DRAFT - DO NOT CITE OR QUOTE
GUIDANCE FOR OWNERS AND MANAGERS OF PUBLIC
AND COMMERCIAL BUILDINGS
VOLUME II:
soi vwe
INDOOR AIR QUALITY PROBLEMS
October 1990
Public Review Draft
NOTICE
THIS DOCUMENT IS A PRELIMINARY DRAFT.
IT HAS NOT BEEN FORMALLY RELEASED BY THE U. S. ENVIRONMENTAL
PROTECTION AGENCY OR THE NATIONAL INSTITUTE FOR OCCUPATIONAL
SAFETY AND HEALTH. IT SHOULD NOT BE CONSTRUED TO REPRESENT
AGENCY POLICY. IT IS BEING CIRCULATED FOR COMMENT ON ITS TECHNICAL
AND POLICY CONTENT.
Indoor Air Division
Office of Atmospheric and Indoor Air Programs
Office of Air and Radiation
U.S. Environmental Protection Agency
National Institute for Occupational Safety and Health
Centers for Disease Control
U.S. Department of Health and Human Services
Printed on Recycled Paper
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1EW4DI I
Pursuant to requirements in the 1986 Superfund Amendments and
Reauthorization Act, the U. S. Environmental Protection Agency (EPA) issued a
Report to Congress on Indoor Air Quality in 1989. This report contained a series of
six recommendations regarding the appropriate Federal role in indoor air quality.
The first three of those recommendations called for expanded research to increase
our understanding of the causes and remedies for indoor air quality problems; the
second three called for developing non-regulatory guidance, technical assistance,
and information dissemination programs regarding methods to correct and prevent
those problems. Much of the focus of EPA’s Indoor Air Program is currently being
devoted to the development of a series of guidance documents on building
construction and operation practices. This volume, Solving Indoor Air Quality
Problems: Guidance for Builiuing Managers and Owners (Volume II) and its
companion document, Preventing Indoor Air Quality Problems: Guidance for
Building Managers and Owners (Volume I) are part of this series.
Since 1971, the National Institute for Occupational Safety and Health (NIOSH)
has conducted several hundred indoor air quality (IAQ) investigations in office
buildings under the authority of the Health Hazard Evaluation Program. Over
time, NIOSH has developed a “solution-oriented t ’ approach to conducting these
investigations, which are triggered by reported health complaints or illness and, in
1987, NIOSH published guidance on conducting indoor air quality investigations.
These two guidance documents for building owners and managers draw extensively
on NIOSH’s experience in investigating and correcting indoor air quality problems
in non-residential buildings.
Much of the literature on indoor air quality in public and commercial
buildings has been in technical publications and proceedings and has been aimed at
the person who is doing investigations on a frequent basis. Little of this
information gets to building owners and managers who are the people in the best
position to prevent problems in the first place and to solve little indoor air quality
problems before they become big problems.
In recognition of the need for some practical indoor air quality advice to
building owners and managers, EPA and NIOSH decided to work jointly to produce
written guidance on preventing, identifying, and correcting indoor air quality
problems. Early in 1990, EPA and NIOSH convened a meeting of their own
technical staff, several professional building investigators, and some building
managers to discuss the scope and content of document that would offer guidance
on the emerging issue of indoor air quality to people with day-to-day responsibility
for managing public and commercial buildings. This two-volume set is the result of
continuing consultations among the people at that initial meeting and extensive
review by EPA and NIOSH staff and indoor air quality authorities outside the
agencies.
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The guidance presented here is based on what is known and generally
accepted at this time in the relevant fields of building science and indoor air quality.
EPA and NIOSH anticipate that this document may later be supplanted by more
detailed guidance as research continues and our knowledge grows. A resource
chapter is induded in this document to give building owners and managers
thoughts on where to go for more information now and in the future.
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NOTE TO UJILDING OWNERS AND
MANAGERS
Marketing, negotiating leases and maintenance contracts, planning for future
expansion.., operating a commercial or public building is a complex process which
leaves you little time for unnecessary activities. Working with facilities staff, you make
an effort to provide a pleasant setting and are accustomed to dealing with occupant
complaints aboul room temperature, noise, plumbing system problems, and other
elements of the building environment. This document is designed to help you cope
with a new problem in the building environment that is receiving increasing attention -
indoor air quality.
Good indoor air quality (lAO) can produce improvements to occupant health and
comfort and workplace productivity. Rental properties can gain a marketing advantage
if they are known to offer a healthy and pleasant indoor environment. Failure to
respond promptly to IAQ problems, on the o lher hand, can have consequences such
as:
• creating life-threatening conditions (e.g. Legionnaire’s disease, carbon
monoxide poisoning)
• increasing health problems such as cough, eye irritation, headache, and
allergic reactions
• reducing productivity due to discomfort or increased absenteeism
• straining relations between landlords and tenants, employers and
employees
• creating negative publicity that could put rental properties at a competitive
disadvantage
• opening potential liability problems
Good air quality requires conscientious effort by both building staff and occupants.
The commitment to address lAO problems starts with the building owner or manager,
the person who has an overview of the organization, sets policy, and assigns staff
responsibilities. You have the authority to see that an lAO policy is articulated and
carried out, the ability to identify staff with skills that enable them to react promptly and
effectively to complaints, and the incentive to initiate a program that will prevent indoor
air problems in the future. As you decide how best to respond to the challenge of
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resolving indoor air quality problems in your building, it will be helpful to keep in mind
the following thoughts:
1. The first step in dealing with an IAQ complaint is recognizing that a problem may
exist. Every complaint merits a response.
2. Building staff are in a position to notice malfunctioning equipment or accidental
events which could produce indoor air quality problems. They can play a critical
role in identifying problem situations and averting IAQ crises. However, without
an awareness of lAO issues, staff activities could make problems worse instead
of solving them.
3. When indoor air quality complaints occur, particular attention must be given to
effective communication with building occupants. Without an open
communications policy that encourages active, two-way sharing of information,
an atmosphere of distrust may be created that complicates your efforts to
diagnose and correct the original problem.
4. Many indoor air quality problems are not difficult to correct and can be solved
with in-house expertise. However, gathering relevant information about the
problem and identifying appropriate corrective actions is likely to require a
coordinated effort by people with a variety of skills.
5. Some indoor air quality problems are complex and may require the assistance
of outside professionals. When contracting for services, you need to be an
informed consumer to avoid unnecessary costs and delays in solving the
problem.
6. The reactions of building occupants to environmental stresses such as noise
and inadequate lighting are sometimes confused with symptoms of lAO
problems. Because these problems may be brought in as “lAO complaints”,
brief guidance is provided at the end of Section 4.
This document was written to be a useful resource for you and your staff in
resolving indoor air problems. Limited guidance is provided on environmental
stressors, which can also result in complaints about air quality. The sections on
diagnosis and mitigation start with brief background information and then contains
“how-to guidance. Many checklists and forms are included to assist you and your staff
in conducting an IAQ investigation. In addition, there are sections on the important
topics of communications and hiring professionals. As you read this document or turn
it over to your staff to implement, EPA and NIOSH urge you to keep a personal
involvement in this issue.
