc. Fuel reservoirs, water, and solution, tanks may also be constructed of plastic and can add to the over-all fuel load of the equipment. 25.14.5.4 Composite Materials. Body panels and other user interface components may be manufactured from fiberglass or other similar composite materials. Paints and resins used in the manufacture of these components may add to the over-all fuel load of the machine. The key concern is that these components may be completely destroyed, altering the significance of remaining fire patterns to sequential fire pattern analysis. Care should be taken by the investigator to recognize the presence of composite materials and consider the impact of their combustion in the post-fire evaluation of indicators of fire origin or spread. 25.14.5.5 Rubber. Rubberized components found on agricultural equipment include tires, tracks, belts, hose material, and doffer pads (cotton pickers). Of these components, tires and rubber tracks are the more significant in terms of fuel load. Agricultural tires may be very large and are constructed for heavy duty use. It is not uncommon to arrive at an agricultural equipment fire to find residue of tires burning or smoldering, several days after the intial fire. Smoke production from a burning or smoldering tire may interfere with the investigation and may require additional suppression efforts before proceeding. 25.14.6 Ignition Sources. As with other motorized equipment, many of the same ignition factors and scenarios exist with agricultural equipment. 25.14.6.1 Electrical Sources. Agricultural equipment may be constructed with a single or multiple battery system. Additional lighting or accessories may demand larger charging or reserve electrical capacities. Refer to the Electrical Sources and Motor Vehicle Electrical System sections of this chapter. 25.14.6.2 Hot Surfaces. Exhaust manifolds, turbochargers, and other related components are generally considered the primary concern for hot surface ignition of combustibles or ignitable liquids in agricultural equipment. Much of what is written in the hot surfaces section of this chapter will also apply to agricultural equipment. Some differences exist such as the configuration of exhaust system components which may lead to the build-up of crop residues. Failure to maintain manufactures required shielding or clearances between hot surfaces and combustible materials may result in ignition. Changes in emissions technology will create other hot surfaces with additional clearances requirements to combustibles. 25.14.6.3 Mechanical Sparks. Mechanical sparks can be created by foreign metals picked up and passed through row units on cotton pickers. Forced mis-alignment from jammed crop residue or from equipment failure that allows spindles to have direct contact with compression plates or other steel components can also generate mechanical sparks. Spindles, which are made of hardened steel with a chrome/alloy coating, can break and be passed through the unit. Mechanical spark events are of a short duration and are a minimally-viable source of ignition. The heat energy of mechanical spark particles is generally insufficient to ignite ordinary combustible materials except in rare circumstances. It may be possible to cause smoldering combustion in fine accumulations of dust. Mechanical sparks may ignite cotton dust or fine crop residue at the base or rear of the row unit. The cotton dust may smolder or flame as a result of forced air injected through the compartment. Harvested cotton passing through the area may then be ignited and blown up into the basket where the cotton continues to smolder or burn. 25.14.6.4 Friction. Friction occurs with the application of brakes or the normal operation of a slip clutch. Friction heating may occur as a result of improper application of a component function, poor maintenance, inadequate or improper Printed on 9/18/2009 212 Report on Proposals – November 2010 NFPA 921 repairs, or part failure. The heat generated may be quite substantial, depending on the type of materials involved, speed of the action between the materials, and the ability of the generated heat to dissipate. Sufficient friction heat may be generated to ignite nearby combustibles, which could include tires, rubberized belts, hoses, lubricating grease, or vegetative debris or crop residue. 25.14.6.5 Brakes. Agricultural equipment may be equipped with disc or drum brakes. Some equipment may be equipped with park brakes. Friction heat generated through normal braking operations is easily handled by the design of the system and the types of materials used. When brakes are misapplied, excessive friction heat occurs. Misapplication of brakes can occur in situations where the equipment operator fails to release the park brake before moving the machine, repeatedly uses brakes for steering, or improper replacement/adjustment of brake components. 25.14.6.6 Slip Clutch. A slip clutch is a safety device which utilizes a friction plate or disc in a coupling configuration with a rotating drive shaft. Excessive forces on the drive system, such as that caused by “plugging” a machine with too much crop material will cause the clutch to “slip” thereby preventing damage to drive components. A slip clutch must be torqued to proper specifications or the clutch may slip too frequently or not at all. Friction heat from a “slipping” clutch may be a competent ignition source in the presence of dry crop residue. 25.14.6.7 Rotating Shafts. Rotating shafts can be a source of friction heat, particularly in situations where the equipment has not been regularly cleaned of vegetative debris or residue. When foreign debris becomes packed into areas around these shafts, the normal operational rotation of the shaft can generate sufficient friction heat to ignite the foreign debris.

***Insert Figure 25.14.6.8(a) Here*** Figure 25.14.6.8 (a) Failed bearing mounting for a rotating shaft on a round hay baler.

***Insert Figure 25.14.6.8(b) Here*** Figure 25.14.6.8 (b) Recovered head of shaft mounting bolt for roller shown in Figure 25.14.6.8 (a).

25.14.6.8 Rotating Bearings. Rotating bearings require regular lubrication via a grease fitting. Other bearings are sealed and are permanently lubricated. Rotating bearings may fail from a lack of lubrication or excessive lubrication, which results in failure of a grease seal. Sealed bearings can fail because of insufficient lubrication during manufacture or from physical damage to the bearing from outside force such as contact with a foreign object. Bearings also fail for other reasons: shaft or roller misalignment, improper installation, and broken mounting bolts. Loose or frozen bearings are both indicators of bearing failure. Particular interest should be given to developing a maintenance and use history for the involved equipment if bearing failure or excessive friction is a concern. 25.14.6.9 Electronics and Aftermarket Equipment. Much like automobiles and trucks, farm machinery now incorporates a number of technologically advanced electronics in the operator’s station. In addition, farmers and operators may also incorporate any number of after-market electronics into the operator’s station for either business or pleasure. Agricultural equipment such as combines and cotton pickers now utilize a number of technologies to assist with harvesting. GPS integrated computer systems are utilized to assist with auto-guidance accuracy, yield and moisture mapping, spraying, prescription planting, and maximizing productivity for optimal crop yields. Data loggers and/or monitors are fast becoming common equipment. In certain types of equipment, electronic, joystick controls are used in conjunction with computer aided guidance systems for precise handling. Such electronic components utilize low-current circuits protected by fuses or circuit breakers. Most cab-equipped units will also have as options an audio system or two-way communications.

Due to the significant variations in fuel loads, ignition sources and specialty systems, the committee believes the expanded discussion and information pertaining to agricultural equipment is useful in the investigation of agricultural equipment fires.

Printed on 9/18/2009 213

INCLUDES File 921 CP#7

Chapter 25 Vehicle Files New Section Agricultural Equipment

1. Figure 25.14.2.2 Combine Terminology (New Figure)

Figure 25.14.2.2 Combine Terminology

2. F i g u r e

2 5 . 1 4 . 2 .4.1(a) Elevation view of internal components of a row unit. (New Figure)

Figure 25.14.2.4.1 (a) Elevation view of internal components of a row unit.

3. Figure 25.14.2.4.1(b) Schematic of a row unit. (New Figure)

Figure 25.14.2.4.1(b) Schematic of a row unit.

4. Figure 25.14.4.2 Collected foreign combustible material on a cotton picker. (New Figure)

Figure 25.14.4.2 Collected foreign combustible material on a cotton picker.

5. Figure 25.14.6.8(a) Failed bearing mounting for a rotating shaft on a round hay bailer.(New

Figure)

Broken roller shaft mounting bolt at bearing.

Figure 25.14.6.8 (a) Failed bearing mounting for a rotating shaft on a round hay baler.

6. Figure 25.14.6.8(b) Recovered head of a shaft mounting bold for roller shown in Figure 25.14.6.8(a) (New Figure)

Figure 25.14.6.8 (b) Recovered head of shaft mounting bolt for roller shown in Figure 25.14.6.8

(a). Report on Proposals – November 2010 NFPA 921 ______921-153 Log #75

______Patrick M. Kennedy, National Association of Fire Investigators Revise text to read as follows: Revise existing text on the: minimum auto-ignition temperatures of brake fluid to >300° C (572° F) to 310° C (590° F); flash point to 110-171° C. (230-340° F.); LEL 1.2; and UEL 8.5; The current text is a typographical error using the figures for flash point in the ignition temperature column. These new suggested figures come from a survey of more than 20 typical “type 3” brake fluid MSDSs.

Revise existing text on the: minimum auto-ignition temperatures of brake fluid to >300° C (572° F) to 3109° C (590606° F); flash point to 110-171° C. (230-340° F.) LEL 1.2; and UEL 8.5.

There is documentation to support the numbers.

Printed on 9/18/2009 214 Report on Proposals – November 2010 NFPA 921 ______921-154 Log #119

______Ronald E. Orlando, General Motors Corporation Revise text to read as follows: Section 25.3.1 ... For example, the range minimum of laboratory autoignition temperatures for gasoline in Table 25.3.1 is 257°C - 280°C 354°C (495°F-536°F 670°F). Studies that simulate conditions in motor vehicles have shown that the minimum temperature of a heated surface required to ignite liquid gasoline is several hundred degrees greater than this range minimum temperature. Table 25.3.1 1. Insert a new column in between “Autoignition Temperature” and “Flammability Limits”. Title the new column as “Hot Surface Ignition Temperature”. Include sub-columns for °C and °F. 2. Insert a new row between “Gasoline” and Diesel Fuel (Fuel Oil #2)”. Title the new row as Gasoline/Ethanol mixture (E85). 3. Revise the Autoignition Temperature for Gasoline as: 257°C - 280°C minimum 354°C and 495°F-536°F minimum 670°F. 4. Add the Autoignition Temperature for Gasoline/Ethanol mixture (E85) as: minimum 424°C and minimum 795°F. 5. Add the Hot Surface Ignition Temperature for Gasoline as: 735°C - 802°C and 1355°F - 1475°F. 6. Add the Hot Surface Ignition Temperature for Gasoline/Ethanol mixture (E85) as: 652°C - 702°C and 1205°F - 1295°F. The above data was determined in a commercial and industrial laboratory study. It was then reported in a Society of Automotive Engineers (SAE) publication #2009-01-0016, titled It was authored by Roy E. Ebersole, Linda C. Matusz, Manoj S. Modi and Ronald E. Orlando. This technical paper was peer (blind) reviewed. Recommendations were made by the peer reivewers and those recommendations were incorporated into the final edition. This technical paper was then presented at the SAE 2009 International Congress on April 20, 2009 in Detroit, Michigan. A copy of this technical paper is attached. Note: Supporting material is available for review at NFPA Headquarters.

Revise text to read as follows: Table 25.3.1 1. Insert a new column in between “Autoignition Temperature” and “Flammability Limits”. Title the new column as “Hot Surface Ignition Temperature”. Include sub-columns for °C and °F. 2. Insert a new row between “Gasoline” and Diesel Fuel (Fuel Oil #2)”. Title the new row as Gasoline/Ethanol mixture (E85). 3. Revise the Autoignition Temperature for Gasoline as: 257°C - 280°C minimum 354°C and 495°F-536°F minimum 670°F. 4. Add the Autoignition Temperature for Gasoline/Ethanol mixture (E85) as: minimum 424°C and minimum 795°F. 5. Add the Hot Surface Ignition Temperature for Gasoline as: 735°C - 802°C and 1355°F - 1475°F. 6. Add the Hot Surface Ignition Temperature for Gasoline/Ethanol mixture (CA E85) as: 652°C - 702°C and 1205°F - 1295°F. Add footnote to the new column titled: Hot Surface Ignition Temperature This should be new footnote “c” and re-letter subsequent footnotes. Footnote: Society of Automotive Engineers (SAE) publication #2009-01-0016, titled Hot Surface Ignition of Gasoline-Ethanol Fuel Mixtures. It was authored by Roy E. Ebersole, Linda C. Matusz, Manoj S. Modi and Ronald E. Orlando. The Committee believes these changes are editorial.

Printed on 9/18/2009 215

Report on Proposals – November 2010 NFPA 921 ______921-155 Log #106

______Jeff D. Colwell, Exponent, Inc. Revise text to read as follows: Exhaust systems manifolds and components can generate sufficiently high temperatures to vaporize or ignite combustible material, including ignitable liquids in the engine compartment an ignitable liquid. Automatic transmission fluid, particularly if heated due to an overloaded transmission, can ignite on a hot manifold. Engine oil and certain brake fluids (DOT 3 and 4) dropping on a hot manifold can also ignite. Under normal operating conditions on level roads, exhaust manifold surface temperatures typically vary from 130°C to 575°C (270°F to 1070°F) as the vehicle speed varies from 0 (idle) to 70 mph. The temperature and transient response time of close-coupled catalytic converter and turbo housing surfaces are similar to those of exhaust manifold surface temperatures. The surface temperatures of underbody catalytic converters under normal operating conditions on level roads typically range from 110°C to 210°C (230°F to 410°F) and are relatively constant with respect to vehicle speed. Studies conducted using dynamometers, where there is little if any airflow underneath the vehicle. have shown that under these conditions the underbody catalytic converter surface temperature can exceed 500°C (930°F). During vehicle warm up, the time generally required for exhaust manifolds to span 80% of the temperature range from ambient temperature to the steady-state temperature at a specific location on the exhaust system and vehicle speed typically range from 0.75 to 2.25 minutes. Underbody catalytic converts are slower to warm up, typically taking 3.8 to 6 minutes to span this same temperature range. When a vehicle is suddenly brought to rest and the engine stopped, the exhaust manifolds. close-coupled catalytic converters and turbo chargers all begin to cool immediately. Studies have shown that the use of hose clamps to attach thermocouples to exhaust surfaces can produce artificially low temperature measurements and can also induce artificial transients, including artificial temperature increases when the vehicle is suddenly brought to rest and shut off. Using hose clamps to mount thermocouples to exhaust surfaces can produce temperature measurement errors in excess of 80°C (145°F). When a vehicle is suddenly brought to rest and shut off, the time for the exhaust manifold temperature to span 80% of the temperature difference between the initial temperatures and the ambient temperature is typically 20 to 30 minutes. While exhaust manifolds cool immediately when the vehicle is suddenly brought to rest and shut off, underbody catalytic converters generally experience a temperature increase lasting several minutes and then begin to cool. The time for underbody catalytic converters to span 80% of the temperature range from the steady-state temperature to ambient temperature typically range from 45 minutes to more than 90 minutes. If unburned fuel flows through the exhaust system, the catalytic converter temperatures can increase as this fuel is oxidized within the catalytic converters. Those fluids may ignite only shortly after the vehicle is shut off. This ignition is due to the loss of airflow through the engine compartment, which disperses these vapors and cools hot engine surfaces. When the engine is shut off, the airflow ceases, and the manifold temperatures can rise or decrease, depending on the amount and direction of heat transfer. This may be sufficient to ignite the fluid vapors for a period during cool down. The internal components of a catalytic converter have operating temperatures of approximately 700°C (1300°F) under normal operation and can be much higher if unburned fuel is introduced due to a fuel or ignition system malfunction. External temperatures of those converters can reach temperatures of 315°C (600°F) under normal operation and can become higher where ventilation or air circulation is restricted. In most vehicles, the pipe surface just upstream of the catalytic converter will operate hotter than the converter itself. For more information, see Colwell, J. D. and Biswas, K. (2009) "Steady-State and Transient Motor Vehicle Exhaust System Temperatures", SAE Paper 2009-01-0013.

The proposed text summarizes recent data (Colwell and Biswas, 2009) that was collected under carefully controlled conditions on a level, oval test track with numerous types of test vehicles. Some comments on specific issues: 1) Use of hose clamps to attach thermocouple wires to the exhaust system - Most previous studies, see Colwell and Biswas (2009) for references, used hose clamps to attach thermocouples to the exhaust system. The hose clamp acts as a fin and cools that location of the exhaust system producing artificially lower temperatures at this location. When the airflow stops, hose clamped mounted thermocouples then experience an artificial temperature rise. This effect was carefully quantified in Colwell and Biswas (2009) by mounting a welded thermocouple and a hose clamp mounted thermocouple at the exact same location on the exhaust system and conducting identical, repeatable, tests with the vehicle. Fournier and Bayne (2007) determined that Fournier's previous work, Fournier (2004), was incorrect due to the

Printed on 9/18/2009 216 Report on Proposals – November 2010 NFPA 921 use of hose clamps. He observed artificial exhaust manifold temperature increase in his 2004 study and did not see it when he used welded thermocouples in his 2007 study with Bayne. 2) Under normal operating conditions (airflow under the vehicle, proper engine performance - no excess, unburned fuel in the exhaust system), the surface temperature of the catalytic converters is lower than the exhaust manifold temperatures. This has been reported by all studies on exhaust system temperature measurements (Colwell and Biswas 2009; Harrison, 1976; Harrison 1976b; Fournier 2004; Fournier and Bayne 2007) Note: Supporting material is available for review at NFPA Headquarters.

Revise text to read as follows: 25.4.3.1* Exhaust systems manifolds and components can generate sufficiently high temperatures to vaporize or ignite combustible material, including ignitable liquids in the engine compartment an ignitable liquid. Automatic transmission fluid, particularly if heated due to an overloaded transmission, can ignite on a hot manifold. Engine oil and certain brake fluids (DOT 3 and 4) dropping on a hot manifold can also ignite. Under normal operating conditions on level roads, exhaust manifold surface temperatures typically vary from 130°C to 575°C (270°F to 1070°F) as the vehicle speed varies from 0 (idle) to 70 mph. The temperature and transient response time of close-coupled catalytic converter and turbo housing surfaces are similar to those of exhaust manifold surface temperatures. The surface temperatures of underbody catalytic converters under normal operating conditions on level roads typically range from 110°C to 210°C (230°F to 410°F) and are relatively constant with respect to vehicle speed. Studies conducted using dynamometers, where there is little if any airflow underneath the vehicle. have shown that under these conditions the underbody catalytic converter surface temperature can exceed 500°C (930°F). During vehicle warm up, the time generally required for exhaust manifolds to span 80% of the temperature range from ambient temperature to the steady-state temperature at a specific location on the exhaust system and vehicle speed typically range from 0.75 to 2.25 minutes. Underbody catalytic converts are slower to warm up, typically taking 3.8 to 6 minutes to span this same temperature range. When a vehicle is suddenly brought to rest and the engine stopped, the exhaust manifolds. close-coupled catalytic converters and turbo chargers all begin to cool immediately. Studies have shown that the use of hose clamps to attach thermocouples to exhaust surfaces can produce artificially low temperature measurements and can also induce artificial transients, including artificial temperature increases when the vehicle is suddenly brought to rest and shut off. Using hose clamps to mount thermocouples to exhaust surfaces can produce temperature measurement errors in excess of 80°C (145°F). When a vehicle is suddenly brought to rest and shut off, the time for the exhaust manifold temperature to span 80% of the temperature difference between the initial temperatures and the ambient temperature is typically 20 to 30 minutes. While exhaust manifolds cool immediately when the vehicle is suddenly brought to rest and shut off, underbody catalytic converters generally experience a temperature increase lasting several minutes and then begin to cool. The time for underbody catalytic converters to span 80% of the temperature range from the steady-state temperature to ambient temperature typically range from 45 minutes to more than 90 minutes. If unburned fuel flows through the exhaust system, the catalytic converter temperatures can increase as this fuel is oxidized within the catalytic converters. Those fluids may ignite only shortly after the vehicle is shut off. This ignition is due to the loss of airflow through the engine compartment, which disperses these vapors and cools hot engine surfaces. When the engine is shut off, the airflow ceases, and the manifold temperatures can rise or decrease, depending on the amount and direction of heat transfer. This may be sufficient to ignite the fluid vapors for a period during cool down. The internal components of a catalytic converter have operating temperatures of approximately 700°C (1300°F) under normal operation and can be much higher if unburned fuel is introduced due to a fuel or ignition system malfunction. External temperatures of those converters can reach temperatures of 315°C (600°F) under normal operation and can become higher where ventilation or air circulation is restricted. In most vehicles, the pipe surface just upstream of the catalytic converter will operate hotter than the converter itself. A.25.4.3.1 For more information, see Colwell, J. D. and Biswas, K. (2009) "Steady-State and Transient Motor Vehicle Exhaust System Temperatures", SAE Paper 2009-01-0013.

The deleted material deals with testing and is covered in the referenced annex material.

Printed on 9/18/2009 217 2009-01-0013

Steady-State and Transient Motor Vehicle Exhaust System Temperatures

Jeff D. Colwell and Kaushik Biswas Exponent, Inc.

ABSTRACT approach, Fournier (3) conducted a study intended to evaluate the risk of ignition of engine compartment fluids One of the known causes of motor vehicle fires is hot by exhaust system components. Engle et al. (4) surface ignition of combustible material that contacts examined the effect of fuel type, gasoline or E85, on the engine exhaust system components. While ignition is a exhaust system temperatures of several 2006 and 2007 complicated phenomenon, the temperature of the model year vehicles. However, in each of the studies, surface is known to be an important parameter. the thermocouples were mounted to the exhaust system However, little data is available in the literature components using hose clamps. Results from the concerning exhaust system temperatures, and much of present study show that this mounting configuration not this data is confounded by thermocouple attachment only leads to artificially low temperature measurements, techniques and undocumented variations in driving it can also produce artificial transient temperature conditions. In the present study, engine exhaust system response, particularly when the vehicle is suddenly temperature measurements were conducted using six brought to rest and allowed to cool. This effect has also test vehicles on a level, 2-mile oval test track at constant been reported by Fournier and Bayne (5) where they vehicle speeds ranging from 0 (idle) to 70 mph. By described how data published in a previous study by normalizing transient temperature curves with these Fournier (3) was erroneous because of this steady-state temperatures along with ambient thermocouple mounting technique. temperature, the rates at which the exhaust system In addition to the measurement error associated with the components warm up and cool down are also compared. use of hose clamps, each of these studies (1-4) was also The effect of thermocouple mounting technique was evaluated by conducting identical testing with the conducted on public streets and highways. Although each study describes changing vehicle speed to negotiate thermocouples located at identical locations on the traffic and/or changes in road grade during the tests, exhaust system but with two different mounting these important parameters were not measured or techniques, namely hose clamps and welding. correlated with the measured temperatures in any of these studies. Because exhaust system temperatures are INTRODUCTION coupled to vehicle speed and road grade, it is unclear what effect changes in vehicle speed or road grade during Over the past 35 years, there have been several studies these tests may have had on the reported temperatures. conducted to evaluate if, and under what conditions, exhaust system components on motor vehicles could While the studies described above used public streets ignite combustible materials. As part of a study funded and highways, Spreen ef al. (6) used a dynamometer to by the Department of Agriculture Forestry Service, conduct temperature measurements on and within Harrison (1 , 2J conducted tests on 1974-1975 vehicles to catalytic converters from six 1998 model year vehicles. evaluate the risk posed by catalytic converters, which Because these data were collected on a dynamometer, had recently been introduced into the vehicle fleet, to cause wildfires. Using a very similar experimental

The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191

~::~f:o:::~:::::'i~.;O i~¥j;i~;~;~:~~~::::~::: 00' O~"ï¡'i '"'III Ti T"iir II ~~i HI ií 'l"l" i SAEPrinted Web Address: in http://www.sae,i USA SA *9-2009-01-0013*International" the catalytic converters were not subjected to airflow as converters. Vehicle #3 was an SUV that was powered by the vehicle was being driven. a V-6 engine that had a right and left underbody catalytic converter. After these catalytic converters, the two In this paper, we present exhaust system temperature exhaust systems joined together to form a single tail pipe. data that were measured using welded thermocouples Vehicle #4 was an SUV made by the same manufacturer while the test vehicles were operated on a 2-mile oval test as Vehicle #2 and had a similar, if not identical, engine track. Comparisons are made between the steady-state and exhaust system. Vehicle #5 was a front-wheel-drive, temperatures of the exhaust manifolds and catalytic 4-door sedan with a transverse mounted V-6 engine (front converters for all test vehicles and to the dynamometer of engine on the passenger side). Downstream of the left results of Spreen et al. (6). Next, by normalizing transient (forward) exhaust manifold, the exhaust system was temperature curves using steady state and ambient routed behind the engine and then tied into the right temperatures, the rates at which the exhaust system exhaust manifold. From here, the exhaust from both components warm up and cool down are also compared. manifolds flowed into a single pipe to the underside of the Finally, the temperature measurement error associated vehicle and then through a single underbody catalytic with hose clamp mounted thermocouples is described. converter. Vehicle #6 was also a front-wheel-drive, 4- door sedan with a transverse mounted engine (front of EXPERIMENTAL SET.UP engine on the passenger side). It was powered by a V-6 engine and had close-coupled catalytic converters just The six test vehicles used in the present study consisted downstream of the exhaust manifolds. The left side of two pickups, two sport utility vehicles and two sedans manifold and close-coupled catalytic converter were ranging in model years from 1999 to 2001. A summary of towards the front of the vehicle. The right side close- each vehicle, including the body style, engine size, coupled catalytic converter was positioned just below the orientation of the engine, engine fuel type, and catalytic right manifold, but was under the body of the vehicle. converter locations, is shown in Table 1. Vehicle #1 was Downstream of the point where the left and right exhaust a pickup powered by a large, V-8 engine that was turbo systems merged together, there was a single underbody charged and had a single underbody catalytic converter. catalytic converter. Each of the test vehicles was in Vehicle #2 was also a pickup and was powered by a V-6 normal operating condition with no check engine or engine that had two sequential underbody catalytic warning lights illuminated,

Table 1. Test Vehicle Summary Vehicle Year Body Engine Type Engine Mount Fuel Catalytic Converter(s)

1 1999 Pickup 7,3L, v-a' Longitudinal Diesel Underbody 2 2001 Pickup 4.3L, V-6 Longitudinal Gasoline Two Underbody 3 1999 Sport Utility 3,2L, V-6 Longitudinal Gasoline Left and Right Underbody 4 2000 Sport Utility 4,3L, V-6 Longitudinal Gasoline Two Underbody 5 2000 4-dr Sedan 3.4L, V-6 Transverse Gasoline Underbody 6 2001 4-dr Sedan 3.0L, V-6 Transverse Gasoline Two Close-Coupled2 and One Underbody

1 Turbo 2 The right close-coupled cataly1ic converter is located on Ihe underside of the vehicle and is referred 10 as "Right Close-Coupled/Underbody" calaly1ic converter in all plots.

