Diagnosing IAQ Problems

he goal of the diagnostic building T Start (reason for concern) investigation is to identify and solve the indoor air quality complaint in a way that t 6 prevents it from recurring and that does not Initial walkthrough n preparation create other problems. This section n visual inspection describes a method for discovering the n talk with occupants and staff cause of the complaint and presents a t “toolbox” of diagnostic activities to assist Do you have Yes you in collecting information. an explanation Just as a carpenter uses only the tools for the complaint ? that are needed for any given job, an IAQ No investigator should use only the investiga- t Collect additional tive techniques that are needed. Many information about indoor air quality complaints can be n building occupants resolved without using all of the diagnostic n the HVAC system n pollutant pathways tools described in this chapter. For n pollutant sources example, it may be easy to identify the (sample contaminants if needed) source of cooking odors that are annoying t nearby office workers and solve the Develop one or more hypotheses problem by controlling pressure relation- to explain the problem. Test by ships (e.g., installing exhaust fans) in the manipulating building conditions or exposure, or by performing food preparation area. Similarly, most appropriate tests. mechanical or carpentry problems prob- ably require only a few of the many tools t t you have available and are easily accom- Do results Attempt plished with in-house expertise. No Yes Follow-up support your a control validation The use of in-house personnel builds hypothesis ? strategy skills that will be helpful in minimizing and resolving future problems. On the t other hand, some jobs may be best handled Is the by contractors who have specialized No problem Yes knowledge and experience. In the same solved ? way, diagnosing some indoor air quality problems may require equipment and skills t that are complex and unfamiliar. Your FIGURE 6-1: Make necessary Conducting an IAQ Investigation changes so that knowledge of your organization and the problem will building operations will help in selecting Note: Outside assistance may be needed at any not recur. the right tools and deciding whether in- point in the investigation, depending upon the complexity of the problem, the skills available in- t house personnel or outside professionals house, time pressures, or other factors. Finish should be used in responding to the specific IAQ problem.

Diagnosing IAQ Problems 45 OVERVIEW: CONDUCTING AN tions of the IAQ complaint. Building IAQ INVESTIGATION occupants and operating staff are often a good source of ideas about the causes of An IAQ investigation begins with one or the problem. For example, they can more reasons for concern, such as occu- describe changes in the building that may pant complaints. Some complaints can be have occurred shortly before the IAQ resolved very simply (e.g., by asking a few problem was noticed (e.g., relocated The IAQ investigation common sense questions of occupants and partitions, new furniture or equipment). facility staff during the walkthrough). At is often a repetitive Hypothesis development is a process the other extreme, some problems could cycle of information- of identifying and narrowing down require detailed testing by an experienced gathering, hypothesis possibilities by comparing them with your IAQ professional. In this section “the observations. Whenever a hypothesis formation, and investigator” refers to in-house staff suggests itself, it is reasonable to pause hypothesis testing. responsible for conducting the IAQ and consider it. Is the hypothesis investigation. consistent with the facts collected so far? The flowchart on page 45 shows that You may be able to test your hypothesis the IAQ investigation is a cycle of infor- by modifying the HVAC system or mation-gathering, hypothesis formation, attempting to control the potential source and hypothesis testing. The goal of the or pollutant pathway to see whether you investigation is to understand the IAQ can relieve the symptoms or other condi- problem well enough so that you can solve tions in the building. If your hypothesis it. Many IAQ problems have more than successfully predicts the results of your one cause and may respond to (or require) manipulations, then you may be ready to several corrective actions. take corrective action. Sometimes it is difficult or impossible to manipulate the Initial Walkthrough factors you think are causing the IAQ An initial walkthrough of the problem area problem; in that case, you may be able to provides information about all four of the test the hypothesis by trying to predict how basic factors influencing indoor air quality building conditions will change over time (occupants, HVAC system, pollutant (e.g., in response to extreme outdoor pathways, and contaminant sources). The temperatures). initial walkthrough may provide enough information to resolve the problem. At the Collecting Additional least, it will direct further investigation. Information For example, if the complaint concerns an If your hypothesis does not seem to be a odor from an easily-identified source (e.g., good predictor of what is happening in the cooking odors from a kitchen), you may building, you probably need to collect want to study pollutant pathways as a next more information about the occupants, step, rather than interviewing occupants HVAC system, pollutant pathways, or about their patterns of discomfort. contaminant sources. Under some circumstances, detailed or sophisticated Developing and Testing measurements of pollutant concentrations Hypotheses or ventilation quantities may be required. As you develop an understanding of how Outside assistance may be needed if the building functions, where pollutant repeated efforts fail to produce a successful sources are located, and how pollutants hypothesis or if the information required move within the building, you may think calls for instruments and procedures that of many “hypotheses,” potential explana- are not available in-house.

46 Section 6 Results of the Investigation serious IAQ problem. You are best able to make the judgment of when to bring in an Analysis of the information collected outside consultant. See Section 8 for a during your IAQ investigation could discussion of hiring professional assistance produce any of the following results: to solve an IAQ problem. The apparent cause(s) of the complaint(s) are identified. INITIAL WALKTHROUGH Remedial action and follow-up evaluation An investigation may require one or many will confirm whether the hypothesis is visits to the complaint area. The amount correct. of preparatory work needed before the Other IAQ problems are identified that initial walkthrough varies with the nature are not related to the original complaints. and scope of the complaint and the These problems (e.g., HVAC malfunc- expertise of the investigator, among other tions, strong pollutant sources) should be factors. For example, an in-house investi- corrected when appropriate. gator who is already familiar with the layout and mechanical system in the A better understanding of potential IAQ building may begin responding to a problems is needed in order to develop a complaint about discomfort by going plan for corrective action. directly to the complaint area to check the It may be necessary to collect more thermostat setting and see whether air is detailed information and/or to expand the flowing from the supply outlets. scope of the investigation to include If the investigator is not familiar with building areas that were previously the building or is responding to complaints overlooked. Outside assistance may be that suggest a serious health problem, more needed. preparation may be needed before the initial walkthrough. The activities listed The cause of the original complaint below can be directed at a localized cannot be identified. “problem area” or extended to include the A thorough investigation has found no entire building: deficiencies in HVAC design or operation or in the control of pollutant sources, and Collect easily-available information about there have been no further complaints. In the history of the building and of the the absence of new complaints, the original complaints. complaint may have been due to a single, Identify known HVAC zones and com- unrepeated event or to causes not directly plaint areas. related to IAQ. Begin to identify potential sources and pollutants (e.g., special use areas near the Using Outside Assistance complaint location). Having a copy of Some indoor air quality problems may be mechanical and floor plans can be helpful difficult or impossible for in-house at this stage, especially if they are investigators to resolve. Special skills or reasonably up-to-date. instruments may be needed. Other factors Notify the building occupants of the can also be important, such as the benefit upcoming investigation. of having an impartial outside opinion or the need to reduce potential liability from a Tell them what it means and what to expect.

Diagnosing IAQ Problems 47 Identify key individuals needed for access to describe the operating schedule of and information. equipment. Obvious problems (e.g., A person familiar with the HVAC systems blocked diffusers, malfunctioning air in the building should be available to assist handlers) can be corrected to see if the the investigator at any time during the complaints disappear. The walkthrough onsite phase. Individuals who have can solve many routine IAQ problems and complained or who are in charge of will suggest directions for a more complex potential sources (e.g., housekeeping, non- investigation, should one be necessary. HVAC equipment) should be aware that Some investigators avoid taking any their information is important and should measurements during the initial walk- be contacted for appointments or telephone through so that they are not distracted from interviews if they will not be available “getting the big picture.” Others find that during the onsite visit. using smoke sticks, digital thermometers, This improvised catch basin The initial walkthrough provides an and direct reading CO2 meters or detector is intended to collect water tubes to take occasional measurements seeping into the building from opportunity to question complainants about below grade. Although the the nature and timing of their symptoms helps them develop a feel for the building. catch basin “solves” the prob- and to briefly examine the immediate area It may help to keep the following lem of uncontrolled water of the complaint. The investigator questions in mind during the initial leakage, it also provides an walkthrough: indoor location that could attempts to identify pollutant sources and support the growth of types and observes the condition and Are there obvious pollutant sources? Do microbiologicals and create layout of the HVAC system serving the IAQ problems. they appear to be adequately controlled? complaint area. Facility staff can be asked n Are pollutant indicators present, such as odors, excessive dust, or staining? n Are there sanitation problems (e.g., debris near outdoor air intake, visible mold growth, major water damage) that could be introducing air contaminants? n Are there any conditions or activities occurring in or near the building that could be related in timing, location and health effects to the complaints? Are there any deficiencies in the HVAC system that serves the complaint area?

n Does equipment serving the area (e.g., thermostats, diffusers, fans, dampers, filters) appear to be operating, clean, and in good condition? n Do operating procedures exist, and does the staff follow them? n Do records indicate that the system was commissioned (set, tested, and balanced) after construction? n Do records indicate that system compo- nents are regularly inspected, calibrated, and adjusted?