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BREAK FOR SIDEBAR
SIDEBAR
Selected Indoor Air Quality Problems
This box shows examples of IAQ problem indicators and associated responses. Some IAQ
problem situations require immediate action. Other problems are less urgent, but still merit a
response.
Problems Requiring Immediate Action
There have been complaints of headaches,
nausea, and combustion odors. Carbon
monoxide poisoning is a possibility.
Investigate sources of combustion
gases.
An occupant of yaw building has been
diagnosed as having Legionnaires disease.
This is a potentially life-threatening
illness. Request Health Department
assistance in determining whether
your building may be the source of the
infection!
Staff report that water from a roof leak has
flooded a portion of the carpeting. If damp
carpeting cannot be lifted and
thoroughly dried within a short time,
it might not be salvageable. Proper
cleaning and disinfection procedures
must be used to prevent the growth of
mold and fungus that could cause
indoor air quality problems.
Problems that Require a Response, but are not Emergencies
Inspection of the humidification system
reveals an accumulation of slime and mold.
There have been no health complaints
suggesting IAQ problems. Inadequately
maintained chillers and humidifiers
can promote the growth of biological
contaminants. Clean equipment
thoroughly, and consider modifying
maintenance practices.
A group of occupants has discovered that they
abase common symptoms of headaches, eye
irritation, and respiratory complaints and
decided that their problems are due to
conditions in the building. The symptoms
described do suggest an IAQ problem
that is not life-threatening, but It
would be wise to respond promptly.
Immediately after delivery of new furnishings
(furniture or carpeting), occupants complain of
odors and discomfort. Outgassing of
volatile compounds from the new
furnishings could be causing the
complaints.
Local news articles suggest that some
buildings in the area have high indoor radon
levels. The only way to determine the
indoor radon concentration In a given
structure is to test in appropriate
locations.
You wonder whether some old pipe insulation
contains asbestos. Asbestos can only be
positively identified by laboratory
analysis.
Ill
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DISCLAIMER
This document was prepared under contract to an agency of the United States
Government. Neither the United States Government nor any of their employees
makes any warranty, expressed or implied, or assumes any legal liability for any third
party’s use of or the results of such use of any information, product, or process
discussed in this document. Mention or illustration of company or trade names, or of
commercial products does not constitute endorsement by the U.S. Environmental
Protection Agency or the National Institute for Occupational Safety and Health.
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TABLE OF CONTENTS
Foreword
Note to Building Owners and Managers . . . .
Section 1 - How to Use this Document . . . 1
Section 2 - Factors Affecting Indoor Air Quality 5
Sources of Indoor Air Contaminants 5
HVAC System Design and Operation . . . . 7
Pollutant Pathways and Driving Forces . . . . . . 9
Building Occupants . 10
SectIon 3 - Communicating with Building Occupants . . . 13
The Importance of Open Communications 13
Responding to Occupant Complaints 14
What Needs to be Said? 14
Establishing Lines of Communication 16
Occupants as Sources of Information 17
Section 4 - Diagnosing IAQ Problems 18
Background: Conducting an IAQ Investigation 20
Tools for Collecting Information 23
Collecting Information about Occupant Complaints 25
Using the Occupant Data 30
Collecting Information about the Ventilation System . . . . 35
Using the HVAC System Data 45
Collecting Information about Pollutant Pathways and Driving Forces 50
Using Pollutant Pathway Data 52
Collecting Information on Pollutant Sources 55
Using Pollutant Source Data 58
Sampling Air for Contaminants and Indicators 60
Using Information to Form and Test Hypotheses 65
Complaints due to non-lAO Environmental Stressors . . . . 67
Section 5 - Mitigating lAO Problems - 69
Background: Basic Approaches to Controlling Indoor Air Problems 69
Sample Problems and Solutions 75
Judging Proposed Mitigation Designs and their Success . . . 91
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Table of Contents (con’t)
Section 6 - Hiring Professional Assistance to Solve an IAQ Problem 95
Make Sure that the Approach Fits Your Needs 96
Selection Ciiteria 96
Section 7: Back on Track 100
Resources 102
Appendix A: Some Common lAO Measurements 115
Appendix B: HVAC Systems and Indoor Air Quality 123
Appendix C: Common lAO Pollutants and Indicators . . . . 128
Appendix D: Moisture , Mold and Mildew 132
Appendix E: Asbestos 140
Appendix F: Radon 142
Blank Forms
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SectIon 1 - how to Use this Lodument
This guide is intended to help you understand and resolve lAO problems. It
provides fundamental information on factors which affect indoor air quality, the process
of investigating lAO complaints and communicating with building occupants during the
investigation, and commonly-used corrective actions. If you judge that outside help is
needed, the document offers guidance on the process of hiring lAO professionals. As
indoor air quality is an evolving field, building owners, managers, and engineers are
urged to keep abreast of new information through professional journals and seminars
in addition to relying on the guidance presented in this document.
EPA and NIOSH recognize that many factors influence how an individual owner or
manager can put the information in this guide to use. Some of the significant
differences are the type of ownership and management arrangement, the variety of
occupant uses of a given building or complex of buildings, and whether or not
functions such as housekeeping, pest control, and maintenance of heating, ventilation,
and air conditioning (HVAC) equipment are handled in-house or under contract with
outside services. You will know best how to integrate IAQ-related activities into your
existing organization and which of your staff have the necessary skills to carry out
those activities.
The intent of this document is to guide you through investigating and resolving
indoor air quality problems in your building. If you do not have a current problem but
are interested in preventing such problems in the future, you may want to go directly to
the companion document, PREVENTING INDOOR AIR QUALITY PROBLEMS.
It is not necessary to read this document cover-to-cover. Rather, it may be more
effective to distribute it to staff members and then make assignments according to their
responsibilities and your current needs. However, while specific responsibilities are
most appropriately handled by specific personnel (e.g. HVAC checklist by operating
engineer), it is likely that lAO problems can best be handled if building management
and operating personnel have been encouraged to skim the entire document for an
overview of the indoor air quality issue.
If you are in the process of responding to an lAO complaint, you may want to give
particular attention to Sections 2, 3 and 4.
Using Section 2 - Factors Affecting Indoor Air Quality: Section 2
provides an overview of the four factors which interact to affect indoor air quality.
• indoor and outdoor sources of contamination or discomfort
• the building HVAC (heating, ventilation, and air conditioning system)
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• pollutant pathways and drMng forces
• building occupants
A basic understanding of these factors is critical to investigating and resoMng
indoor air quality problems.
Using Section 3- Communicating with Building Occupants: Section 3
discusses communication with building occupants and suggests ways to maintain
credibility while responding to lAO complaints. The key points to understand are:
• When appropriate communications are established quickly in response to a
complaint, building occupants can be valuable allies in resolving IAQ problems.
• If basic trust is not established through a prompt response to occupant
complaints, even a small problem can have disruptive and potentially costly
consequences.