For each test vehicle, a single thermocouple was welded Each catalytic converter thermocouple was mounted to to each exhaust manifold and catalytic converter. the converter surface at the mid-point between the However, the right manifolds of the front-wheel-drive entrance and exit. In some cases, shields for either the vehicles (Vehicle #5 and Vehicle #6) were in confined exhaust manifolds or catalytic converters were removed spaces between the engine and the bulkhead, which so that the thermocouples could be installed. Once precluded welding thermocouples to these manifolds. installed, the shields were placed back into their original Each exhaust manifold thermocouple was welded 1-3 in. positions. On Vehicle #1, additional thermocouples were (2.5 - 7.6 cm) downstream of where the last (most mounted on the turbo inlet, housing and exit, along with downstream) cylinder exhaust port tied into the exhaust the surface of the muffler near the inlet location. The manifold. Tests with a handheld infrared thermometer engine coolant temperature was also recorded on this indicated that this location was generally one of the vehicle. hottest locations on the exhaust manifold. The selected measurement locations on both the exhaust manifolds At each exhaust system measurement location, the and catalytic converters are not necessarily the hottest oxide layer on the surface was sanded away and a points on either component. Type-K thermocouple was welded in place. The temperature of each thermocouple was then captured with a data acquisition system sampling at a rate of 2 were among the hottest locations along the exhaust Hz. The vehicle speed was measured with a MicroSAT system, as was the turbo housing. The turbo inlet and GPS velocity sensor or a Corrsys-Datron optical fifth exit were cooler than the manifolds, with the catalytic wheel and was also sampled at a rate of 2 Hz. converter and muffler being the lowest temperature locations measured. Testing was conducted on a 2-mile oval test track with banked turns. Although the track appears to be level, The temperature variations at each location as the the measured grade of the track was -0.67% (-6.7 ft. vehicle is driven around the track, shown in Figure 1, per 1000 ft.) on the slightly downhill straightaway and depended on the measurement location and the vehicle 0.78% (+7.8 ft. per 1000 ft.) on the slightly uphill speed. Generally, components closest to the engine, straightaway, with the banks having sufficient elevation such as the exhaust manifolds, experienced the greatest change to make up the difference in elevation. The temperature variation, while the underbody catalytic ambient temperature for all the tests conducted ranged converters experienced the least. The maximum from 26°C to 42 °C. temperature variations were approximately :t 15 C relative to the ayerage at the 20 mph test speed and TEST PROCEDURE AND DATA REDUCTION then decreased to less than :t 10°C at higher speeds.

Using the experimental set-up described above, exhaust The speed variation over the three to six laps used to system temperatures for each vehicle were recorded as determine the averages was also largest at 20 mph, as functions of time at constant vehicle speed and during the vehicle cruise control could not be used at this engine warm-up and cool-down. The following sections speed. For all vehicles tested, the maximum speed describe the procedures used to collect and process variation was approximately :t 5.0 mph relative to the these data as well as the reproducibility of the reported average at the 20 mph test speed and then decreased to values. less than :t 1 mph at higher test speeds.

CONSTANT VEHICLE SPEED TESTING To assess the reproducibility of the average temperature versus speed data, tests involving the exhaust manifolds Typical temperature and speed data as functions of time on Vehicle #1 were repeated. The temperature during the constant speed testing are shown in Figure 1. differences between tests, conducted several weeks In these test types, the vehicle is brought up to test apart, were less than 6 °C at all speeds with the speeds ranging from 20 mph to 70 mph in 10 mph exception of 14 DC when at the 70 mph test speed. increments. At each of these test speeds, the speed is held nominally constant while the vehicle is driven TRANSIENT ENGINE WARM-UP AND COOL-DOWN around the track 5-10 laps or 10-20 miles. Although TESTING vehicle speed is constant for each speed condition, the A typical vehicle warm-up and cool-down test used to slight grade of the track resulted in changes to the quantify transient effects is shown in Figure 3. For this exhaust system temperatures. The measured type of test, the vehicle was started cold and then temperatures increased on the slight uphill straightaway immediately accelerated up to the test speed, 70 mph in until reaching a maximum and then decreased as the this case. Once the temperatures stabilized, the vehicle vehicle drove along the slight downhill straightaway. was then stopped as quickly as possible and the engine To facilitate comparison of the temperature data as shut off while continuing to monitor the exhaust system functions of vehicle speed, the temperatures at each temperatures. measurement location and the vehicle speed were While the raw temperature versus time data presented in averaged. This averaging was performed over the last Figure 3 is useful, the data from different locations along three to six laps of each constant speed segment, with the exhaust system and from different vehicles can more the first several laps (two or more) excluded due to readily be compared by defining a normalized possible transient effects, These average temperature temperature, e. values were then plotted as a function of the average vehicle speed as shown in Figure 2. This averaging of T-T B = 00 (1 ) measured temperature also compensates, to some Tss - Too extent, for the slight variation in track grade. Also shown in Figure 2 are the exhaust system temperatures at idle. where In these tests, the exhaust system temperatures were T = temperature as a function of time monitored as the engine warmed up from a cold condition. Once the temperatures had reached Too = ambient temperature nominally constant values, the temperature at each T,,= steady-state temperature at the test speed location was averaged over the last several minutes to This normalized temperature is also useful for comparing give the average idle temperature data shown in Figure transient warm-up and cool-down data associated with 2. Although the test results will be described in more different vehicle test speeds. Values for T" in equation detail in the following sections, the left and right manifold (1) are those shown in Figure 4 and Figure 5 while the ambient temperature ranged from 26°C to 42 DC. 600 80

-- Left Manifold 70 500 -- Underbody Cat. Converter 60

400 I -- Speed I 50 en E -0 ..Q) (1 :: a.(1 ro.. 40 3' Q) 300 a. -0 E 2: i-Q) 30 200 20

100 10

o o o 10 20 30 40 50 60 70 80 90 Time (min)

Figure 3. Transient warm-up and cool-down data at a test speed of 70 mph for Vehicle #5.

0 #1 - Left 0 #3 - Left 'V #5 - Left . #1 - Right . #3 - Right e: #6 - Left o #2 - Left 6 #4 - Left . #2 - Right .. #4 - Right 600

0Ü~ 500 .. . Q) 0 .. 0 . :; 6 . 'V ro .. a.Q¡ 400 l. ~ E .. ,. . .. 0 ~ 0 e: i-Q) !'. 'V !' ~ -0 0 'V . . 0 e: :§.¡: 300 ~ f . ro Cf :: 0. 1i to :: 200 ~ ro ~ to ..x to W 100

0 0 10 20 30 40 50 60 70 80 Speed (mph)

Figure 4. Comparison of exhaust manifold temperatures as functions of vehicle speed. RESULTS repeated. For most vehicles, there was a difference between the left and right exhaust manifolds, but the two In this section, the steady-state exhaust manifold and temperatures tended to have the same trends with catalytic converter temperatures of the six test vehicles respect to vehicle speed. Even though Vehicle #2 and are presented as functions of vehicle speed, Next, the Vehicle #4 had very similar, if not identical, engines and rates at which the exhaust system components warm up exhaust systems, the manifold temperatures were higher and cool down are also compared. This comparison is for Vehicle #4. made by normalizing the transient temperature versus time curves using steady-state and ambient temperatures. A comparison of the catalytic converter temperatures for Finally, data illustrating the error associated with the use the six vehicles tested shows that the underbody of hose clamps to attach thermocouples to exhaust catalytic converters were much cooler than the exhaust system components are described. manifolds and generally fell into the same temperature range, as shown in Figure 5. The close-coupled Steady-State Exhaust Svstem Temperatures catalytic converters on Vehicle #6 had temperatures that were similar to exhaust manifold temperatures. These For most of the exhaust manifolds tested, the steady- temperatures ranged from 210°C at idle to 575 °C at a state temperatures were lowest at idle and then speed of 70 mph. The temperatures of the underbody increased with vehicle speed, as shown in Figure 4. catalytic converters for all the gasoline powered engines These exhaust manifold temperatures ranged from fell into the same range (110°C-210°C) and were 130°C for Vehicle #1 at idle to 480 °C for Vehicle #4 at relatively constant as functions of vehicle speed. The 60 mph. The data acquisition system failed during the catalytic converter associated with the diesel engine 70 mph test on Vehicle #4 and the test was not (Vehicle #1) had the lowest temperature of all catalytic converters at all speeds.

o #1 - Underbody .. #4 - 2nd Underbody 0 #2 - 1st Underbody 'V #5 - Underbody 8 #2 - 2nd Underbody r, #6 - Left Close-Coupled 0 #3 - Left Underbody 10 #6 - Right Close-Coupled/Underbody . #3 - Right Underbody .: #6 - Underbody 6 #4 - 1st Underbody 600 r,

~ ~ 500 ~ :: r, ro 10 Q¡ ~ a. 400 r, E 10 IJ t- 10 .. ~ IJ 10 10 tIJ 300 :; 10 i: 0 U u 200 .: ~ 6 6 .; ii .. íI. O ro it ~II ~e 'V u ~ e \, i 0 100 0 0 0 0 0

0 0 10 20 30 40 50 60 70 80 Speed (mph)

Figure 5. Comparison of catalytic converter temperatures as functions of vehicle speed. Although the temperature of the underbody catalytic this difference, the two sets of data generally fall within converters was relatively constant as a function 01 the same range. speed, for many of the vehicles there was a slight decrease in temperature from idle to higher test speeds. While the data Irom the present study and that Irom Because the exhaust manifold temperatures generally Spreen et at. (6) are generally in the same range lor the increase with test speed, this decrease in the underbody close-coupled catalytic converters, Spreen et al. (6) catalytic converter temperature may be associated with report much higher temperatures for the underbody increased airflow that is created when the vehicle catalytic converters, as shown in Figure 7. While this moves. difference could be due to differences in the vehicles tested, it may also be due to the absence of vehicle- The temperatures 01 the close-coupled catalytic induced airflow over the underbody catalytic converters converters associated with Vehicle #6 in the present in the Spreen et at. (6) study. study were very similar to those reported by Spreen et al. (6) as shown in Figure 6. As described previously, TRANSIENT BEHAVIOR OF EXHAUST SYSTEM the Spreen et al. (6) data were collected from vehicles TEMPERATURES operating on a dynamometer at a level grade. During this testing, the vehicle speed would be increased to a Even though there was considerable diversity in the vehicle certain test speed and then later decreased back to the types, the shapes of the normalized temperature, B, versus same test speed, which produced two temperature time curves for the exhaust manifolds were very similar, as measurements at about the same speed. As shown in shown in Figure 8 and Figure 9. The manifolds warm up Figure 6, these temperatures are sometimes appreciably relatively quickly, spanning 80% of the temperature range different. This difference is likely due to the catalytic from ambient to the steady-state values (B = 0.8) in 0.75 to converter not reaching steady state belore the 2.25 minutes. These exhaust manifolds take much longer temperature was recorded, particularly when the to cool, with e decreasing to 0.2 in 20-30 minutes. During catalytic converter is cooling down from the previous this cool-down process, the temperature of every exhaust test. Because these data were collected using a manifold tested decreased once the vehicle was brought to dynamometer, there would not have been airflow around rest and the engine shut off. the vehicle as there was in the present study. Despite

o #6 - Left Close-Coupled 8 #2 - Right Close-Coupled ¡6) o #6 - Right Close-Coupled/Underbody . #3 - Left Close-Coupled (6) . #1 - Close-Coupled (6) . #5 - Close-Coupled (6)

Û 600 0 0 ~ .. CL . :; . ñí ~ . Q¡ 500 . a. 0 E .. CL . I- .. l 8 0 CL a . t 400 CL . . r ;: c: . 0 0 a 0 Ü . u 300 . 0 ~ 8 0 ii ñí "' 200 üCL a. :: 0 Ü i CL 100 (/ õ0 0 0 10 20 30 40 50 60 70 80 Speed (mph)

Figure 6. Comparison of close-coupled catalytic converter temperatures for Vehicle #6 to the Spreen et at. ¡6) data. o #1 - Underbody æ #4 - 2nd Underbody 0 #2 - 1st Underbody 0 #5 - Underbody 0 #2 - 2nd Underbody 'V #6 - Underbody 6 #3 - Left Underbody . #2 - Underbody (6) 0 #3 - Right Underbody 8 #3 - Left Underbody (6) ~ #4 - 1st Underbody . #4 - Underbody (6) 600 E Q).. . :: ro 500 . c.(¡ E Q) . f- .. 400 . . t:Q) Q) . ;: 0c: . 0 300 .~:; 8 . ro ro . 0 200 - 'V ;: ~ IS 'V "Co ~B æ 906 .c l ~ ~g ~ 0 .. 9 9 Q) "C 0 c: 100 0 0 :: 0 0 0

o o 10 20 30 40 50 60 70 80 Speed (mph)

Figure 7. Comparison of underbody catalytic converter temperatures for Vehicles #1-6 to the Spreen et at. (6) data.

1.2

-- #1 - Left 0.8 -- #1 - Right -+ #3 - Left ~ -- #3 - Right -- #5 - Left 0.6 -- #6 - Left

0.4

0.2

o o 2 4 6 8 10 12 14 Time (min)

Figure 8. Comparison of exhaust manifold warm-up for a final vehicle speed of 70 mph. o #1 - Underbody æ #4 - 2nd Underbody 0 #2 - 1st Underbody 0 #5 - Underbody 0 #2 - 2nd Underbody 'V #6 - Underbody 6 #3 - Left Underbody . #2 - Underbody (6) 0 #3 - Right Underbody 8 #3 - Left Underbody (6) ~ #4 - 1st Underbody . #4 - Underbody (6) 600 E Q).. . :: ro 500 . c.(¡ E Q) . f- .. 400 . . t:Q) Q) . ;: 0c: . 0 300 .~:; 8 . ro ro . 0 200 - 'V ;: ~ IS 'V "Co ~B æ 906 .c l ~ ~g ~ 0 .. 9 9 Q) "C 0 c: 100 0 0 :: 0 0 0

o o 10 20 30 40 50 60 70 80 Speed (mph)

Figure 7. Comparison of underbody catalytic converter temperatures for Vehicles #1-6 to the Spreen et at. (6) data.

1.2

-- #1 - Left 0.8 -- #1 - Right -+ #3 - Left ~ -- #3 - Right -- #5 - Left 0.6 -- #6 - Left

0.4

0.2

o o 2 4 6 8 10 12 14 Time (min)

Figure 8. Comparison of exhaust manifold warm-up for a final vehicle speed of 70 mph. 1.2

-- # 1 - Left -- #1 - Right -- #2 - Left -- #2 - Right ~ #3- Left 0.8 -- #3 - Rig ht -- #5 - Left ~ -- #6 - Left 0.6

0.4

0.2

o o 10 20 30 40 50 60 70 80 90 Time (min)

Figure 9. Comparison of exhaust manifold cool-down for an initial vehicle speed of 70 mph.

1.2

0.8 ~ 0.6 -- #1 - Underbody ~ #3 - Left Underbody 0.4 -- #3 - Right Underbody ~ #5 - Underbody -- #f - Left Close-Coupled --- #6 - Right Close-Coupled/Underbody 0.2 ~ #6 - Underbody

o o 2 4 6 8 10 12 14 Time (min)

Figure 10. Comparison of catalytic converter warm-up time for a final vehicle test speed of 70 mph. 2

-- #1 - Underbody -- #2 - 1st Underbody -- #2 - 2nd Underbody -- #3 - Left Underbody -- #5 - Underbody 1.5 -t #6 - Left Close-Coupled -- #6 - Right Close-Coupled/Underbody -- #6 - Underbody

0.5

a a 10 20 30 40 50 60 70 80 90 Time (min)

Figure 11. Comparison of catalytic converter cool-down for an initial vehicle speed of 70 mph.

While the transient behavior of the exhaust manifolds in Figure 4, the shapes of the cooling curves are similar. was similar, the transient behavior of the catalytic While the cooling characteristics of the catalytic converters shown in Figure 10 and Figure 11 varied, As converter in Vehicle #1 and #5 are different, the shapes expected, the close-coupled catalytic converters warmed of the curves for a given vehicle, but from different initial up more rapidly than the underbody catalytic converters, speeds, are similar. reaching () = 0.8 in less than 0.8 minutes. This warm-up period is within the range of the exhaust manifolds Temperature Measurement Error Associated with the described above. The underbody catalytic converters Use of Hose Clamps took longer, between 3.8 and 6 minutes, to reach this To assess the error associated with the use of hose same value of e. clamps to mount thermocouples on exhaust system components, steady-state and transient tests were Unlike the exhaust manifolds, where the temperature conducted using Vehicle #1. I n the first set of tests, the decreased after the vehicle was brought to rest and shut thermocouple was welded to the left exhaust manifold. off, all of the underbody catalytic converters initially In this configuration, the steady-state temperatures and experienced a temperature increase, as shown in Figure transient response of the left exhaust manifold were 11, The close-coupled catalytic conyerters behaved measured, as described above. In a second set of tests, similarly to the exhaust manifolds and cooled a thermocouple bead of identical type was attached, immediately after the vehicle was shut off and at about using a hose clamp, to the exact same location in which the same rate, reaching e = 0.2 in about 25 minutes. the thermocouple had been welded. The steady-state The shape of the () versus time curve for each temperature and transient cooling tests were performed underbody catalytic converter varied, including the again. As shown in Figure 14, the temperatures extent of the temperature rise after the vehicle was measured by the hose clamp mounted thermocouple are brought to rest and shut off. The time for these much lower than the welded thermocouple, and this underbody catalytic converters to cool to a value of temperature error, shown on the right-hand y-axis, is ()= 0.2 was at least 45 minutes and, in some cases, speed dependent. This temperature error ranges from longer than 90 minutes. 23 °C at 20 mph to 88 °C at 70 mph. As described previously, this error is much larger than variations from A comparison of the cool-down characteristics of both repeated tests, which generally had differences of iess exhaust manifolds and catalytic converters at different than 6°C. initial vehicle speeds is shown in Figure 12 and Figure 13. Even though the initial temperatures of the exhaust manifolds for Vehicle #1 and #5 were different, as shown Not only does the use of a hose clamp to mount the thermocouple to the exhaust manifold result in artificially low temperature measurements, it also introduces an Furthermore, measured temperature from the hose artificial transient response as shown in Figure 15. clamped thermocouple artificially increases and then When the vehicle is brought to rest from 70 mph, there is begins to decrease. After several minutes, the two a significant temperature difference between the welded curves approach similar values. and hose clamped thermocouple measurements. 1.2

-- #1 - Left, 40 mph ~ #1 - Right.. 40 mph -- #1 - Left, (0 mph -- #1 - Right, 70 mph -f #5 - Left, 40 mph ~ #5 - Left, 70 mph

0.8

Q: 0.6

0.4

0.2

0 0 10 20 30 40 50 60 70 80 90 Time (min)

Figure 12. Comparison of exhaust manifold cool-down at different initial vehicle speeds.

-- #1 - Underbody, 40 mph ~ #1 - Underbody, 70 mph -- #5 - Underbody, 40 mph -- #5 - Underbody, 70 mph 1.5

0.5

o o 10 20 30 40 50 60 70 80 90 Time (min)

Figure 13. Comparison of catalytic converter cool-down at different initial vehicle speeds. 400 200 t . Thermocouple Welded to Sunace ..Q) :: 0 Thermocouple Clamped to Sunace with Hose Clamp . 1i.. 350 a.Q) E 150 Q) -- I- CD "C 300 3 . "C -Õ CD ï= Q! cc 0 :! . .. 250 100 Ëro ::V) ~ cc . 0 0"" ..x "" W D 0 ii 200 . Q) .9 .. D Error "C . D 50 ~ .. :: V) 150 cc Q) :!

100 0 0 10 20 30 40 50 60 70 80 Speed (mph)

Figure 14. Comparison of measured exhaust manifold steady-state temperatures and associated error, using a thermocouple held in place with a hose clamp and one welded at the identical location, as a function of vehicle speed.

t 350 ..Q) -- Thermocouple Welded to Sunace :: -- Thermocouple Clamped to Sunace with Hose Clamp 1i.. 300 a.Q) E I-Q) "C 250 .¡::E ro :! 200 ii:: ro ..x w ii 150 ..Q) "C ..Q) :: V) ro 100 Q) :!

