CONTINUING

AIA/CES COURSE #K1306T GBCI COURSE #0090009863 COURSE GBCI . CONTINUING EDUCATION CONTINUING (IBC) EARN ONE GBCI CE HOUR FOR LEED LEED FOR HOUR CE GBCI ONE EARN EARN ONE AIA/CES HSW (LU) UNIT LEARNING CREDENTIAL MAINTENANCECREDENTIAL

Identify and select tested -rated -frame assemblies to use or, non-listed assemblies, calculate the fire endurance of load-bearing and the using assemblies wood non-load-bearing (CAM). Method Additive Component Discuss the fundamentals of passive and active . Determine allowable wood use in in accordance with the 2015 IBC. Describe provisions in the IBC for increasing the height and area of wood buildings beyond the amounts. tabular base Analyze fire protection in wood buildings in terms of compliance with the 2015 International Code

To receiveTo credit, you are required to read the entire article and pass the test. Go to ce.enr.com Learning Objectives Learning After reading this article, you should be able to: 1.  2.  3.  4.  5.  for complete text and to take the test for free. This course may also qualify for one Professional Development Hour (PDH). Most states now accept Check requirements. engineers’ for credits AIA your state licensing board for all laws, rules and confirm. to regulations

Based on the Code | and area of the building, prescribe the use of fire-rated building elements or provide for Active adequate means of egress. features are those such as automatic fire detection or suppression systems that provide occupant notification, alarm transmittance and the ability to suppress fire growth until the fire service arrives. Codes are relying increasingly on active systems, since, with proper maintenance and alarm supervision, they have a high degree of This CEU covers the fundamentals of reliability. passive and . It includes a summary of allowable wood use in buildings in accordance with the 2015 IBC, emphasizing the design flexibilities permitted for wood in non- residential and multifamily . FIRE PROTECTION PASSIVE While most people are familiar with the basics of an active fire suppression system, including the use of sprinklers, fire extinguishers, etc., is what actually contains a fire at its point of origin. Passive fire protection, despite its name, is always at work. Components and systems are intended to contain or slow the spread of fires through the use of fire-resistant building elements such as fire-resistant floors and walls, and open space.

By Jeffrey B. Stone, Ph.D. and David ood construction offers economic, economic, offers construction ood performance and environmental advantages not typically found

Vox on Two in on Cambridge,Vox Two Massachusetts, includes four stories of wood-frame a construction over podium.

In terms of fire protection, building codes This CEU provides an overview of fire Building fire safety incorporates a

with other structural materials. Wood is cost Wood with other structural materials. renewable It’s versatile and adaptable. effective, and has a light carbon footprint. It also has evidenced by its a proven record for safety, use not only in 90 percent of all U.S. home most construction but in some of today’s innovative non-residential architecture. require all buildings to perform to the same level buildings Wood of safety regardless of materials. can be designed to meet rigorous standards for performance, which is why the International (IBC) allows the use of wood in a wide range of building types—including structures that are taller and have more area than some designers realize. protection in wood buildings with a focus on compliance with the 2015 IBC, and is based Design Series on the Code Conforming Wood Council Wood American developed by the and the International Code Council. (AWC) A combination of passive and active features. passive fire safety feature may limit the height W

Expanding the possibilities of wood design design wood of Expanding possibilities the Think Sponsored by | Wood Designing for Fire Protection Protection Fire for Designing P. Tyree, PE, CBO, American PE, CBO, Council Tyree, Wood P. Conforming Wood DesignConforming Wood Series by the American Council andWood International Code Council Architect: CUBE 3 Studio. Structural engineer: Veitas & Veitas Engineers. Photo: CUBE 3 Studio & Rixon Photography. Rixon & Studio 3 CUBE Photo: Engineers. Veitas & Veitas engineer: Structural Studio. 3 CUBE Architect: DESIGNING FOR FIRE PROTECTION