Using Section 4 - Diagnosing lAO Problems: Section 4 begins by
providing background information that will be useful to anyone who is trying to resotve
or prevent indoor air quality problems or who is charged with hiring outside
professionals to resolve such problems. This background material describes the
factors that interact to cause indoor air quality problems:
• a heating, ventilation, and air conditioning (HVAC) system that is inadequate (in
design or operation) to control contaminants
• a pathway for pollutant movement and a drMng force that moves contaminated
air along the pathways
• a pollutant source
• a recipient (the building occupant)
The section continues by describing the information-gathering strategies used to
identify the cause of an indoor air quality problem. it is expected that Section 4 will be
used as a reference by in-house staff who have been given the responsibility of
investigating the problem. It will also help building management to understand and
oversee the activities of any outside professionals who may be brought in to assist in
the investigation.
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Using Section 5 - Mitigating tAO Problems: Section 5 opens with
background material on the basic approaches to mitigating (correcting) indoor air
quality problems:
• control of pollutant sources
• modifications to the ventilation system
• air cleaning
The remainder of the section describes common indoor air quality problems and
their solutions, criteria for judging potential mitigation approaches, and methods of
determining whether a problem has been solved. This guidance will be useful in
evaluating plans for corrective action, whether it is to be handled by in-house staff or
by outside contractors.
Using Section 6 - Hiring Professional Assistance to Resolve an IAQ
Problem: Section 6 provides guidance in hiring professional assistance if you
decide that outside expertise is needed to determine the cause of the lAO problem.
Using Section 7- Back on Track: When the time pressure of facing an
immediate problem has been relieved, developing a building profile and IAQ
management plan can help to prevent future problems. Section 7 provides a brief
introduction to the points that are covered in the companion document,
PREVENTING INDOOR AIR QUALITY PROBLEMS.
Using the Resource Section: The resource section is intended for readers
who want to pursue more detailed information about indoor air quality.
Using the Appendices: The appendices present information that may not be
critical to resoMng most indoor air quality problems but could be useful reading for
additional background on major lAO topics.
Appendix A is an introduction to measurement techniques such as those used in
evaluating airf lows and measuring airborne contaminants. It may be particularly
helpful to the person who is responsible for using Section 4 to investigate the lAO
problem.
Appendix B presents basic information on HVAC systems designs as they affect
indoor air quality. The information may be useful to building owners and managers
who are not familiar with HVAC concepts.
Appendix C describes a few common indoor air pollutants and their sources.
Appendix D discusses indoor moisture and its relationship to mold and mildew
growth.
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Appendix E is a brief discussion of asbestos. If asbestos is a concern in your
building, the Resource section will direct you to sources of detailed guidance.
Appendix F is a brief discussion of radon. If radon is a concern in your building,
the Resource section will direct you to sources of detailed guidance.
Using the Blank Forms: This section contains a full set of copies of the forms
described in Section 4. You may need to modify elements of these forms to reflect
conditions in your particular building.
Please note the following warnings as you prepare to use this manual:
• Modification of building functions to remedy air quality complaints may create
other problems. A thorough understanding of all of the factors that interact to
create indoor quality problems can help to avoid this undesirable outcome.
• The guidance in this document is not intended as a substitute for appropriate
emergency action in the event of a hazardous situation that may be imminently
threatening to life or safety.
• The implementation of mitigation recommendations reached as a result of an
indoor air quality evaluation should always be done in accordance with local
laws and good practice. Changes to the overall design and operation of the
building may necessftate the involvement of a registered professional engineer
or other registered or certified professionals.
• In the event that medical records are utilized in the course of evaluating an IAQ
or comfort problem, appropriate legal confidentiality must be maintained.
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Sectlcn 2 - Iact rs Affectln
indccr Air I ualItv
The indoor environment in any building is a result of the interaction between the
sue, climate, building system (original design and later modifications in the structure
and mechanical systems), potential contaminant sources (furnishings, moisture
sources, processes and activities within the building, and outdoor sources), and
building occupants.
The following four elements are involved in the development of indoor air quality
problems:
• there is an indoor or outdoor source of contamination or discomfort
• the HVAC (heating, ventilation, and air conditioning) system is not able to
control air contaminants and ensure thermal comfort
• building occupants are present
• a po’lutant pathway and driving force connect the pollutant source to the
occupants
it is important to understand the role that each of these factors may play in order to
investigate and solve indoor air quality problems.
Sources 01 Indoor Dir Contaminants
indoor air contaminants can originate within the building or be drawn in from
outdoors. It may be helpful to think of air pollutant sources as fitting into one of the
categories listed below. The examples given for each category are not intended to be
a complete list.
• Sources outside the building
• contaminated outside air (sometimes referred to as ambient” air)
- pollen, dust
• smog
• emissions from nearby sources
- vehicle exhaust from busy roads, parking garages, loading docks
- odors from dumpsters
- re-entrained exhaust from the building itself or from neighboring buildings
- unsanitary debris near the outdoor air intake
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• soil gas
• radon
- leakage from underground fuel tanks
- contaminants from previous uses of the sfte (e.g.landf ills)
• moisture
Equipment
• HVAC system
• dust or dirt in ductwork or other components
• microbiological growth at drip pans, humidifiers, ductwork, etc.
- improper use of biocides and/or cleaning compounds
- improper venting of combustion products
• non-HVAC equipment
- emissions from office equipment (volatile organic compounds, ozone)
- supplies (solvents, toners, ammonia)
Human activities
• smoking
• personal actMties
- respiration
- body odor
-cosmetic odors
• housekeeping activities
- cleaning materials and procedures
- emissions from stored supplies or trash
- deodorizers
• maintenance activities
-dust
- volatile organic compounds (known as VOCs) from paint, caulk, adhesives
- biocides from pest control actMties
- emissions from stored supplies
Building components and furnishings
• dust
- TM fleece factor - fuzzy surfaces such as carpeting, curtains, and other
textiles
- dust-catching areas such as open shelving
- dust and fiber sources such as old or deteriorated furnishings
• unsanitary conditions and water damage
- microbiological growth on or in soiled or water-damaged furnishings
- microbiological growth in areas of surface condensation
- dry traps passing sewer gas
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• chemicals released from building components or furnishings
• materials containing asbestos
- volatile organic compounds
Other sources
• accidental events
- spills of water, paint, beverages, or other liquids
- microbiological growth due to flooding or to leaks from roofs, piping
- fire damage (soot, PCBs from electrical equipment, odors)
• special use areas and mixed use buildings
• smoking lounges
• laboratories
- print shops, art rooms
- exercise rooms
- beauty salons
• food preparation areas
• redecorating/remodelling/repair activities
- emissions from new furnishings
- dust and fibers from demolition
- odors and volatile compounds from paint, caulk, adhesives
Indoor air often contains a variety of contaminants at concentrations which are far
below any standards or guidelines for occupational exposure. It is possible that the
effects of these contaminants may be additive, synergistic (interacting in a way that
makes their combined effect stronger than their independent effects) or antagonistic
(interacting in a way that tends to cancel out their effects) under some circumstances.
These factors often make it difficult to relate complaints of health effects to the
concentration of a single specific pollutant.