48 Section 6 Are there pathways and pressure differ- Forms and checklists such as the ences which could be moving contami- samples provided in this document (modi- nants into the complaint area from the fied if needed) can help investigators to outdoors or from other parts of the record information in an organized way. building? Small copies of basic floor plans, such as fire evacuation plans, are convenient for COLLECTING ADDITIONAL noting locations of observations. INFORMATION Any instruments that will be used should be inspected to make sure they are Additional information will be needed if in working order and calibrated. IAQ the initial walkthrough does not identify investigations generally include the use of, the cause of the problem. The following at a minimum: heatless chemical smoke pages present techniques for collecting devices and instruments for measuring information about the occupant com- temperature and humidity. plaints, HVAC system, pollutant pathways, Carbon dioxide measuring devices and pollutant sources and using that (detector tubes with a hand pump or a information to develop a hypothesis that direct reading meter) are helpful for most could explain the problem. Common sense investigations. Other instruments may be will suggest the appropriate sequence of needed as the investigation progresses. steps during this part of the investigation. See Appendix A for additional guidance on For example, if the complaint is limited to common IAQ measurements. a single room, it makes sense to evaluate pollutant pathways into that room before Tools for Collecting Information attempting to inventory sources in loca- tions outside of, but connected to, the The following pages present strategies, complaint area. On the other hand, if the tools, and forms for the investigator to use complaint involves a recognizable odor during an in-depth investigation. The (e.g., exhaust fumes), it may be more Incident Log shown below (and in Tab V) SEE practical to begin by locating the potential can be used to track the course of an inves- COMPLETE source(s) of the odor before trying to tigation from the receipt of the original FORM identify pollutant pathways. complaint. PAGE 183

Sample Form Incident Log Investigation Record (check the forms that were used) File Date Problem Location Outcome / Log Entry By Number Comments (initials)

Diagnosing IAQ Problems 49 buildings. They are intended to present a problem-solving approach that can help COLLECTING OCCUPANT INFORMATION facility staff to understand and resolve Strategies Tools many common indoor air quality prob-

Review existing n Existing Records lems. If you decide to hire outside information about n IAQ Complaint Form professionals to resolve your IAQ com- complaints n Incident Log plaint, this discussion of strategies and

Collect additional n Occupant Interview tools should help you to understand and information from n Occupant Diary oversee their investigative work. occupants COLLECTING INFORMATION ABOUT OCCUPANT COMPLAINTS Occupant data falls into two categories: complaints of discomfort or other symp- toms (e.g., teary eyes, chills) and percep- tions of building conditions (e.g., odors, draftiness). Investigators can gather valuable information about potential indoor air problems from listening to occupants, and use that information for:

n defining the complaint area within the building n suggesting directions for further investi- gation, either by identifying other events that seem to happen at the same time as the incidents of symptoms or discomfort, or by identifying possible causes for the types of symptoms or discomfort that are occurring n indicating potential measures to reduce or eliminate the problem An initial walkthrough may The discussion that follows has been uncover problems such as divided into categories of occupant data, Review Existing Records of this unsanitary condition in HVAC system data, pollutant pathway the HVAC system. Bird Complaints droppings have collected in data, and source data. However, the an air supply plenum near an suggestions for collecting and using If there is a record of occupant complaints, outdoor air intake that was information reflect the interdependence of a review of that record can help to define not protected by a birdscreen. these factors. For example, the operation the location of the IAQ problem and of the air distribution system affects identify people who should be interviewed pollutant pathways, and the air distribution as part of the investigation. Information system can also be a source of pollutants. about the history of complaints could also Indoor air quality-related complaints stimulate theories about potential causes of may develop from a variety of causes. the problem. Neither the discussion of strategies for collecting information nor the suggestions Interview Occupants for interpreting data can present the full The most obvious way to collect informa- range of possible situations encountered in tion from building occupants is to talk to

50 Section 6 them in person. If it is not possible to interview everyone who has complained Sample Form about building conditions, the investigator Occupant Interview should attempt to interview a group of individuals that reflect the concerns of the SYMPTOM PATTERNS affected areas. What kind of symptoms or discomfort are you experiencing? The investigation may also include occupant interviews with building occu- Are you aware of other people with similar symptoms or concerns? pants who do not have complaints. Then Yes____ No____ conditions in the complaint area can be If so, what are their names and locations? compared to conditions in similar building locations where there are no complaints. A sample Occupant Interview form is Do you have any health conditions that may make you particularly susceptible to environmental problems? shown here (there is another copy in Tab V). It can also be presented in a written form in order to get information TIMING PATTERNS from more people than can be interviewed. When did your symptoms start? The following key points will help interviews to be productive: hypotheses (or your own) about what n Read the discussion of evaluating may be causing the problem. Always be occupant data before you conduct SEE open to answers that may not fit your interviews, to be certain that you COMPLETE hypotheses. understand what sort of information is FORM n You may sometimes need to clarify a PAGE 185 needed. question by giving examples of the sort n Make a copy of the interview form for of information you are interested in. Try each person you speak with, and use the to provide more than one example so that form to record the answers to your you don’t seem to be telling the person questions. the answer you want. Be particularly n Choose a location in which the person cautious about mentioning specific you are interviewing feels comfortable to health effects. speak freely. n Explain that the interview is intended to The Occupant Interview includes help discover and correct the cause of the many basic points that are found in complaints. Encourage the person you questionnaires used by professional IAQ are interviewing to join in this coopera- investigators. It is important to note, tive problem-solving effort. however, that this form is not called a n Give the person you are interviewing “questionnaire.” Formal questionnaires enough time to think about your ques- may be useful for quantitative epidemiol- tions. ogy, IAQ research, complex IAQ investi- n If complainants are reluctant to answer gations, or when litigation is a possibility. questions about health symptoms, In these cases, questionnaires must be respect their desire for privacy. Planning carefully designed and executed by people for how to maintain this privacy is with an understanding of representative warranted, and in some cases may be sampling and expertise in public health, mandated. industrial hygiene, or medicine. Use of n Feel free to expand the interview by questionnaires for such purposes is beyond adding questions that help to improve the scope or expertise of most in-house your understanding or explore their investigations; if such questionnaire data is

Diagnosing IAQ Problems 51 needed, building owners and managers should use professionals.

Sample Form Occupant Diary Ask Occupants and Facility Staff to Keep More Detailed On the form below, please record each occasion when you experience Records a symptom of ill-health or discomfort that you think may be related to an environmental condition in the building. Many events occur simultaneously in and around a complex building, and it can be

Time/Date Location Symptom Severity/Duration Comments very difficult to judge which of those events might be related to the IAQ complaints. In trying to resolve stubborn problems, professional investigators sometimes ask occupants and facility staff to keep day-by-day records. Occupants are asked to record the date and time of symptoms, where they are when the symptoms appear, and any other informa- tion that might be useful. Such informa- tion could include observations about the severity and duration of symptoms and Sample Form comments on weather conditions, events, Log of Activities and System Operations and activities that are happening at the same time. Facility staff are asked to On the form below, please record your observations of HVAC system record the date and time of events such as operation, maintenance activities, and any other information that you maintenance work, equipment cycles, or think may be helpful in identifying the cause of IAQ complaints in this deliveries. If symptoms seem to occur at building. Please report any other observations (e.g., weather, other particular times of day, staff can focus associated events) that you think may be important as well. their attentions on recording events that occur before and during those periods. Equipment and activities of particular interest: Such records are likely to produce more Air Handler(s): accurate and detailed information than can Exhaust Fan(s): be obtained by relying on memory. (Use Other Equipment or Activities: the Occupant Diary and the Log of Activities and System Operations shown Date/Time Day of Week Equipment Item/Activity Comments here and included in Tab V.)

SEE COMPLETE FORMS PAGES 187 AND 189

52 Section 6 USING THE OCCUPANT DATA The pattern of complaints within the building helps to define the complaint area. The timing of symptoms and the types of symptoms reported may provide clues about the cause of the problem. Strategies for Using Occupant Data n Define the complaint area n Look for timing patterns n Look for symptom patterns

Exhaust fumes are drawn into this building’s outdoor air intake when trucks are idling at the nearby loading dock. Tools such as the Occupant Diary and Log of Activities and System Operation can help to identify intermittent pollutant sources such as this one.