The allowable area of a building is now noncombustible and combustible materials CODE HISTORY determined in accordance with the applicable in structural elements and exterior and interior provisions of Sections 506.2.1 through 506.2.4 and walls. The IBC was introduced in 2000, Section 506.3. However, the values determined by Types I, II, III and V construction are further consolidating three regional model building these sections can be increased through the presence subdivided into two categories (IA and IB, IIA codes into one uniform code that has since of passive and active fire protection systems. and IIB, IIIA and IIIB, and VA and VB) with the been adopted by most jurisdictions. This consolidation increased the possibilities difference being the degree of fire resistance required for wood construction by recognizing fire STRUCTURAL FRAME for various building elements and assemblies. protection systems and techniques that had Although the combustibility of building materials For example, in Type VA construction, all interior a demonstrated history of fire safety in one is important in determining levels of safety, the and exterior load-bearing walls, floors, roofs of the legacy codes. Subsequent versions expected response that a building will have in a fire and structural members are required to have a of the IBC have expanded the opportunities condition is vital to determining equivalent risk, minimum 1-hour fire-resistance rating. In Type VB for wood use even further through the which is fundamental to the IBC. The code classifies construction, no fire-resistance rating is required. application of additional state-of-the-art fire structures by type of construction in an effort to protection features. account for the expected response that building ESTABLISHING FIRE RESISTANCE The IBC is intended to protect public elements will have in a fire. The IBC defines five Table 601 of the IBC shows the required fire health, safety and general welfare as related to the construction and main types of construction: Types I, II, III, IV and resistance of building elements (structural frame, of buildings and structures. To this end, it V. For each, it specifies the materials permitted and walls, floors and rwoofs) for each construction requires all building systems to perform to the minimum fire-resistance ratings associated with the type. Ratings are given in hours. The exception same level of safety regardless of the building various structural members. is Type IV, where the wood structural elements material used. u Types I and II construction must only have are assumed to have inherent fire resistance due noncombustible building elements, except as to their required minimum dimensions (no fire permitted in Section 603. resistance rating is necessary except for exterior Occupancy classification or use of a building u Type III construction must have noncombustible walls). Required fire resistance is based on the plays a key role in the organization and prescription of or fire-retardant-treated wood (FRTW) exterior expected intensity of a fire that originates within appropriate fire protection measures. Throughout the walls, while combustible or noncombustible the building as a result of its fire load and the level IBC, occupancy group classifications are fundamental materials may be used for interior elements. of risk associated with the size of the building and in determining the necessary features of construction u Type IV, often called Heavy Timber (HT) its occupancy. and occupant safety, including limitations to building construction, has exterior walls made of Fire resistance describes the rate at which a geometry, means of egress, fire protection and noncombustible materials, cross laminated timber building material or assembly degrades due to a interior finishes. For example, regulation of the size (CLT) or FRTW, and interior building elements fire. Resistance is based on how rapidly the strength of structures is based on specific hazards associated made of or laminated timber without of the member or assembly is affected by the fire with the occupancy as well as the characteristics of concealed spaces. and whether the member or assembly can maintain construction materials used. u Type V construction allows the use of both its design strength while preventing the passage of heat or flames. Fire resistance of wood members Architect: Lord Aeck Sargent. Photo: Richard Lubrant. and assemblies may be established by any one of six means listed in IBC Section 703.3. The most common methods—tested assemblies and calculated fire resistance—are discussed in the following pages.

TESTED ASSEMBLIES Code recognition of 1- and 2-hour wood-frame walls, floors, ceilings and roofs are predicated on successful fire and hose stream testing conducted in accordance with ASTM E119, Standard Test Methods for Fire Tests of Building Construction Materials or UL 263, Standard for Fire Tests of Building Construction and Materials. Depending on the application, building elements may need to be fire-rated from one side or both sides. For specific exterior wall applications where there is adequate fire distance separation from adjacent structures or the property line, the IBC allows wood-frame walls to be tested for exposure to

EXAMPLE OF TESTED 1-HOUR FLOOR/CEILING ASSEMBLY

3/4” plywood parallel chord truss

At Crescent Terminus in Atlanta, stairs are designed with double stud walls providing a 2-hour fire separation. The team specified concrete block construction at the elevator shafts, and used a wood-frame wall to separate the elevator shaft from the rest of the construction. They also filled the interstitial space between floors with blown insulation instead of using sprinklers, which avoided technical concerns related steel furring channel to having sprinklers in inaccessible spaces. 5/8” proprietary Type X wallboard Courtesy: The American Wood Council

2 DESIGNING FOR FIRE PROTECTION

Architect: CUBE 3 Studio. Structural engineer: Veitas & Veitas Engineers. Photo: CUBE 3 Studio & Rixon Photography.