HIJRC System Design and Operation
The HVAC system includes all heating, cooling, and ventilation equipment in a
building: furnaces or boilers, chillers, air handling units, exhaust fans, ductwork, steam
(or heating water) piping. A properly functioning HVAC system:
• provides thermal comfort
• distributes adequate outdoor air to all building occupants
• isolates or dilutes odors and contaminants to acceptable levels or removes
them using exhaust fans
Most air handling units distribute a blend of outdoor air and recirculated air (air
withdrawn from building spaces). HVAC designs may also include units that bring in
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100% outside air or that simply transfer recirculated air within the building.
Uncontrolled quantities of additional outdoor air enter buildings through natural
infiltration through openings. Thermal comfort and ventilation needs are met by
supplying conditioned air, often in combination with supplemental heat (e.g. radiators)
at the building perimeter. Large buildings often have interior spaces in which constant
cooling is required (to compensate for heat generated by occupants, equipment, and
lighting), while perimeter rooms require either heating or cooling according to outdoor
conditions.
Two of the most common HVAC designs used in modern public and commercial
buildings are constant volume and variable air volume systems. Constant
volume systems provide a constant airflow and vary the air temperature to meet
heating and cooling needs. The percent of outside air may be held constant, but is
often controlled to vary with outside temperature, with a minimum setting that allows
the system to meet ventilation guidelines. Variable air volume (VAV) systems
condition air to a constant temperature and vary the airflow to ensure thermal comfort.
Early VAV systems did not allow control of the outside air quantity. Some more recent
designs address this problem through the use of static pressure devices in the outside
air stream, and additional features such as economizer control or heat recovery are
also found in some buildings. Good quality installation, testing and balancing are
critically important to the proper operation of VAV systems. See AppendI I for
further discussion of HVAC system types.
The amount of outdoor air considered adequate for proper ventilation has varied
over time. The current guideline issued by the American Society of Heating,
Refrigeration, and Air Conditioning Engineers is ASHRAE 62-1989. (A table of
outdoor air quantities recommened by ASHRAE is reproduced on pages 42-44. Note
that other important aspects of the standard are not included in this table.)
Mechanical engineers can design HVAC systems to isolate odors and
contaminants by controlling pressure relationships between rooms. This is
accomplished by controlling the air quantities that are supplied to and removed from
each room. If more air is supplied to a room than is exhausted, the excess air tends to
leak out of the space and the room is said to be under positive pressure. If less air
is supplied than is exhausted, air tends to leak into the space and the room is said to
be under negative pressure. Control of pressure relationships is critically important
in mixed use buildings or buildings with special use areas. Bathrooms, kitchens, and
smoking lounges are examples of rooms that should be maintained under negative
pressure. Lobbies are often intended to operate under positive pressure to prevent
thermal discomfort. Computer rooms may be kept under positive pressure to keep out
dust.
Another technique for controlling odors and contaminants is to dilute them with
outdoor air. Some of the recirculated air is exhausted (to compensate for the outdoor
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air that is being brought in). Additional exhaust fans can be used to isolate and
remove contaminants from local areas. Where local exhaust is used, it must function
in coordination with the rest of the ventilation system. Air should be exhausted, not
recirculated, from locations which produce significant odors and high concentrations of
contaminants (such as smoking lounges, custodial closets, copy rooms, bathrooms,
kitchens, and beauty salons). Under some circumstances, ft may be practical to
transfer conditioned air from relatively clean parts of a building to comparatively dirty
areas and use it as make-up air for a local exhaust system.
Pollutant Patbwags and Driuing Forces
Airflow patterns in buildings result from the combined action of mechanical
ventilation systems and natural forces. All of a building’s components (walls, ceilings,
floors, penetrations, HVAC equipment and occupants) interact to control or to distribute
contaminants.
Pressure differentials move airborne contaminants from areas of relatively
higher pressure to areas of relatively lower pressure. This basic principle can produce
a variety of patterns of contaminant movement, including:
• local circulation in the room containing the pollutant source
• air movement into adjacent spaces that are under lower pressurization
• recirculation of air within the zone containing the pollutant source or in adjacent
zones where return systems overlap
• stack effect movement from lower to upper levels of the building
• exhaust recycling (re-entrainment of exhausted air back into the building)
Air movement between zones and between the building’s interior and exterior is
intimately linked to the building structure and the functioning of the HVAC system.
Walls, ceilings, and floors divert or obstruct airflow, while openings provide pathways
for air movement. Some openings are intentional (doors, windows, ducts); others are
accidental (cracks, holes, utility chases). It is useful to think of the entire building - the
rooms and the connections (e.g. chases, corridors, stairways) between them - as
behaving like part of the duct system. Air must move from supplies through a room to
returns, making the room serve the function of channeling the air. Any obstructions or
openings in the room can affect the direction and amount of airflow.
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As described in the previous discussion, the HVAC system is one of the dominant
forces controlling air movement in most buildings. Natural forces also exert an
important influence. Stack effect is used to describe the pressure driven flow
produced by convection (the tendency of warm air to rise) and other factors (such as
wind blowing across the top of a chimney). It draws outdoor air into openings at the
lower levels of buildings and moves indoor air from lower to upper floors. Stack effect
airflow can transport contaminants between floors by way of stairwells, elevator shafts,
utility chases, or other openings. The stack effect is strengthened when indoor air is
warmer than outdoor air. Wind effects are transient, creating local areas of high
pressure (on the windward side) and low pressure (on the leeward side) of buildings.
Depending on the leakage openings in the building exterior, wind can affect the
pressure relationships within and between rooms. Both the stack effect and wind
can overpower a building’s mechanical system and disrupt air circulation
and ventilation.
Indoor air contaminants are distributed within the building by pressure differences
between rooms and between floors. Air moves from areas of higher pressure to areas
of lower pressure through any available openings. Even if adjacent building zones
are both under positive pressure relative to the outdoors, one of them is usually at a
higher pressure than the other. Similarly, outdoor air contaminants are drawn into
buildings by pressure differences between the outdoor air and the building interior. If
the building or any zone within it is under negative pressure relative to the outdoors,
any intentional or accidental opening will serve as an entry point. For example, a
small crack or hole in the floor can admit significant amounts of soil gas, if pressure
differentials are large enough.
Although the building as a whole may be maintained under positive pressure, there
is always some location (e.g. the outdoor air intake) which is under negative pressure
relative to the outdoors. Entry of contaminants may be intermittent, occurring only
when the wind blows from the direction of the pollutant source. If the pressure
differential which brings the pollutant into the building is intermittent or acts upon
different portions of the building, the lAO problem may move from one location to
another.
Building Occupants
The term ‘building occupants’ is generally used in this document to describe
people who spend extended time periods (e.g. a full workday) in the building. Clients
and visitors are temporary ‘occupants’; they may have different tolerances and
expectations from those who spend their entire work days in the building.