Diagnosing IAQ Problems 53 Define the Complaint Area SPATIAL PATTERNS SUGGESTIONS Use the spatial pattern (locations) of

Widespread, no apparent spatial n Check ventilation and tem- complaints to define the complaint area. pattern perature control for entire Building locations where symptoms or building. discomfort occur define the rooms or zones n Check outdoor air quality. that should be given particular attention n Review sources that are spread during the initial investigation. However, throughout building (e.g., cleaning materials). the complaint area may need to be revised as the investigation progresses. Pollutant n Consider explanation other than air contaminants. pathways can cause occupant complaints in parts of the building that are far Localized (e.g., affecting indi- n Check ventilation and tempera- removed from the source of the problems. vidual rooms, zones, or ture control within the complaint air handling systems) area. n Review pollutant sources affecting the complaint area.

n Check local HVAC system components that may be acting as sources or distributors of pollutants.

Individual(s) n Check for drafts, radiant heat (gain or loss), and other localized temperature control or ventilation problems near the affected individual(s).

n Review local pollutant source(s) near the affected individual(s).

n Consider that common back- ground sources may affect only susceptible individuals.

n Consider the possibility that individual complaints may have different causes that are not necessarily related to the building (particularly if symp- toms differ among the individu- als).

54 Section 6 Look for Timing Patterns Look for patterns in the timing of com- TIMING PATTERNS SUGGESTIONS plaints. The timing of symptoms and Symptoms begin and/or n Review HVAC operating cycles. complaints can indicate potential causes are worst at the start of Emissions from building for the complaints and provide directions the occupied period materials, or from the HVAC system itself, may build up for further investigation. Review the data during unoccupied periods. for cyclic patterns of symptoms (e.g., worst during periods of minimum ventila- Symptoms worsen over n Consider that ventilation may tion or when specific sources are most course of occupied period not be adequate to handle routine activities or equipment active) that may be related to HVAC operation within the building. system operation or to other activities in and around the building. Intermittent symptoms n Look for daily, weekly, or seasonal cycles or weather- related patterns, and check linkage to other events in and around the building.

Single event of symptoms n Consider spills, other unrepeated events as sources.

Recent onset of symptoms n Ask staff and occupants to describe recent changes or events (e.g., remodeling, renovation, redecorating, HVAC system adjustments, leaks, or spills).

Symptoms relieved on leaving the n Consider that the problem is building, either immediately, likely to be building-related, overnight, or (in some cases) after though not necessarily due to air extended periods away from the quality. Other stressors (e.g., building lighting, noise) may be involved.

Symptoms never relieved, n Consider that the problem may even after extended absence from not be building-related. building (e.g., vacations)

Diagnosing IAQ Problems 55 Look for Symptom Patterns which toxicology has found specific effects. Therefore, it may be more useful Look for patterns in the types of symptoms to look for patterns of symptoms than or discomfort. IAQ investigations often for specific pollutant and health effect The following chart lists some fail to prove that any particular pollutant relationships. common symptom groups or group of pollutants are the cause of the that can be related to indoor Investigators who are not medically problem. Such causal relationships are air quality, along with possible trained cannot make a diagnosis and should sources or causes of those extremely difficult to establish. There is not attempt to interpret medical records. symptoms. Building little information available about the health managers are cautioned that Also, confidentiality of medical informa- effects of many chemicals. Typical indoor this is only a partial listing. tion is protected by law in some jurisdic- levels are much lower than the levels at tions and is a prudent practice everywhere.

SYMPTOM PATTERNS SUGGESTIONS

THERMAL DISCOMFORT n Check HVAC condition and operation. n Measure indoor and outdoor temperature and humidity (see Figure 6-2 on page 57). See if extreme conditions exceed design capacity of HVAC equip- ment. n Check for drafts and stagnant areas. n Check for excessive radiant heat gain or loss.

COMMON SYMPTOM GROUPS Headache, lethargy, nausea, If onset was acute, arrange for medical evaluation, as the problem may be carbon drowsiness, dizziness monoxide poisoning. n Check combustion sources for uncontrolled emissions or spillage. Check outdoor air intakes for nearby sources of combustion fumes. n Consider evacuation/medical evaluation if problem isn’t corrected quickly. n Consider other pollutant sources. n Check overall ventilation; see if areas of poor ventilation coincide with com- plaints.

Congestion; swelling, itching or May be allergic, if only small number affected; more likely to be irritational irritation of eyes, nose, or response if large number are affected. throat; dry throat; may be n Urge medical attention for allergies. accompanied by non-specific n Check for dust or gross microbial contamination due to sanitation problems, symptoms (e.g. headache, water damage, contaminated ventilation system. fatigue, nausea) n Check outdoor allergen levels (e.g., pollen counts). n Check closely for sources of irritating chemicals such as formaldehyde or those found in some solvents.

Cough; shortness of breath; May be hypersensitivity pneumonitis or humidifier fever. A medical evaluation fever, chills and/or fatigue after can help identify possible causes. return to the building n Check for gross microbial contamination due to sanitation problems, water damage, or contaminated HVAC system.

Diagnosed infection May be Legionnaire’s disease or histoplasmosis, related to bacteria or fungi found in the environment. n Contact your local or State Health Department for guidance.

Suspected cluster of rare or n Contact your local or State Health Department for guidance. serious health problems such as cancer, miscarriages

OTHER STRESSORS Discomfort and/or health n Check for problems with environmental, ergonomic, and job-related complaints that cannot be psychosocial stressors. readily ascribed to air contami- nants or thermal conditions

56 Section 6 Figure 6-2 shows the range of tempera- tures and relative humidities that fall FIGURE 6-2: Acceptable Ranges of Temperature and Relative within the comfort zone for most individu- Humidity During Summer and Winter 1 als dressed in “typical” clothing and involved in light, mostly sedentary Relative Humidity Winter Temperature Summer Temperature activity. Recent research suggests that 30% 68.5°F - 76.0°F 74.0°F - 80.0°F indoor air quality is judged to be worse as 40% 68.5°F - 75.5°F 73.5°F - 79.5°F temperatures rise above 76°F, regardless of 50%2 68.5°F - 74.5°F 73.0°F - 79.0°F the actual air quality. 60% 68.0°F - 74.0°F 72.5°F - 78.0°F There is considerable debate among researchers, IAQ professionals, and health 1 Applies for persons clothed in typical summer and winter clothing, at light, professionals concerning recommended mainly sedentary activity. levels of relative humidity. In general, the 2 See left for discussion of relative humidities. range of humidity levels recommended by SOURCE: Adapted from ASHRAE Standard 55-1981, Thermal Environmental different organizations seems to be 30% to Conditions for Human Occupancy 60%. Relative humidities below this level may produce discomfort from dryness. On the other hand, maintaining enough to answer the following questions: relative humidities at the lowest possible n Are the components that serve the WHAT DO YOU level helps to restrict the growth of mold immediate complaint area functioning KNOW SO FAR? and mildew. The concerns (comfort for properly? n Use the Hypothesis the most part) associated with dry air must Form on page 223 to n Is the HVAC system adequate for the be balanced against the risks (enhanced make brief notes after current use of the building? microbiological growth) associated with reviewing the occupant n Are there ventilation (or thermal com- data. humidification. If temperatures are fort) deficiencies? maintained at the lower end of the comfort n Decide whether you n Should the definition of the complaint have a hypothesis that range (68 - 70°F) during heating periods, area be expanded based upon the HVAC might explain the relative humidity in most climates will not complaints. If so, test it. layout and operating characteristics? fall much below 30% (also within the (See page 78 for a An evaluation of the HVAC system discussion of comfort range) in occupied buildings. hypothesis testing. may include limited measurements of temperature, humidity, air flow, and CO , n Decide what else you COLLECTING INFORMATION 2 need to know. ABOUT THE HVAC SYSTEM as well as smoke tube observations. Consider whether Complex investigations may require more in-house expertise is IAQ complaints often arise because the extensive or sophisticated measurements of sufficient or outside quantity or distribution of outdoor air is assistance is needed the same variables (e.g., repeated CO inadequate to serve the ventilation needs of 2 (See Section 8 for measurements taken at the same location guidance on hiring building occupants. Problems may also be under different operating conditions, outside assistance.) traced to air distribution systems that are continuous temperature and relative introducing outdoor contaminants or humidity measurements recorded with a transporting pollutants within the building. data logger). A detailed engineering study The investigation should begin with the may be needed if the investigation discov- components of the HVAC system(s) that ers problems such as the following: serve the complaint area and surrounding rooms, but may need to expand if connec- n airflows are low tions to other areas are discovered. Your n HVAC controls are not working or are goal is to understand the design and working according to inappropriate operation of the HVAC system well strategies n building operators do not understand (or are unfamiliar with) the HVAC system