Vox on Two in Cambridge,

DESIGN TOOLS FOR ASSEMBLIES CONTINUING EDUCATION Massachusetts, includes four stories of Type VA wood-frame Many sources are available for identification and construction over a Type IA selection of tested fire-rated assemblies. Generally, concrete podium. A 3-hour publications from recognized testing laboratories fire-rated horizontal assembly are the source for listings. Fire-rated wood-frame separates the wood-frame assemblies can be found in listings contained in such residential portion from the concrete garage. Fire walls were publications as: also used to divide the wood- u Underwriters Laboratories (UL) Fire Resistance frame portion of the structure Directory into four separate buildings u Intertek Testing Services’ Directory of for the purpose of determining Listed Products allowable height and area. (See u  Association’s Fire Resistance Fire Walls on page 5.) A project Design Manual of Criterion Development Partners, the 335,500-square- Fire-rated assemblies may also be selected from foot structure was completed in one of the prescriptive assemblies provided in IBC 2014 for a construction cost of $46.6 million. Section 721 based on ASTM E 119 or UL 263 test results, or by calculating an assembly’s capacity using IBC Section 722. The AWC publication Design for Code Acceptance (DCA) 3 – Fire-Rated Wood Floor and Wall Assemblies is also helpful in determining the fire rating of wood-frame wall and floor/ceiling/roof assemblies, and is available free at www.awc.org/codes/dcaindex.html. To permit use of “non-listed” assemblies, IBC Section 722.6 also recognizes a methodology for calculating the fire endurance of load-bearing and non-load-bearing wood assemblies (floor, wall, ceiling and roof assemblies) through a calculation methodology called Component Additive Method (CAM). CAM was developed in the early 1960s by the Board of the National Research Council fire from the inside only. Rating for both interior and of Canada and validated through full-scale wood- exterior fire exposure is only required when the wall framed assembly fire tests. has a fire separation distance of less than 10 feet. For CAM calculates fire endurance to equal floors, ceilings and roofs, resistance to fire exposure the sum of: is measured from below. u the contribution of the fire exposed membrane, For a detail of a 2-hour exterior wall assembly, u the time to failure of the framing members, and, see page 8. if applicable, u additional protection due to the use of cavity CALCULATED FIRE RESISTANCE insulation or reinforcement of the membrane. The fire resistance of exposed wood members Section 722.6 contains the procedures by which may be calculated using the provisions of fire-resistance ratings of wood assemblies can be Photo: FPInnovations Chapter 16 of the National Design Specification® established using this calculation method. AWC’s CHAR (NDS®) for Wood Construction (see IBC Section publication DCA 4 – Component Additive Method 722). AWC’s Technical Report No. 10 (TR10), (CAM) for Calculating and Demonstrating Assembly Calculating the Fire Resistance of Exposed Fire Endurance provides a history of the method and Wood products such as the large beams used in heavy timber construction and cross Wood Members, contains full details of the NDS an in-depth explanation of its use and application. laminated timber may perform better in a method as well as design examples. Previous fire situation than noncombustible materials. versions of the IBC contained a separate method EXTERIOR WOOD-FRAME WALLS Because these products are thick and solid, of calculating fire resistance of exposed wood Wood stud framing is permitted for all load-bearing they char on the outside at a slow and members, which was limited to 1-hour fire and non-load-bearing exterior walls in Type V predictable rate while retaining strength, resistance. This provision has been deleted in construction. In Type III buildings, exterior walls may slowing and allowing time to the 2015 edition of the IBC, since the NDS be FRTW in compliance with IBC Section 2303.2 evacuate the building. The char protects the Chapter 16 method has broader application and when the exterior wall assembly is required to have wood from further degradation, helping to provides a more reliable calculation procedure. a 2-hour rating or less. In Type IV buildings, exterior maintain the building’s structural integrity Additionally, with the 2015 NDS referenced in walls may be of FRTW (the same as in a Type III and reducing its fuel contribution to the fire, which in turn lessens the fire’s heat and flame the IBC, the calculation method of determining a building) or of cross laminated timber in accordance propagation. Section 602.4 of the 2009 IBC fire-resistance rating may now be used for cross with Section 602.4.2. The required rating of exterior has prescriptive provisions for wood members laminated timber. walls in Type III and IV buildings is predicated on which meet the definition of heavy timber. fire separation distances contained in Table 602, so care must be taken when using this alternative to the