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Groups which tend to be particularly susceptible to effects of poor IAQ include, but
are not limited to:
• allergic individuals, including asthmatics
• people with chronic respiratory disease
• people whose immune systems are suppressed due to chemo- or radiation
therapy, disease, or other causes
• contact lens wearers
• children
• senior citizens
• pregnant women
Sometimes only one individual is sensitive to a particular indoor air contaminant
while surrounding occupants have no ill effects. (Symptoms which are limited to a
single person can also occur when only one work station receives the bulk of the
pollutant dose.) In other cases, complaints may be widespread throughout the
building.
People often have different responses to the same pollutant. Further, different
pollutants may cause similar physical reactions. Respiratory tract irritation can result
from exposure to formaldehyde or other volatile organic compounds, dust, excessively
dry air, or other influences. Allergic reactions are caused by a wide array of materials.
For the purposes of solving IAQ problems, it is generally more useful to observe the
pattern of symptom occurrence than to focus solely on the symptoms of one individual.
However, it is worthwhile to collect symptom information in hopes that it will help you to
understand the problem.
Types of Symptoms and Complaints
Health
The effects of lAO problems are often non-specific symptoms rather than clearly
defined illnesses. Common symptoms include:
• headache, fatigue
• respiratory function problems
• eye, nose and throat irritation
• allergies (including asthma)
Building-related illness is a term referring to illness brought on by exposure to
the building air, where symptoms of diagnosable illness are identified (e.g. certain
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allergies or infections) and can be directly attributed to airborne building sources.
Legionnaire’s disease and hypersensitivity pneumonitis are building-related illnesses
that can have life-threatening consequences.
The term sick building syndrome or SBS is sometimes used to describe cases
in which a significant number of building occupants experience acute health and
comfort effects that are apparently linked to the time they spend in the building, but in
which no specific illness or etiology can be identified. The complaints may be localized
in a particular room or zone or may be widespread throughout the building. Many
different symptoms have been associated with SBS, including respiratory problems,
irritation, and fatigue. Analysis of air samples often fails to detect significant
concentrations of any contaminants, so that the problem appears to be caused by the
combined effects of many pollutants at low concentrations, with other environmental
stresses (e.g. overcrowding, noise) as complicating factors.
A small percentage of the population may be sensitive to a number of chemicals in
indoor air, each of which may occur at very low concentrations. This condition, which
is known as multiple chemical sensitivity (MCS) , is not currently recognized by the
medical establishment. Research that has been conducted to date has not been
sufficient to determine whether MCS exists, its possible causes, or effective treatments.
Further research to address these issues is planned.
Comfort
Some complaints by building occupants are clearly related to discomfort rather than
to health problems. The distinction is not always simple. One of the most common IAQ
complaints is that “there’s a funny smell in here”. Odors are often associated with a
perception of poor air quality, whether or not they cause symptoms. Environmental
stresses such as over- or under-heating, humidity extremes, drafts, lack of air
circulation, noise, vibration, and overcrowding can produce symptoms that may be
confused with the effects of poor air quality. For example, excessive heat can produce
fatigue, stuffiness, and headache, while low temperatures can cause chills and “flu-
like” symptoms. Further, physical discomfort or psychosocial problems (such as job
stress) can reduce tolerance for substandard air quality.
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S [ CIIO1 3 - CCMMU ICAtP G WiTh
t UILLiP G ()CCIJI)A IS
In many cases, building managers may be alerted to potential indoor air quality
problems by complaints from occupants. The complaints can be vague, to the effect
that one or more people feel sick” or uncomtortable or that someone has noticed an
unusual odor. They may be specific, blaming a particular material as the cause of
discomfort or health problems.
Indoor air quality problems often vary over time as occupant activities and
mechanical system operation affect building dynamics. IAQ complaints can, and often
do, arise from a combination of conditions rather than a single cause. It is critically
important to treat occupant complaints seriously and respond in a straighfforward way
to their inquiries.
A single complaint is sufficient to indicate an lAO problem, and every complaint
deserves a prompt response. The guidance provided by ASHRAE 62-1989
may be interpreted as meaning that indoor air quality is acceptable if fewer than
20% of bu4ding occupants complain. However, this rule of thumb reflects the
practical impossibility of guaranteeing thermal comfort for every occupant; it is
not applicable to other types of lAO complaints.
Communication requires an interaction between the owner, manager, facilities
staff, and building occupants. Each can play a different, and imporlant role, in
maintaining good indoor air quality in a building and, if problems do occur, in
helping to identify and resolve those problems.
The Importonte of Open Communicntlon
Indoor air quality problems can sometimes be identified and resolved quickly. On
other occasions, complaints originate from the interaction of several variables, and
detailed investigation may be necessary in order to resolve the problem. Listening
and responding to building occupants is critical to achieving a successful resolution of
indoor air quahty complaints. Without open communication, any lAO problem can
become complicated by frustration and distrust, delaying its resolution.
lAO complaints sometimes arise from labor-management conflicts or other ob
stresses. One employee’s expressions of discomfort or illness can generalize to
others in the same work area. Individual variations in comfort mean that it is probably
impossible to satisfy all occupants of a building. However, it is in the building
managers best interest to respond to all complaints about the indoor environment
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promptly and seriously and to establish credibility through open communications with
building occupants. The biggest mistake that building managers can make in the face
of an lAO complaint is to underestimate the anxiety and frustration that can result if
building occupants believe that no action is being taken or that important information is
being withheld.
Responding to Occupant Complaints
If there are no established procedures for communicating with building occupants
and an lAO complaint arises, consider developing a communications plan that
includes the following key elements:
• Define the complaint area based upon the location and distribution of
complaints. (The extent of the complaint area may be revised as time goes on.)
• Identify key people (tenants, supervisors, building staff, management). Work
with the health and safety committee, if you have one. If you have no health and
safety committe and the problem is widespread or appears serious, consider
establishing a joint management-tenant task force to help collect and
disseminate information during the investigation and correction of the problem.
• Establish a system to record the timing and location of complaints. This could
include complaint logs, symptom logs, and/or occupant questionnaires.
What Needs to be Said?
Paying attention to communication channels as soon as an IAQ problem arises
helps to ensure the support and cooperation of building occupants as the complaint is
investigated and resolved. The message to be conveyed is that management believes
that it is important to provide a healthy and safe building, that good indoor air quality is
an essential component of a healthful indoor environment, and that complaints about
indoor air quality are taken seriously.
If a number of occupants are making complaints and an lAO problem of some
sort is suspected, building managers may want to consider communicating directly
with occupants who have complaints or with ocupants in general. Notices or
memoranda can be delivered directly to selected occupants or posted in general use
areas. (Many building managers are used to posting announcements about other
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types of building problems that are being corrected.) Such notices might contain
succinct information about:
• what types of complaints management has received
• management’s policy in regard to
- providing a healthy and safe environment
- responding to occupant complaints
• what management has done to date (e.g. collecting data, responding to the
problem)
• what management plans to do in order to further investigate and correct the
problem (including the fact that outside consultants have been called in, if they
have been)
• the names and telephone numbers of appropriate facilities management,
medical, or health and safety staff to whom the occupants should turn if they
have additional complaints or questions, Or it they have information that may
help in resolving the complaints
As investigation of the IAQ problem continues, occupants may become frustrated by
delays and skeptical that building management is proceeding in good faith. This
exasperation could hamper attempts to resolve the problem if occupants begin to lake
matters into their own hands by attempting to adjust grilles and dampers or interfering
with equipment operation in other ways. On the other hand, building occupants can
be valuable allies in solving lAO problems, particularly in observing patterns of odors
or other lAO phenomena. To encourage this cooperation, it is advisable to take
occupants’ theories into account during the investigation.