50 o 2 4 6 8 10 12 14 Time (min)

Figure 15. Comparison of measured exhaust manifold transient temperature using a thermocouple held in place with a hose clamp and one welded at the identical location. CONCLUSIONS the hose clamp mounted thermocouple measured temperatures which were artificially low, ranging from In this paper, both steady-state and transient exhaust 23°C to 88 °C lower than the welded thermocouple. manifold and catalytic converter temperatures were Additionally, the hose clamp mounted thermocouple presented for a diverse group of six test vehicles ranging measured an artificial temperature rise during the cool- from 1999 to 2001 model years. The temperatures of down test, whereas the temperature measured by the exhaust manifolds and close-coupled catalytic welded thermocouple continuously decreased. converters varied with vehicle speed. These temperatures were generally lowest at idle and then ACKNOWLEDGMENTS increased with increasing vehicle speed, ranging from 130°C to 575 °C over yehicle speeds from 0 (idle) to 70 The authors would like to thank Scott Lindsay, Richard mph. The temperatures of underbody catalytic Taylor and Ryan Hoover at Exponent for their assistance converters for each vehicle were lower than the exhaust finding, preparing and instrumenting the test vehicles manifold and close-coupled catalytic converter used in this work. temperatures, particularly at higher vehicle speeds. The underbody catalytic converter temperatures for the REFERENCES gasoline powered vehicles ranged from 110°C to 210°C and were relatively constant with respect to 1. Harrison, R.T, "Catalytic Converter Temperature vehicle speed. The catalytic converter temperature of Tests", Paper 760781, Society of Automotive the diesel engine powered vehicle was lower than all of Engineers, 400 Commonwealth Dr., Warrendale, the gasoline powered engines over all speeds. The PA,1976. selected measurement locations on both the exhaust 2. Harrison, R.T, "Catalytic Converter Temperatures manifolds and catalytic converters were not necessarily Tested", Automotive Engineering, Vol. 84, No. 10, the hottest points on either component. pp. 54-58, 1976. 3. Fournier, E., "Under Hood Temperature The exhaust manifolds and close-coupled catalytic Measurements of Four Vehicles", Report No.: R04- converters tended to warm up and cool down more quickly than the underbody catalytic converters. The 13b, Motor Vehicle Fire Research Institute, 1334 Pendleton Ct., Charlottesville, VA, September 7, time to warm up to ()= 0.8 (temperature increase is 80% 2004. of the total temperature difference between ambient temperature and the steady-state temperature) for the 4. Engle, J.J., Olson, J.S., and Sharma, S.S., "A exhaust manifolds and close-coupled catalytic Comparison of the Effect of E85 vs. Gasoline on converters ranged from 0.75 to 2.25 minutes. These Exhaust System Surface Temperatures", Paper same components cooled to a value of e= 0.2 in times 2007-01-1392, Society of Automotive Engineers, ranging from 20 to 30 minutes. Once the vehicle was 400 Commonwealth Dr., Warrendale, PA, 2007. brought to rest and shut off, the temperature of these 5. Fournier, E. and Bayne, T., "Under Hood components immediately began to decrease. Temperature Measurements", Paper 2007-01-1393, Society of Automotive Engineers, 400 The transient response of the underbody catalytic Commonwealth Dr., Warrendale, PA, 2007. converters was both slower and varied more from 6. Spreen, K.B., Fox, D.J., Heimrich, M.J., Beason, R., vehicle to vehicle than the exhaust manifolds and close- Montalbano, A., and Kisenyi, J., "Catalytic Converter coupled catalytic converters. When warming up, the Thermal Environment Under Dynamometer time to reach e= 0.8 ranged from 3.8 to 6 minutes. Simulated Roadloads", Paper 2000-01-0216, Society When the yehicle was suddenly brought to rest and shut off, the temperatures of all of the underbody catalytic of Automotive Engineers, 400 Commonwealth Dr., converters initially increased and then, several minutes Warrendale, PA, 2000. later, began to decrease. The cooling rates varied with the time to reach e = 0.2 of at least 45 minutes and more CONTACT than 90 minutes in some cases. Jeff D. Colwell, Ph.D., P.E., Principal Engineer, The error associated with mounting thermocouples to Exponent, 23445 North 19'h Avenue, Phoenix, Arizona exhaust surfaces with hose clamps versus welding was 85027 (623) 582-6949 jcolwell (§ exponent.com quantified by measuring the temperature of an identical location on an exhaust manifold using each mounting Kaushik Biswas, Ph.D., Associate, Exponent, 23445 technique during identical tests. The results showed that North 19'h Avenue, Phoenix, Arizona 85027 (623) 582- the hose clamp mounted thermocouple measured 6949. kbiswas (§ exponent.com Report on Proposals – November 2010 NFPA 921 ______921-156 Log #27

______Scott Broad, Giffin Koerth Forensic Engineering Revise text as follows: 25.5.1.1 Vacuum/Low-Pressure Carbureted Systems. In the ... to the carburetor fuel bowl. The fuel flows is then drawn from the bowl into the venturi due to the vacuum created by the velocity of the air accelerated as it passes through the throat of the venturi. In the venturi, the fuel is mixed with air in a ratio of approximately 15 to 1. ... The original wording may be misunderstood to indicate the fuel flows into the air stream by either pump pressure or gravity flow, which it does not. It also might be misinterpreted to suggest that the fuel flow into the air stream could continue once the engine is off, which it does not.

Printed on 9/18/2009 218 Report on Proposals – November 2010 NFPA 921 ______921-157 Log #CP8

______Technical Committee on Fire Investigations, Move to “Exhaust Systems” Revise Section 25.5.2.4.1 to read as follows: 25.5.2.4.1 Diesel particulate filters (DPF). Diesel particulate filters are unique to diesel exhaust systems. The DPF is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. In addition to collecting the particulate, a method must exist to clean the filter. Some filters are single use disposable filters, while others are designed to burn off the accumulated particulate, referred to as regeneration. Regeneration can be passive, (through the use of a catalyst), or active, which may use an injected fuel to heat the filter to a temperature sufficient to burn carbon soot. In either case, high surface temperatures exist, creating an ignition hazard. Failure to maintain manufacturer-required shielding and clearance between these hot external surfaces and combustible materials may result in ignition of combustible materials.

The committee believes that the additional discussion of Diesel particulate filters (DPF) should be included in the exhaust discussion.

Printed on 9/18/2009 219 Report on Proposals – November 2010 NFPA 921 ______921-158 Log #148

______Christopher J. Bloom, CJB Fire Consultants, Kim May, Tri-Fire Sulsultants, Joe Bloom, Bloom Fire Investigation Reword the entire section of NFPA 921 Section 25.12 and add the following language.

***See include 921_L148_R.pdf***

Most investigators agree that the recreational vehicle section, currently three paragraphs, is woefully inadequate. RVs are a separate and unique vehicle, which by code standard NFPA 1192 are different than houses and vehicles. As such, the burning characteristics, construction methods, and even flame spread are much more different than other vehicles. Just like the Marine section required a detailed update, this proposal should dramatically increase the value of the document to those who investigate such losses.

Deleting all existing text and providing the following re-write: 25.12 * Recreational Vehicles. This section deals with factors related to the investigations of fires involving recreational vehicles (RV). Information relative to the investigation of RV fires includes construction materials, systems, and failure modes. Additional information regarding RV systems and standards is available in NFPA 1192 Standard for Recreational Vehicles. RVs incorporate many similarities to houses and mobile homes. They are also in many cases, a motorized vehicle, containing all the intricate details of automobiles. However, because of the standards required for their lightweight construction methods they may utilize large volumes of plastics and other combustible materials, and there will often be additional large fuel items like polyurethane foam (in couches, mattresses, and refrigerator insulation) and propane gas. 25.12.1 General. Because Recreational vehicles are a unique hybrid of a vehicle and residence, utilizing unique construction materials and methods. The investigator needs to have a basic familiarity of the construction methods, the systems, and associated subsystems of the unit. As with any other fire, the first step is to determine an area of origin. Recreational vehicles can be divided into six seven major areas; i.e., the exterior, the engine compartment, the basement or storage compartment(s), coach, the galley, the lavatory, and the bedroom. The size, construction, and fuel load of these compartments can vary considerably depending upon the size, style, and manufacturer of the RV. 25.12.2 Recreational Vehicle Investigation Safety. Safety should always be the investigator’s first concern. Documentation can be conducted during the safety assessment. See Safety Chapter 12 for further information. 25.12.2.1 Confined Spaces. By their nature, fire investigations on RVs may involve working in confined spaces. The investigator should be aware of confined space entry concerns (e.g. entry/egress and atmospheric issues), and appropriate precautions should be taken. Prior to entry, the investigator should ensure the space does not contain hazardous levels of explosive or toxic vapors or gases (i.e., carbon monoxide) or is not oxygen deficient. The hazards of the space should be evaluated before entering, and the appropriate level of personal protective equipment should be worn. Lights and other equipment should be intrinsically safe and suitable for such environments. 25.12.2.3 Airborne Particulates. Because many RVs incorporate large quantities of fiberglass in their construction, resin used as part of the construction process generally burns away, leaving small, irritating particles of fiberglass. When dealing with issues such as refrigerator fires, some materials (such as Ssodium Cchromate) can be carcinogenic nature. These particles, when combined with burned resin, are highly irritating to the respiratory system and The appropriate level of personal protective equipment, including respiratory protection, should be worn as indicated by the level of hazard. 25.12.2.4 Energy Sources. There may be numerous energy sources present in an RV. Electrical hazards may be from 12vcd V DC batteries, or 120/240V AC V AC from shore power or a generator. Fuels such as gasoline, diesel fuel, or propane, may pose a spill, fire, or explosion hazard. Pressurized containers may rupture or pneumatic cylinders may fail. Precautions must be taken to ensure that the hazards are disabled, minimized, or otherwise made safe to prevent personal injury, as well as the possible recurrence of a fire or explosion. The investigator should employ personal protective equipment that is appropriate for the anticipated hazards. 25.12.2.5 Stability. RV fire scenes may be unstable. Care should be exercised when accessing the interior of an RV due to potential collapse of roof, side wall sidewall, or floor. RV manufacturers often place heavy items such as air

Printed on 9/18/2009 220 Report on Proposals – November 2010 NFPA 921 conditioners and satellite dishedes on roofs. Sidewalls Side walls may appear stable but may fail just by movement of debris. Never place any portion of your body underneath an RV without proper support of the RV. 25.12.3 Recreational Vehicle (RV). A recreational vehicle is a vehicular unit primarily designed to provide temporary living quarters for recreational, camping, travel, or seasonal use that either has its own motive power or is mounted on or towed by another vehicle. The living section of most RVs is referred to as the “coach”. 25.12.3.1 Motor homes are a vehicular unit mounted on or permanently attached to a self-propelled motor vehicle chassis or on a chassis cab or van, that is an integral part of the completed vehicle. 25.12.3.2 “Fifth wheels” are a vehicular unit mounted on wheels, of such size or weight as not to require special highway movement permit(s), of gross trailer area not to exceed 400 ft2 in the when set-up for occupancy mode, and designed to be towed by a motorized vehicle that contains a towing mechanism that is mounted above and forward of the tow vehicle's rear axle. 25.12.3.3 Camping trailers are a vehicular unit mounted on wheels, constructed with collapsible partial side walls that fold for towing by another vehicle and unfold at the campsite. 25.12.3.4 Travel trailers are a vehicular unit, mounted on wheels of such size or weight as not to require special highway movement permits when towed by a motorized vehicle, and a gross trailer area less than 320 ft2. 25.12.4 Unique Systems or Components. Many RVs are equipped with a variety of components and equipment typically not found in any other vehicle. 25.12.4.1 Shore Power. 120/240V AC V AC electrical power supplied from a land source via a cord set. 25.12.4.1 Generator. The auxiliary power generator systems in RVs vary. Generators may be fueled by gasoline, diesel, or propane. Gasoline and diesel fueled generator engines will operate similar to the descriptions earlier in this chapter. Propane generator engines will have the propane delivered as a liquid typically through a reinforced rubber hose. Generators may be air or liquid cooled. RV operators may also use portable generators, which are typically gasoline fueled. 25.12.4.2 Automatic Generator Starting System (AGS). A control system that automatically starts and stops engine generators when pre-set RV conditions occur, such as beginning and end of quiet time, low or high battery charge or demand, availability or loss of shore power connection, or appliance demand changes. 25.12.4.6 Electrical Converter. Because there are two different electrical systems (12V DC and 120V AC), at times there is a need to interchange their use. Some components and appliances are designed to operate at 12V DC, while at the same time, others may be designed to operate at 120V AC. An electrical converter is used to transform 120V AC input to 12V DC output. This is usually performed when the recreational vehicle is connected to shore power or when the generator is in operation. The converter is also used for battery charging. 25.12.4.7 Electrical Inverter. While converters change 120V AC to 12V DC, inverters perform the opposite function. The inverter changes 12V DC input to 120V AC output. This allows the use of regular appliances without having to operate the generator or be connected to a shore power source. The disadvantage of inverters is they can use large amounts of energy from the batteries in a short time. It should be noted that some RVs are equipped with a single unit that incorporates both the converter and inverter functions. The investigator may observe only one unit that serves both functions. 25.12.4.8 Batteries. While batteries are not unique to vehicles, the quantity and arrangement may be quite different. In a motorhome, there is typically a 12V DC battery or batteries for the starting and operating of the engine. The coach typically has a separate system of batteries. This system may consist of a single 12V DC battery, a pair of 12V DC batteries in parallel, a pair of 6V DC batteries in series, a set of two pairs of 6V DC batteries (in series) in parallel. The manufacturer provides the separation of 12V DC systems so that the starting batteries cannot be depleted by operating the coach accessories or appliances. While these systems are separate for output, the engine-mounted alternator (generator) can recharge the coach batteries while the engine is running. Some generator systems have direct battery charging capabilities while other work through the converter. Most RVs are equipped with battery disconnects for the coach side of the 12V DC system. The batteries may not be all located in the same area of the RV. The engine starting batteries are typically located at the engine area. The coach batteries are typically located in an accessible area. 25.12.4.9 Means of Escape. The means of escape in a RV are the exit door(s) and typically emergency exits are specially constructed windows. The An emergency exit, in a RV is typically a specially constructed window. , to the outside of a recreational vehicle. 25.12.4.10 Liquid Holding Tank. RVs may be equipped with sewage holding tanks. Tanks for the containment of toilet waste are referred to as “black water” tanks and those for the containment of sink and shower waste are referred to as “grey water” tanks. A fresh water holding tank may also be present 25.12.5 Systems 25.12.5.1 Electrical Systems. Recreational vehicles typically contain two different electrical wiring systems; 120V AC and 12V DC. All electrical wiring in RVs is required to adhere to NFPA 70. Most 120V AC system components will be similar to that found in residential settings. Stranded conductors are used for 12V DC and solid conductors are used for Printed on 9/18/2009 221 Report on Proposals – November 2010 NFPA 921 120V AC wiring. Lighting systems, for instance, may use both 12V DC and 120V AC in the same fixture. When connected to shore power, the electrical demands of the RV are met by the 120V AC input. 12V DC components are powered through the converter. When disconnected from shore power, 120V AC generator output may be the coach input power source. When not connected to any 120V AC source, 12V DC components are utilized. Solar panels may be present. These panels are typically used for battery recharging. Detailed information regarding the 12V DC system for the chassis is generally the same as a motor vehicle. 25.12.5.1.1 Shore Power. The most common RV shore power is a 30-ampere input. This is a three-wire system. This system is designed to power up to five 120V AC circuits. Some larger RVs use a 50-ampere input. This is a four-wire system. The four wire system utilizes two hot legs, a neutral, and a ground. Even though there are two hot legs, RVs do not use the traditional 240V AC input. There are no 240V AC systems in RVs. Campgrounds commonly have both 30-ampere and 50 ampere receptacles available in the same housing. Many homeowners install electrical services for their RV. Adapters may also be used. For instance, an RV manufactured with a four-wire, 50 ampere system may use an ‘adapter’ to plug into a three-wire, 30-ampere receptacle. This may limit the branch circuits available for use in the RV. 25.12.5.2 Propane Systems. Propane is used for cooking, heating, and refrigeration. Portable propane cylinders must be constructed in accordance with U.S. Department of Transportation Specifications for LP-Gas Containers (49 CFR) or fabricated to Transport Canada (TC). A fixed propane tank must be constructed in accordance with the ASME Boiler and Pressure Vessel Code, Section VIII, “Rules for the construction of unfired pressure vessels”. 25.12.5.2.1 Propane Regulators. Two-stage regulators are typically used on RVs. They are required to have a capacity exceeding the total input of all propane fueled appliances. The first stage of the regulator reduces the tank pressure of the propane to an output not to exceed 10psi. The second stage of the regulator reduces the pressure further to within the tolerances of the entire vapor system. Unless utilizing propane as a secondary propulsion fuel, propane withdrawn from the cylinder or tank is required to be a vapor at no more that 14-inches water column (3.49kPa or approx. 0.51psi). Tampering to the adjustment screw and plastic cap can indicate alterations to the system pressure. 25.12.5.2.2 Maximum Propane Container Capacities. NFPA 1192 limits the capacity of propane containers stored in an RV should be to no more than three cylinders or two tanks. The maximum capacity of each of the individual cylinders is a water capacity of 105 lb (47.6 kg) [approximately 45 lb (20.4 kg) propane capacity]. The maximum aggregate water capacity of one or both tanks is 200 gallons (0.8 m3) 25.12.5.2.3 Propane Container Shielding Requirements. Many manufacturers provide shielding of the container. Measurements should to be taken of the distances from the propane container to heat producing components. The container may be shielded by a vehicle frame member or by a noncombustible baffle with an air space on both sides of the frame member or baffle. 25.12.5.2.4 Propane Piping Clearances. Measurements should be taken of the distances between the propane piping or hoses to heat-producing components. The piping or hose may be shielded by a vehicle frame member or by a noncombustible baffle with an air space on both sides of the frame member or baffle. 25.12.5.2.5 Stoves. There are two basic types of kitchen stoves, a cook top and a range. A cook top is an appliance mounted in a drop-in configuration in the countertop. It does not have an oven. A cook top with an attached oven is a range. Ranges are installed in a cabinet cutout. These components are fueled by propane gas. Cooking control is via a manifold assembly and burner control valves. Stoves are equipped with a non-adjustable propane regulator as a mandatory safety feature. Stoves may have standing pilots for the oven and spark ignition for the surface burners. The orientation of the control knobs or control valve stems may yield information on operation of the stove at the time of the fire. Clearances are important as these devices are specifically designed for the tight spaces encountered in RVs. Residential-style appliances are not typically designed the same and are not suitable for installation in an RV. 25.12.5.2.6 Water Heaters. Water heaters are fueled by propane or electrically energized by 120V AC. 12V DC is typically required for controls. These units are typically self-contained. Propane is ignited in a burner. The heat is then passed through a flue tube inside the water tank and the hot exhaust gases are vented to the exterior. The entire process is outside of the living quarters of the coach. Water heaters may have standing pilots or spark ignition. Water heaters use an internal thermostat to regulate water temperature. Water heaters use a combination pressure and temperature relief valve (P&T valve). The P&T valve is designed to open and release pressure prior to reaching a dangerous level. 25.12.5.2.7 Furnaces. Forced-air and ducted furnaces operate on the principles of combustion and heat transfer. Air from outside of the coach is drawn into the furnace’s sealed combustion chamber. The burner uses the incoming combustion air and fuel to produce a flame. The exhaust gases then exit the furnace to the exterior of the coach. Furnaces may have standing pilots or spark ignition. The heat exchanger allows interior air to circulate around the sealed burnerd system. A thermostat regulates the operation of the burner and interior blower. Most furnaces use 12V DC for controls and blower operation. 25.12.5.2.8 Anhydrous Ammonia Absorption Refrigerators. RV refrigerators do not typically have compressors. These Printed on 9/18/2009 222 Report on Proposals – November 2010 NFPA 921 refrigerators use a heat absorption system whereby the anhydrous ammonia is heated and then flows through a system of tubes. The cooling of the gas is what cools the refrigerator interior. The anhydrous ammonia is heated by propane in a burner or a 120V AC heating element (2-way system), or additionally 12V DC heating element (3-way). Typical operation will be on electricity when available; however, the operator may select the fuel. 12V DC is typically necessary to operate the controls. Refrigerators may have standing pilots or spark ignition for the propane fuel. The anhydrous ammonia is combustible and may become ignited if it escapes from the tubing. 25.12.5.3.1 Microwaves. Microwaves are typically only 120V AC. The unit may be energized any time that 120V AC power is available. Microwave fires are the similar whether installed in an RV or residence. 25.12.5.3.2 Radiator Heating Systems. This type of system is generally found only on ‘upper-end’ more expensive motorhomes. Radiator heating systems use a diesel fuel fired burner to heat water. This unit supplies heat for comfort via residential-style radiators as well as domestic hot water needs. The unit may also be connected to the engine cooling system. This has the effect of warming the engine to ease cold-start issues. 25.12.5.4 Safety Systems 25.12.5.4.1 Smoke Alarms. The smoke detector alarm(s) should be installed as recommended by the manufacturer and marked as being suitable for installation in recreational vehicles under the requirements of ANSI/UL 217. The supply wiring (if present) should be examined. The An alarm battery compartment should also be checked to verify determine if the battery has been removed, tampered with, or installed improperly. 25.12.5.4.2 Carbon Monoxide (CO) Alarms. The CO alarm should be installed as recommended by the manufacturer and marked as being suitable for installation in recreational vehicles under the requirements of ANSI/UL 2034 or CSA 6.19. The supply wiring (if present) should be examined. The An alarm battery compartment should also be checked to verify determine if the battery has been removed, tampered with, or installed improperly. 25.12.5.4.3 Propane Alarm Detectors. The propane alarm detector should be installed as recommended by the manufacturer and marked as being suitable for installation in recreational vehicles under the requirements of ANSI/UL 1484. The supply wiring (if present) should be examined. The An alarm battery compartment should also be checked to verify determine if the battery has been removed, tampered with, or installed improperly. 25.12.5.4.4 Fire Extinguishers. NFPA 1192 requires all RV manufacturers to be manufactured install with at least a10B:C fire extinguisher. 25.12.6 Construction 25.12.6.1 Exterior Construction. The investigator should be familiar with the composition of the RV. General construction is practices are to assemble a welded steel frame to which a floor is attached. The floor system may be constructed of steel, aluminum, or wood frames with a wood or composite sub-floor material attached. Unlike residential construction, RVs are commonly built from the inside out. All of the interior structural components are installed on the floor prior to the installation of the exterior walls. This may include some of the appliances and fixtures. The side walls are then added. These components may be wood, steel, or aluminum framing, with fiberglass, aluminum, or stainless steel exterior siding and interior wall coverings. Newer methods use a vacuum process to ‘bond’ all the wall materials into a thinner, stronger, lighter-weight assembly. These assemblies can include all of the necessary wiring (both 12V DC and 120V AC). The final major component is the attachment of the roof assembly. The most common style roof is a wood sheath over frame construction covered by a waterproof membrane. A one-piece fiberglass roof may be used. Manufacturers may keep on end of the RV open to facilitate the installation of large appliances or fixtures. 25.12.6.2 Interior. Due to design and weight concerns, the interior construction materials may differ from those found in a residential structure. Interiors may be constructed with Fiber Reinforced Panels (FRP) or wood framing and exterior grade plywood or veneer. NFPA 255 flame spread ratings of 200 or lower are required for interior finishes of walls, partitions, ceilings, exterior passage doors, cabinets, habitable areas, hallways, bath rooms, including shower/tub walls. Counter surfaces may be natural (marble or granite), synthetic (plastic laminate), or wood veneer. Additional fuel loads may exist in the form of carpeting and other synthetic materials utilized as vertical and overhead finishes. The flame spread limitations do not apply to moldings; trim; furnishings; windows, door, skylight frames, casings; interior passage doors; countertops; cabinet rails; stiles; mullions; toe kicks; or padded cabinet ends. These fuels can dramatically affect any fire incident, ultimately affecting the spread and growth of the fire. 25.12.7 Recreational Vehicle Examinations. RV tolerances and clearances designed into the coach are sometimes critical, depending on the system. Any examination and documentation of any evidence, including the removal and securing of items of evidence, should be performed in accordance with the guidelines specified in the Physical Evidence Chapter 16 and the ASTM standards presented in Annex A of this document. If improperly removed, the investigator may destroy key pieces of evidence and information relevant to a potential cause. (See Section 16.3.) 25.12.7.1 Examination of the exterior of the recreational vehicle may reveal significant fire patterns. Caution should be exercised when interpreting patterns around enclosures such as the refrigerator, furnace, or water heater compartments. These compartments in the RV that are ventilated and may contain have significant fuel packages. This which may affect exterior fire patterns. Printed on 9/18/2009 223 Report on Proposals – November 2010 NFPA 921 25.12.7.2 Analyzing the fire patterns can determine whether the fire spread from inside the compartment. NFPA 1192 requires that the interior of the coach be vapor resistant to the exterior. The arrangement of the cabin, appliances, fixtures, whether windows were open or closed, may influence the fire spread characteristics and fire patterns. Compartments typically used for sleeping, lounging, cooking, storage, or lavatory, may include a variety of materials and ignition scenarios. 25.12.8 Ignition Sources. In most cases, the sources of ignition energy in RVs will be similar to those already described in this chapter and those associated with structural fires such as arcs, mechanical sparks, overloaded wiring, open flames, and smoking materials. Additional considerations are the added appliances described previously. Consideration should also be given to the effects of vibration, mechanical damage, rodent activity, or movement, due to being driven or towed over the road. 25.12.9 Recreational Vehicle Identification. NHTSA requires all RVs be identified by a 17 digit VIN. Manufactures commonly apply a serial number to the coach as well as identify the make, model, and serial number of the major appliances. This information is found in the owner’s documents, a label on the exterior of the coach, and a placard located in a galley cabinet. 25.12.10 Recreational Vehicle Information. There are many different sources available to the investigator to assist in origin and cause determination. Such sources include but are not limited to sales brochures, owner’s manuals, and Internet web sites such as that of the specific manufacturer of the unit. Floor plans and options can be found on the Internet from general public sales sites. 25.12.11 Recreational Vehicles in Structures. 25.12.11.1 RVs within garages and carports should be examined with consideration of the additional combustibles within the garage or carport, especially when considering the origin. Heat transfer from a fire originating in the structure may damage the RV. 25.12.11.2 If applicable, the building electrical service needs to be inspected for electrical supply voltage and polarity to verify if they are consistent with the requirements of the coach and associated subsystems. Information about the shore power receptacle may be important. 25.12.11.3 NFPA 1194 covers parks or campgrounds. Similar considerations need to be made when the RV is parked at one of these properties. If applicable, all services (propane/electricity/sewer/etc) provided by the park or campground need to be inspected and verified. 25.12.11.4 RV Coach system operational requirements typically require the coach to be parked in level. The type of surface the coach was parked on should be documented. The use of an angle finder can be employed to measure any slope present to establish the specific angles of the scene. 25.22 Legal Considerations. Legal considerations during a RV fire investigation are similar to those involving other investigations and may include the right to investigate, the right to enter, spoliation, and preservation, of evidence. Other legal considerations include if the vehicle was manufactured under NFPA, CSA, or another countries regulations. A full discussion on legal considerations may be found in the Legal Chapter 11.