3 DESIGNING FOR FIRE PROTECTION general requirement for noncombustible material. with a rated opening protective assembly when the exterior wall is within relatively close proximity (< INTERIOR WOOD-FRAME 30 feet) of the property line. IBC Tables 601 and 602 WALLS AND PARTITIONS determine when the exterior walls are required to be rated In Types I and II construction, interior partitions and Table 705.8 defines the allowable percentages of dividing single tenant offices or retail and not protected and unprotected openings in those walls. creating corridors serving 30 or more occupants Unlimited amounts of unprotected openings are permitted to be FRTW, 1-hour fire-resistance- are permitted by Table 705.8 provided the exterior rated construction, or wood panels or similar light walls are 30 feet or more from the property line, construction up to 6 feet in height. In Types III and or 10 feet or more in a Type IIB or VB building. V construction, interior building elements may be No unprotected openings are permitted in the wood. In Type IV construction, however, wood exterior wall within 5 feet of the property line stud-framed partitions must be 1-hour fire-resistance- for nonsprinklered buildings and no openings are rated construction or solid wood formed by at least permitted if the wall is closer than 3 feet from the two layers of 1-inch matched boards or 4-inch-thick property line. laminated construction. Bay and oriel windows must conform to the type of construction required for the building; ROOFS AND ROOFTOP STRUCTURES however, FRTW is permitted for Type I, II, III and In Type I and II construction, FRTW framing in IV buildings not more than three stories above roofs is permitted when certain conditions are grade plane. Untreated wood may be used in Type met. FRTW framing can be used in roof elements V buildings (IBC Section 1406.4). in Type II construction of any height and in Type Interior wood are required to be protected I construction of any height provided the vertical when the wall assembly they are in requires a distance between the roof and floor below is at fire-resistance rating, such as exit enclosures or exit above: For the Jackson Hole Airport in Wyoming, least 20 feet. Heavy timber is allowed in any access corridor walls. The minimum required fire designers chose wood because of its varied grain construction where a 1-hour or less fire-resistance protection rating of the fire is given in IBC Table and color palette, as well as its ability to perform rating is required. 716.5 and ranges from 20 minutes to 3 hours based on structurally under a variety of loading conditions. The inherent fire performance of heavy timber the required fire-resistance rating of the wall assembly. construction was vital in allowing the wood to be SEPARATIONS AND OPENINGS exposed. Winner of a 2015 WoodWorks Wood Exterior openings are generally required to be protected FIRE WALLS Design Award. Ideally, fire growth and fire spread will be contained

Photo: FPInnovations to the building of origin and any adjacent buildings edge of horizontal projecting elements, such as will be protected against fire exposure. A fire balconies and roof overhangs. wall, as defined in the IBC, is commonly used Chapter 7 identifies acceptable techniques and to divide a structure into separate buildings or to methods by which construction can be evaluated to separate a new addition from the existing portion determine fire performance requirements, including of a structure. Each portion of a building separated fire walls. In addition, NFPA 221: Standard for by one fire wall or more is considered a separate High Challenge Fire Walls, Fire Walls, and Fire structure. Generally, fire walls must be of approved Barrier Walls specifies requirements for the design noncombustible materials, but may be wood-frame and construction of high challenge fire walls, fire in Type V construction. walls and fire barrier walls including protection of By definition: “A fire wall is a fire- openings and penetrations. Fire walls are required resistance-rated wall having protected openings, to be designed and constructed to allow collapse of which restricts the spread of fire and extends the structure on either side without collapse of the continuously from the foundation to or through wall itself. When NFPA 221 is used in the design of CROSS the roof, with sufficient structural stability under a fire wall, it is deemed to have met the structural fire conditions to allow collapse of construction stability requirement specified in Section 706.2. LAMINATED TIMBER on either side without collapse of the wall.” A A successful ASTM E119 fire endurance test of fire wall is not required to be cantilevered and EXTERIOR WALL FINISH a cross laminated timber wall was key to the remain in place if construction on both sides of Wood veneer is permitted on Type I, II, III or decision to recognize CLT in the 2015 edition it collapses. Fire walls must extend to the outer IV buildings up to 40 feet above grade—60 feet of the IBC. The wall, a 5-ply CLT specimen if FRTW is used, provided the veneer is 1-inch EXAMPLE OF 1-HOUR RATED WALL – approximately 7 inches thick, was covered on COMPONENT ADDITIVE METHOD (CAM) nominal thickness, 7/16-inch exterior hardboard each side with a single layer of 5/8-inch Type siding or 3/8-inch exterior-type wood structural X gypsum wallboard. The wall was loaded to 2’ X 4” Wood Stud panels or particleboard. Open or spaced veneers the maximum attainable by the test equip- without concealed spaces are not permitted to ment, although it remained significantly below project more than 24 inches from the building wall the full design strength of the CLT. It was then (IBC Section 1405.5). exposed to a standard fire that reached over 5/8” Type X Gypsum Board 1,800 degrees Fahrenheit in the first 90 min- 2” x 4” Wood Stud 20 min. utes of exposure. While only seeking a 2-hour INTERIOR FINISH rating as required by building code provisions, 5/8” Type X Gypsum Board 40 min. Wood and wood-based products are widely used in