Productive relations will be enhanced if occupants are given basic information
during the process of investigation and mitigation, such as:
• the progress of the investigation, including the types of information which are
being gathered and ways that they can help
• the seriousness of the health problems being reported (this helps people to
put their symptoms into perspective)
• the estimated duration of the investigation
• attempts which are being made to improve indoor air quality
• work which remains to be done and ihe schedule for its completion
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It is advisable to explain the nature of investigative activities, so that rumors and
suspicions can be averted with factual information. Problems can arise from saying
either too little or too much. Premature release of information when data-gathering is
incomplete can produce confusion, frustration, and mistrust at a later date. Similar
problems can result from incorrect representation of risk- assuming the worst case (or
the best). However, if progress reports are not given, people may think nothing (or
something terrible) is happening.
The vague discomfort, intermittent symptoms, and complex interactions of job stress
with environmental factors which make IAQ problems difficult to investigate can also
obscure the effects of mitigation efforts. Even after the proper mitigation strategy is in
place, it may take days or weeks for contaminants to dissipate from indoor air. If
building occupants are informed that their symptoms may persist for some time after
mitigation, the inability to bring instant relief is less likely to be interpreted as a failure.
Establishing Lines of Communication
An early step in establishing communications is the identification of responsible
personnel who can receive and respond to IAQ complaints. Tenants may also have
an internal system for channeling complaints, for example through a supervisor or
company doctor.
Indoor air quality complaints which can be resolved quickly and which involve
small numbers of people (odors from an easily-identified source, for example) can be
handled matter-of-factly like other minor problems without risking confusion and bad
feeling among other building occupants. Communication becomes a more critical
issue when there are delays in resolving the problem and when serious health
concerns are involved.
If the problem seems to be widespread or potentially serious, it is advisable to work
with your health and safety committee. If you do not have a health and safety
committee, consider forming a joint management-tenant lAO task force. This
group will be most successful if it represents the diverse interests in the building,
including:
• building owner
• building manager
• facilities personnel
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• health and safety officials
• occupants of the lAO complaint area (this may be as small as a single
room or HVAC zone, or may encompass the whole building)
• union representatives (if they represent occupants in the complaint area)
Potential critics can become allies if they are invited to be part of the problem-
solving process and are educated about lAO and building operations. Building
managers may be understandably reluctant to share test results or consultants’ reports
with their tenants or employees, but secrecy in such matters can backfire if information
leaks out at a later time.
As the lAO investigation progresses, newsletter articles or other established
communications channels can be used to keep building occupants up-to-date.
Notices posted on bulletin boards will not necessarily be widely-read; it is sometimes
worth the effort to put a memo on every desk.
Occupants as Sources of Information
Written records of the nature of the symptoms, location, and timing of complaints
are important for understanding lAO problems. If an IAQ complaint logging system is
not already in place, it would be a good idea to set one up as soon as an apparent
problem arises. An example COMPLAINT LOG is provided in the I Iank ftrms
section of this document. When more detailed information is needed, the occupants
may be interviewed or asked to respond to a questionnaire.
lAO complaints often change over time. Occupants of the complaint area can help
the investigation by recording the time and location of odors or other IAQ observations
and whatever events seem to occur at the same time (e.g. strong winds, use of
machinery). This occupant diary can be compared to a log of activities and system
operations (kept by facilities staff) to shed light on the relationship between IAQ
incidents and HVAC functions or other phenomena.
The lAO investigation will be most successful in an atmosphere of trust and
cooperation between management, facilities staff, and other building occupants.
However, confidentiality of records can be important to occupants, especially if they
are concerned that lAO complaints will lead to negative reactions from their employers.
There may be legal penalties for violating confidentiality of medical records.
Reassurance that privacy will be respected can help investigators obtain honest and
complete information. Questionnaires which are distributed to groups of people within
the building can be coded to provide as much anonymity as possible.
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S [ CTIC 4 - HM3%CSI%& IAC R?CI L [ MS
It is difficult to select the most effective and permanent solution to a problem unless
you understand its cause. This section begins with a discussion of the factors that
interact to create indoor air quality problems. It then describes how to conduct an
indoor air quality investigation and presents a ‘toolbox” of diagnostic activities to
assist you in collecting information.
Many indoor air quality complaints can be resolved without using all of the
diagnostic “tools” described in this chapter. Some IAQ complaints can be diagnosed
simply by observing components of the building mechanical system which require
cleaning or adjustment to function properly. Similarly, most mechanical or carpentry
problems probably require only a few of the many tools you have available and are
easily accomplished with in-house expertise. On the other hand, some jobs may be
best handled by contractors who have specialized knowledge and experience. In the
same way, diagnosing some indoor air quality problems may require equipment and
skills that are complex and unfamiliar. Your knowledge of your organization and
building operations will help in selecting the right tools and deciding whether in-
house personnel or outside professionals should be used in responding to the specific
lAO problem.
The goal of the diagnostic building investigation is to identify and solve the indoor
air quality complaint in a way which prevents it from recurring and which does not
create other problems. To achieve this goal, it is necessary to:
• discover whether the complaint is related to indoor air quality;
• identify the cause of the complaint; and
• determine the most appropriate corrective actions.
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Conducting an lAO Investigation
STAR1 Reason for concern
lN AL WAU(THROUGH
• preparation
• visuai inspection
• taflc with occupants and staff
Doyouhavean
explanation
for the
$
Note: Outside assistance may be needed at any point
in the inveStigation, depending upon the complexity of
the problem, the skills available in-house, time pressures,
or other factors.
19
Make necessary changes
so that the problem
w I not recur.
DRAFT
I
—0
COLLECT ADDITIONAL INFORMATiON
about:
• Building occupants
• the HVAC system
• Pollutant pathways
• Pollutant sources
(sample contaminants if needed)
DEVELOP ONE OR MORE HYPOTHESES
to explain the problem. Test your hypotheses
by manipulating building conditions.
-------
•ockground: Conducting on IOU Inuiestigotion
The flowchart on page 19 shows the process of an lAO investigation. The
investigation is spurred by one or more reasons for concern, such as occupant
complaints. Some complaints can be resolved very simply (e.g. by asking a few
common sense questions of occupants and facilities staff during the initial
walkthrough). At the other extreme, some problems could require detailed testing by
an experienced lAO professional. In this section Nthe investigators refers to in-house
staff responsible for conducting the lAO investigation.