The committee believes that the modified text more clearly conveys the submitter’s content and eliminates redundancy.

Printed on 9/18/2009 224 NFPA 921 ---Motor Vehicle Chapter ---RV Task Group 2011 Ed. Proposed Changes Recreational Vehicle Section Submission by: Chris Bloom, Joe Bloom, Kim May 25.12 * Recreational Vehicles. This section deals with factors related to the investigations of fires involving recreational vehicles (RV). Information relative to the investigation of RV fires includes construction materials, systems, and failure modes. Additional information regarding boat systems and standards is available in NFPA1192 Standard for Recreational Vehicles. For investigation of RV fires outside U.S. boundaries, additional information may be obtained in local and regional standards and codes. (See CSA Z240-08). 25.12.1 Recreational vehicles (RVs) and motor homes incorporate many similarities to houses and mobile homes. They are also in many cases, a motorized vehicle, containing all the intricate details of automobiles. However, because of the standards required for their Lightweight construction methods they utilize large volumes of plastics and other combustible materials are present, and there will often be additional large fuel items like polyurethane foam (in couches, mattresses, and refrigerator insulation) and propane gas. (See NFPA 1192, Standard on Recreational Vehicles.) 25.13 Recreational Vehicle Terminology. The following select definitions contained in this section apply to Recreational Vehicles. For a complete set of terms, See NFPA 1192 as well as those published by the Recreational Vehicle Industry Association (RVIA).

(1) Automatic Generator Starting System (AGS). A control system that automatically starts and stops engine generators when pre-set RV conditions occur, such as beginning and end of quiet time, low and high battery charge, availability or loss of shore power connection, or appliance demand changes such as cycling of temperature- controlled air conditioning (2) Recreational Vehicle (RV). A vehicular-type unit primarily designed to provide temporary living quarters for recreational, camping, travel, or seasonal use that either has its own motive power or is mounted on or towed by another vehicle a. Motorhome. A vehicular unit designed to provide temporary quarters for recreational, camping, or travel use, built on or permanently attached to a self-propelled motor vehicle chassis or on a chassis cab or van that is an integral part of the completed vehicle. b. Fifth Wheel. A vehicular unit, mounted on wheels, designed to provide temporary quarters for recreational, camping, or travel use, of such size or weight as not to require special highway movement permit(s), of gross trailer area not to exceed 400 ft2 in the set-up mode, and designed to be towed by a motorized vehicle that contains a towing mechanism that is mounted above and forward of the tow vehicle's rear axle. c. Camping Trailer. A vehicular portable unit mounted on wheels and constructed with collapsible partial side walls that fold for towing by another vehicle and unfold at the campsite to provide temporary living quarters for recreational, camping, or travel use. d. Travel Trailer. A vehicular unit, mounted on wheels, designed to provide temporary quarters for recreational, camping, or travel use, of such size or weight as not to require special highway movement permits when towed by a motorized vehicle, and a gross trailer area less than 320 ft2. (3) Bulkhead. A vertical partition separating compartments. (4) Cabin. A compartment for passengers or crew. (5) Circuit Breaker. A device designed to open and close a circuit by non automatic means and to open the circuit automatically on a predetermined over-current without damage to itself When properly applied within its rating. (6) Compartment. Within a recreational vehicle, an enclosed volumetric space designed to provide for a separate area. (7) Container Pressure. Unregulated pressure from a propane container. (8) Dispensing. As applied to gasoline or diesel fuel systems, withdrawing fuel from applicable recreational vehicle fuel tank(s) to other motorized vehicles or approved containers by means of a hose and hose nozzle valve. (9) Distribution. As applied to gasoline or diesel fuel systems, the flow of fuel from the recreational vehicle fuel tank(s) to an onboard fuel-burning generator by means of a closed system of tubing or hoses. (10) Frame. Chassis rail and any addition thereto of equal or greater strength. (11) Fuel System. Any arrangement of pipe, tubing, fittings, connectors, tanks, controls, valves, and devices designed and intended to supply or control the flow of fuel. (12) Galley. The kitchen area of a RV. (13) Heat-Producing Appliance. An appliance that produces heat by utilizing electric energy or by burning fuel. (14) Lavatory. Commonly referred to as the Bathroom, hosing a shower/tub, sink, and toilet. (15) Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. (16) Means of Escape (Recreational Vehicle). A way to the outside of a recreational vehicle. (17) Overfilling Prevention Device. A safety device that is designed to provide an automatic means to prevent the filling of a container in excess of the maximum permitted filling limit. (18) Pipe. Rigid conduit of iron, steel, copper, brass, aluminum, or plastic. (19) Pressure Relief Valve. A type of pressure relief device designed to both open and close to maintain internal fluid pressure. (20) Propane (Liquefied Petroleum Gas, LP-Gas, LPG). Any material having a vapor pressure not exceeding that allowed from commercial propane composed predominantly of the following hydrocarbons, either by themselves or as mixtures: propane, propylene, butane (normal butane or iso-butane), and butylene. (21) Propane Container. A tank or cylinder. (22) Cylinder. For recreational vehicles, a portable container constructed in accordance with U.S. Department of Transportation Specifications for LP-Gas Containers (49 CFR) or fabricated to Transport Canada (TC). (23) Tank. A container constructed in accordance with the Section VIII, “Rules for the Construction of Unfired Pressure Vessels” of the ASME Boiler and Pressure Vessel Code. (24) Vapor Resistant. Constructed so that gas or air is inhibited from entering or leaving except through vents or piping provided for the purpose. (25) Shall. Indicates a mandatory requirement. (26) Shore power. Electrical power supplied from shore via a cord set. (27) Tubing A semi rigid conduit of copper, steel, aluminum, or plastic.

25.14 Recreational Vehicle Investigation Safety. Safety should always be the investigator’s first concern. Scene documentation can also be conducted during safety assessment. See Chapter 12 for further information). 25.14. Specific Safety Concerns. 25.14.1 Confined Spaces. By their nature, fire investigations on boats may involve working in confined spaces. The investigator should be aware of confined space entry concerns (e.g. entry/egress and atmospheric issues), and appropriate precautions should be taken. Prior to entry, the investigator should ensure the space does not contain hazardous levels of explosive or toxic vapors or gases (i.e., carbon monoxide) or is not oxygen deficient. The hazards of the space should be evaluated before entering, and the appropriate level of personal protective equipment should be worn. Lights and other equipment should be intrinsically safe and suitable for such use. 25.14.2 Airborne Particulates. Because most RVs incorporate a large amount of fiberglass in their construction, resin used as part of the construction process generally burns away, leaving small, irritating particles of fiberglass. When dealing with issues such as refrigerator fires, some materials (such as Sodium Chromate) which may be found post-fire can be carcinogenic nature. These particles, when combined with burned resin, are highly irritating to the respiratory system and the appropriate level of personal protective equipment, including respiratory protection, should be worn as indicated by the level of hazard. 25.14.3 Identify and Assess Energy Sources. There are numerous energy sources onboard; precautions must be taken to ensure they are disabled to prevent personal injury, as well as possible recurrence of a fire. The investigator should employ personal protective equipment that is appropriate for the anticipated hazards. 25.14.3.1 Batteries. Recreational vehicle 12-volt systems are generally supplied by the use of either multiple-6volt batteries or a single 12-volt battery. Additional 12-volt service can be supplied by the use of a converter when the coach is plugged into shore power. After proper documentation and photography, battery cables, should be disconnected at each battery, as there may be more than one battery and multiple locations. Prior to disconnecting the battery cables, the investigator should ensure the atmosphere is properly ventilated and free of explosive vapors. During disconnection, arcs from battery terminals can cause a fire or explosion. 25.14.3.2 Inverters. Inverters that convert 12-volt DC to 120/240-volt AC power (after proper documentation and photography) should be disabled by disconnecting the dc input power. 25.14.3.3 Converters. Converters that convert 120VAC to 12-VDC should also be examined, documented with photographs, and disabled (after proper documentation and photography). 25.14.3.4 Shore Power. After proper documentation, shore power sources (cord sets) should be de-energized and disconnected. This should be done prior to conducting an investigation. 25.14.3.5 Automatic Generation Systems (AGS Generators). Care should also be taken on RVs equipped with AGS systems to avoid the possibility of electrocution. . 25.14.4 Fuel Leaks. Engine fuels, heating fuels, and cooking fuels, including propane from onboard LP gas systems can leak due to fire and explosion damage or during investigative activity. Such leaks can produce additional fire hazards. Investigators should be alert to the presence of such leaks and be prepared to prevent or mitigate these hazards. 25.14.5 Sewage Holding Tank. RV’s that contain sewage holding tanks may accumulate methane gas. Proper venting and explosion prevention techniques must be employed during the fire scene investigation. Sewage holding tanks may be damaged, and if the contents escape, a biological hazard may be encountered. Care should be taken when working in areas containing sewage. 25.14.6 Hydrogen Gas. Depending upon the types of batteries in use, Hydrogen gas may be present in any battery compartment. Care should be taken to avoid static discharges, short circuiting, and arcing during the removal of battery cables and batteries. 25.14.7 Flame Damage to the Structure. The RV may have sustained sufficient damage due to the fire, causing it to become unsafe. The structural integrity may be compromised and the weight of the investigator may cause collapse of flooring further resulting in instability. Fires involving the interior can cause structural damage, weakening of the flooring, and the weakening of structural supports. 25.15. Major RV System Identification and Function. 25.15.1 Fuel Systems: Propulsion and Auxiliary. 25.15.1.2* Gasoline High-Pressure Fuel-Injected Systems. In the high pressure fuel- injected system, the fuel is typically pumped from the fuel storage tank under pressures of 240 kPa to 480 kPa (35 psi to 70 psi). This pumping is accomplished with an electric pump in or near the fuel storage tank. This pump is typically energized any time the ignition key is in the run position. Most late model vehicles have electric fuel pumps that are integrated with the engine’s computer. This computer is designed to shut the pump off if the engine is not running. Some vehicles are also equipped with an inertial switch. This switch will shut the fuel pump down in case of an impact of sufficient severity. The fuel is pumped to either a single venturi-mounted fuel injector or a fuel rail assembly on the engine. The single venturi-mounted fuel injector is typically located inside a device that resembles a carburetor. Fuel is injected (atomized) in a much more controlled manner than in a carburetor, increasing fuel economy and power. Additionally, by providing a stable fuel–air mixture, this injector reduces pollution. The fuel rail assembly is a tube located on top of the engine to supply constant fuel pressure and flow to cylinder-mounted fuel injectors. Both of these types of high pressure systems may also include a fuel return system. The fuel return system carries the unused fuel back to the fuel storage tank at generally much lower pressure than the supply line, typically 20 kPa to 35 kPa (3 psi to 5 psi). Some vehicles are equipped with components in the supply and return fuel lines that are designed to prevent fuel from the fuel tank entering the lines with the fuel pump off. Potential problems with this system include leaks at fittings. When a leak develops, the system pressure can propel a stream of fuel several feet. If the leak develops on the supply side of the system, operational problems may be noticed by the operator. These leaks can result in poor performance of the vehicle, including starting difficulties, erratic operation, and stalling. A fuel leak involving the return side of the system, downstream from the fuel pressure regulator, may not have a noticeable effect on the engine operation; therefore, a leak here may go undetected. Even vehicles that are not running typically have residual pressure in the fuel system. Many vehicles are being equipped with flow detection equipment that monitors fuel usage and fuel return. If this system detects an imbalance, the system will shut down. Afire originating in a system other than the fuel system, if allowed to progress unchecked, can compromise the fuel lines of a vehicle. Residual pressure within the delivery fuel line can result in fuel spillage once the line is compromised, however this spillage is generally minimal. Fuel lines running to and from the fuel storage tank can create a siphoning effect if compromised; however, check valves placed within the fuel delivery system can act to minimize or eliminate this conditioning from contributing to further fuel leakage. Some vehicles may incorporate a two-pump system consisting of a low pressure lift pump (in the tank) and a high-pressure delivery pump (located outside the tank). During an impact, if a fuel line is compromised, fuel siphoning may occur. Siphoning is dependent upon several factors to permit a continued flow of fuel, including: fuel line opening, fuel level in the tank, and vehicle orientation. Factors that can reduce or prevent siphoning include: fuel tank pressure or vacuum, and flow restrictions such as fuel pumps, check valves, and fuel line kinking. The investigator should be careful to consider all of these elements before rendering the opinion that fuel siphoned from a damaged fuel line. The investigator should also recognize that internal fuel tank pressure created when the tank is exposed to heat from a fire can force fuel from lines that have been previously damaged by either the impact or the fire. 25.15.1.3* Diesel Fuel Injection Systems. Diesel-powered vehicles typically use a combination of pumps to deliver the fuel from the fuel storage tank to the engine. Sometimes, electric lift pumps are used in or near the fuel storage tank, or enginemounted mechanical pumps are used. These lift pumps are typically high- volume, low-pressure devices. They supply fuel to the engine-mounted fuel injector pump. The fuel injector pump meters and delivers the fuel into each cylinder at the appropriate time for combustion. Combustion air is brought in through natural aspiration or under pressure from a turbocharger. Diesel fuel delivery systems are typically very robust. Leaks may develop at fittings loosened by the vibration of the engine. While difficult, under the right conditions, diesel fuel may ignite on contact with a hot surface. “Runaway” diesel engines are a rare occurrence, but they do happen occasionally if a vehicle is operated in a fuel rich atmosphere. This may occur when airborne combustible vapors are taken into the intake system via the engine air supply. The engine can over speed or mechanically fail, possibly igniting the fuel-rich atmosphere. The only sure way to stop an engine under these circumstances is to shut off the air supply containing the vapors. 25.15.1.4 Turbochargers. Turbocharging is the utilization of a turbine to add to the power output of an engine by increasing the amount of air being forced into the cylinders. The turbine used to drive the compressor can turn up to 100,000 rpm under full load. The turbocharger uses exhaust gases for propulsion, and in many cases, the turbocharger and exhaust manifold are the hottest external points on an engine. The heat created can ignite fuels and other combustible materials. Both gasoline- and dieselfueled engines can be turbocharged, with almost all new diesel fueled engines being turbocharged. Some engines use two turbochargers mounted in series or parallel. The center bearings for the main shaft are lubricated by engine oil from a separate tube from the pressurized side of the engine lubricating system. A leak from this tube or fitting can spray oil onto the hot turbocharger housing and exhaust manifold, resulting in ignition of the oil. A broken shaft may allow a large quantity of oil to leak into the exhaust pipe causing a severe overheating of the catalytic converter if so equipped. Oil may also leak into the intake and be burned by the engine. 25.15.1.5 Exhaust System. The exhaust system does more than carry the exhaust gases from the engine. It also serves as a part of the emission control system. The exhaust manifold is bolted directly to the engine. It is the collector for the exhaust gases coming from each cylinder. This manifold is generally located below the valve cover. A leak in the valve cover or gasket may allow engine oil to contact the manifold, which may result in ignition. (See 25.4.3.) In the inlet header pipe (the first section of pipe from the engine), there is usually an oxygen sensor. This sensor detects the oxygen content in the exhaust stream and sends a signal to the onboard computers to make fuel delivery and timing adjustments. The next device downstream, in the exhaust system is the catalytic converter. Surface temperatures range between 316°C to 538°C (600°F to 1000°F) under normal operations, depending on the engine design. However, temperatures may exceed 538°C (1000°F) due to high engine loads or during abnormal engine conditions (i.e., misfires), or rich fuel concentrations due to other sensor malfunctions. 25.15.1.5.1 A potential danger in a normally operating motor vehicle is contact with combustible items, such as tall grass or debris, with exhaust and catalytic converter surfaces. A malfunction in the engine can cause the catalytic converter to run hot enough to ignite undercoating and interior carpeting. 25.15.1.6 Electrical Systems: General . Recreational vehicles contain two different electrical wiring systems, 120-volt Alternating Current (AC) and 12-volt Direct Current (DC). Most recreational vehicles are equipped with 120-volt wiring, powered by a large "shore power" cord, the system inverter/converter, and sometimes a generator. These units also contain a 12-volt service connected to a battery (set) designed solely for the domestic coach service. Occasionally, solar panels are also installed to charge the batteries and provide minimal 12-volt power. All electrical wiring in RVs is required to adhere to the NFPA 70. Wiring methods and distribution in a RV are similar to a house. In general, stranded wiring is used for lower 12-volt installations and solid wire is used for the 110-volt “house” wiring. A motorhome will also be found to have more than one battery, generally of differing sizes. One set of batteries are for the engine, and the remaining batteries are for the interior coach. When examining a motorhome involved in a fire, it is important to attempt to determine which batteries were used for each purpose. 25.15.1.6.1 Alternating Current -120VAC System 25.15.1.6.1.1 SHORE POWER. The most common service for RV shore power is 30- amp, which handles up to five 120-volt circuits. Some of the larger RVs use a 50-amp service. Some RV owners also provide a 120-volt specialized receptacle for a direct shore power connection at their home, while others use an adapter connection to allow the shore power plug to connect to a normal three-prong receptacle. Use of a smaller gauge extension cord with the factory shore power connection is not recommended by manufacturers. The investigator should inspect the receptacle as part of the examination. Tracing the conductors back to the circuit breaker providing power to that receptacle may be necessary to determine if the circuit provides 120 or 240 volts. Plugging the circuit into the wrong voltage can immediately destroy the appliances, electronics and circuitry in the coach and cause a fire. Extreme care should be taken, and the services of an electrician may be required to determine if a circuit is 120 or 240 volts. 25.15.1.6.1.2 GENERATOR. The auxiliary power generator systems in motorhomes vary. Most are gas fed, using a carburetor. Some models are also diesel powered. A new type uses propane to power the generator. This is brought about by the advent of the diesel pusher engine, which eliminates the need for gasoline. The propane-powered generator creates a new potential hazard. Liquid propane under pressure is distributed directly to the generator by a reinforced flexible hose. A propane hose failure, failure of the vaporizer or a connection failure can release a large volume of propane under high pressure (up to 312.5psi), resulting in the coach being enveloped in a cloud of propane vapor and increasing dramatically the potential for a fire and/or explosion. 25.15.1.6.1.3 INVERTER. While converters change 120 volts to 12 volts, inverters perform the opposite function. The inverter switches 12 volts to 120 volts, which allows the use of regular appliances without having to operate the generator or be connected to a shore power source. The disadvantage of inverters is they can use enormous amounts of energy from the batteries in a short time, depending on the application and 120-volt draw, thus draining them quickly. It should be noted that some RVs are equipped with a single unit that incorporates both the inverter and converter functions. The investigator may find only one unit that serves both functions. 25.15.1.6.2 Twelve Volt System 25.15.1.6.2.1. Detailed information regarding the 12VDC electrical system for the chassis is generally the same as a motor vehicle. See 25.5.3.1 for details pertaining to the chassis 12VDC electrical system. 25.15.1.6.2.2 Batteries The location of the batteries will vary with each manufacturer and model, and an attempt should be made to determine their pre-fire sites. As part of the examination, battery cables should be traced to determine if massive shorting occurred at a specific location. Although the cable faulting location may not be the origin, this could also explain any additional severe damage, as most cables are not fused or do not contain a cut-off. Issues such as corrosion also are important and should be documented when found. It should also be noted in testing that battery cables may sever or melt, breaking a contact connection when exposed to dead shorting over an extended period of time. The expected flame height from burning insulation should be considered low and can be documented through testing using the same make, model and size of battery and the same length cables. 25.15.1.6.2.3 Converter. Because there are two different electrical systems on recreational vehicles (12-volt DC and 120-volt AC), at times there is a need to interchange their use. Some components and appliances are designed for use with 12- volt, while at the same time, others may be set up to use 120-volt. A power converter is used to transform 120 volts to 12 volts. This is usually performed when the recreational vehicle is connected to a shore power connection or when the generator is in operation. 25.15.2 Propane Systems: Cooking and Heating. 25.15.2.1* Liquefied Petroleum Gases. Liquefied petroleum gases (LPG) can be used as a cooking or heating fuel. The investigator should verify if the LPG cylinder or tank is secured either outside the vehicle on the frame or within an enclosure that is vented from the bottom to the outside. Unless utilizing propane as a secondary propulsion fuel, propane withdrawal from the cylinder or tank is required to be a vapor withdrawal at no more that 14 inches water column (3.49kPa or approx. 0.51psi). 25.15.2.2 Propane Regulators. The investigator should aware that two-stage regulators are the most common regulator found on RVs. They are required to have a capacity exceeding the total input of all propane powered appliances in the RV. The first stage of the regulator reduces the tank pressure of the propane to an output not to exceed 10psi. The second stage of the regulator reduces the pressure further to within the tolerances of the entire vapor system. The investigator should check and verify in there has been any tampering to the adjustment screw and plastic cap , which can indicate alterations to the system pressure. 25.15.2.3 Maximum Propane Container Capacities. Investigators should be aware that there are limitations on the capacity of propane containers stored in a recreational vehicle. Per NFPA 1192 code requirements, there should be no more than three (3)cylinders or two(2) tanks on a RV. The maximum capacity of each of the individual cylinders is a water capacity of 105 lb (47.6 kg) [approximately 45 lb (20.4 kg) propane capacity]. The maximum aggregate water capacity of one or both tanks is 200 gal (0.8 m3) 25.15.2.4 Propane Container Storage. Investigators should be aware that only new propane cylinders that have never contained propane and are supplied as original equipment shall be permitted to be transported inside the vehicle. 25.15. 2.5 Propane Container Shielding Requirements. If an incident involving propane is suspected, investigators should verify if proper shielding of the container, piping, and hoses were employed. Whenever possible, measurements should to be taken of the distances from the exhaust system, the transmission, or a heat producing component of a combustion engine or heating appliance to the propane container. Documentation should also be made to verify if there was a heat shield installed or if the container was protected by a vehicle frame member or by a noncombustible baffle with an air space on both sides of the frame member or baffle. 25.15.2.6 Propane Piping Clearances. With incidents suspected involving propane supply piping and hoses, investigators should also try to verify the distances between the propane piping and hose and the exhaust system, the transmission, or a heatproducing component of an internal combustion engine. Documentation should also be made to verify if the piping/hose was shielded by a vehicle frame member or by a noncombustible baffle with an air space on both sides of the frame member or baffle.