Diagnosing IAQ Problems 57 Review Documentation on HVAC Design, Installation, and COLLECTING HVAC SYSTEM INFORMATION Operation Strategies Tools A review of existing documentation (e.g., Review existing documen- Collect: plans, specifications, testing and balancing tation on HVAC design, n design documents, testing and reports) should provide information about installation, and operation balancing reports the original design and later modifications, n operating instructions, control manufacturer’s installation data particularly: n the type of HVAC system (e.g., constant Talk to facilities staff Ask facilities staff to record their observa- volume, VAV) tions of equipment cycles, weather conditions, and other events using n locations and capacities of HVAC Log of Activities and System Operations equipment serving the complaint area n the planned use of each building area n supply, return, and exhaust air quantities Inspect system layout, Use: n location of the outdoor air intake and of condition, and operation n Zone/Room Record the supply, return, and exhaust registers, n HVAC Checklist - Short Form and/or n HVAC Checklist - Long Form diffusers, and grilles that serve the n thermometer and sling psychrometer complaint area (or electronic equivalent) to measure temperature and humidity The most useful way to record this n micromanometer (or equivalent) to information is to make a floor plan of the measure pressure differentials complaint area and surrounding rooms. l 0-2" and 0-10" water gauge (w.g.) You may be able to copy an existing floor to measure at fans and intakes plan from architectural or mechanical l 0-.25" w.g. with pitot tube to check drawings, fire evacuation plans, or some airflow in ducts other source. n chemical smoke for observing airflow patterns If there is no documentation on the n a device to assess airflow from mechanical system design, much more on- diffusers site inspection will be required to under- l rough quantitative: anemometer; stand the HVAC system. The HVAC velometer system may have been installed or l accurate quantitative: flow hood modified without being commissioned, n carbon dioxide measurement devices so that it may never have performed l detector tubes with a hand pump according to design. In such cases, good l direct reading meter observations of airflow and pressure differentials are essential. In addition, load Instruments often used by professional Use additional instruments analyses may be required. as appropriate IAQ consultants include: n a hygrothermograph to log temperature and humidity Talk to Facility Staff n tracer gas and measurement equip- ment Facility staff can provide important current n a device to measure airborne particu- information about equipment operating and lates maintenance schedules and breakdowns or n measurement devices for carbon other incidents. There may be inspection monoxide and other contaminants reports or other written records available of interest for review. Staff members who are familiar with building systems in general and with the specific features of the

58 Section 6 building under investigation can be very helpful in identifying conditions that may explain the indoor air quality complaints. Some facility operators have extensive preventive maintenance programs. On the other hand, discussion could reveal that facility staff are not operating the building according to its design, because: n they do not understand the design logic of the HVAC system n they have been asked to run the HVAC system at the lowest possible energy cost n they do not have the manpower to operate the building properly n the HVAC system has not been modified to accommodate changes in the use of space or increases in the occupant population Staff may have noticed occupant activities that are indicators of inadequate ventilation or poorly-controlled tempera- tures, such as: n desktop fans, heaters, or humidifiers n supply diffusers blocked off with tape or cardboard n popped-up ceiling tiles n interference with thermostat settings IAQ complaints are often intermittent. Discussions with staff may reveal patterns that relate the timing of complaints to the cycles of equipment operation or to other events in the building such as painting, installation of new carpeting, or pest control. These patterns are not necessarily obvious. Keeping a day-to-day record may help to clarify subtle relationships between Above: An investigation of this building occupant symptoms, equipment operation, revealed no problems with the HVAC sys- tem, although the amount of outdoor air was and activities in and around the building. very low. In a more thorough inspection of (See Occupant Diary and Log of Activi- the HVAC system, investigators found that ties and System Operations on page 52 the wiring to this outdoor air damper motor and in Tab V.) Staff members may have had never been connected. No outdoor air was entering the building through the intake theories about the cause of controlled by this damper. Below: These the problem. investigators are examining a perimeter fan- coil unit. Self-contained heating or cooling units such as this one are often overlooked Inspect System Layout, during routine maintenance. There may be Condition, and Operation many such units in a single building, some- times in remote or inaccessible locations. If the building is new or if there is a pre- ventive maintenance program with recent

Diagnosing IAQ Problems 59 Check for indicators of inadequate ventilation.

n Check supply diffusers to see if air is moving (using chemical smoke). If it is not, confirm that the fan system is operat- ing, and then look for closed dampers, clogged filters, or signs of leaks. n Compare design air quantities (if avail- able) to building codes for the current occupancy or ventilation guidelines (e.g., ASHRAE 62-1989, see Appendix B). If the HVAC system, performing as de- signed, would not provide enough venti- lation air for current needs, then there is good reason to believe that actual ventila- tion rates are inadequate.

n Measure carbon dioxide (CO2) in the complaint area to see whether it indicates ventilation problems. (See Appendix A for a discussion of techniques for measur-

ing and interpreting CO2 concentrations.) n Measure air quantities supplied to and exhausted from the complaint area, in- cluding calculation of outdoor air quanti- ties (see Appendix A for further guid- The design specifications for test and balance reports, it is possible (but ance). Be aware of damper settings and this building called for a mini- not necessarily likely) that the HVAC equipment cycles when you are measur- mum 20% setting on the outdoor air damper control. system is functioning according to its ing (e.g., are you evaluating minimum Facility staff lowered the original design. Otherwise it is probable outdoor air, “normal” conditions, or minimum outdoor air setting that one or more features of building usage maximum airflow?). Note that evalua- to 10% in order to save en- or system operation have changed in ways ergy and reduce operating tion of variable air volume (VAV) sys- costs. As a result, the build- that could affect indoor air quality. tems requires considerable expertise. ing was underventilated Elements of the on-site investigation Compare the measured air quantities to whenever outdoor tempera- can include (but are not limited to) the your mechanical system design specifica- tures were either very hot or very cold. following: tions and applicable building codes. Also compare ventilation rates to ASHRAE Check temperature and/or humidity to see 62-1989. Some of the ventilation recom- whether the complaint area is in the com- mendations of ASHRAE 62-1989 are fort range. reproduced in Appendix B. Take more than one measurement to ac- count for variability over time and from Check that equipment serving the com- place to place. Compare to Figure 6-2 on plaint area (e.g., grilles, diffusers, fans) is page 57 (see also Appendix B ). operating properly.

n Confirm the accuracy of reported operat- n Check thermostat operation. ing schedules and controls sequences; for n Check whether the supply air tempera- example, power outages may have dis- ture corresponds to the design criteria. rupted time clocks, fans reported as n Use a hygrothermograph (if available) to “always running” may have been acci- log temperature and humidity changes in dentally switched off, and controls can be the complaint area. in need of calibration.

60 Section 6 n Check to see that equipment is properly installed. For example, look for shipping screws that were never removed or fans that were reversed during installation, so that they move air in the wrong direc- tion. Compare the current system to the original design. n Check to see that all equipment called for in the original design was actually installed. n See whether original equipment may have been replaced by a different model (i.e., a model with less capacity or differ- ent operating characteristics). See whether the layout of air supplies, returns, and exhausts promotes efficient air distribution to all occupants and iso- sive dust in ductwork, debris or damaged The dark streaks at the lates or dilutes contaminants. building materials in ceiling plenums). outlet of this supply diffuser could indicate a filtration prob- (See Appendix A for guidance on using n If the mechanical room serves as a mix- lem. Poorly maintained or im- chemical smoke to study airflow and mix- ing plenum (i.e., return and outdoor air properly sized filters can allow dirt to be distrib-uted ing patterns and CO2 to help determine the are drawn through the room into the air adequacy of ventilation.) handler), check very carefully for poten- through the building. tial contaminants such as stored solvents n If supplies and returns are close together, and deteriorated insulation. heatless chemical smoke can be used to check for short-circuiting (supply air that Use the forms provided in this document does not mix properly with air in the to inspect the HVAC system.

breathing zone, but moves directly to the n Use the Zone/Room Record to describe

return grille). CO2 can also be used to the ventilation system serving the com- evaluate air mixing. plaint area and surrounding rooms or n Use heatless chemical smoke to observe zones. The Zone/Room Record is airflow patterns within the complaint reproduced on page 62 and in Tab V. area and between the complaint area and n Use the HVAC Checklist (short and/or surrounding spaces, including outdoors. long form) to evaluate the condition of Compare airflow directions under vari- HVAC system components that affect air ous operating conditions. distribution and IAQ in the complaint n If the system layout includes ceiling area. A portion of the HVAC Checklist- plenums, look above the ceiling for inter- Short Form is reproduced on page 62. ruptions such as walls or full-height The HVAC Checklist - Long Form is partitions. useful for more detailed examination of Consider whether the HVAC system itself the system. Complete copies of both may be a source of contaminants. forms can be found in Tab V. n Check for deterioration or unsanitary conditions (e.g., corrosion, water damage or standing water, mold growth or exces-

Diagnosing IAQ Problems 61 Sample Form Zone/Room Record This form is to be used differently depending on whether the goal is to prevent or diagnose IAQ problems. During development of a profile, this form should be used to record more general information about the entire building; during an investigation, the form should be used to record more detailed information about the complaint area and areas surrounding the complaint area or connected to it by pathways.