the test specimen lasted 3 hours 6 minutes. Total 60 min. interior wall, ceiling and floor surfaces in all types

Courtesy: The American Wood Council of buildings. Appearance, acoustical qualities and

4 DESIGNING FOR FIRE PROTECTION

Architect: Gensler. Structural Engineer: Martin/Martin. Photo: Matthew Millman. CONTINUING EDUCATION or less, meeting Class A requirements. Traditional wood floor coverings are exempt from floor finish requirements. Wood interior trim, such as baseboards, chair rails and handrails, are required to meet a Class C classification and cannot exceed 10% of the wall or ceiling area to which it is attached.

NEW HEIGHT AND AREA PROVISIONS Chapter 5 of the 2015 IBC has been heavily revised. However, the revisions focus primarily on format and are not intended to be technical in nature. The increases for both height and area, when sprinklers are installed, are now integrated into the tables with separate tables used for height and area.

OPEN PERIMETER FIRE PROTECTION In general, there are two passive measures that decrease a building’s fire hazard: isolating the building from other structures and constructing the building with fire-resistive materials. IBC Chapter 5 provides for increases to the allowable area factor in Table 506.2 for Architect: EHDD. Structural engineer: Tipping Mar Structural. Photo: Jeremy Bittermann. the addition of open perimeter spacing and the use of fire-resistive assemblies. Isolating a building from adjacent structures decreases the fire hazard of a building as well as that of adjacent structures. The allowable area of a building is determined in accordance with the applicable provisions of Sections 506.2.1 through 506.2.4 and Section 506.3. In a single occupancy building with no more than one story above grade plane, allowable area is determined in accordance with Equation 5-1.

Equation 5-1: Aa = At + (NS x If) where: Aa = Allowable area (square feet) At = Tabular allowable area factor (NS, S1, or S13R value, as applicable) in accordance with Table 506.2 NS = Tabular allowable area factor in accordance with Table 506.2 for nonsprinklered building (regardless of whether or not the building is sprinklered) The area factor increase based on frontage is At the David & Lucile Packard Foundation company headquarters, wood was an determined in accordance with the following Equation important part of the strategy to achieve 5-5: LEED Platinum certification. If = Area factor increase due to frontage (percent) as calculated in accordance with Section 506.3 interior design versatility have made wood surfaces spread characteristics of wood building materials highly desired. In general, wood materials may be is ASTM E-84, Standard Test Method for Surface ALLOWABLE INCREASES FOR FRONTAGE used as interior finish within almost all . Burning Characteristics of Building Materials. PROTECTION IBC Table 803.11 places minimum finish Nonsprinklered buildings typically require lower Buildings located next to a public way or open space performance classifications on finish materials flame-spread materials than sprinklered buildings. adjoining a public way, with the exterior wall a based on their location within the building. They are Tested wood products typically have a flame minimum of 20 feet from the public way for more expressed in terms of flame spread index numbers. spread index of less than 200, making them than 25% of the building perimeter, may qualify for These values are determined in a standard fire test acceptable under the IBC for a wide range of interior an area factor increase based on frontage distance in which evaluates the surface burning characteristics finish uses. Most wood species qualify as Class C, accordance with Equations 5-4 and 5-5. of a material. Different maximum flame spread while some, such as cedar, western hemlock, Idaho indices are permitted depending on building white pine, redwood and spruce, can qualify as Class Equation 5-4: occupancy, location of the material in the building, B. Flame spread indices for a range of proprietary W = (L1 × w1 + L2 × w2 + L3 × w3…)/F (Equation 5-4) and the presence of sprinklers—Class A (flame wood-based interior finish materials are available where: spread index 0-25); Class B (26-75); or Class C from manufacturers. Commercially available fire- W (Width: weighted average) = Calculated width of public (76-200). retardant treatments for wood and panel products can way or open space (feet).