25.15.3 Major RV Appliances. During the course of an investigation, an investigator may determine that an appliance was the origin and cause of a fire. However, the investigator is cautioned that extreme care must be taken when examining appliances in order to properly determine the extent of the damages suffered and whether those damages are consistent with the being cause or the effect of the incident. The investigator is also cautioned about the need to eliminate as much as possible any surrounding potential causes and owner related issues before attributing a fire to an appliance failure. 25.15.3.1 Microwaves. The investigator is cautioned to avoid presumption when dealing with reports that no appliance was on except for a specific product. Microwaves, even though they may not be in operation at the time, still drop our through the 110-volt AC electrical system for their circuit board as well as visual clock display. The investigator should try to identify the specific make and model of the microwave to verify or negate any potential issues or recalls. 25.15.3.2 Stoves. There are two basic types of kitchen stoves, a cooktop and a range. A cooktop is an appliance mounted in a drop-in configuration on the countertop. It does not have an oven. If a cooktop has an attached oven, it is classified as a range. Another feature of ranges is they are installed in a cabinet cutout instead of in a drop-in configuration. The investigator should be aware that both types of stoves are powered by propane gas supplied from the tank via a manifold assembly and burner control valves. Stoves are also manufactured with a mandatory safety feature, a small non- adjustable propane regulator, between the propane manifold and the propane tank. It is extremely important for the investigator to document the stove when it is involved in any fire incident. The orientation of the control knobs, or is burned away the orientation of the valve controls, can yield important information on whether any knobs were in the on or off position. If it is suspected that the knobs may be in a position other than off, that the individual knobs be taped to the stove remains to preserve the orientation of the valve assemblies in and unaltered condition. 25.15.3.3 Water Heaters. Water heaters are primarily powered by propane, but, in some cases, also by an optional 120VAC source. When using propane, the water heaters draw air and propane into a burner. The flame then passes through a flue tube inside the water tank, and the hot exhaust gases are piped out to the exterior. The entire process is conducted outside the living quarters of the coach. Propane water heaters also work automatically, using a thermostat to turn on and off the propane supply. If there is a problem, the unit is designed to fail in the "off" position. Water heaters use not only a thermostat, but a combination pressure and temperature relief valve, commonly called a P&T Relief Valve. The P&T Relief Valve is designed to open and release water and pressure in case the temperature and pressure inside the storage tank reach dangerous levels. The thermostat allows the water to be heated to a preset temperature, and then the water heater will automatically stop heating. 25.15.3.4 Furnaces. Forced-air and ducted furnaces, regardless of manufacturer, operate on the same principles of combustion and heat transfer, with the same basic design features. Air from the outside of the coach is drawn, or forced, into the furnace’s sealed combustion chamber. The burner uses the incoming air with fuel and flame, causing combustion. The heat exchanger allows interior air to circulate around the sealed exhaust system, heating it. The hot exhaust gases rise and circulate through a heat exchanger. The exhaust gases then exit the furnace to the exterior of the coach. 25.15.3.5 Floor Radiant Heat. This type of system is generally found only on the upper- end motorhomes and is powered by diesel burners. It accomplishes two things at the same time, creating a continuous supply of hot water and circulating heat via old style radiators throughout the coach. One additional benefit of these systems is many times they are incorporated into the engine compartment to preheat the engine prior to its startup, allowing it to start effortlessly in cold weather. 25.15.3.6 Anhydrous Ammonia Absorption Refrigerators. 25.15.3 Safety Systems 25.15.3.1 Smoke Alarms. The investigator should examine the remains of the smoke detector to ensure that is listed and marked on the device as being suitable for installation in recreational vehicles under the requirements of UL 217. The wiring should be examined for any signs of tampering. The battery compartment should also be checked to verify if the battery inside has been removed, tampered with, or installed improperly. 25.15.3.2 Carbon Monoxide (CO) Alarms. The investigator should examine the remains of the CO detector to ensure that is listed and marked on the device as being suitable for installation in recreational vehicles under the requirements of UL 2034 or CSA 6.19. The wiring should be examined for any signs of tampering. The battery compartment should also be checked to verify if the battery inside has been removed, tampered with, or installed improperly. 25.15.3.3 Propane Detectors. The investigator should examine the remains of the propane detector to ensure that is listed and marked on the device as being suitable for installation in recreational vehicles under the requirements of UL 1484. The wiring should be examined for any signs of tampering. It is also recommended that for incidents where propane is involved, the investigator should try to determine if there were other mitigating circumstances on why the detector may have been disabled (housekeeping issues, modifications, tampering, covered by housekeeping issues, etc.). 25.15.3.4 Fire Extinguishers. The investigator should examine the remains of the onboard extinguisher to verify if it was original or aftermarket equipment. The investigator should make sure that the extinguisher was a minimum 10BC as required by NFPA 1192. 25.16 Construction 25.16.1 Exterior Construction. The investigator should be familiar with the composition of the RV. General construction materials for either wood, steel, or aluminum framing, and fiberglass or stainless steel exterior siding. Consideration of the construction materials and flame spread ratings should be considered when identifying fuel loads. 25.16.2 Interior. Due to design and weight concerns, the interior construction of a RV utilizes many different materials than those found in a normal dwelling. Interiors are generally found to be constructed from FRP material and/or conventional building materials, such as solid stock woods and exterior grade plywood and veneers.. Investigators should note that unlike heavy equipment, vehicles, and structures, NFPA 255 flame spread ratings of up to 200 are allowed on Interior finishes of walls, partitions, ceilings, exterior passage doors, cabinets, habitable areas, hallways, and bath or toilet rooms, including shower/tub walls. Counter surfaces may be synthetic (plastic laminate) or wood veneer. Abnormal fire loading may exist in the form of carpeting and other synthetic materials utilized as vertical and overhead finishes. The investigator should also note that the flame spread limitations shall not apply to moldings; trim; furnishings; windows, door, or skylight frames and casings; interior passage doors; countertops; cabinet rails; stiles; mullions; toe kicks; and padded cabinet ends. These ratings can dramatically affect any fire incident, ultimately affecting the spread and growth of the fire. 25.17 Ignition Sources. Ignition Sources. In most cases, the sources of ignition energy in motor vehicle fires are similar to those associated with structural fires such as arcs, mechanical sparks, overloaded wiring, open flames, and smoking materials. There are, however, some unique sources that should be considered, such as the hot surfaces of the engine exhaust system. This system may consist of the exhaust manifold, exhaust pipe, one or more catalytic converters, mufflers and tailpipes. Other hot surface ignition sources may include brakes, bearings, and turbochargers. Because some of these ignition sources may be difficult to identify following a fire, the description in 25.4.1 through 25.4.5 are provided to assist in their recognition 25.17.1 Open Flames. Open Flames. The most common sources of an open flame in a RV are appliance pilots or operating burners of ranges, ovens, water heaters furnaces, etc. Lit matches, candles, and smoking materials may also be found and should be considered. 25.17.2 Electrical Sources. 25.17.2.1 Overloaded Wiring. Faults in wiring can raise the conductor temperature to the point of deteriorating, melting, or igniting the insulation, particularly in bundled cables such as the wiring harnesses or the accessory wiring routed within the RV, through bulkheads, and in cable trays where the heat generated is not readily dissipated. This can occur without activating the overcurrent circuit protection devices. The addition of accessories, such as radios, GPS systems, and radar may contribute to the overloading of the original factory wiring. The pre-fire history of aftermarket additions and any prior electrical malfunction should be evaluated in the fire analysis. 25.17.2.2 Electrical Short Circuiting and Arcs. Electrical arcing can result when a conductor’s insulation becomes worn, brittle, cracked, or otherwise damaged, allowing it to contact a grounded conductor or surface. Insulation failure may occur as a result of chafing, crushing, or cutting of wires. Battery and starter cables are not provided with overcurrent protection and are designed to carry high currents. capable of igniting materials such as engine oil accumulations, some plastic materials, and electrical wiring insulation. 25.17.2.3 Electrical Connections. In addition to the electrical failures associated with a structure or vehicle electrical system, corrosion-induced failures may occur from the RV being exposed to year-round weather. This corrosion may result in high resistance heating, providing energy sufficient for ignition of adjacent common combustibles. The electrical connections on a boat should be protected in a similar manner as those comprising the electrical systems for motor vehicles. A detailed discussion of poor connections is located in Chapter 8. 25.17.3 Hot Surfaces. 25.17.3.1 Manifolds. Exhaust manifolds and manifold components can generate high temperatures sufficient to ignite diesel spray and vaporized gasoline. Engine oil and transmission fluid coming in contact with a hot manifold can ignite. These fluids may ignite after the engine is shut off due to the loss of cooling water flowing through the engine. When the engine is shut off, the water flow ceases, and manifold temperatures may rise to a level sufficient to ignite atomized fluids or fuel vapors. 25.17.3.2 Exhaust Systems. 25.17.3.3 Cooking Surfaces. RV cooking surfaces include a range or oven, and in some cases an external BBQ or Stove. The heat is provided by burning propane. The open flame from the normally operating gas range, oven, or cooking surface can ignite common combustibles found on a RV in the same manner as would occur in a structure. The same analysis used in a structure should be used in a RV when a cooking surface is considered as a source of ignition. A further discussion on appliances can be found in Chapter 16. 25.18 Vehicle Identification. Recreational Vehicles, possess unique identifiers, both unit serial numbers and VINs, which may vary, depending on the manufacturer. These are commonly located on the vehicle frame, as well as a copy in the owner’s manuals, and generally a third placard is located either in the galley cabinet or rear bedroom closet. 25.19 Fire Scene History. It is recommended that an attempt be made to develop a scenario of the events leading up to the fire, as well as the progression of the fire itself. The operator of the Recreational Vehicle, passengers, bystanders, the fire department, and police personnel should be interviewed. Most of the time, there are witnesses that have taken photos and video of the fire, and attempts should be made to obtain this important evidence whenever possible. This information may be used to assist in the investigation. 25.19.1 Actions Before the Fire. Information regarding the circumstances surrounding the RV immediately prior to the fire may be obtained from the operator or owner to determine the following: (1) Were there any problems with the Recreational Vehicle (i.e. operational issues, electrical issues, modifications, servicing, etc.) (2) When the recreational vehicle last serviced e.g.: oil change, repairs (3) When the recreational vehicle last fueled, including the amount and type of fuel (propane, gasoline, diesel) (4) Who was the last person to be inside the RV (5) When the last time the boat was observed prior to the fire (6) What aftermarket equipment was installed on the boat (e.g., Handsfree Cellphone, Radio, CB, GPS, Satellite Receiver, Solar Panels, etc) (7) Was the vehicle loaded with Personal items that were present on the boat (e.g., clothing, tools, recreational items, fishing gear, skis) (8) What appliances or systems were on in the RV at the time of the fire? (9) Were any recalls received by the owner concerning the RV or a component or appliance? (10) Were the repairs that were specified in the recall completed? 25.19.2 Actions During the Fire. If the recreational vehicle was being driven at the time of the fire, the following information may assist in the investigation: (1) When the recreational vehicle was last operated and for how long (2) The route (3) Water and weather conditions (x) What speed and transmission gear was the vehicle in (x) Was there a tow vehicle involved at the time (year/make/model/fully fuelled?) (4) When and where the odor, smoke, or flame was first noticed (5) Actions taken by the operator when the fire was first noticed (e.g., actions if any were taken to extinguish the fire, power disconnection, propane disconnection, if and when public officials were notified) (x) What appliances were in operation at the time? (7) The length of time the fire burned prior to help being summoned as well as when help arrived (8) The estimated time the fire burned until help arrived and was extinguished (9) What suppression methods were used (fire extinguishers, water, foam) (10) Other observations 25.19.3 Actions After the Fire. Information regarding actions or events after the fire may assist the investigator. Those may include the following: (1) Information regarding recovery operations if applicable (raising, towing, etc.) (2) Actions of salvage crews to recover pieces at scene (DOT actions, Towing Companies, Fire Crews, etc.) (3) Actions and location of occupants and fire victims (4) Actions taken by other public officials (5) Other investigations conducted post fire by other parties 25.19.4 Recreational Vehicle Information. There are many different sources available to the investigator to assist in origin and cause determination. Such sources include but are not limited to sales brochures, owner’s manuals, and Internet web sites such as that of the specific manufacturer of the unit. Floor plans and options can be found on the Internet from general public sales sites. 25.19.4.1 As with all the other types of inspections, proper background checks of prior problems, recalls, repairs, and malfunctions should be obtained. In some cases, appliances designed for residential uses, such as a refrigerator or a furnace, will be placed in a recreational vehicle as a replacement for the original item. Often, these items require different clearances and power supplies to operate properly. 25.20 Recreational Vehicle Examination. On RVs, tolerances and clearances designed into the coach are sometimes critical, depending on the system. Any examination and documentation of any evidence, including the removal and securing of items of evidence, must be performed in accordance with the guidelines specified in Chapter 16 and the ASTM standards presented in Annex A of this document. If improperly removed, the investigator may destroy key pieces of evidence and information relevant to a potential cause. (See Section 16.3.) 25.20.1 General. Because Recreational Vehicles are a unique hybrid of a vehicle and residence, utilizing unique construction materials and methods, one of the most important aspects of any investigation is that the investigator needs to have at least a basic familiarity of the systems and associated subsystems of the unit. As with any other fire, the first step is to determine an area of origin. Recreational Vehicles can be divided into Interior/Exterior and six major compartments. The compartments are the engine compartment, basement compartments, the cabin quarters, the galley, the lavatory, and the bedroom. The size, construction, and fuel load of these compartments can vary considerably depending upon the size of the vehicle and manufacturer. 25.20.1.1 Examination. 25.20.1.1.1 Examination of the exterior of the recreational vehicle may reveal significant fire patterns. Caution should be exercised when interpreting patterns around the refrigerator, furnace, and water heater compartments, as they compartments in the RV that are ventilated and have large fuel packages, which may affect exterior fire patterns. 25.20.1.1.2 Analyzing the fire patterns can determine whether the fire spread from inside the compartment. By code, the interior of the coach is are required to be vapor resistant to the exterior. The spatial arrangements of the cabin, due to its shape and whether windows were open, may influence the fire spread characteristics. 25.20.1.1.3 Compartments typically used for sleeping, lounging, cooking, storage, lavatory, etc. also pose special consideration. These multiple configurations result in varied potential ignition sources and fuel loads. Since some of these compartments may have limited space and some are ventilated, normal structural patterns relied upon by the investigator may not be present. 25.20.1.1.4 Engine and fuel compartment fires typically are fuel vapor–related and this may consume the compartment, resulting in fire spread to the cabin and other portions of the recreational vehicle. Attention should be given to the carburetor or fuel injection systems on the engine, as well as the ignition system components, fuel delivery systems, and fuel tanks. The exhaust system should be inspected for evidence of heat failure (often due to water starvation), which may result in combustion of nearby boat components. 25.20.2 Examination of Recreational Vehicle Systems. The individual systems within the RV should be examined to determine their role, if any, in the cause of the fire using the system identifications and functions described in (25.15). 25.20.3 Switches, Handles, and Levers. During the inspection of the RV, the position of switches should be noted to determine their position. An attempt should be made to determine if any appliances were on and what doors/windows were open or closed prior to the fire. The position of the battery switches, generator, shore power transfer switch, etc., should be noted. The entry door and ignition switches should be examined, if possible, for any signs of a key, tampering, or breaking of the lock. Most of these elements are made of materials that may be easily consumed in a fire; however, there may be enough residue left to assist in the investigation. 25.21 Recreational Vehicles in Structures. 25.21.1 RVs within garages and carports should be examined with consideration of the combustibles within the garage or carport, especially when considering the origin. Heat transfer from a fire originating in the structure may ignite the boat. 25.21.2 Whenever possible, the building electrical service needs to be checked for electrical supply voltage and polarity to verify if they are consistent with the requirements of the coach and associated subsystems. Information also may need to be gathered on the shore power pedestal (date/time/who installed, service permits, etc.) One of the most commonly overlooked yet important items of evidence at the scene is the documentation of the floor of the building. Coach system operational requirements also require the coach to be parked in a generally level condition. The type of flooring the coach was parked on should be documented (gravel, dirty, concrete, etc.). The use of a angle finder should also be employed whenever possible to measure the slope at the scene to verify the specific angles of the scene. 25.21.3 Recreational Vehicle Parks/Campgrounds. Additional considerations need to be examined when dealing with incidents where the coach is parked at a park or campground. NFPA Standard 1194 is the code covering these properties. Care should be taken to make sure that all services (propane/electricity/sewer/etc) provided by the park/campground are proper. 25.22 Legal Considerations. Legal considerations during a RV fire investigation are similar to those involving other investigations and may include the right to investigate, the right to enter, and spoliation and preservation of evidence. Other legal considerations include if the vehicle was manufactured under NFPA, CSA, or another countries regulations. A full discussion on legal considerations may be found in Chapter 11. Report on Proposals – November 2010 NFPA 921 ______921-159 Log #CP9

______Technical Committee on Fire Investigations, The Committee is proposing to add a section on Hydrogen –Fueled Vehicles to read as follows: 25.16 Hydrogen-Fueled Vehicles. The investigator is cautioned to obtain information specific to the hydrogen-fueled vehicle prior to the investigation. 25.16.1* Hydrogen-Fueled Vehicle Investigation Safety. The investigator should be aware of the potential hazards associated with hydrogen vehicles, such as the extremely wide flammability range (4% - 75%), ease of ignition, and high voltage battery potential, and proceed with caution. The hydrogen systems are often maintained at high pressures. Immediately after a fire or crash, the hydrogen tank or downstream fuel system may be venting fuel. The escaping hydrogen from high pressure systems may auto-ignite. If the tank or fuel system is damaged due to a crash or fire it can result in a hazardous condition, and a hydrogen release may occur at a later time. An investigation should not commence until all venting of the hydrogen is completed or the fuel system is stabilized. Specific vehicle models may have an electronic or mechanical means for safely venting the hydrogen before commencing a vehicle fire investigation. Hydrogen has a very low ignition energy of 0.018 mJ and can be ignited by an energy source such as a static electric discharge (See Table 25.3.2). Hydrogen burns with a pale blue, almost invisible flame that can be difficult to detect. It diffuses rapidly and is lighter than air, but hydrogen has a large range of flammability that may create a safety concern where hydrogen may have collected. Ignition of hydrogen may result in an explosion under some conditions and leaks in confined spaces may be hazardous. Hydrogen vehicles can also be battery hybrids, and so all of the precautions for high voltage electrical safety from the Hybrid Vehicle section apply. 25.16.2 Hydrogen-Fueled Vehicle Description. Hydrogen-fueled vehicles may be powered by internal combustion engines or by a fuel cell powering an electric drive. 25.16.2.1 A fuel cell powered vehicle utilizes electrical power to drive the vehicle and accessories such as the air conditioning compressor and the power steering pump. The fuel cell and major electrical components are cooled by a system similar to those used to cool internal combustion engines. The surface temperatures of under-hood components are typically lower than those associated with internal combustion engine vehicles. 25.16.2.2 The manufacturer’s manuals should be consulted for fuel system configuration details. Hydrogen vehicles, parking garages, and fueling stations may have hydrogen sensors designed to set off an alarm when leaking hydrogen is detected. Some vehicle manufacturers have proposed using reformers to supply the source of hydrogen. A reformer uses chemical processes to free hydrogen from a standard fuel such as gasoline. Vehicles of this type will most likely have a gasoline fuel system as well. Hydrogen vehicles should have standardized markings as recommended by SAE J2578, with a diamond label consisting of white letters on a blue background, which caption: “CHG” or “LH2,” referring to compressed or liquid hydrogen respectively (See Figure 25.16.2.1). (add SAE J2578 to Chapter 2, Reference Publications “SAE J2578-2009 Recommended Practice for General Fuel Cell Vehicle Safety, SAE International, Warrendale, PA”)

***Insert Figure 25.16.2.2 Here*** Figure 25.16.2.2 Hydrogen Labels

25.16.2.3 Vehicles fueled with hydrogen may store the hydrogen as a high-pressure compressed gas (34.5 MPa – 69.0 MPa [5,000 psi – 10,000 psi]), in a moderate pressure tank (up to 10.3 MPa [1500 psi]) as a hydride, or in the form of a cryogenic liquid at low pressure. These storage devices and the downstream fuel system will be protected by one or more pressure relief devices (PRDs) or rupture disks. The devices may be actuated by either high pressure or high temperature resulting from a vehicle fire. There will also be one or more pressure regulators to reduce the pressure of the hydrogen provided by the storage vessel pressure to the fuel cell or the internal combustion engine. Additionally, there will be a fill line, one or more electrically actuated normally closed shut-off valves, and vent lines for the PRDs and the fuel cell exhaust. 2.3.8 SAE International Publications. SAE International, 400 Commonwealth Dr., Warrendale, PA 15096-0001 SAE J2578, Recommended Practice for General Fuel Cell Vehicle Safety, 2009.

The development of hydrogen fueled vehicles brings new potential hazards to the investigation of vehicle fires of which the investigator should be aware.