PROFILE AND DIAGNOSIS INFORMATION DIAGNOSIS INFORMATION ONLY

Building Area Use** Source of Mechanical Comments Peak Number of Total Air Outdoor Air (Zone/Room) Outdoor Air* Exhaust? Occupants or Supplied Supplied (Write “No” Sq. Ft. Floor Area* (in cfm)** per Person or or estimate per 150 sq. cfm airflow) Ft. Area****

USING THE HVAC SYSTEM Sample Form DATA HVAC Checklist — Short Form As you review the HVAC data, consider Sections 2, 4 and 6 and Appendix B discuss the relationships between the whether the system is adequate to serve HVAC system and indoor air quality. the use of the building and whether the timing, location, and impact of apparent MECHANICAL ROOM deficiencies appear related to the IAQ complaint. Deficiencies in HVAC n Clean and dry? Stored refuse or chemicals? design, operation, or maintenance may

n Describe items in need of attention exist without producing the complaint under investigation; some defects may not cause any apparent IAQ problems. MAJOR MECHANICAL EQUIPMENT Strategies for Using the HVAC n Preventive maintenance (PM) plan in use? System Data

Control System n Compare the original design to the current system. Type n Compare the original uses of space to System operation current uses. n Consider the condition of the HVAC system.

SEE COMPLETE FORMS PAGES 177 AND 191

62 Section 6 HEALTH AND SAFETY CONSIDERATIONS FOR IAQ INVESTIGATORS

Normal safety precautions observed during routine operation of the building must be followed closely during IAQ inspections. When the IAQ investigator is not familiar with the mechanical equipment in that particular facility, an operator or engineer should be present at all times in equipment areas. Potential safety hazards include: n electrocution n injury from contacting fans, belts, dampers or slamming doors n burns from steam or hot water lines When the IAQ investi- n falls in ventilation shafts or from ladders or roofs gator is not familiar Investigators evaluating building IAQ generally do not encounter situations in which with the mechanical specific personal protection measures (e.g., protective garments and respirators) are required. However, safety shoes and eyeglasses are generally recommended for equipment in that working around mechanical equipment. When severe contamination is present (e.g., particular facility, an microbiological, chemical, or asbestos), IAQ investigators may need additional operator or engineer protection in the vicinity of certain building areas or equipment. Such decisions are site specific and should be made in consultation with an experienced industrial should be present at hygienist. General considerations include the following: all times in equip- ment areas. Microbiological: Care must be taken when serious building related illness (e.g., Legionnaire’s disease) is under investigation or when extensive microbiological growth has occurred. Investigators with allergy problems should be especially cautious. The array of potential contaminants makes it difficult to know what sort of personal protec- tion will be effective. At a minimum, investigators should minimize their exposure to air in the interior of ducts or other HVAC equipment unless respiratory protection is used. If there is reason to suspect biological contamination (e.g., visible mold growth), expert advice should be obtained about the kind of respiratory protection to use and how to use it. Possible protective measures against severe microbiological contamination include disposable coveralls and properly fitted respirators.

Chemical: Where severe chemical contamination is suspected, specific precautions must be followed if OSHA action levels are approached. Such instances rarely occur in IAQ investigations. One possible exception might be a pesticide spill in a confined space. In this case, an appropriate respirator and disposable coveralls may be needed.

Asbestos: An IAQ investigation often includes inspection above accessible ceilings, inside shafts, and around mechanical equipment. Where material suspected of containing asbestos is not only present, but also has deposited loose debris, the investigator should take appropriate precautions. This might include disposable coveralls and a properly fitted respirator.

Note: The requirements for proper fit, physical condition of the wearer, and other considerations involved in selection of the proper respirator must be evaluated by an occupational safety and health specialist. There is a NIOSH Respirator Decision Logic for proper respirator selection, and OSHA has regulations for an appropriate respirator protection program.

Diagnosing IAQ Problems 63 Compare the Original Design to the Current HVAC System ALL SYSTEMS SUGGESTIONS Consider the original HVAC design and Ventilation and n Revise definition of complaint area (if compare it to the current equipment, temperature needed) to add spaces linked to the control zones original complaint area by ductwork or layout, and controls. A variety of HVAC controls. system designs have been used in public and commercial buildings. The type of n Check to see that thermostats are properly located and function system used in your building affects the properly. control of ventilation air quantities and distribution, as well as thermal comfort. Changes in n Note equipment changes that See Appendix B for a discussion of HVAC equipment could be affecting the system’s performance (e.g., removal or addition system types. of equipment, replacement by a differ- ent model).

Operating n Review operating procedures for oc- cycles cupied and unoccupied periods.

n Compare timing of occupied/ unoccupied periods to equipment cycles and occupant complaints. Confirm that time clocks are reading the actual time. See ASHRAE 62- 1989 for suggested lead times to allow proper flushing before occupants ar- rive. In some cases (e.g., warm, hu- mid climates), fans may need to oper- ate during unoccupied periods to pre- vent mold growth or other problems.

64 Section 6 Use HVAC Data to Evaluate Mitigation Measures SYSTEM TYPES SUGGESTIONS As you use the HVAC data to evaluate potential mitigation measures, review the No mechanical n Identify the source(s) of ventilation air ventilation or suggestions made in both the box on the (e.g., operable windows, doors exhaust only propped open). facing page for all HVAC systems and in n Check whether the location of open the box on this page for the type of HVAC windows, doors, or other openings system in your building. promotes the introduction of odors or contaminants.

Room units n Check whether outdoor air intakes are (e.g., unit obstructed. Does their location pro- ventilators) mote the introduction of odors or con- taminants?

n Note design airflows in the complaint area (outdoor air, supply, return, and exhaust) and surrounding spaces; compare to ASHRAE 62-1989 and to actual measured airflows.

Constant n Note design airflows in the complaint volume area (outdoor air, supply, return, and exhaust) and surrounding spaces; compare to applicable building codes, ASHRAE 62-1989, and to actual mea- sured airflows.

n Check whether outdoor air intakes are obstructed. Does their location pro- mote the introduction of odors or con- taminants? Check for unsanitary con- ditions.

n Check outdoor air damper controls.

Variable In addition to all suggestions made for air volume constant volume systems: (VAV) n Confirm whether the system design al- lows regulation of outdoor air quanti- ties. Do VAV boxes have stops to en- sure that minimum amounts of out- door air are delivered at all times dur- ing occupied periods? Are the system controls providing a constant ventila- tion rate per person regardless of total system airflows?

n Observe changes (if any) in airflow patterns within and around the com- plaint area as the VAV system throttles from maximum to minimum flow.

Diagnosing IAQ Problems 65 Compare the Original Uses of ROOM USE CHANGES SUGGESTIONS Space to Current Uses Compare the original uses of the complaint Increased occupant n Compare temperature and humidity to density comfort zone in ASHRAE 55-1981 area and surrounding rooms to current guidelines. uses of those areas. Indoor air quality n Compare minimum outdoor air problems often arise when the usage of quantities to the original design, applicable building codes, and rooms changes without corresponding ASHRAE 62-1989 guidelines. adjustments to the HVAC system. For example, if ventilation appears to be a Change in type of occu- For example introduction of a more problem despite a properly-functioning pant population physically active group of occupants can change thermal comfort requirements. HVAC system, the existing system may be inadequate to meet current needs. n Compare temperature and humidity to comfort zone in ASHRAE 55-1981 guidelines. n Compare minimum outdoor air quantities to the original design, applicable building codes, and ASHRAE 62-1989 guidelines. n Check for low-level contaminant sources.

Additional non-HVAC n Compare temperature and humidity to equipment comfort zone in ASHRAE 55-1981 guidelines. n Consider the need for local exhaust at point sources of contaminants.

Conversion to or addition Example: Modifications that convert or of special uses add such special uses as smoking lounges, print shops, or kitchen facilities may also require changes in the operation of the HVAC system.

n Check pressure relationships between special use areas and surrounding spaces. n Consider the need for local exhaust at point sources of contaminants.

Rearrangement of work n Check that thermostats are properly stations (e.g., relocation of located. Compare temperature and partitions) humidity to comfort zone in ASHRAE 55-1981 guidelines. n Check layout of supplies, returns, and exhausts. n Check to make sure that partitions do not block proper air circulation.

66 Section 6 Consider the Condition of the HVAC System SYSTEM CONDITIONS SUGGESTIONS Consider whether the HVAC system is Unsanitary conditions n Correct sanitary problems and reasonably clean and functioning properly. n Moisture or standing water adopt necessary measures to Review the results of the onsite inspection. prevent recurrence of problems. n Debris If you identified sanitary or operating n Dust and/or mold growth problems in the HVAC system serving the HVAC malfunctions n Evaluate whether the HVAC complaint area, you may want to correct defect could have caused the those problems and see whether the n Equipment breakdown IAQ complaint. n Obstructed diffusers or grilles complaints are resolved before continuing n Correct the malfunction(s), and n Air distribution or mixing problems: with the investigation. see whether complaints are (e.g., equipment is resolved. out of balance, requires n Review maintenance program calibration, or needs other adjust- and revise as needed to prevent ment) future problems. n Air bypasses filters (due to loose filter tracks, incorrect filter size, or filter overloaded with dirt) n Air distribution system leaks (e.g., leaky ductwork; unin-tended openings in pressurized ceilings or in return air plenums)

HVAC functions properly. n Consider what adjustments However, there is evidence of could be made to increase the underventilation. supply of outdoor air (or decrease the ventilation demand) in the complaint area.