The standard fire test used to evaluate flame reduce flame spread performance to an index of 25 Ln = Length of a portion of the exterior perimeter wall.

5 DESIGNING FOR FIRE PROTECTION

Nonsprinklered Buildings Minimum Interior Finish Classification by Occupancya IBC Chapter 9, Fire Protection Systems, prescribes minimum requirements for active fire Minimum Interior Finish Classification Location protection systems to perform one or more of the Ab B C following functions: detect a fire, alert the occupants Exit enclosures and A, B, E, I, M or of a fire emergency, control , F, S, R-2 R-3 exit passagewaysc R-1, R-4, and control or extinguish the fire. Fire protective systems must be installed, operated and repaired in Ad, I-2, I-3, B, E, M, S, I-1, R-1, Corridors F, R-3 accordance with the International Fire Code (IFC). I-4 R-2, R-4 A-3, A-4, A-5, Enclosed spaces I, A-1, A-2, AUTOMATED SPRINKLER SYSTEMS B, E, F, M, S, and rooms R-4 Automatic sprinkler systems must be equipped with R-1, R-2, R-3 approved audible alarms that are monitored for

a This simplified table is not comprehensive; more exceptions c Exit enclosures and exit passageways are permitted to use integrity by an approved supervising station. The can be found in IBC Table 803.9 footnotes. Class C wainscoting or paneling in the grade lobby for not alarm must be installed on the exterior of the building b Buildings less than three stories above grade plane permit more than 1,000 square feet of applied surface when applied in a location approved by the building official. This the reduction of the exit enclosure and exit passageway to a noncombustible base. classifications to Class B. d Lobby areas in corridors may use Class B interior finishes alarm is not intended to be an evacuation alarm. for Group A occupancies. However, when a is installed, the sprinkler system must be interconnected with the building fire alarm system so that, when the sprinkler Sprinklered Buildings Minimum Interior Finish Classification by Occupancya,b system activates, it sounds the evacuation alarms required for the fire alarm system. Minimum Interior Finish Classification Location Where the code requires that a building or c A B C portion thereof be equipped throughout with an Exit enclosures and A, B, E, M, R-1, R-4, automatic sprinkler system, the sprinklers must I-3 F, R-2, R-3, S exit passagewaysd I-1, I-2, I-4 be in accordance with NFPA 13, Standard for the Corridors I-3 A, I-2, I-4 B, E, F, M, R, S, I-1 Installation of Sprinkler Systems. However, where allowed in buildings of Group R occupancy, up to Enclosed spaces A, B, E, F, M, R, S, I-2, I-4 and including four stories and not greater than 60 and rooms I-1, I-3 feet in height, the automatic sprinkler system shall a This simplified table is not comprehensive; more exceptions the reduction of the exit enclosure and exit passageway be in accordance with NFPA 13R, Standard for can be found in IBC Table 803.9 footnotes. classifications to Class C. the Installation of Sprinkler Systems in Low-Rise b Automatic sprinkler system meeting the requirements of d Exit enclosures and exit passageways are permitted to use NFPA 13 or NFPA 13R as appropriate Class C wainscoting or paneling in the grade lobby for not Residential Occupancies. more than 1,000 square feet of applied surface when applied c Buildings less than three stories above grade plane permit IBC Chapter 9 regulates the installation to a noncombustible base. of automatic sprinklers in a building based on certain factors, such as occupancy group, height, size of the building/fire area, and occupant load. Flame Spread Performance of Wood Products All water supply control valves and water- Class Example Flame Spread Smoke Development flow switches are required to be electrically A Fire-retardant-treated wood 0-25 0-450 supervised in accordance with Section 903.4. Central stations, remote supervising stations or B Redwood, cedar 26-75 0-450 proprietary supervising stations are approved Most other wood species; softwood plywood; C 76-200 0-450 services recognized in NFPA 72. hardwood plywood; particleboard Note: The construction of one- and two-family Courtesy of the American Wood Council dwellings is generally governed by the provisions of the International Residential Code (IRC), which wn = Width (≥ 20 feet) of a public way or open space obtained for frontage would occur when 100% of the allows the installation of an automatic sprinkler associated with that portion of the exterior perimeter wall. perimeter has frontage of 30 feet or more and would system in accordance with NFPA 13D, Standard for F = Building perimeter that fronts on a public way or open result in a 75% floor area increase. the Installation of Sprinkler Systems in One- and space having a width of 20 feet (6,096 mm) or more. Two-Family Dwellings and Manufactured Homes. ACTIVE FIRE PROTECTION If the one- or two-family dwelling does not comply Equation 5-5: Active fire protection is characterized by detection and with the building geometry limitations of the IRC, The area factor increase based on frontage is determined in response. Detection of a fire through smoke or heat then the building must comply with the requirements accordance with the following sensors initiates a chain of events that reduces threats of the IBC and an NFPA 13D system can still be