Printed on 9/18/2009 225 Report on Proposals – November 2010 NFPA 921 ______921-160 Log #CP3

______Technical Committee on Fire Investigations, The Committee is revising Chapter 26 Wildfire Investigations to read as follows: NFPA Chapter 26 Wildfire Investigations 26.1* Introduction. Wildfire investigation involves specialized techniques, practices, equipment, and terminology. While the basic principles of fire science and dynamics are the same in a wildfire, the fire development and spread is influenced by different factors such as wildland fuels, fire weather, topography, and unconfined burning. 26.1.1 The purpose of this chapter is to identify and explain those aspects unique to wildfire investigation. This chapter is intended as a basic introduction and the user is urged to consult the reference material listed in Annex A and B. As with other types of fire investigation covered in this guide, specialized personnel may be needed to provide technical assistance. 26.2 Wildfire Fuels. Keen observation of variations in wildfire fuels is essential to accurately analyze fire behavior. 26.2.1 Fuel Condition Analysis. In a wildland, great differences exist in the character of flammable materials. Deep duff, newly fallen dead leaves, clumps of grass, litters of dry twigs and branches, downed logs, low shrubs, green tree branches, hanging moss, snags, and many other types of material are present. Each of these materials has distinctive burning characteristics. The flammability of a particular fuel matrix is governed by the burning characteristics of individual materials and by the combined effects of the various types of materials present. 26.2.1.1 Before fuel condition can be analyzed, the physical characteristics of combustible wildland materials must be classified. Such a classification permits the identification of the fuel factors that influence flammability. After the fuel has been classified properly, topographic and weather factors must be considered before the rate of spread and the general behavior of fires in that fuel can be determined. 26.2.1.2* Forest fuels are varied and complex therefore it is necessary to develop a systematic approach to fuel condition analysis. First, the fuel matrix is subdivided into three broad vertically arranged categories: ground, surface, and aerial fuels. Wildland fire investigators must concern themselves with how fuels are stratified, their physical characteristics, and the fuel quantity in the general origin area to determine the fire behavior context. Within these broad categories, fuels are broken down into four major fuel groups. These groups are described as grass, shrub, timber litter, and logging debris. Each group is further divided into fuel-type models that are an identifiable association of fuel elements for distinctive species, fuel form, size, and arrangement. These characteristics determine a predictable rate of spread or resistance to control under specified weather conditions. Finally, fuels are also classified according to their size as it relates to their fuel moisture retention characteristics. Dead fuels are grouped according to 1, 10, 100 and 1000 hour time lag fuels and living fuels are grouped as herbaceous (either annual or perennial) or woody. 26.2.2 Ground Fuels. Ground fuels include all flammable materials located between the mineral soil layer and the ground surface. These fuels typically include twig, leaf and needle litter, and decomposing vegetation such as duff, peat moss, buried limbs and roots. Buried limbs and roots can burn along their entire length and ignite a surface fire in a different location. When sufficiently dry, ground fuels can be a very receptive fuel bed for a wide variety of ignition sources due to their high surface area-to-volume ratio. They can also smolder for long periods of time before transitioning to open flame. Ground fuels by themselves are not typically associated with rapid fire progression; however they can contribute to significant long term fire residency, depending upon the depth of the materials. 26.2.2.1 Duff. Duff seldom has a major influence on the spread rate of fire because it is typically moist and tightly compressed so that little of its surface is freely exposed to air, and its rate of combustion is slow. In forest fires, most of the duff is consumed down to mineral soil. Occasionally, duff contributes to the rate of spread by furnishing a path for the fire to creep along between patches of more flammable material. 26.2.2.2 Roots. Roots are not an important factor in rate of fire spread, as the greatly restricted air supply prevents rapid combustion. However, fires can burn slowly in roots. Some fires have escaped control because a root provided an avenue for the fire to cross the control line. Large roots from dead and partially decayed vegetation will more readily spread fire than the roots of live vegetation. 26.2.3 Surface Fuels. Surface fuels are those flammable materials located from the surface of the ground to approximately 2 m (6 ft) above the surface. Surface fuels include grasses, leaves, twigs, needles, field crops, slash and downed limbs. Surface fuels in the one-hour time lag fuel moisture category are the most common materials first ignited. Surface fuels contribute to rapid fire propagation and the rate of fire spread. They also serve as the primary fuel ladder to aerial fuels. 26.2.3.1 Fine Dead Wood. Fine dead wood consists of twigs, small limbs, bark particles, and rotting material. Normally,

Printed on 9/18/2009 226 Report on Proposals – November 2010 NFPA 921 the fine dead wood classification is confined to material with a diameter of less than 25.4 mm (1 in.). These fuels are included in the 1 and 10 hour time lag fuel category. These fine dead surface fuels are among the most important of all materials influencing the rate of fire spread and general fire behavior in forest areas. Fine dead wood ignites easily and often provides the main avenue for carrying fire from one area to another. It is the kindling material for larger, heavier fuels. 26.2.3.1.1 In areas where a great volume of fine dead wood exists, a fire can rapidly develop tremendous heat. The greatest volume of fine dead wood is usually found in areas containing logging slash. Under dry conditions, fires in such areas burn violently, and the strong convection currents created by the intense heat pick up burning embers and carry them out ahead, causing spot fires beyond the main fire front. 26.2.3.1.2 Granulated dry rotten wood, while not an especially important factor in the rate of fire spread, is a highly ignitable fuel. Embers from the main fire often cause spot fires in rotten wood lying on the ground or in hollow places on old logs or stumps. 26.2.3.2 Dead Leaves and Coniferous Litter. As leaves and coniferous litter decay on the ground, they gradually become part of the duff layer. Before this decay takes place, however, leaves and coniferous litter are a highly flammable material and should be considered surface fuels not ground fuels. In many forests, lower level surface fuels may be composed primarily of needles dropped from coniferous trees. Ponderosa pine needles, for example, are extremely flammable because their large size and shape create a jumbled arrangement, allowing free circulation of air. Smaller needles, like those of Douglas fir, generally burn less intensely, as they are more tightly compacted. 26.2.3.2.1 Needles that are still attached to dead branches are especially flammable because they are exposed freely to air and are not typically in direct contact with the more moist material on the ground. Needles remaining on fallen limbs form highly combustible kindling for larger material. For this reason, logging slash containing dry needles is dangerous fuel. 26.2.3.3 Grass. Grass, weeds, and other small annual or perennial plants are important surface fuels that influence rate of fire spread. The key factor in these fuels is the degree of curing. Succulent green grass acts as a fire barrier. During the course of a normal fire season, however, grass gradually becomes drier and more flammable as the plant cures or as the stems and leaves die due to lack of moisture. At this time, the grass cover becomes easily ignitible. Cured grass, if present in a large and uniform volume, becomes the most flammable, fastest spreading surface fuel. Grass and other small plants occur on the floor of almost all forests. Fire investigators need to determine the volume and continuity of the grass cover. In dense forests where little sunlight reaches the ground, very little grass is found. In more open forests, such as in mature stands of pine, there may be a large amount of grass fuel. If there is a more-or-less continuous cover of dry grass on the forest floor, the spread rate of a fire will be governed largely by that cover, rather than by the heavier fuels normally associated with a forest. Fires in dry grass often have high rates of spread. 26.2.3.4 Downed Logs, Stumps, and Large Limbs. Heavy fuels, such as downed logs, stumps, and large limbs comprise the 100 and 1000 hour time-lag fuel category and therefore require long periods of hot, dry weather before they become highly flammable. When such material reaches a dry state, however, high intensity fires may develop. The most dangerous heavy fuels are those containing stringers of dry wood, or many large checks and cracks. Smooth-surfaced material is less flammable, as it dries out more slowly, has little surface exposed to air, and contains less attached kindling fuel. 26.2.3.4.1 Sustained high intensity fires may develop in piles of downed logs and large limbs or in crisscrossed windfalls, as the various fuel components radiate heat to each other. Isolated individual limbs and logs will not burn very intensely unless the fire is supported by large accumulations of fine dead wood. 26.2.3.5 Low Brush and Reproduction. Low brush, tree seedlings, and small saplings are classified as surface fuels. This understory vegetation may either accelerate or slow down the spread rate of a fire. During the early part of a fire season, the shade normally provided by understory vegetation prevents other surface fuels from drying out rapidly. As the season progresses, however, continued high air temperature and low relative humidity dry out both the fuel lying on the ground and the understory vegetation. When this happens, most of the low vegetation, particularly small coniferous trees, become contiguous fuel that sustains fire spread. 26.2.3.5.1 The understory vegetation in a forest often provides a link between surface fuels and aerial fuels. The crowns of small trees may catch fire and, in turn, spread the fire to aerial fuels in the forest canopy. Either thickets of tree reproduction or dead brush may provide the first means for a surface fire to flare up and spread into the crowns of the overstory trees. 26.2.4 Aerial Fuels. Aerial fuels are those flammable materials located from approximately 2 m (6 ft) above the surface to the crowns of the canopy. These fuels include tree branches, leaves, needles, snags, moss, and tall brush. These fuels are only infrequently the materials first ignited and typically require significant amounts of heat from surface fuels. Combining steep slopes and/or higher wind speeds can easily transition the fire to a running crown fire. Aerial fuels can contribute to rapid fire spread, primarily through the generation of aerial firebrands. Printed on 9/18/2009 227 Report on Proposals – November 2010 NFPA 921 26.2.4.1 Tree Branches and Crowns. The live needles of coniferous trees are a highly flammable fuel. Their arrangements on the tree branches allow free circulation of air. In addition, the upper branches of trees are more freely exposed to wind and sun than many surface fuels. These factors, plus the volatile oils and resins in coniferous needles, make tree branches and crowns important components in aerial fuels. 26.2.4.1.1 Tree branches and crowns are fuels that can ignite quickly with decreased relative humidity. Crown fires seldom occur when relative humidity is high. However, coniferous needles dry out quickly when exposed to hot, dry air. The dryness of needles is influenced by the transpiration process in a tree. When the ground is moist, trees release a large amount of moisture into the air through the leaves. As the ground becomes drier, the transpiration process slows, and, as a result, leaves and branches become drier and more flammable. 26.2.4.1.2 Dead branches on trees are an important aerial fuel. Concentrations of dead branches, such as those found in insect or disease killed stands, may enable fire to spread from tree to tree. Concentrations of dead branches on the lower trunks of trees may provide an additional avenue for fires to spread from surface fuels to aerial fuels. The most flammable dead branches are those still containing needles. 26.2.4.2 Tree Moss. Moss hanging on trees is the lightest and the most apt to ignite of all aerial fuels. Moss is important principally because it provides a means of spreading fires from surface fuels to aerial fuels or from one aerial component to another. Like other light fuels, moss reacts quickly to changes in relative humidity. During dry weather, crown fires may develop easily in heavily moss-covered stands. 26.2.4.3 High Brush. Crowns of high brush, above 2 m (6 ft.), are classified as aerial fuels because they are separated distinctly by distance from ground and surface fuels. In many forest regions, heavy stands of brush may develop in old burns, and they often form the principal vegetative cover in such areas. Crown fires in brush fuels ordinarily do not occur unless heavy surface fuels are present to develop the required heat. In some brush stands, however, a high proportion of dead stems may create a sufficient volume of fine dead aerial fuels to permit very hot and fast spreading crown fires. Key factors in evaluating the behavior of fires in high brush are volume, arrangement, the general condition of surface fuels, and the presence of fine dead aerial fuels. 26.2.5 Species. The species of vegetation involved can determine the rate of spread and intensity of the fire. Each type of vegetation has different characteristics, that is, size, moisture content, shape, and density 26.2.6 Fuel Size. A major factor governing both the ignitibility and burning rate of a fuel is its diameter. The smaller the fuel element (surface area-to-mass ratio), the easier it will be to ignite and the faster it will be consumed. These smaller fuels are classified as fine fuels and are comprised of such items as seedlings and small trees, twigs, dry grass, brush, dry field crops, and pine needles and cones. Larger-diameter fuels, classified as heavy fuels, are much more difficult to ignite, and burn at slower rates than that of light fuels. Most often, it requires burning light fuels to serve as kindling to ignite the heavier fuels. Some examples of heavy fuel classifications are large-diameter trees and brush, large limbs, logs, and stumps. 26.2.7 Fuel Moisture Content. The amount of moisture present in the fuel plays a major role in determining the ignitibility and the rate of fire spread. As the vegetation (fuel) dries out, it becomes more readily ignitible and will burn with greater intensity. Green vegetation, or vegetation having high moisture content is more difficult to ignite and will burn more slowly due to the moisture within the vegetation requiring more heat to evaporate that moisture. Once the moisture is evaporated, the temperature will continue to rise to the fuel’s ignition temperature. The moisture content of the fuel will vary, depending on the type and condition of the vegetation, solar exposure, weather, and geographic location. Fuel moisture content in dead fuels is rated by four broad time lag categories. This is an indication of the rate a fuel gains or loses moisture due to changes in its environment, or the time necessary for a fuel particle to gain or lose approximately 63 percent of the difference between its initial moisture content and its equilibrium moisture content. Dead fuels are grouped into four classes based on their size: 1-hour fuels: up to ¼ inch in diameter; 10-hour: ¼ to 1 inch in diameter; 100-hour:1 to 3 inches in diameter; and 1000-hour: 3 to 6 inches in diameter. 26.2.8 Oil Content. The presence of oil within vegetation typically increases the fuel’s ease of ignition, fire intensity, and spread factors. 26.3 Weather. Weather plays a substantial role in the behavior of wildfires. Weather elements can be described as the state of the atmosphere with respect to atmospheric stability, temperature, relative humidity, wind velocity, cloud cover, and precipitation. 26.3.1 Weather History. An important item to consider during an investigation is the weather history. Weather history is a description of atmospheric conditions over the preceding few days or several weeks. Weather elements should be analyzed to determine what influences they may have had on the fire’s ignition and burning characteristics. 26.3.2 Temperature. The temperature of the ambient air directly influences the temperature of the fuel. The sun is one factor that affects temperature. As the radiant solar energy of the sun heats the ground and vegetation, the fuel becomes more susceptible to ignition. Temperature differences of more than 10°C (18°F) can occur between shaded areas and areas exposed to direct sunlight. Another factor influencing temperature is altitude. The lower air pressure at high altitudes allows the air to expand and cool. Printed on 9/18/2009 228 Report on Proposals – November 2010 NFPA 921 26.3.3 Relative Humidity. Humidity is the measure of water vapor in the air. Humidity is usually expressed as relative humidity, which is the ratio of the amount of moisture in the air to the amount that known volume of air at a particular temperature can hold, expressed as a percentage. The moisture in the air directly affects the amount of fuel moisture and vice versa. Dry air will draw moisture out of the vegetation, making it more susceptible to fire. Fine fuels are more responsive to relative humidity than are large fuels. If the air has a high relative humidity, the vegetation will take in some of that moisture, making it less susceptible to ignition, or the moisture may slow the rate of spread of a fire in progress. Warm air can hold more water than can cool air. This is illustrated by early morning dew. As the night air cools, the air loses its ability to hold moisture. The moisture condenses at the air’s dew point and forms the dew. 26.3.4 Wind Influence. Wind greatly affects the speed at which a fire will spread. Wind pushes the flame ahead, resulting in a preheating of the fuel. The wind also assists in drying out vegetation, increasing the ease of ignition. Wind further results in the creation of airborne firebrands, carried aloft by the heated convective air column. The accompanying fire wind can blow embers and hot sparks ahead of the main fire to ignite secondary fires in areas of unburned fuel. The different types of wind influencing fire behavior are classified as meteorological, diurnal, foehn, and fire winds. 26.3.4.1 Meteorological Winds. Meteorological winds are caused by atmospheric pressure differentials in upper level air masses that generate regional weather patterns. The earth’s rotation, oceans, and topographic features create these major air movements to form wind and pressure belts. 26.3.4.2 Diurnal Winds. Diurnal winds are formed by solar heating and nighttime cooling. As air warms during daytime, the rising air creates upslope and up valley winds. When air cools after sunset, this denser, heavier air sinks and causes downslope and down valley winds. 26.3.4.3 Foehn Winds. Foehn winds are a dry, downslope wind that is formed as a result of air flow between pressure gradients. As the air flows downhill, it is accelerated by gravity and is heated through the process of adiabatic compression. Foehn winds can raise temperatures by as much as 300 C (540 F) and drop relative humidity significantly in just a matter of hours. These winds are also frequently channeled through mountain passes and drainages which further increases their velocity. It is not uncommon to see wind speeds in excess of 70 mph associated with this phenomenon. In the western United States, the most well known Foehn winds are the Santa Ana in Southern California and the Chinook winds associated with the Rocky Mountains. 26.3.4.4 Fire Winds. Fire winds are caused by the fire itself. These winds are the result of the rising expanding fire plume. Fire winds influence the spread of the fire. 26.4 Topography. Topography relates to the form of natural or man-made earth surfaces. Topography affects the intensity and spread of a fire. Winds, as well, are greatly affected by the topography of the land. 26.4.1 Slope. The slope of an area is determined by measuring the rise over run, or the change in elevation over a given distance. Zones on a given slope are often described as top third, middle third, and bottom third. Slope allows the fuel on the uphill side to be preheated more rapidly than if it were on level ground as the distance between the flame and the fuel is decreased. This allows the fire to burn with more intensity and speed. Wind currents, which prevalently move uphill during the day, can accelerate the fire uphill. Slope may also result in burning debris rolling down the hill, starting spot fires below the primary fire and across control lines. 26.4.2 Aspect. The aspect of the slope is the compass direction in which the slope faces. This is an important consideration because solar heating on the fuel and ground surface raises the potential for ignition and increases the rate of spread. Slopes facing the sun are typically drier, and they may have a more combustible fuel type or character of vegetation resulting in a greater ease of ignition and faster spread. Sun angle and the amount of radiant energy a particular area receives daily or over a season has a direct affect on forest fuels. 26.5 Fire Shape. The parts of a wildland fire are generally described in relation to the type of fire spread occurring at that portion of the perimeter as illustrated in Figure 26.5. 26.5.1 Fire Head. The portion of a fire that is moving most rapidly is called the fire head. The direction the local wind is blowing while the fire is burning primarily determines the route of the head’s advance, subject to influences of slope and other topographic features. Large fires burning in more than one drainage or fuel type can develop additional heads. The head is generally the area of most rapid fire spread and greatest fire intensity. Fire spread at the head of the fire is referred to as advancing fire.

FIGURE 26.5. Anatomy of Fire Showing Fire Head and Heel (Rear).

26.5.2 Fire Flanks. The fire flanks are located on either side of the head. These are the parts of a fire's perimeter that are roughly parallel to the main direction of fire spread. Fire progression on the flanks of the fire is characterized by less intense fire behavior than at the head of the fire. Fire spread on the flanks of the fire is referred to as lateral fire. 26.5.3 Fire Heel. The fire heel is located at the opposite end of the fire from the head. The fire at the heel is less intense and is easier to control. Generally, the fire at the heel will be backing or burning slowly against the wind or Printed on 9/18/2009 229 Report on Proposals – November 2010 NFPA 921 downslope. Fire spread at the heel of the fire is referred to as backing fire. 26.5.4 Factors Affecting Fire Spread. There are numerous factors to be considered when assessing the shape of a wildland fire in order to help locate the general origin area. The major factors are the wind speed, wind direction and the slope. These factors relate directly to the resulting speed and direction of fire spread and create the largest fire effects resulting in the easiest indicators to read. 26.5.4.1 Lateral Confinement. When wildfires are confined by landforms such as gullies, ravines, or narrow valleys, convective heating by confined gases and radiation feedback from flames and burning vegetation increases the heat release rate of the burning fuels. Rapid fire spread is also enhanced by the acceleration and channeling of wind through these topographical features. These factors may result in a more rapid combustion and spread than that of an unconfined vegetation fire. 26.5.4.2 Fuel Influence. Following wind and slope, fuel type and characteristics provide the third greatest influence on the rate of spread and fire intensity. 26.5.4.3 Suppression. Fire suppression is the combination of all activities that lead to the extinguishment of the fire. Suppression includes everything from the initial stage of fire discovery to the final stage of completely extinguishing the fire. Protection by fire crews of potential areas of origin is of extreme importance in establishing the fire origin and cause. It may be useful for the investigator to review and analyze the fire suppression tactics and their effects on spread to assist in identifying the fire origin. 26.5.4.3.1 Fire Breaks. Fire breaks, fire lines, or control lines are any natural or man-made barriers used to slow, stop, or reroute the direction of the fire spread by separating the fuel from the fire. Natural fire break examples are bodies of water, cliffs, and areas lacking vegetation or areas where the fuel moisture is higher than that of surrounding area. Examples of man-made breaks include roads, fire lines, pre-burned areas, and barriers of water, retardant, or foam. 26.5.4.3.2 Air Drops. An air drop is the aerial application of water or retardant mixture directly onto the fire, onto the threatened area, or along a strategic position ahead of the fire to stop or slow the spread of fire. Air drops may alter fire indicators in or near drop zones. 26.5.4.3.3 Firing Out. Firing out is the process of burning the fuel between a fire break and the approaching fire to extend the width of the fire barrier. These fires are normally started at a fire control line (normally on the downwind side of the fire) and are burned back toward the leading edge of the fire. Several different sources of ignition are used, including drip torches, fusees, matches, and helitorches. 26.5.5 Other Natural Mechanisms of Fire Spread. The direction and rate of fire spread may be altered by natural or self-induced means. 26.5.5.1 Embers and Firebrands. Embers and firebrands can be lofted by the convective column and fall out or be blown by wind into unburned fuel great distances from the original fire. These embers often start new fires outside the perimeter of the main fire. These new fire origins are referred to as spot fires. Care should be taken to distinguish spot fires from possible independent fires unassociated with the main fire. 26.5.5.2 Fire Storms. A fire storm is an intense and violent fire created by strong convective winds produced by a large plume associated with atmospheric instability. The indrafts created by the fire’s convection column may be strong enough to uproot vegetation and propel small rocks. One characteristic of a fire storm is the tornadic fire whirls, which accompany the powerful indrafts. 26.5.5.3 Animals. Animals and birds can spread fire from flaming fur or feathers. Animals have been set afire accidentally and deliberately to start a wildfire. Burned animals that are fire victims can start fires in unburned areas during their flight. A bird’s feathers or an animal’s fur can be ignited by contact with power lines and can start a wildfire when the electrocuted body falls to the ground. 26.6 Indicators. The indication of the direction of a fire’s spread is imprinted on partially burned fuels and noncombustible objects. These visual fire effects may include differential damage, char patterns, discoloration, carbon staining, shape, location, and condition of residual unburned fuel. Analysis of the directional pattern shown by multiple indicators in a specific area will identify the path of fire spread through this site. By applying a systematic approach to backtrack the spread of the fire, the investigator can retrace the path of the fire to the point of origin.

FIGURE 26.6 Anatomy of Fire Showing Fire Head and Heel (Rear). (Old Figure 26.3.3, not shown)

26.6.1 Wildfire V-Shaped Patterns. Wildfire V-shaped patterns are horizontal ground surface burn patterns generated by the fire spread. When viewed from above, they are generally shaped like the letter “V.” These are not to be confused with the traditional plume-generated vertical V patterns associated with structure fires. These V-shaped patterns are affected by wind direction, and/or the slope on which the fuel is located. As the fire spreads in the direction of the wind or up a slope, the widening legs of the V are created. The width of the pattern increases as the fire advances from the area of ignition. The origin of the heat source that created the pattern often is found at or near the base or most narrow point of the pattern. Therefore, the analysis of these horizontal V-shaped patterns can be useful in identifying a general Printed on 9/18/2009 230 Report on Proposals – November 2010 NFPA 921 location of the fire origin.

***Insert Figure 26.6.1 Here*** FIGURE 26.6.1 V-Shaped Pattern

26.6.2 Degree of Damage. The degree of damage to a fuel is an indication of the fire’s intensity, duration, and direction. Leaves, branches, and limbs will show greater damage on the side from which the fire approached. This is one of the useful indicators in determining the direction of advancing fire spread. Also, items lying on and protecting fuels leave a pattern that can assist in locating the origin. Vegetation on the side of an object exposed to an oncoming fire front will be burned away, while the basal stems of vegetation adjacent to the reverse (shielded) side will remain only partially burned. Also, items lying on and protecting fuels leave a similar pattern on residual vegetation. This indicator is closely related to the indicator discussed in Exposed and Protected Fuels.

***Insert Figure 26.6.2 Here*** (Old Figure 26.4.3 Revised Title) FIGURE 26.6.2 Degree of Damage

26.6.3 Grass Stems. The charred remains of grass stems left in the fire’s wake will have different appearances depending upon the direction of the fire’s travel. In advancing fire areas, the flames will attack the stem from the top and burn them to ground level, completely consuming all but the very base of the stem. Advancing areas are typically characterized by an absence of residual stems. Grass that grows in clumps may not be entirely consumed, showing protection on the side opposite the direction the fire came from. When this occurs in advancing areas, the residual basal stalks in the clump may show an angle of char that is steeper than the slope and exhibit cupping on the tips, with the low side of the cup on the side facing the direction the fire came from. In areas of backing fire spread, and occasionally in the lateral areas, the flames will first attack the stalk at the base, toppling the remainder of the stalk into the burned area as shown in figure 26.4.3. The remaining grass heads will point generally in the direction the fire came from.

FIGURE 26.6.3 An Example of Grass Stems Indicating the Direction of Backing Fire Movement (left to right).

26.6.4 Angle of Char. Angle of char indicators are divided into two groups based on the types of fuels they occur in. Angle of char can occur in pole type fuels (tree trunks, utility poles, fence posts, etc.) or in the foliage crowns of brush or timber type fuels. 26.6.4.1 Angle of Char, Pole Type Fuels. Standing, pole type fuels are burned at an angle that corresponds to the flame angle and height associated with the area of fire progression. Reliability is generally greater on individual specimens in open canopy settings. On pole-type vertical fuels, an eddy vortex creates flame-wrap on the side opposing the oncoming fire, leaving a characteristic angle of char. On fires backing against the wind or down slope, the char angle will be parallel to the slope angle, see Figure 26.6.4.1 (a). Accumulation of debris may cause char up the side of the tree above the debris, but it will have little effect on the char pattern around the rest of the tree. A fire advancing with the wind or upslope will exhibit a char pattern that is steeper than the slope, see Figure 26.6.4.1(b).

FIGURE 26.6.4.1(a) A Fire Burning Uphill or with the Wind, Creating Char Patterns That Slope Greater Than the Ground Slope. (Old Figure 26.4.5.1(a), not shown)

FIGURE 26.6.4.1(b) A Fire Burning Downslope or Against the Wind, Creating Char Patterns That Are Even or Parallel to the Ground Slope. (Old Figure 26.4.5.1(b), not shown)

26.6.4.2 Angle of Char, Foliage Crown. On foliage crowns, the flaming front will consume or char fuels at an angle that is consistent with the fire's direction of travel. Backing fire will leave angle of char patterns parallel to the slope. Advancing fire will leave angle of char steeper than the slope due to the flame front entering low on the exposed side and exiting high on the back side see Figure 26.6.4.2(a). Height of char angle is often correlated to fire intensity. This pattern is best viewed from the side of the object. Figure 26.6.4.2(b) shows the typical effect on the crown of trees or brush as a fire starts at point “A” and moves out, slowly building up heat and speed. At the point of origin (point A), the fire is still relatively cool as surface fuels are burned, but the tree’s crown is left mostly intact. Farther from the point of origin, the fire has become more intense, and more crown is burned. All the crowns may be burned as the fire intensifies. Printed on 9/18/2009 231 Report on Proposals – November 2010 NFPA 921

***Insert Figure 26.6.4.2(a) Here*** (Old Revised Figure 26.4.5.1(c)) FIGURE 26.6.4.2(a) An Example of Char Patterns Created by the Way a Fire Moves Through Trees and Brush.