WHAT DO YOU KNOW SO FAR?

n Use the Hypothesis Form on page 223 to make brief notes. n Decide whether you have a hypothesis that might explain the complaints. If so, test it. (See page 78 for a discussion of hypoth- esis testing.) n Decide what else you need to know. Consider whether in- house expertise is sufficient or outside assistance is needed (See Section 8 for guidance on hiring outside assistance.)

Diagnosing IAQ Problems 67 COLLECTING INFORMATION evaluation of pathways could be a very ABOUT POLLUTANT PATHWAYS time-consuming process, and it may be AND DRIVING FORCES more practical to look for major contami- nant sources before trying to discover how Unless the IAQ problem is caused by an the contaminants move within the building. obvious contaminant located in the complainant’s immediate workspace, you Identify Pollutant Pathways will need to understand the patterns of Architectural and mechanical pathways airflow into and within the complaint area. allow pollutants to enter the complaint area Correction of IAQ problems often involves from surrounding spaces, including the controlling pollutant movement through outdoors. An examination of architectural sealing of pollutant pathways or manipula- and mechanical plans can help in develop- tion of the pressure relationships. ing a list of connections to surrounding If the complaints being investigated are areas. These include: limited to a few areas of the building, pollut- ant pathways can be evaluated so that the n doors complaint area is properly defined before n operable windows conducting the source inventory. If com- n stairways plaints are spread throughout the building, n elevator shafts n utility chases n ductwork and plenums n areas served by common HVAC controls COLLECTING PATHWAY INFORMATION (e.g., shared thermostats) Strategies Tools Onsite inspection is needed to confirm Identify pollutant n Architectural and mechanical the existence of these connections and to pathways drawings identify other openings (e.g., accidental n Pollutant Pathway Form for Investigations n Sketch plan of complaint area openings such as cracks and holes). Fire codes usually require that chases and hid- Observe direction n Testing and balancing reports den openings be firestopped. Check for the n Chemical smoke tests of air movement existence and condition of firestops in n Micromanometer or equivalent chases, especially those that connect both vertically and horizontally.

Chemical smoke is being used to detect the direction and amount of airflow through this closed doorway. A building investigator must know how the ventilation in the building is designed to operate in order to decide whether the observed flow of smoke is appropriate.

68 Section 6 The Pollutant Pathway Form for Investigations shown to the right can be Sample Form used along with a sketch plan of the complaint area (similar to the example on Pollutant Pathway for Investigations Form page 70) to record pathways and directions Building Name File Number of pollutant movement. A blank copy of the form is included in Tab V. Address:

Completed By (name): Observe Air Movement Direction Rooms or Zones Pressure Relative to Comments The airflow quantities shown in mechani- Connected to the Use Complaint Area (e.g., potential cal plans or in testing and balancing Complaint Area by polluntant Pathways +/- date/time sources) reports can be used to determine the direction of air movement intended by the designer. Onsite examination is necessary to determine the actual direction of airflow at each available pathway. Chemical smoke tubes can be used to determine airflow directions between the complaint area and surrounding spaces (including the outdoors), and to reveal air “toothpaste” smell. If this technique is SEE used, it is important that the assistant have circulation patterns within the complaint COMPLETE area. A micromanometer (or equivalent) an acute sense of smell. If the building is FORM can measure the magnitude of pressure in use during the investigation, occupants PAGE 211 differences between these areas. The may also notice the odor and could find it sketch plan and the Pollutant Pathway distracting. Some investigators prefer to Form for Investigations can be used to use methods that release an odor during record the results. unoccupied periods. Investigators should It may be necessary to make observa- note two common causes of false negative tions under different conditions, as airflow results (falsely concluding that no pathway direction can change depending upon exists): weather conditions, windspeed and n The nose quickly becomes tolerant of direction, equipment operation within the strong odors, so that the assistant may building, traffic through doors, and other need to take a long rest (breathing fresh factors (e.g., as VAV systems throttle air) between tests. back). Switching air handlers or exhaust n If there is substantial airflow through the fans on and off, opening and closing doors, pathway, the peppermint oil odor could and simulating the range of operating be diluted so that it is imperceptible. conditions in other ways can help to show the different ways that airborne contami- Tracer gases such as sulfur hexafluo- nants move within the building. Dust ride (SF6) can provide qualitative and tracking patterns around door frames can quantitative information on pollutant path- reveal the dominant direction of air and ways and ventilation rates. Use of tracer pollutant movement. gases to obtain quantitative results re- Some investigators study air movement quires considerable technical expertise. If by releasing a small amount of peppermint it appears that a sophisticated study of oil at the opening to a suspected pathway pathways (or ventilation rates) is required, and asking an assistant to sniff for the you need to use trained investigators.

Diagnosing IAQ Problems 69

Evaluate Airflow Patterns Evaluate airflow patterns into and within the complaint area. Because of AIRFLOW PATTERNS SUGGESTIONS the complexity and variability of air- n Onsite observations n Look for temporal patterns flow patterns, investigators cannot be linking changes in airflow expected to understand how air moves direction to incidents of within the building under all potential complaints. operating conditions. However, data n Look for spatial patterns on pathways and driving forces can linking potential sources to help to locate potential pollutant the locations of complaints. sources and to understand how con- taminants are transported to building occupants.

Confirm or Revise Bound- aries of the Complaint Area The discovery of unexpected pollutant COMPLAINT AREA SUGGESTIONS pathways can show a need to study n Complaint area connected n Check whether pressure relationships areas of the building that may be by architectural features to between complaint area and sur- distant from the original complaint other areas rounding locations follows intent of area. n Complaint area connected ventilation design. by mechanical system to n Check whether air from other other areas locations flows into the complaint area under some conditions. If so, n Unintentional pathways (e.g., cracks, holes) consider expanding the investigation to inventory pollutant sources (and perhaps collect HVAC or occupant data) in those locations.

WHAT DO YOU KNOW SO FAR?

n Use the Hypothesis Form on page 223 to make brief notes after reviewing the pollutant pathway data.

n Decide whether you have a hypothesis that might explain the complaints. If so, test it. (See page 78 for a discussion of hypothesis testing.)

n Decide what else you need to know. Consider whether in-house expertise is sufficient or outside assistance is needed. (See Section 8 for guidance on hiring outside assistance.)

Diagnosing IAQ Problems 71 COLLECTING INFORMATION COLLECTING SOURCE INFORMATION ON POLLUTANT SOURCES Strategies Tools Throughout the investigation, the building investigator will try to identify pollutant Conduct onsite n Pollutant and Source Inventory sources that may be causing the occupant inspection n Chemical Inventory complaints. Any public or commercial building is likely to contain a number of Talk with building n Pollutant and Source Inventory occupants, facilities sources that produce odors, contaminants, n Chemical Inventory staff, and contractors or both. The investigator’s task is to identify the source(s) that may be respon- sible for the complaint(s). The area included in the pollutant source Sample Form inventory should be defined by the invest- Pollutant and Source Inventory Form igator’s understanding of the building’s architectural and mechanical layout and Using the list of potential source categories below, record any pollutant pathways. Common sense will indications of contamination or suspected pollutants that may require help to differentiate unusual sources (e.g., further investigation or treatment. spills, strong odors from new furnishings or equipment) from those that are normally Source Category Checked Needs Attention Location Comments found within or near the building.