The goal of the investigation is to understand the lAO problem well enough so that
you can solve it. This understanding can be described as a “hypothesis , an educated
guess about the cause of the complaint(s). As the flowchart shows, the lAO
investigation is a cycle of information gathering, hypothesis formation, and hypothesis
testing. An initial walkthrough of the problem area provides information about all four
of the basic factors influencing indoor air quality (occupants, HVAC system, pollutant
pathways, and contaminant sources). The initial walkthrough may provide enough
information to resolve the problem. At the least, it can help to direct further
investigation. For example, if the complaint concerns an odor from an easily-identified
source (e.g. cooking odors from a kitchen), you may want to study pollutant pathways
as a next step, rather than interviewing occupants about their patterns of discomfort.
Whenever a hypothesis suggests itself, It is reasonable to pause and
consider It. Is the hypothesis consistent with the facts you have collected so far?
You can test your hypothesis by manipulating the potential source, the pollutant
pathway, or the ventilation system and observing how that manipulation affects the
symptoms or other conditions in the building. If your hypothesis successfully predicts
the results of your manipulations, then you may be ready to take corrective action. If
your hypothesis does not seem to be a good predictor of what is happening in the
building, you probably need to collect more information. Under some circumstances,
detailed or sophisticated measurements, pressure differentials, pollutant
concentrations or ventilation quantities may be required. Outside assistance may be
needed if repeated efforts fail to produce a successful hypothesis or if the information
required calls for instruments and procedures that are not available in-house.
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INITIAL WALKTHROUGH
You should organize your effort before starting the walkthrough, even though you
will not be using formal checklists or worksheets. The preparations can be focussed
on a localized “problem area” or extended to include the entire building:
• Document easily-available information about the history of the building and of
the complaints.
• Identify known HVAC zones and complaint areas. Begin to identify potential
sources and pollutants (e.g. exhaust from attached parking garages, chemical
odors from print shops). A copy of mechanical and floor plans are helpful at this
stage, especially if they are reasonably up-to-date.
• Notify the building occupants of the upcoming investigation - what it means and
what to expect.
• Identify key indMduals needed for access and information. A person familiar
with the building’s HVAC systems should be available to assist the investigator
at any time during the onsite phase. Individuals who are responsible for the
complaints or who are in charge of potential sources (e.g. housekeeping, non-
HVAC equipment) should be aware that their information is important and
should be contacted for appointments or telephone interviews if they will not be
available during the onsite visit.
The initial walkthrough provides an opportunity to question complainants about the
nature and timing of their symptoms and to briefly examine the immediate area of the
complaint. Without taking measurements, the investigator attempts to identify pollutant
sources and types and observes the condition and layout of the HVAC system serving
the complaint area. Facilities staff can be asked to describe the operating schedule of
equipment. Obvious problems (e.g. blocked diffusers, malfunctioning air handlers)
can be corrected to see if the complaints disappear. This approach can solve many
routine lAO problems and suggest directions for more complex investigation if
necessary.
It may help to keep the following questions in mind during the walkthrough:
• Are there any conditions occurring in the building which could be related in
timing, location and health effects to the complaints?
• Are there any HVAC deficiencies in the complaint area?
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• Are there obvious pollutant sources? Do they appear to be adequately
controlled? Are pollutant indicators present, such as odors, excessive dust, or
staining?
• Are there pathways and pressure differences which could be introducing
contaminants from the outdoors or from other building areas?
• Are there sanftation problems (e.g. debris near outdoor air intake, visible mold
growth, major water damage) that could be introducing air contaminants?
The initial walkthrough could have any of three possible results:
(1)The apparent cause(s) of the complaint(s) are identified. Remedial action and
follow-up evaluation will confirm whether the hypothesis is correct.
(2) Other lAO problems are identified which are not related to the original
complaints. These problems should be corrected when appropriate.
(3) Potential lAO problems are still not well understood. Further study of potential
sources, pathways of pollutant movement, or HVAC operation is needed in
order to develop a plan for corrective action. It may be necessary to expand the
scope of the investigation to include building areas which were previously
overlooked.
COLLECTING ADDITIONAL INFORMATION
Additional information will be needed if the initial walkthrough does not identify the
cause of the problem. The following pages present techniques for collecting
information about the occupant complaints, HVAC system, pollutant pathways and
pollutant sources and using that information to develop a hypothesis that could explain
the problem. Common sense will determine the appropriate sequence of steps during
this part of the investigation. For example, it may make sense to look over the HVAC
system before interviewing building occupants.
The investigator should make the following preparations:
• Make copies of forms and checklists (modified if needed) to record information.
Small copies of basic floor plans (e.g. fire evacuation plans) are convenient for
noting locations of observations.
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• Collect any instruments needed to conduct measurements and inspect them
to make sure they are in working order and calibrated as required.
Investigations should include chemical smoke tubes (with a squeeze bulb
and a tube snapper), a thermometer, and a device to measure humidity
(sling psychrometer , thermohygrometer, etc.). These basic tools represent a
minimum. Carbon dioxide measuring devices (detector tubes with a hand
pump or a direct reading meter) are helpful for most investigations.
Other instruments may be needed as the investigation progresses.
Analysis of the information during this phase of your investigation could produce
any of the following outcomes:
(1) The apparent cause(s) of the complaint(s) are identified. Remedial action and
follow-up evaluation will confirm whether the hypothesis is correct.
(2) Other lAO problems are identified which are not related to the original
complaints. These problems should be corrected when appropriate.
(3) Potential lAO problems are still not well understood. Outside assistance may be
needed.
(4) The cause of the original complaint cannot be identified. However, a thorough
investigation has found no deficiencies in HVAC design or operation or in the
control of pollutant sources, and there have been no further complaints. In the
absence of new complaints, it appears that the original complaint may have
been due to a single, unrepeated event or to factors unrelated to the building.
USING OUTSIDE ASSISTANCE
Some indoor air quality problems may be difficult or impossible for in-house
investigators to resolve. Special skills or instruments may be needed. Other factors
can also be important, such as the benefit of having an impartial outside opinion. You
are best able to make the judgement of when to bring in an outside consultant. See
Section 6 for a discussion of hiring professional assistance to solve an lAO problem.
Tools for Collecting Information
The following pages present strategies, tools and forms for the investigator to use
during the in-house investigation. Note that indoor air quality-related complaints may
develop in response to a variety of causes. Neither the discussion of strategies for
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collecting information nor the suggestions for interpreting data can present the full
range of possible situations encountered in buildings. They are intended to present a
problem-solving approach that can help facilities staff to understand and resolve many
common indoor air quality problems. If you decide to hire outside professionals to
resolve your IAQ complaint, this discussion of strategies and tools should help you to
understand and oversee their investigative work.
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Collecting Information about Occupant Complaints
Strategies and Tools:
• Review records of complaints
use existing records or initiate use of COMPLAINT LOG
• Interview occupants
OCCUPANT INTERVIEW
OCCUPANT QUESTIONNAIRE
• Ask occupants to document their observations
OCCUPANT DIARY
Occupant data falls into two categories: complaints of discomfort or other symptoms
(e.g. teary eyes, chills) and perceptions of building conditions (e.g. odors, draftiness).