FIGURE 26.6.4.2(b) Progressive Crown Burning from the Point of Origin (Point A) (Old Figure 26.4.5.2, not shown)

26.6.5 White Ash Deposit. White ash can be the byproduct of combustion. More white ash will be created on the sides of objects exposed to greater amounts of heat and flame. Ash is often dispersed downwind and deposited on the windward sides of objects. Ash can also be used to reconstruct probable fuel volumes. Fuels facing the advancing fire will appear lighter on the side facing the oncoming fire and darker on the side opposite the direction the fire came from. Ash indicators can begin to quickly degrade and lose reliability after only a few hours or when exposed to moisture or high winds. White ash deposits on tree boles will be on the side facing the oncoming advancing fire. By comparing and contrasting the two opposing sides, the investigator can distinguish the side facing the oncoming fire as it has more white ash present. White ash can also reveal the direction of fire travel in grass fuels. White ash can remain on the exposed sides of grass stems and clumps. When looking in the direction the advancing fire spread, the burned area will appear lighter. When viewed looking back towards the area the fire came from, the burned area will appear darker. 26.6.6 Cupping. Cupping is a concave or cup-shaped char pattern on grass stem ends, small stumps and the terminal ends of brush and tree limbs. Limbs and twigs on the side facing the oncoming fire will have their tips burned off by the approaching flames leaving a rounded or blunt end. On the opposing side, twigs and limbs will be exposed to flames from underneath, along the base to the terminal end, creating a tapered point. Therefore, in advancing areas of the fire, twigs and limbs on the side opposite the direction the fire came from will show a sharply pointed or tapered end. Limbs of the brush or tree on the side facing the oncoming fire will usually be blunt or rounded off., as shown in Figure 26.4.6. Stumps, terminal ends of upright twigs and the remains of grass stems can also exhibit a tapered point, with the sharp end on the non-exposed side. The low side of the cup will face the oncoming fire. This indicator is usually not associated with backing areas of the fire, except in areas of steep slopes or under high wind conditions. Partially charred branch tips may sometimes be found on the ground on the oncoming fire side of brush and small trees, where they have fallen after being burned off. Large diameter stumps and limbs should not be considered when using this indicator due to their longer term fire residency.

***Insert Figure 26.6.6 Cupping Here*** FIGURE 26.6.6 Cupping

26.6.7 Die-Out Pattern. As a fire enters different fuel types, areas where there is increased fuel moisture or other locations where conditions cause a decrease in rate of spread and intensity, progress may slow or the fire may self extinguish. These areas will exhibit fingers and islands of unburned or partially burned fuels. This pattern is most often associated with the lateral and backing areas of the fire, however these areas should not be assumed to be the origin of the fire. These areas may be useful as macro-scale indicators to establish general fire progression. 26.6.8 Exposed and Protected Fuels. A non-combustible object or the fuel itself shields the unexposed side of a fuel from heat damage. Fuels will be unburned or exhibit less damage on the side shielded from the advancing fire. Look for charring, staining, white ash and clean burn lines on exposed sides of fuels and non-combustible objects. Compare and contrast to the opposing sides of objects. Lift or remove objects to detect the exposed and protected fuels. Objects resting on top of ground and surface fuels will protect the fuels on the unexposed side. Surface fuels on the exposed side will exhibit a clean burn line see point "A" in Figure 26.6.8. Surface fuels on the protected side will appear ragged and uneven, see point "B" in Figure 26.6.8.

FIGURE 26.6.8 A Clean Burn Line on the Front Side (Point A) and a Ragged Burn Line (Point B) on the Other Side, Showing That the Fire Moved from Point A to Point B. (Old Figure 26.4.6.1(b), not shown)

26.6.9 Staining and Sooting. Staining is caused by hot gases, resins and oils condensing on the surface of objects. This occurs most commonly with non-combustible objects such as metal cans, glass bottles, or rocks. Stains will appear on the side of the object exposed to the flames as shown in Figure 26.6.9.(a). These yellow to dark brown stains will often feel tacky to the touch and may be covered with a thin layer of white ash. Closely related to staining is sooting. Carbon soot is caused by incomplete combustion and the natural fatty oil content in some vegetation. Carbon soot is Printed on 9/18/2009 232 Report on Proposals – November 2010 NFPA 921 typically more heavily deposited on the side facing the approaching fire. Soot will be deposited on the side of fence wires facing toward the origin and can be detected by rubbing your fingers along the wire. On larger objects, soot deposits can also be noticed by rubbing your hand across the surface. In many cases there will be other indicators, such as protected fuel or staining. When checking a wire fence for soot, check the lower wires as they will show more evidence of soot than higher wires as shown in Figure 26.6.9(b).

FIGURE 26.6.9(a) Staining (Shaded Area) of Noncombustible Objects by Vaporized Fuels and Minute Particles Carried by the Fire. (Old Figure 26.4.6.2(a), not shown)

FIGURE 26.6.9(b) Soot Deposited on the Side of Fences Facing the Approaching Fire. The soot can be noticed by rubbing a hand along the wire. (Old Figure 26.4.6.2(b), not shown)

26.6.10 Depth of Char. Char on limbs, trunks, and finished lumber products exhibit a fissured or scale-like appearance. Wood materials lose mass and shrink as they burn, forming a scale-like surface. Compare and contrast the amount of charring on all sides of the object. The side with the deepest charring will typically be on the side facing the oncoming fire. Figure 26.6.10 shows that the char on the fence posts is deeper on the exposed side, as indicated by the arrow. This means that the fire moved from left to right.

FIGURE 26.6.10 Greater Depth of Char on Side of Fencepost, Indicating the Fire Moved from Left to Right. (Old Figure 26.4.6.1(c), not shown)

26.6.11 Spalling. Spalling will appear as shallow, light-colored craters or chips in the surface of rocks within the fire area. They will usually be accompanied by slabs or flakes exfoliated from the surface of the rock. Spalling is caused by a breakdown in the tensile strength of the rock’s surface that has been exposed to heat. Spalling is generally associated with advancing fire areas and will appear on the side of the rock exposed to the flames.

***Insert Figure 26.6.11 Here*** FIGURE 26.6.11 Spalling

26.6.12 Foliage Freeze. When leaves and small stems are heated, especially in the advancing areas of the fire, they tend to become soft and pliable and are easily bent in the direction of the prevailing wind or drafts created by the fire. They often remain pointed in this direction (freeze) as they cool following the passage of the flame front. While this indicator is almost always an accurate reflection of wind direction at that precise point, it may not always coincide with fire direction. Validate freezing indicators with other indicator categories nearby to confirm the fire’s direction.

***Insert Figure 26.6.12 Here*** FIGURE 26.6.12 Foliage Freeze

26.6.13 Curling. Curling occurs when green leaves curl inward toward the heat source. They fold in the direction the fire is coming from. This usually occurs with slower moving, lighter burns associated with backing and lateral fire movement.

***Insert Figure 26.6.13 Here*** Figure 26.6.13 Curling

26.7 Origin Investigation. The first objective of a wildfire investigation is to identify the area of origin. Considering the factors of wind, topography, and fuels, the origin is normally located close to the heel or rear of the fire.

***Insert Figure 26.7 Here*** Figure 26.7 Anatomy of Origin Area

26.7.1 Initial Area of Investigation. The initial area of investigation can be determined from information from first-arriving fire fighters and eyewitnesses. The fire fighters and witnesses can verify the location and size of the fire during its early involvement. These accounts will assist the investigator in narrowing down the search area. 26.7.1.1 Observations of Reporting Parties. The reporting party or parties may have seen the fire at an early stage and Printed on 9/18/2009 233 Report on Proposals – November 2010 NFPA 921 can provide valuable information that may assist in determining origin and cause. The observations of the reporting parties are important because origin investigation can be narrowed to the area burned at the time of the report. They may also be able to verify or supplement some of the information obtained from other witnesses and attack crews. 26.7.1.2 Observations of Initial Attack Crew. The initial attack crew can play a vital role in the investigation by making observations while en route and upon arrival on the scene. Crew members may be able to provide valuable information pertaining to the investigative area, the identification of people or vehicles leaving the area, the weather, the condition of locks and gates, and damage or abnormal conditions. If any potential evidence is found, it should be marked and protected. Questions to ask first-arriving crews include the location of the fire upon arrival, the direction the fire was spreading, general fire behavior, descriptions of persons or vehicles in or leaving the area, and weather conditions. 26.7.1.3 Observations of Airborne Personnel. Airborne personnel can make the same types of observations as ground crews but could have a valuable different perspective of the potential area of origin, direction of fire spread, and people or vehicles leaving the area. The information should be given to ground personnel promptly and as accurately as possible. Photographs of the fire area taken by airborne personnel often prove invaluable in showing areas burnt, the direction of fire travel, and intensity at a given location and point in time. 26.7.1.4 Observations of Other Witnesses. Witnesses can often provide vital information in the investigation of a wildfire. Witnesses can provide information about vehicles or people that may have been in the area. They are often familiar with the area and can give information as to the area of origin and a possible cause. They can also provide information on the condition of the fire, such as smoke conditions, intensity, rate of spread, and weather. 26.7.1.5 Satellite Imaging or Remote Sensing. Satellite or imaging tools that are used primarily to establish fire suppression tactics can also be utilized to assist in the establishment of the area of origin, based on the direction of fire spread and data indicating the fire location when it was first detected. Pre-fire imagery can provide information regarding pre-fire fuel conditions and activity in the area. 26.7.2. General origin area. The area of the fire that the investigator can narrow down based on macro-scale indicators, witness statements, and analysis of fire behavior. It may be a limited area on a small fire, or several acres on a large fire. 26.7.2.1 Specific origin area. The smaller area, within the general origin area, where the fire’s direction of spread was first influenced by wind, fuel, or slope. Generally this area is characterized by subtle and micro-scale fire direction indicators. It will usually be no smaller than about 5’x 5’, and may be substantially larger, depending on fire spread indicators and other factors. It is typically characterized by less intense burning. 26.7.2.2 Point of origin. Contained within the specific origin area will be the precise location where the ignition source came into contact with the material first ignited and sustained combustion occurred. Physical evidence of the actual ignition source is likely to be located at or within close proximity to the point of origin. 26.7.3 General Origin Investigation Techniques. Once the location of the general origin has been determined, the cause of the fire's ignition must still be determined. The investigator should conduct the examination of this area with minimum disturbance, seeking to expose evidence of fire spread from the origin, rather than destroying or removing it during the investigation. A photographic record should be continued throughout the investigative process. 26.7.3.1 Protection of General Origin. The integrity of the fire scene needs to be preserved. Foot and vehicle traffic moving through the area must be kept to a minimum or eliminated. Firefighters should enter this area only if necessary for fire operations. Evidence should not be handled or removed without documentation. The area should be cordoned off by the use of flags, tape or posting personnel at the scene to restrict access. 26.7.3.2 Identifying Evidence. During the investigation, metal flagging stakes can be used to mark items that could be considered potential evidence. Labeled flags can also be used to mark the position of an item of evidence that has been removed from the scene. Care must be continually exercised not to destroy evidence, such as tracks left by individuals or vehicles in the suspected area of origin. The surrounding area should be examined for other evidence. 26.7.3.3 General Principles of Burn Pattern Interpretation. When analyzing a fire’s progression using burn patterns, the investigator should keep in mind the following general principles. The interpretation should be based on the majority of the indicators within an indicator category, the totality of the indicators, and fire behavior principles. A single indicator may only be accurate within a 180 degree arc. Indicators will usually become less pronounced near the origin. The indicators should be documented as they are observed. Work from the area of most intense burning, to the area of least intense burning, following the fire’s advancing spread back to the origin. Preliminary fire shapes may be primarily dependent on effective wind speeds. Direction of spread will be influenced by obstacles. 26.7.3.4 Walk the Exterior Perimeter of the General Origin. Due to the influence of light, shadows and terrain it is recommended that the investigator walk the perimeter of the general origin area at least twice: once in a clockwise direction and once in a counter clockwise direction. Look at the unburned area as well as the burned area. Examine and mark directional burn pattern indicators at the perimeter of the general origin with colored flags or other appropriate Printed on 9/18/2009 234 Report on Proposals – November 2010 NFPA 921 markers as they are located. If relevant physical evidence is located, it is standard practice to protect and mark it with white flags. 26.7.3.5 Identify Advancing Fire. Identify the initial run, the rapid advance at the head of the fire that the fire made. Frequently this will be the area which shows the cleanest burn, and may be characterized by a classic “V” or “U”-shaped pattern. It is often bounded on both flanks by lateral fire spread indicators showing less complete consumption of fuels. 26.7.3.6 Enter the General Origin Area. Photograph the general origin area prior to entering. Once the initial run has been identified, the general origin area should be entered from the head or advancing side of the run; this is the side farthest away from the suspected point of origin. The reason to enter from the advancing side is that the burn pattern indicators are more obvious in this area and the investigator is less likely to disturb the specific origin area than if the general origin area is entered from the heel or backing side of the fire. There is one exception to this rule: if the general origin is on a very steep slope where material and soil may be dislodged by the investigator and roll down hill and disturb the specific origin, then the investigator may be forced to enter from the backing or heel side of the general origin area and work up hill.

***Insert Figure 26.7.3.7 Here*** FIGURE 26.7.3.7 Working the General Origin Area

26.7.3.7 Working the General Origin Area. A suggested method for working the general origin area is as follows: Enter from the advancing area. Work across the run until the lateral transition zone is reached. Move several feet closer towards the origin and re-cross the advancing run to the opposing lateral transition zone. Repeat above steps until specific origin area is reached Figure 26.7.3.7. Document each indicator located with a visible marker. Color-coded surveyors’ flags have been found to be the most visible and easiest markers to use. Standard recommended colors are: red for advancing fire indicator, yellow for lateral fire indicator, blue for backing fire indicator, and white for evidence. 26.7.4 Specific Origin Investigation Techniques. The following are suggested techniques for investigating the specific origin. 26.7.4.1 Walk Specific Origin Perimeter. Just as with the general origin area, walk the perimeter of the specific origin at least twice, once clockwise and once counter clockwise before entering. During this walk carefully examine the specific origin area, note and mark any items of potential evidence, and continue to note and mark burn pattern indicators. Consider using a spotting scope or binoculars to first visually search this area prior to entering it. 26.7.4.2 Establish Grid Lanes. Use colored twine and four stakes to establish a grid lane. Each lane should be 12” to 18” in width and be oriented perpendicular to the first fire run. The grid lane should extend from the lateral indicators on one flank to the lateral indicators on the opposite flank on the advancing side of the fire. Number and photograph each lane prior to searching. Measure each lane end to reference point(s) if needed. 26.7.4.3 Search Each Lane. Search each lane visually and then visually with magnification. Once the surface layer has been examined; remove lightweight debris and ash by brushing or blowing. Many investigators find it useful to use a ruler or straight edge to help focus their search pattern. Continue locating and marking indicators with flags as each lane is searched. After the visual search employ a strong magnet to search for ferrous metals. Additionally, a metal detector should be used to search for nonferrous metals. In some cases it may be necessary to screen the remaining debris for evidence. Continue this process, one lane at a time, until the point of origin is reached and/or an ignition source is located. After any evidence has been documented and secured, continue searching past the point of origin or evidence until clear backing fire indicators are encountered. 26.7.5. Search Equipment. Different tools are used by investigators in search of the origin and cause of wildfires. 26.7.5.1 Magnifying Glass. A magnifying glass or reading glasses allows the investigator to see evidence that may not be visible without magnification. It also enhances small details that would otherwise go unnoticed. 26.7.5.2 Magnet. A pull-release type magnet with a stainless steel bottom, with a rating of at least 1.36 kg (3 lbs), is used to locate ferrous metal fragments or particles. Moving a magnet over the burned area will cause such materials to be attracted to the magnet. When an item is located, the pull-release can be operated and the item will fall into an appropriate evidence container. 26.7.5.3 Straight Edge. A straight edge can be used to segment the origin area. By reducing the search area, the investigator will find it easier to focus on small objects. This is very helpful when using a magnifying glass. 26.7.5.4 Probe. A probe is particularly useful in uncovering small pieces of evidence from the surrounding vegetation, for example, removing grass stems from the underlying matchbook. 26.7.5.5 Comb. A wide-gap comb can be used to separate evidence from debris. It also works well for picking up evidence without damaging it. By using the comb like a scoop, the investigator can pick up small pieces of evidence while letting burnt grass and other debris sift out through the teeth. Hair picks work exceptionally well for this task. 26.7.5.6 Hand-Held Lights. Hand-held lights assist in locating items in lowlight areas. They also eliminate shadows. 26.7.5.7 Air Blower. A small air blower (sold for camera cleaning) is useful to separate light ash from items of interest. Printed on 9/18/2009 235 Report on Proposals – November 2010 NFPA 921 Air expelled through pursed lips provides similar results, but is not as controlled. 26.7.5.8 Metal Detector. Metal detectors are used to locate ferrous and nonferrous metal objects that may be of evidentiary value. 26.7.5.9 Sifting Screen. Sifting screens of various sizes assist in the separation of a suspected item of evidence from the surrounding dirt and vegetation. 26.7.5.10 Global Positioning Satellite (GPS) Recorder. A GPS may be utilized to obtain the accurate longitudinal and latitudinal position of the fire origin. The position can be cross-referenced against site survey information, lightning strike data, aerial photography, or satellite imagery. 26.8 Fire Cause Determination. The objective of every origin and cause investigation is to establish the cause of the fire and to confirm this finding by identifying and, if possible, recovering the heat source or ignition device (see Fire Cause Determination Chapter). If the fire was ignited intentionally, the ignition source may have been discarded nearby or removed from the scene. 26.8.1 Natural Fire Cause. Wildfires are not always started by the actions of people. Many are ignited by natural causes such as lightning and some occasionally by volcanoes. 26.8.1.1 Lightning. Lightning is a well-recognized cause of wildfires, particularly in forested areas, with lightning striking trees, power lines, and rock outcrops. The action of the lightning strike in a tree can splinter the trunk and can form glassy clumps, called fulgurites, which are formed in the soil by melting sand in the root area. Lightning may simply strike the ground, igniting nearby fuels. When lightning is suspected, a GPS may be used to gather data, which then can be provided to a lightning detection service for confirmation of that activity. Lightning-caused fires may smolder undetected for several weeks after a lightning strike before conditions change and the fire transitions to an active wildfire. 26.8.2 Human Fire Cause. Human-caused fires are a result of human action or omission and are classified as accidental or incendiary. Accidental fires involve all those for which the proven cause does not involve an intentional human act to ignite or spread fire into an area where the fire should not be. The incendiary fire is one intentionally ignited under circumstances in which the person knows that the fire should not be ignited. 26.8.2.1 Campfire. A circle of rocks, a pit with a large amount of ash, or a pile of wood is a good indicator of a campfire. Even camp areas that have burned completely leave evidence of their prior existence. Discarded food containers, metal tent stakes, or metal grommets from a tent may be found, indicating the possibility of a campfire. 26.8.2.2 Smoking.*Discarded ignited smoking materials, such as cigarettes, cigars, pipe tobacco, and matches, can start wildfires. Evidence of these ignitions may survive at or near the point of origin. The ash and filter of a cigarette butt or a burned match may be identifiable at the point of origin. 26.8.2.2.1 Smoldering smoking materials require receptive fuels for ignition. Fuel factors such as type, size, moisture content, temperature and arrangement affect the potential for ignition. The fuel is typically fine or powdery, such as litter or punky wood, which is conducive to ignition of smoldering combustion. 26.8.2.2.2 Ignition of wildland fuels by smoldering smoking materials is very sensitive to environmental conditions at the point of ignition. These factors include relative humidity, temperature, wind speed, and wind direction. There can be significant differences between microclimatic conditions at the point of origin and readings from distant weather stations. Typically relative humidity is below 25% for ignition to occur but the complexity of interactions of conditions leading to ignition, especially microclimatic variations including wind and impinging solar radiation, preclude that percentage as being absolute. 26.8.2.2.3 The position of the smoldering smoking material on the fuel is a significant factor in ignition. The area of contact between the ignition source and the fuel and the duration of that contact influences ignition of the fuel. The orientation of the ignition source on the fuel, such as whether the glowing tip of a cigarette is aligned downward or upward which would influence preheating of the adjacent fuel, is another factor for ignition. 26.8.2.3 Debris Burning. Fires occur at dumpsites, timber harvesting operations, and land clearing operations as well as at residences from garbage and other debris set on fire. These fires can spread to the neighboring vegetation. Burn barrels or incinerators may be a consideration as a fire cause. In windy conditions, hot ash and debris can blow away from the debris burn and start a fire some distance away. Large woody debris piles, especially if mixed with soil, have been known to hold long term thermal residency for many months, including over winter, before escaping into adjacent wildland. Witnesses are often useful in determining whether or not debris burning was the cause of the fire. A prescribed fire is a fire resulting from intentional ignition by a person or a naturally caused fire that is allowed to continue to burn according to approved plans to achieve resource-management objectives. 26.8.2.4 Incendiary. These fires are sometimes set in more than one location, and in areas that are frequently traveled. A time-delay ignition device may have been used. Items to look for include matches, fuses, cigarettes, rope, rubber bands, tape, candles, and wire. For further information on incendiary fires, refer to the Incendiary Fire Chapter. 26.8.2.5 Equipment Use. Vehicles and power machinery can cause wildfires in countless ways, from operating failures, overheated equipment, exhaust particles, ignition of fuel leaks and spills, and friction. Any power or motorized Printed on 9/18/2009 236 Report on Proposals – November 2010 NFPA 921 equipment that uses electricity or flammable products in its operation or that creates ignition temperatures in its operation is capable of starting a fire when being operated in or adjacent to combustible vegetation. This includes vehicles, powered portable and mobile machinery, harvesting and construction equipment, chain saws, grinding tools, and cutting torches. Defective or failed parts add to the fire potential through friction such as heating of bearing-worn brakes, “frozen” shafts, or abrasion. 26.8.2.6 Railroad. Wildfires are sometimes started along railroads. Occasionally, fire intended to clear a right-of-way will escape. Diesel and diesel-electric powered locomotives can cause trackside fires from exhaust particles, ignition of external buildups of lubricating oil, and exhaust and fuel line failure, while rolling stock can start fires from hot brake metal and overheated wheel bearings (hot box). Fires can also result from derailments, cutting or grinding on rails, or warning flares. 26.8.2.7 Fire Play. Fire play-caused wildfires are those started by children 12 years of age or younger. These fires are often motivated by normal curiosity and the use of fire in experimental or play fashion. Matches or lighters are the most frequent ignition source. These cases often involve multiple children. These fires most commonly occur around residences, schools, playgrounds, campsites, wooded areas and other areas frequented by children. Determine if the actions are due to normal curiosity or a pathological behavior. Consider referral to juvenile authorities and/or a juvenile firesetter intervention program. 26.8.2.8 Fireworks. Fireworks provide means of ignition through sparks and flaming debris. Sparklers are a smaller hazard, but may ignite dry grass or other fuels. Most sparklers include a metal (wire) or wood core that may be found at or near the point of fire origin. The remains of fireworks or their packaging may be found near the area of origin. Some fireworks have the potential to create small indentations in the ground due to their explosive force. 26.8.2.9 Utilities. Public and private utilities often are present through wildfire areas and therefore provide a potential ignition source. 26.8.2.9.1 Electricity. Overhead power lines may cause wildfires when trees contact a conductor and ignite the branch or foliage involved. This contact may leave unique fire damage on the portion of the tree that made contact and create a pit or flash mark on the power conductor. After ignition, burning portions of the tree may fall to the ground and ignite surface fuels. In addition to tree contact, conductors may be blown against each other (phase to phase) during a windstorm, creating a hot metal globule that falls to the ground. Conductors and transformers may fail, starting the pole or other equipment on fire, and may drop flaming or hot material onto the ground. Underground conductors can be damaged by heavy equipment or digging operations, resulting in fire. Electric fences are likewise a source of energy resulting in ignition of combustible materials.