SOURCES OUTSIDE THE BUILDING Remember that very few sources of indoor air contaminants are both continu- Contaminated Ambient Air ous and constant in volume over time. Pollen, dust Pollutant concentrations often vary in Industrial contaminants strength over time, and may not be evident General vehicular at the time of the site visit. Some sources contaminants are subtle and might only be noticed by a trained investigator. As the investigation progresses, the inventory of pollutant sources may need to be revised by expand- ing the definition of the complaint area or Sample Form examining specific locations more closely Chemical Inventory (e.g., under various operating conditions). The inventory should include chemicals stored or used in the building for cleaning, maintenance, operations, and pest control. Onsite Inspection Depending upon the nature of the com- Date Chemical/ Use Storage MSDS plaint, the investigator may find some of Brand Name Location(s) on File? the following activities to be useful. This list is not intended to be complete. Inventory outdoor sources n Examine the area around the outdoor air intake for unsanitary conditions, standing water, or nearby pollutant sources such SEE as exhaust vents or motor vehicles. COMPLETE n Observe patterns of traffic, construction FORMS activity, and other potential sources in PAGES 213 the neighborhood of the building. AND 221

72 Section 6 n Inquire about outdoor ambient air on these materials whenever possible. problems in the area. (This information (See Section 4 for further discussion of may be available from your local Health MSDSs.) Portions of both forms are Department.) shown on the poopsite page; the complete n Observe soil gas entry points. form is included in Tab V. Inventory equipment sources Talk With Building Occupants n Review non-HVAC equipment, particu- and Facility Staff larly large office equipment such as engineering drawing reproduction Building occupants and facility staff can machines and wet-process copiers. provide valuable information about the Learn about usage patterns and identify location and timing of activities that items that are not equipped with local produce odors or contaminants (e.g., exhaust. smoking, cooking, housekeeping, mainte- nance). They may also suggest explana- n Review biocides, water treatment used on HVAC equipment. tions for the IAQ problem that can help in the development of hypotheses. Facility Review building components and staff and outside contractors (e.g., persons furnishings involved in housekeeping, pest control, or n Check drain traps to make sure they are remodeling) should be interviewed or not dry. asked to provide a current list of materials, n Identify areas of excessive dust and/or procedures, and schedules used for deteriorated furnishings. cleaning and pest control. n Identify areas of soil or water damage. It may be useful to discuss the following n Identify locations of new furnishings. items with building occupants: Inventory other potential sources Inventory activities n Identify special use areas such as n Review smoking policy (and actual smoking lounges, laboratories, print practice; cleaning staff may know where shops. smoking occurs in violation of policy, n Identify areas where remodeling, repair, especially in private offices). or redecorating activities are in progress n Identify areas of overcrowding. or recently completed. Check proce- n Review products used for housekeeping, dures being used to isolate demolition maintenance, and pest control and the dust, paint fumes, and other contami- schedules of their use. nants related to the process. n Inquire about housekeeping schedules n Inventory cleaning materials used in the and procedures. building. n Identify supply storage areas and check (See Section 4 for another discussion of for well-sealed containers and proper problem indicators and common problems ventilation. that may become obvious during a Discuss incidents that could be sources walkthrough of the building.) n Inquire about prior and neighboring uses of land (e.g., landfills, underground fuel The Pollutant and Source Inventory tanks). can be used to record your observations. n Inquire about events such as spills, fires, The Chemical Inventory form is intended or leaks. to serve as a record of materials such as n If such events have occurred, learn what solvents, biocides, pesticides, and cleaning remedial actions were taken to clean up compounds that may require special care in after the incidents and to prevent their storage and handling. Material Safety recurrence. Data Sheets (MSDSs) should be collected

Diagnosing IAQ Problems 73 identify potential contaminant sources that PATTERNS SUGGESTIONS are unrelated to the present IAQ complaint (i.e., either the location of the source, the Location(s) n Compare locations of sources to locations of timing of emissions, or both fit poorly with of sources complaint(s). n Identify pathways linking potential sources to the the pattern of complaints). These should complaint area. be prioritized for remedial work according n Revise definition of complaint area if necessary. to their potential for causing health

Timing n Note whether the sources emit on a continuous problems or complaints in the future. of emissions or intermittent basis. A detailed study of pollutants and n Compare the timing of emissions to the timing sources may involve an engineering of complaints. evaluation of equipment that is releasing n Identify occasions when the source is likely to be strongest. IAQ contaminants, diagnostic sampling to n Determine whether pathways between the assess sources in operation, or other source(s) and the complaint location could measurements. These may require skills or account for the occasions of complaints. instruments that are not available in-house.

SAMPLING AIR FOR USING POLLUTANT SOURCE CONTAMINANTS AND WHAT DO YOU DATA INDICATORS KNOW SO FAR? If a strong pollutant source is identified in Although air sampling might seem to be n Use the Hypothesis Form on page 223 to the immediate vicinity of the complaint, a the logical response to an air quality make brief notes after simple test (e.g., sealing, covering, or problem, such an approach may not be reviewing the pollutant removing the source) can sometimes reveal required to solve the problem and can even source data. whether or not it is the cause of the IAQ be misleading. Air sampling should not be n Decide whether you have a hypothesis problem. If a number of potential sources undertaken until some or all of the other that might explain the have been found in and around the investigative activities mentioned previ- complaints. If so, test complaint area, other data (e.g., the pattern ously have been used to collect consider- it. (See page 78 for a of symptoms, the HVAC system design discussion of hypoth- able information. Before beginning to take esis testing.) and operation, and pollutant pathways) air samples, investigators should develop a n Decide what else you may be needed in order to determine which sampling strategy that is based on a need to know. source(s), if any, may be related to the comprehensive understanding of how the Consider whether in- complaint. house expertise is building operates, the nature of the sufficient or outside Strategies for Using Source complaints, and a plan for interpreting the assistance is needed. results. (See Section 8 for Information It may be desirable to take certain guidance on hiring n Identify patterns linking emissions to outside assistance.) routine air quality measurements during an complaints investigation to obtain a “snapshot” of n Evaluate unrelated sources current conditions. These tests should be limited to those that are indicative of very Identify Patterns Linking common IAQ concerns such as tempera- Emissions to Complaints ture, relative humidity, air movement, or Look for patterns linking emissions from carbon dioxide (CO2). Unusual readings potential sources to the IAQ complaints. may or may not indicate a problem, and should always be interpreted in perspec- Evaluate Unrelated Sources tive, based upon site-specific conditions. Evaluate sources that appear unrelated to Measurement of specific chemical or the complaints. It is not unusual to biological contaminants can be very expensive. Before expending time and

74 Section 6 money to obtain measurements of indoor air pollutants, you must decide: n how the results will be used (e.g., comparison to standards or guidelines, comparison to levels in complaint-free areas) n what substances(s) should be measured n where to take samples n when to take samples n what sampling and analysis method to use so that the results provide useful information

It is often worthwhile for building staff to develop skills in making temperature, humidity, airflow, and CO2 measurements and assessing patterns of air movement n expected “background” range for Occupants in this one-story (e.g., using chemical smoke). Appendix A typical buildings without perceived office building were complain- ing of intermittent gasoline provides a brief introduction to ventilation IAQ problems odors. Exhausts from under- and thermal measurement strategies and to Test a hypothesis about the source of the ground gasoline storage tank methods of sampling for specific air vent pipes (visible in the problem, such as lower right portion of this contaminants. n checking emissions from a piece of photograph) were being equipment drawn into the office building How Will the Results Be Used? through outdoor air intakes on 2. Testing for “indicator” compounds this roof. The gasoline stor- Although air sampling will generate associated with particular types of age tanks belonged to an adjacent service station. numbers, it will not necessarily help building conditions: resolve the IAQ problem. Many IAQ Peak carbon dioxide (CO2 ) concentra- complaints are resolved without sampling tions over 1000 ppm (parts per million) or with inconclusive sampling results. are an indicator of underventilation The design of an air sampling strategy Carbon monoxide (CO) over several should fit the intended use of the measure- ppm indicates inappropriate presence ments. Potential uses of indoor air of combustion by-products (which may measurements include: also account for high CO2 readings) 1. Comparing different areas of the building 3. Comparing measured concentrations or comparing indoor to outdoor condi- to guidelines or standards tions in order to: Occupational exposure standards and Confirm that a control approach has guidelines, such as the desired effect of reducing pollutant n OSHA PELs (Occupational Safety and concentrations or improving ventilation Health Administration’s Permissible Establish baseline conditions so that Exposure Limits) they can be compared to concentrations n NIOSH RELs (National Institute for at other times or locations, such as Occupational Safety and Health’s n concentrations in outdoor air Recommended Exposure Limits) n concentrations in areas where no n ACGIH TLVs (American Conference symptoms are reported of Governmental Industrial Hygienists’ Threshold Limit Values)