If = [F/P - 0.25] W/30 where: from the fire. Once a detection system is activated, used, but the installation of the 13D system will not If = Area factor increase due to frontage other programmed actions ensue, including: sounding provide for any increases to the allowable height or F = Building perimeter that fronts on a public way or open of alarms, closure of smoke and fire dampers, closure area. Automatic 13D systems in one- and two-family space having minimum distance of 20 feet (6,096 mm) of automated fire doors through de-energizing of dwellings do not require electrical supervision, P = Perimeter of entire building (feet) magnetic door stops, and opening of fire sprinklers through exception. W = Width of public way or open space (feet) in accordance or other fire suppression system. Once detected, Sprinklers offer a substantial increase to life with Section 506.3.2 the fire can be controlled or extinguished manually safety, which is well documented and merits the It should be noted that frontage widths (W) through the use of extinguishers and fire hoses or consideration of designers for that reason alone. greater than 30 feet will only receive credit for a automatically by fire sprinklers, fire fighting foam But their advantages can also be economic. The value of 30 feet. The maximum increase that can be systems, hypoxic air systems or other devices. code offers considerable trade-offs for providing

6 DESIGNING FOR FIRE PROTECTION sprinklers, including: EXAMPLE OF 2-HOUR EXTERIOR WALL u Increases to allowable heights and areas CONTINUING EDUCATION u Reductions in corridor ratings and corridor opening protection u Flexibility in means of egress (travel distance to For more examples, exits, number and separation of exits, common a library of free path of travel) architectural and u Reductions in dwelling unit separations engineering details u Relief from emergency escape openings is available at woodworks.org. u Relief from certain fire and smoke damper requirements u Interior finish flexibility

ALLOWABLE INCREASES FOR AUTOMATIC SPRINKLER SYSTEM PROTECTION Under previous versions of the IBC, an allowable increase of either 200% for a multi-story building or 300% for a one-story building was permitted. However, the 2015 IBC introduced a new, more user-friendly method of determining allowable increases. Maximum allowable height and number of stories can now be determined directly from Tables 504.3 and 504.4, and the maximum allowable sprinkler area increase can be determined from Table 506.2. These tables now have tabulated values for nonsprinklered buildings, buildings with NFPA 13-compliant systems, and buildings with NFPA 13R-compliant systems, or a multi-story sprinklered building two or more stories in height.