Printed on 9/18/2009 237

INCLUDES FILE for 921 CP3

Chapter 26 Wildfire Investigations

1. FIGURE 26.6 Anatomy of Fire Showing Fire Head and Heel (Rear). (Old Figure 26.3.3)

2. Figure 26.6.1 (New Photo)

FIGURE 26.6.1 V-Shaped Pattern

3. Figure 26.6.2

FIGURE 26.6.2 Degree of Damage

4. Figure 26.6.3 An Example of Grass Stems Indicating the Direction of Backing Fire Movement (left to right). (Old Figure 26.4.3 Revised Title)

5. Figure 26.6.4.1A Fire Burning Uphill or with the Wind, Creating Char Pattern That Slope Greater Than the Ground Slope. (Old Figure 26.4.5.1(a) )

6. Figure 26.6.4.2(b) A Fire Burning Downslope or Against the Wind, Creating Char Patters That are Even or Parallel to the Ground Slope. (Old Figure 26.4.5.1(b) )

7. Figure 26.6.4.2(a)

FIGURE 26.6.4.2(a) An Example of Char Patterns Created by the Way a Fire Moves Through Trees and Brush. (Old Revised Figure 26.4.5.1(c))

8. Figure 26.6.4.2(b) Progressive Crown Burning from the Point of Origin (Point A). (Old Figure 26.4.5.2 )

9. Figure 26.6.6 Cupping

FIGURE 26.6.6 Cupping

(New Photo)

10. Figure 26.6.8 A Clean Burn Line on the Front Side (Point A) and a Ragged Burn Line (Point B) on the Other Side, Showing That the Fire Moved from Point A to Point B. (Old Figure 26.4.6.1(b)) 11. Figure 26.6.9(a) Staining (Shaded Area of Noncombustible Objects by Vaporized Fuels and Minute Particles Carried by the Fire. (Old Figure 26.4.6.2(a)) 12. Figure 26.6.9(b) Soot Deposited on the Side of Fences Facing the Approaching Fire. The Soot can be noticed by rubbing a hand along the wire. (Old Figure 26.4.6.2(b) 13. Figure 26.6.10 Greater Depth of Char on Side of Fencepost, Indicating the Fire Moved from Left to Right. (Old Figure 26.4.6.1(c)) 14. Figure 26.6.11 Spalling

FIGURE 26.6.11 Spalling

(New Photo)

15. Figure 26.6.12 Foliage Freeze

FIGURE 26.6.12 Foliage Freeze

(New Photo)

16. Figure 26.6.13 Figure 26.6.13

Curling

Figure 26.6.13 Curling

(New Photo)

17. Figure 26.7 Anatomy of Origin Area

Figure 26.7 Anatomy of Origin (New Figure)

18. Figure 26.7.3.7 Working the General

Origin Area

FIGURE 26.7.3.7 Working the General Origin Area Report on Proposals – November 2010 NFPA 921 ______921-161 Log #97

______Bonnie Stevens, USDA Forest Service Change illustration 26.4.5.1(b) as follows:

*****Insert artwork here**** (921-L97/f2010/Rop/Rec)

When wind approaches a tree it eddies around the back, drawing the heat up the back and creating the char, whether the fire is backing or advancing. The illustration listed above, shows the char happening on the windward side of the trunk, this is not correct. Please see attached picture of a fire that is burning under the exact conditions as the illustration and notice the fire going up the lee side (uphill) of the trunks. A fix would be to; either change the wind direction or omit it and the vertical char all together with a footnote that vertical char can happen with a backing fire but it will be on the leeward side Or show the char going up the leeward side with an emphasized horizontal char.

See the revision of Chapter 26 by Committee Proposal 3. The committee altered the figure in the revision of the chapter.

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Report on Proposals – November 2010 NFPA 921 ______921-162 Log #32

______Richard T. Ford, Fire Scene Investigations Revise text to read as follows: Visual indicators should be backtracked to the smallest area that the investigator is able to identify with certainty. Whenever possible, this technique should be followed to locate the point of fire origin. Extreme care should be taken to protect any potential causal evidence observed in the origin area. 26.5.2.4.1 26.5.3.4.2 26.5.2.4.3 26.5.2.4.4 Backtracking wildfire spread is the basic premise and technique of wildfire investigation. Identifying the "point of ignition" by using this method eliminates other "suspect" sites which may also exist. Only when the investigator is no longer capable of "reading" residual pictographs should this technique be abandoned for an alternative "search" procedure. As one specific illustration, significant additional evidence is available to an investigator who has backtracked a wildfire ignited by a match at a grassland point of origin*, e.g., 1. Match dropped accidentally or deliberately 2. Signing/tracking depressions in immediate area 3. Grass depressed before or after fire 4. Match recovered at or nearby point of ignition 5. Match extinguished or burning when in contact with fuels 6. More than one similar match in origin area 7. Ignition point in upper stems or at base of standing grasses 8. Match dropped or placed in fuels 9. Match dropped by right or left handed person *Each of these nine points is documented by my personal observations at thousands of wildfires investigations during the past 48 years and none has ever been rejected in court actions. I have tested and photographically validated each of these specific causal determinants and also have explained and demonstrated them at training seminars. Backtracking fire spread within the initial burn area is often practiced by expert wildfire investigators who are able to use the myriad of small surface level visual indicators to pin-point the precise point of the fire origin.

See 921-160 (Log #CP3) on Chapter 26. This section is not included within that proposal.

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______Patrick M. Kennedy, National Association of Fire Investigators Add new section et seq.

Most modern residential smoke alarms are designed and operate a similar manner. The basic components are a power source, smoke-sensing chamber, printed circuit board, horn, and an outer container or cover (See Figure 26.6.16.1).

The power sources include a 9-volt battery, hardwired connection to a household 120 volt AC electrical system, or both hardwired as a primary power source with a battery backup in the event of power failure. Smoke sensing chambers are of two basic types, ionization or photoelectric. Ionization types detect smoke particles by sensing small decreases in current in a monitored circuit. Inside an ionization smoke detection chamber is a small amount of the radioactive element Americium-241. The alpha-radiation from this material ionizes the oxygen and nitrogen atoms of the air between two parallel plate electrodes. The detector senses the small amount of electrical current that flows between these plates. When smoke enters the ionization smoke detection chamber, it disrupts this current and the smoke alarm senses the drop in current between the plates and sends an alarm signal to the horn. ( Photoelectric types detect smoke particles by sensing small increases in current in a monitored photoelectric cell. Inside the photoelectric smoke sensing chamber there is a small light source and a light sensitive sensor. They are positioned at right angles from one another, so that the light source does not normally illuminate the photo sensor. When smoke enters the chamber, however, the smoke particles scatter the light and some amount of light hits the sensor. This creates a small increased current flow and the smoke alarm senses the increased current and sends an alarm signal to the horn. Some more up-to-date smoke alarms are available with dual (ionization and photoelectric) sensor systems. Underwriters Laboratories sets the Visible Smoke Obscuration Limits within which a smoke alarm must activate at 0.5 – 4.0% / ft. Most smoke alarms on the market today list their smoke obscuration sensitivity between 0.64% / ft. - 0.04% / ft. and 2.08% / ft.-1.23% / ft. The majority of smoke alarms have their sensitivities the area of 1.1% / ft. -0.4% / ft. For more information see: UL 217, Single and Multiple Station Smoke Alarms The printed circuit boards contain the circuitry for power input connections (either pigtail connections for AC or battery connection terminals for 9 volt operation), smoke detection chamber operation, alarm activation, low battery (no power) alert, the test button function, temporary alarm deactivation warning, escape or test light circuits, and LED indicator light. The actual smoke detection chambers and horn assemblies are often attached to the circuit boards themselves as well. Modern smoke alarm horns are small ~1.25” diameter stainless steel disks. They are frequently, but not always, enclosed in molded thermoplastic compartments, which have small (0.43” and 0.375”) central openings that serve as sound outlets. In some older model smoke alarms the horn compartments and the horns themselves are of a brass alloy. Some horn enclosures have additional smaller openings. The horn is activated by electrical current that causes the horn disk to vibrate at frequencies up to ~4000 hz, depending upon which function the circuitry is calling for (full alarm, low battery warning, temporary alarm deactivation warning). The outer covers and bases of modern smoke alarms are constructed of thermoplastics. They are capable of melting and deforming at elevated temperatures. UL 217 section 62.2 sets the maximum temperature to which smoke alarm thermoplastic components must maintain their shapes at 194°F. (90°C). Our testing disclosed an initial softening temperature of a representative smoke alarm cover at 199°F. (93°C), initial softening of the plastic horn compartment at 250°F. (121°C), and smoke sensing chamber plastic components at 351°F. (177°C). Among the various manufactures there are many minor design differences, but virtually every manufacturer’s smoke alarm covers contain some arrangement of grillwork or other opening for smoke entrance, for alarm sound exit, and an opening for a test button and or alarm condition LED indicator light. Most smoke

Printed on 9/18/2009 240 Report on Proposals – November 2010 NFPA 921 alarms are basically designed as a squat cylinder in shape with outside diameters ranging from ~5.0” to ~5.5” and heights from ~1.25” to ~1.5.” They are all designed to be installed in the ceilings of rooms not closer than 4” from the sidewalls or on sidewalls not less than 4” or more than 12” down from the ceiling. For more information see: NFPA 72 the National Fire Alarm Code. The phenomenon of acoustic soot agglomeration is a soot deposition pattern which can, under the right circumstances, indicate to the investigator whether or not a given smoke alarm has activated during a fire event. ( ) Though mentioned elsewhere in the text, no general discussion of smoke alarms appears in the document. This section gives a general discussion of how smoke alarms work and their significance to the fire investigator's work.

The proposed text was inadvertently labeled as applying to Chapter 26 and was intended to apply to Chapter 24. Chapter 24 covers the analysis of appliances as it relates to investigation of cause of fires. Smoke alarms do not apply.

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Smoke Sensing Chamber Horn Enclosure

Cover Battery Circuit Board

Figure 26.6.1 – Typical smoke alarm components

Report on Proposals – November 2010 NFPA 921 ______921-164 Log #76

______Patrick M. Kennedy, National Association of Fire Investigators New text to read as follows: Change current text and add new section 27.6.4.1.1.

Inspections may be conducted so that interested parties can view, make notes, photograph, measure, and make other visual observations of the evidence in a nondestructive manner. All interested parties need not be present for such nondestructive inspections. Nondestructive inspections which are intrusive, involving insignificant physical changes to evidence without any permanent change to the evidentiary value of the evidence, should have all interested parties who are present at the scene or the inspection notified and allowed to attend if they choose to do so. ***(to be added at the POP meeting)*** Inspections may occur where it could be reasonably anticipated that evidence will be altered or destroyed. Before such inspections occur, all interested parties should receive notice and a protocol should be agreed upon for the inspections. Prior to any testing of evidence which may alter the evidentiary value of the evidence all interested parties should be notified, protocols should be developed, and testing facilities should be agreed upon. Each of the interested parties may decide to have its own expert view or participate in the testing. Modern, organized fire investigation first began in the late 1940’s, over 65 years ago. The Technical Committee on Fire Investigations has been in existence since 1985, nearly a quarter of a century. Its premier document, NFPA 921, was first introduced to the fire investigation community with the ROP of 1990. In retrospect, this document proved to be an epiphany to the fire investigation community. Since that 1990 publication, the six subsequent editions of NFPA 921 have reformed the boundaries of fire investigation in this country, introducing fire science and the “scientific method” to a wide spectrum of fire investigators. NFPA 921 has also served as the engine for more scientific, technological, and engineering innovations and research than in all of the prior years from 1947. The National Association of Fire Investigators has been the leading organizational supporter of NFPA 921 since even before 921’s first edition. NAFI has officially recognized each edition of NFPA 921 as the professional “standard of care” in the industry. With the production of the 2011 edition, which we undertake with these proposals, the Technical Committee on Fire Investigations, marking its twenty-fifth anniversary, bears a continuing responsibility to keep up with the current “state of the art” of our profession. To that end, in this cycle, the National Association of Fire Investigators is putting forward a number of proposals which will keep a pace with the current practices which are being used by our constituency in the field, but are not currently addressed in our document. This is one of those proposals. For many years now current common practice involving the inspection of physical evidence in the fire investigation profession has classified these types of inspections by the nature of any changes to the evidentiary value necessitated by those inspections, examinations, or testing. The definitions of what changes or destroys the evidentiary value of materials or artifacts and what does not, have frequently been misinterpreted by unsophisticated or inexperienced investigators who do not have an authoritative, peer-reviewed, context by which the difference between non-destructive, intrusive, or destructive inspections can be judged. This has produced many unnecessary and dilatory arguments of evidence inspection protocols. This proposal merely elucidates the practical definitions of such inspections which have been in use by the forensic investigation profession for years. NFPA 921-2008 contains thirteen (13) current references to “destructive” or “non-destructive” evidence alterations, examinations, and testing in six separate chapters, (Legal, Documentation, Physical Evidence; Appliances, Vehicles, and Complex Investigations). Nowhere in the document are these terms or intrusive examinations defined.

Revise text to read as follows: 27.6.4 Evidence Inspections. 27.6.4.1 Nondestructive Inspections. Inspections may be conducted so that interested parties can view, make notes, photograph, measure, and make other visual observations of the evidence in a noninvasive and nondestructive manner. All interested parties need not be present for such nondestructive inspections. 27.6.4.1.1 Intrusive Inspections. Nondestructive inspections which are intrusive, involving insignificant physical changes to evidence without any permanent change to the evidentiary value of the evidence, should have all interested parties who are present at the scene or the inspection notified and allowed to attend if they choose to do so.

Printed on 9/18/2009 242 Report on Proposals – November 2010 NFPA 921 27.6.4.2 Destructive Inspections. Inspections may occur where it could be reasonably anticipated that the evidence will be altered or destroyed. Before such inspections occur, all interested parties should receive notice and a protocol should be agreed upon for the inspections. 27.6.4.3 Testing of Evidence. Prior to any testing of evidence, which may alter the evidentiary value of the evidence all interested parties should be notified, protocols should be developed, and testing facilities should be agreed upon. Each of the interested parties may decide to have its own expert view or participate in the testing. The committee believes that the text as modified provides the best guidance on this issue.

Printed on 9/18/2009 243 Report on Proposals – November 2010 NFPA 921 ______921-165 Log #45

______Christopher M. Wanka, College Park, MD This chapter deals with factors related to the investigations of fires involving recreational boats generally defined as less than 19 m (65 ft) in length. Included in this discussion are motor boats, sailing boats, yachts, and other watercraft. (Although nothing shall preclude the use of this chapter for vessels exceeding this length, as many of the marine principles discussed in this chapter apply to all vessels, regardless of size or use.) The definition appears to limit the content of this chapter to vessels less than 65 feet. While many fires occur in smaller vessels, they also tend to occur in larger ones as well, especially in the South Florida, as well as other coastal areas. It should be noted that many of the same marine principles discussed in the chapter apply to larger vessels, and nothing should restrict this chapter to only being applied to investigations with smaller vessels. In addition, many yachts, which are included in the chapter's inclusive boats, are greater than 65 feet in length.

Add new text at the end of existing 28.1: The use of this chapter in the investigation of marine fires within vessels exceeding this length may still be of value. The Committee believes that the additional language further clarification as to the intent of the chapter.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of common industry terminology: 28.2(15) Freeboard. The vertical distance between the water line and the gunwale. The amount of freeboard for a given boat can change depending on how the boat is used. Investigators can use freeboard to help assess seaworthiness of a boat prior to boarding. For example, if there is greater freeboard to the port side of the vessel as compared to the starboard side, that would indicate to the investigator that the boat is listing to starboard. The investigator would need to investigate further and determine the reason why the boat is listing prior to boarding.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of common industry terminology: 28.2(17) Gunwale. The upper edge or surface of a boat's side. The gunwale of a vessel can be an important indicator in clearly and accurately defining damage to a vessel. It is another portion of the vessel that has a fixed and known location when produced by the manufacturer. It is also capable of showing obvious signs of physical damage, including burn patterns, to the vessel.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Revise terminology to reflect boating industry terminology standards: 28.2 (21): Inboard/Outboard Out-Drive (I/O). 28.4.1.1 Vacuum/Low Pressure Carbureted. Carbureted inboard and inboard/outboard out-drive (I/O)... Figure 28.4.3 Inboard/Outboard Out-Drive Profile. The I/O type of propulsion system is commonly, yet incorrectly, referred to as "inboard/outboard." However, the correct term, as used by the boat manufacturing industry, is "inboard/out-drive." In this type of propulsion system, the motor is housed "inboard" while the propeller assembly, or "drive" unit, is located outside the hull of the vessel, becoming an "out-drive."

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of common industry terminolgy: 28.2(24) Port. The left side of a boat when looking forward. Terminology currently included in this section includes a reference to the starboard, or right, side of the vessel, but no reference is made to the port, or left, side of the vessel. During boat fire/accident investigation, it is important to refer to the correct side of the vessel when making comment on that vessel.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of common industry terminology: 28.2(25) Rub Rail The rubberized, plastic or metal bumper that extends along both sides of the vessel, usually immediately below the gunwales. The rub rail of a vessel can be an important indicator in clearly and accurately defining damage to a vessel. It is another portion of the vessel that has a fixed and known location when produced by the manufacturer. It is also capable of showing signs of physical damage to the vessel while also frequently causing obvious physical damage to other vessels.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of common industry terminology: 28.2(4) Aft. Towards the rear of the vessel. Terminology currently included in this section includes a reference to the forward end of the vessel, but no reference to the aft end. It is common in boat fire/accident investigation to refer to something as being "aft of" some other portion of the vessel. Inclusion of this term should allow for more accurate references to positioning within the vessel.

Printed on 9/18/2009 250 Report on Proposals – November 2010 NFPA 921 ______921-172 Log #46

______Christopher M. Wanka, College Park, MD Care should also be taken to ensure the structural stability of wharves, docks, and jetties that are attached or in contact with a vessel that has been subjected to fire. Listing vessels may cause these structures to be weakened and/or collapse if they are in contact with the structure, or still tied to these structures. Many fires occur in vessels that are still docked to these types of structures. Often, they will still be attached to these structures after the fire is extinguished using normal marine dock lines to secure them. If the vessel is listing due to the application of water from fire suppression, it may place excessive strain on these dock lines and this has caused docks to collapse due to these excessive forces. Also, if the vessel is being supported by the dock when listing, and not by ropes or chains, the dock may collapse due to this undesigned load being placed upon it.

The proposed text will go at the end of 28.3.5.10.

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______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of text providing further clarification on the importance of backfire flame arrestors: 28.8.1 Open Flames. Backfire Flame Arrestors. A common source of an open flame in a carbureted engine is a backfire through an unprotected carburetor. (See Figure 28.8.1). Propagation will rarely occur if the flame arrestor is properly in place. In order to prevent these flames from causing a fire, all inboard and I/O boats are requried to have an approved backfire flame arrestor attached to the air intake with a flame-tight connection. Backfire flame arrestors must be approved for marine use by the United States Coast Guard or comply with Society of Automotive Engineers Standard SAE J-1928 or Underwriters Laboratories (UL 1111) standards. A frequent cause of engine compartment fires is the failure of the owner to keep the arrestor clean and free of oil or gasoline residues. Replace existing image with the following image:

****Insert figure here***

Source: United States Coast Guard Auxiliary — Vessel Safety Check Program

The section, as written, provides incomplete information that does not do justice to the importance of backfire flame arrestors. The USCG and state boat safety program administrators require that backfire flame arrestors be correctly installed and maintained on all inboard and I/O boats because of the frequency with which they can start engine compartment fires. The photograph included for clarification of the topic is unclear and provides no assistance to the investigator. It is more important to show the investigator what a backfire flame arrestor is supposed to look like, and/or where to find it on the engine, rather than showing the investigator what it may look like after a fire.

Keep title “Open Flames”, delete: Backfire Flame Arrestors. Accept wording, but reject the photograph. The committee believes that the existing photo and description more clearly demonstrates the subject.

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NFPA 921 LOG 42 Report on Proposals – November 2010 NFPA 921 ______921-174 Log #43

______Tyler Drage, Loveland Fire & Rescue - Fire Prevention Bureau Addition of text providing further clarification on location of HIN: 28.9.3.1 Hull Identification Number (HIM). The primary location varies, depending on the year of manufacture, but is typically located on the right rear (starboard transom) below the boat's rub rail. The HIN is required to be permanently affixed to the hull of the boat by means of stamping, engraving or the attachment of plastic or metal plate. This is a point of further clarification that may allow an investigator to more easily identify and locate the vessel's hull identification number.

Make the following editorial change: Addition of text providing further clarification on location of HIN: 28.9.3.1 Hull Identification Number (HIMN). The primary location varies, depending on the year of manufacture, but is typically located on the right rear (starboard transom) below the boat's rub rail. The HIN is required to be permanently affixed to the hull of the boat by means of stamping, engraving or the attachment of plastic or metal plate. The Committee believes that is editorial.

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______Bob Eugene, Underwriters Laboratories Inc. Revised text to read as follows: A.20.1 For more information, see the following: Kimamoto, H., and E. J. Henley. Probabilistic Risk Assessment and Management for Engineers and Scientists. IEEE Press, 1996. Fire test methods: NFPA 253, Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source, 2006 edition. ASTM D 56, Standard Test Method for Flash Point by Tag Closed Tester, 2002. ASTM D 92, Standard Test Method for Flash and Fire Points by Cleveland Open Cup, 2002. ASTM D 93, Standard Test Method for Flash Point by Pensky-Martens Closed Cup Tester, 2002. ASTM D 1230, Standard Test Method for Flammability of Apparel Textiles, 2001. ASTM D 1310, Standard Test Method for Flash Point and Fire Point of Liquids by Tag Open-Cup Apparatus, 2001. ASTM D 1929, Standard Test Method for Determining Ignition Temperature of Plastics, 2001. ASTM D 2859, Standard Test Method for Flammability of Finished Textile Floor Covering Materials, 1993. ASTM D 3065, Standard Test Methods for Flammability of Aerosol Products, 2001. ASTM D 3828, Standard Test Methods for Flash Point by Small Scale Closed Tester, 2002. ASTM D 4809, Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (precision Method), 2000. ASTM D 5305, Standard Test Method for Determination of Ethyl Mercaptan in LP-Gas Vapor, 1997. ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, 2003. ASTM E 108, Standard Test Method for Fire Tests of Roof Coverings, 2000. ASTM E 119, Standard Methods of Tests of Fire Endurance of Building Construction and Materials, 2000. ASTM E 603, Standard Guide for Room Fire Experiments, 2001. ASTM E 648, Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source, 2000. ASTM E 659, Standard Test Method for Autoignition Temperature of Liquid Chemicals, 2000. ASTM E 681, Standard Test Method for Concentration Limits of Flammability of Chemicals, 2001. ASTM E 800, Standard Guide for Measurement of Gases Present or Generated During Fires, 200 I, ASTM E 906, Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products, 1999. ASTM E 1226, Test Method for Pressure and Rate of Pressure Rise for Combustible Dusts, 2000. ASTM E 1352, Standard Test Method for Cigarette Ignition Resistance of Mock-up Upholstered Furniture Assemblies, 2002. ASTM E 1353, Standard Test Methods for Cigarette Ignition Resistance of Components of Upholstered Furniture, 2002. ASTM E 1354, Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter, 2003. ANSI/UL 263, Standard for Safety Fire Tests of Building Construction and Materials, 2003. Update standards titles to indicate ANSI approvals.

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