Diagnosing IAQ Problems 75 Public health guidelines for specific Air sampling for specific pollutants pollutants works best as an investigative tool when it n EPA National Ambient Air Quality is combined with other types of informa- Standards tion-gathering. It is prudent to begin a n World Health Organization Air Quality program of chemical sampling only if Guidelines symptoms or observations strongly suggest n Canadian Exposure Guidelines for that a specific pollutant or a specific source Residential Air Quality may be the cause of the complaint and if sampling results are important in determin- There are no widely accepted procedures ing an appropriate corrective action. It is prudent to begin to define whether IAQ test results are ac- a program of chemi- ceptable. Extreme caution must be used in Where Should Air Samples Be cal sampling only if comparing contaminant concentrations to Taken? symptoms or obser- existing occupational standards and guide- vations strongly lines. Although a contaminant concentra- The identified problem area is an obvious tion above those guidelines is a clear prob- site for air sampling. Measurements taken suggest that a spe- lem indicator, occupants may still experi- outdoors and in a control location (e.g., a cific pollutant or a ence health and comfort problems at con- complaint-free area of the building) are specific source may centrations well within those guidelines. It helpful in interpreting results from the be the cause of the is extremely rare for occupational stan- complaint area. complaint and if dards to be exceeded — or even ap- The conditions experienced by building sampling results are proached — in public and commercial occupants are best simulated by sampling air from the “breathing zone” away from important in deter- buildings, including those experiencing indoor air quality problems. the influence of any particular individual. mining an appropriate Where specific exposure problems are However, if an individual sits at a desk all corrective action. suspected, more detailed diagnostic testing day (except for brief periods), samplers may be needed to locate or understand placed on the desk when the individual is major sources, confirm the exposure, and elsewhere can provide a good estimate of to develop appropriate remedial actions. that person’s exposure. For example, the control of microbial or There are several ways to locate sam- pesticide contamination may involve sur- pling sites for an IAQ investigation. One face or bulk sampling. (Surface sampling approach first divides the building into involves wiping a measured surface area homogeneous areas based on key factors and analyzing the swab to see what organ- identified in the building inspection and isms are present, while bulk sampling interviews. Examples of how a building involves analyzing a sample of suspect might be divided include: material.) Specialized skills, experience, n control zones (e.g., individual rooms) and equipment may be needed to obtain, n types of HVAC zones (e.g., interior vs. analyze, and interpret such measurements. perimeter) n complaint vs. non-complaint areas What Substance(s) Should Be n relationship to major sources Measured? (e.g., spaces directly, indirectly, or not Measurement of “indicator” compounds impacted by smoking areas) n complaint types such as CO2 or CO can be a cost-effective strategy. Such measurements can help the Test sites can then be selected to repre- investigator understand the nature of the sent complaints, controls, and potential problem and define the complaint area. sources with a reasonable number of samples.

76 Section 6 When Should Indoor Air What Sampling and Analysis Samples Be Taken? Method Should Be Used? Samples may be designed to obtain “worst- Take care to select appropriate measure- case” conditions, such as measurements ment techniques and to provide interpreta- during periods of maximum equipment tions so that the results provide useful emissions, minimum ventilation, or distur- information. Appendix A provides bance of contaminated surfaces. Worst- guidance on measurement techniques that case sample results can be very helpful in are commonly used in IAQ investigations. characterizing maximum concentrations to which occupants are exposed and identify- COMPLAINTS DUE TO Investigators should ing sources for corrective measures. CONDITIONS OTHER THAN bear in mind that It is also helpful to obtain samples during POOR AIR QUALITY complaints produced average or typical conditions as a basis of Complaints that initially seem to be linked by these stressors comparison. It may, however, be difficult to thermal discomfort, underventilation, or are sometimes mis- to know what conditions are typical. Re- indoor air pollutants may actually be search shows that exposure to some pollut- takenly blamed on caused or complicated by factors such as: ants may vary dramatically as building contaminated air. To conditions change. Devices that allow n environmental stressors (e.g., lighting, complicate matters, continuous measurements of key variables noise, vibration) such stressors also n ergonomic stressors can be helpful. can produce a height- Symptoms or odors that only occur occa- n job-related psychosocial (human rela- ened sensitivity to sionally will not generally be seen during tions) stressors poor indoor air qual- the IAQ investigation. Air samples should The following briefly discusses each of ity. not be taken if an incident is not occurring, these three kinds of stressors. Investiga- unless the purpose of the sample is to es- tors should bear in mind that complaints tablish a baseline for future comparisons. produced by these stressors are sometimes One approach to intermittent IAQ prob- mistakenly blamed on contaminated air. lems is for the IAQ investigator to ask To complicate matters, such stressors also appropriate building staff or other occu- can produce a heightened sensitivity to pants to document changes over time using poor indoor air quality. Thus, even when day-to-day records such as the Occupant specific stressors are obvious, the investi- Diary and Log of Activities and System gator should not assume that they are the Operation. When an odor episode does only reason for the complaints. occur, the building engineer could inspect the air handler and intake area while an- Lighting other staff member documents the status of several potential sources. Stresses from inadequate or poorly Another strategy is to manipulate designed lighting (e.g., glare, flicker, poor building conditions to create worst-case illumination of work surfaces) can produce conditions during the building investiga- symptoms such as eyestrain and head- tion (e.g., arrange for the trash truck to idle aches. Lack of natural sunlight can also be at the loading dock or close outdoor air a source of stress. These complaints are dampers to minimum settings). Chemical sometimes mistakenly interpreted as signs smoke and tracer gases can be used to of poor indoor air quality. Lighting assess where emissions may travel under problems may be evident in large areas or various building conditions. (Such localized in particular workspaces. strategies should be carried out in ways that minimize occupant exposure.)

Diagnosing IAQ Problems 77 Ergonomic Stressors Fatigue, circulatory problems, and other physical problems can be produced by furniture that is mismatched to the task, such as chairs that are the wrong height for computer terminals. If IAQ investigators inquire about whether new furniture has recently been installed in the problem area (to determine if the furniture could be contributing to increased contaminant levels), they should also ask about whether the occupant finds the furniture comfortable.

Job-related Psychosocial Stressors It is well documented that various job- related psychosocial conditions can produce symptoms in workers. Excessive workload and work pressure are easily The glare from the windows Noise recognized job stressors. Lack of clarity was causing a variety of about what is expected of the worker (role occupant complaints in this Noisy surroundings can reduce the ability building and was disrupting to concentrate and produce stress-related ambiguity) and the presence of conflicting the workers’ ability to use the symptoms such as headaches. Noise can expectations (role conflict) are also video display terminals. commonly encountered stressors in Complaints such as also contribute to job dissatisfaction, headaches are sometimes particularly if the problem is caused by modern organizations. Poor interpersonal incorrectly blamed on poor overcrowding or other factors likely to relations, management styles that allow indoor air quality. produce a sense of substandard work little participation in decision-making, and conditions. factors related to career development are The ear gets used to sounds quickly, so it also thought to be potentially stressful. is possible for a complainant to be unaware of a constant or regular sound. Investiga- FORMING AND TESTING tors should recognize that noise can be a HYPOTHESES source of stress, even if it is not reported as As the building investigation progresses, a problem and is within current industrial you should be developing one or more exposure criteria (which are designed hypotheses that could explain the occupant primarily to prevent hearing loss). complaints. The investigation can then be shaped to collect information that will Vibration either support or refute your hypotheses. Low-frequency vibration is another source The Hypothesis Form on the opposite of stress that may go unreported by page is designed to pull together the building occupants or become confused separate pieces of information that have with pollutant problems. Vibration can be been collected by summarizing the results caused by nearby machinery or movement of the investigation. More pages can be of the building as a whole; motion sickness added if desired, but the form is designed has been reported in some high rise for brief notes that can be scanned easily. buildings that sway in the wind. As you review the information, write down

78 Section 6 any explanation(s) for the IAQ problem that The changes that are made during make sense, and think about how the hypothesis testing may offer a practical pieces of the puzzle fit together when solution to the IAQ problem, or may be building conditions are compared to only temporary measures. The mitigation SEE occupant complaints. chapter presents a variety of approaches COMPLETE Is all (or most) of your information that have been used in correcting some FORM consistent with your hypothesis? If not, is selected categories of IAQ problems and PAGE 223 there a reasonable explanation for the discusses how to evaluate those strategies. inconsistencies? A different hypothesis might provide a better fit with your information. Sample Form You may find that there are several IAQ Hypothesis Form problems (e.g., underventilation in one zone, a strong contaminant source in Complaint Area (may be revised as the investigation progresses): another room). If you have discovered potential IAQ problems that do not appear ______related to the original complaint, they can be prioritized and corrected as time and ______funding permit. Think of ways to test your hypotheses. Complaints (e.g., summarize patterns of timing, location, people affected): You may want to change ventilation rates, change the pressure relationship between ______spaces, cover or remove suspected sources, seal pathways, or temporarily relocate ______affected individuals. If your manipulations HVAC: Does the ventilation system appear to provide adequate air, can reduce occupant complaints, you have efficiently distributed to meet occupant needs in the complaint area? If found a reasonable hypothesis. Sometimes not, what problems do you see? it is not possible (or not practical) to manipulate important factors. You can also ______test your hypothesis by seeing how accu- rately you can predict changes in building ______conditions (e.g., as outdoor temperature Pathways: What pathways and driving forces connect the complaint changes). area to locations of potential sources? If you are having difficulty developing hypotheses, review the information you ______have collected and the suggestions about ______how to use that information. For sugges- tions on using occupant complaint data, see pages 53-57; on using HVAC system information, see pages 62-67; on using pollutant pathway information, see pages 70-71; on using pollutant/source inventory data, see page 74; on using air sampling information, see pages 75-76.

Diagnosing IAQ Problems 79