CHAPTER 9 AREA LIMITS FOR NONSPRINKLERED BUILDINGS Many occupancies have area thresholds beyond which sprinklers are required per IBC Section Image courtesy Togawa Smith Martin, Inc 903. The same thresholds apply to all construction types. When increases are taken for open frontage limited provided the building is surrounded and construction, when a building height reaches 50 in nonsprinklered buildings, the allowable area per adjoined by public ways or yards not less than 60 feet or four stories, a minimum of one temporary floor can exceed allowable fire areas and a sprinkler feet in width. This particular provision applies to lighted stairway shall be provided unless a system may be required. If sprinklers are provided, any construction type. permanent stairway is available for use at all times however, allowable area increases for both sprinklers per IBC Section 3310. and open frontage may be taken. Alternatively, fire SAFEGUARDS DURING CONSTRUCTION areas may be kept below sprinkler thresholds by IBC Chapter 33 provides minimum safety Standpipes compartmentalizing floor areas with fire-resistance- precautions for fire during construction and In buildings required to have standpipes, not rated construction in accordance with the definition the protection of adjacent public and private less than one standpipe shall be available during for fire area and the requirements of Chapter 7. properties. The section includes provisions for fire construction for fire department use. The standpipe The requirement for sprinklers can also extinguishers, standpipes, means of egress, and shall be installed before the construction is 40 be triggered by specific use, height above grade, or sprinkler system commissioning. The IFC also feet above fire department access. The standpipe occupant load. For instance, although unsprinklered contains detailed requirements for fire precautions is placed adjacent to usable stairs and has fire Group A-2 occupancies (restaurants) may exceed during construction. department hose connections. The standpipe is one story above extended during construction to within one floor of grade in Type III construction, if the A-2 is above Fire Extinguishers the highest point of construction having flooring per the level of exit discharge (typically the first story), During construction, one portable IBC Section 3311. During demolition a standpipe or has an occupant load exceeding 100, the A-2 shall be placed at each stairway shall be maintained in operable condition. The building must be sprinklered in accordance with IBC on all floor levels with combustible materials, in standpipe may be demolished floor by floor as Section 903.2.1.2. Increases for both open frontage each storage or construction shed and where special demolition proceeds, but not more than one floor and sprinklers could then be taken. hazards exist, such as the storage and below the floor being demolished. use of flammable and combustible liquids. UNLIMITED AREA BUILDINGS Sprinkler System Commissioning Section 507 provides provisions which allow Maintaining Means of Egress The sprinkler system must be tested and approved certain occupancies or types of construction to Required means of egress must be maintained at all before the certificate of occupancy is awarded per IBC be of unlimited area. As an example, the area of a times during construction, demolition, remodeling Section 3312 and the building is occupied, except as nonsprinklered one-story F-2 or S-2 building is not or alterations and additions to buildings. During provided in Section 111.3, temporary occupancy.

7 DESIGNING FOR FIRE PROTECTION

Photo: VanDorpe Chou Associates

Additional Requirements SUMMARY Additional requirements in the IFC include: Wood construction offers advantages in terms of u Temporary heating equipment must be listed cost, design versatility and sustainability—while and labeled; installation and maintenance of the meeting code requirements for safety in buildings equipment must be in accordance with the listing that range from schools and offices to mid-rise/ (IFC 3303). multifamily, civic, institutional, industrial and u Smoking is prohibited except in approved areas retail. Building codes are paying less attention with posted signage (IFC 3304). to the combustibility of the building components u A fire watch must be maintained with qualified and more attention to design and construction personnel if required by the fire code official (IFC techniques intended to improve fire resistance NEW WEBSITE: 3304). and protect life safety. As such, the restrictions for CONSTRUCTION u Welding operations must follow the provisions of large wood buildings are quietly disappearing, as FIRE SAFETY IFC Chapter 35. must follow the required levels of structural and fire performance are provisions of NFPA 70 (IFC 3304). being emphasized in the code. Wood has a history Although less than 2% of building fires occur u The owner must designate a of proven structural and fire performance, and is during construction, this phase presents superintendent responsible for the fire prevention making history with new mass timber products unique risk scenarios that make any building program during construction. Requirements for such as CLT, which offer exceptional strength and more vulnerable regardless of material. The the program are listed in IFC Section 3308. continue to expand the possibilities wood design. For IBC provides extensive safety precautions u An accessible emergency phone is provided more detailed information on the subjects covered for this phase, but the fires that do occur are in an approved location at the construction in this CEU, a new version of the American Wood often caused when required elements—such site. The construction site street address and fire Council’s Code Conforming Wood Design based as fire doors, smoke alarms and sprinklers— on the 2012 IBC is available as a free download at have not been put in place. For this reason, department emergency phone number must be construction site fire safety includes some posted by the phone (IFC 3309). www.awc.org. unique challenges that are best addressed u Fire-fighting vehicle access must be provided through education and increased planning. within 100 feet of temporary or permanent fire A new website, www.construction department connections (IFC 3310). firesafetypractices.com, offers information u An approved water supply for fire protection must and resources on construction fire safety from be available when combustible material is at the a broad range of sources. It identifies best construction site (IFC 3312). management practices, places emphasis on u Requirements for safeguards during roofing personal accountability of stakeholders, and operations are listed in IFC Section 3317. provides guidelines for using model codes and standards to reduce fire loss.

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8 Updated from the June 3, 2013 issue of ENR. Reprinted from the August 1, 2015 issue of ENR.