You can gather valuable information regarding potential indoor air problems from
listening to occupants. This information can be useful in:
• defining the complaint area within the building
• suggesting directions for further investigation by
• identifying other events that seem to happen at the same time as the
incidents of symptoms or discomfort
• identifying the types of symptoms or discomfort that are occurring
• indicating potential measures to reduce or eliminate the problem
The investigation should include information from building occupants who do not
have complaints. This allows comparison of conditions in the complaint area to similar
building locations in which there are no complaints.
Review Existing Records of Complaints
If there is a record of occupant complaints, a review of that record can help to define
the location of the lAO problem and identify people who should be interviewed as part
of the investigation. Information about the history of complaints could also stimulate
theories about potential causes of the problem.
If you do not already have a system for recording and processing occupant
complaints, the companion to this document offers a sample COMPLAINT LOG
form. (See PREVENTING INDOOR AIR QUALITY PROBLEMS, Hank
hrms section).
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Interview Occupants
The most obvious way to collect information from building occupants is to talk to
them in person. If it is not possible to interview everyone who has complained about
building conditions, the investigator should attempt to pick a representative sample (for
example, several people from each area where complaints occur and from similar non-
complaint areas).
Distribution of a questionnaire that occupants can fill out themselves may help the
investigator(s) to collect information from more people than could easily be
interviewed. The example of an OCCUPANT QUES11ONNALRE shown in the
[ lank l rms section may not be appropriate for use by in-house investigators and
is best used by people with public health, industrial hygiene, or medical training.
A sample OCCUPANT INJ’ERVLEW form is shown on page 27 (there is another
copy in the [ lank lcrms section). It can also be presented in a written form (i.e. as
a short questionnaire). The following key points will help interviews to be productive:
• Choose a location in which the person you are interviewing feels comfortable to
speak freely.
• Read the discussion of evaluating occupant data before you conduct interviews,
to be certain that you understand what sort of information is needed.
• Make a copy of the interview form for each person you speak with, and use the
form to record the answers to your questions.
• Feel free to expand the interview by adding questions that explore your
hypotheses about what may be causing the problem. However,always be open
to answers that may not fit your hypotheses.
• Explain that the interview is intended to help discover and correct the cause of
the complaints. Encourage the person you are interviewing to join in this
cooperative problem-solving effort.
• If complainants are reluctant to answer questions about specific heath
symptoms (such as questions 2 and 5 below), respect their desire for privacy.
• Give the person you are interviewing enough time to think about your questions.
• You may sometimes need to clarify a question by giving examples of the sort of
information you are interested in. Try to provide more than one example so that
you don’t seem to be telling the person the answer you want.
26
D ?’flT
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OCCUPANT INTERVIEW
Name____________________ Building namelwkh’ess_____
Work Location__________________________
Date of Inteaview ________________________ Interviewer___________
I) Where do you spend most of your time in the building?
Where are you when you experience symptoms (or discomfort)?
2) What kind of symptoms or discomfort are you experiencing?
3) When did your symptoms start?
When are they generally worst?
Have you noticed any other events (such as weather events or activities in the building) that tend to occur around
the same time as your symptoms?
4) When are your symptoms relieved?
5) Do you have allergies or other health problems that may make you particularly sensitive to environmental problems?
Do you wear contact lenses?
6) Do you have any complaints about bwlding conditions?
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Statistically defensible questionnaires and distribution methods, which are
useful for quantitative epidemiology may be appropriate for IAQ research, detailed
investigations, or when litigation is a possibility.
Ask Occupants to Document Their Observations
An OCCUPANT DIARY is likely to produce more accurate and detailed
information than can be obtained by relying on memory. The individual is asked to
record the timing of his or her symptoms and/or discomfort and observations of other
events as they occur.
A portion of an OCCUPANT DIARY form is shown on page 29 (it is reproduced in
full in the flank Icrms section). The most important information to obtain from this
record are the times at which incidents of health symptoms or discomfort occur and the
locations of the complainant on those occasions. Judgements of symptom severity
may be expected to vary from person to person, but can provide some guidance about
the degree of exposure to a pollutant or other stressor. The duration of the symptoms
may show a relationship with other events in or around the building (e.g. equipment
operation, weather events). The occupant is encouraged to use the “Comments
section to note any observations he or she thinks could help promote understanding of
the problem.
Consider having the building manager or facilities staff fill out the LOG OF
ACTIVITIES AND SYSTEM OPERATIONS (see page 38 and the flank Ferms
section) during the same time period as the occupants are asked to keep their diary.
The log of activities and system operations records events such as the operation of
HVAC equipment and potential pollutant sources (e.g. loading docks, kitchen
equipment). It can be cross-referenced against the occupant diary and help to show
whether or not the symptoms seem related to other events occurring in the building.
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CCUPANT DIARY
Pnmal7 Location in the building —
Phone
On the form below, please record each occasion that you experience a symptom of ill-health or discomfort
that you think may be linked to environmental conditions in the building.
ft is important that you record the time and date and your location within the building as accurately as
possible, because that will help to identify conditions (e.g. equipment operation) that may be associated with
your problem. Also, please try to describe the severity of your symptoms (e.g. mild, severe) and their
duration , the length of time that they persist. Any other observations that you think may help in identifyir
the cause of the problem should be noted in the column marked comments . Feel free to attach additional
pages or use more than one line for each event if you need more room to record your observations.
Time/Date
Location
Symptom
Seventy
Duration
Comments
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Using the Occupant Data
Strategies:
• Use the spatial pattern of complaints to define the complaint area
• Look for patterns in the timing of complaints
• Look for patterns in the types of symptoms or discomfort
Use the spatial pattern of complaints to define the complaint area
Building location(s) where symptoms or discomfort occur define the complaint area
that should be given particular attention during the initial investigation. The complaint
area may need to be revised as the investigation progresses. Pollutant pathways can
cause occupant complaints in parts of the building that are far removed from the
source of the problems.
SPATIAL PATTERNS SUGGESTIONS
Widespread, no apparent - check ventilation for entire building
spatial pattern - check outdoor air quality
- review sources that are spread throughout
building (e.g. cleaning materials)
• Localized - review ventilation within and sources
affecting the complaint area
- HVAC system may be source or distributor
of pollutants
• Individual(s) - review local source(s) near the affected
individual(s)
- consider that common background sources
may affect only sensitive individuals
Look for patterns In the timing of complaints
The timing of symptoms and complaints can indicate potential causes for the
complaints and provide directions for further investigation. Review the data for cyclic
patterns of symptoms (e.g. worst during periods of minimum ventilation or when
specific sources are most active) that may be related to HVAC system operation or to
other activities in and around the building.
30
DRAFT
-------
TIMING PATTERNS SUGGESTIONS
• Symptoms begin andlor are - review HVAC operation; emissions from
worst at the start of the building materials may build up during
occupied period unoccupied period
• Symptoms worsen over course - consider that ventilation may not be
of occupied period adequate to handle routine activities or
equipment operation within the building
• Intermittent symptoms - look for daily, weekly, seasonal cycles or
weather-related patterns, check linkage to
other events in and around the building
• Single event of symptoms - consider spills, other unrepeated events as
sources
• Symptoms relieved on leaving - suggests that the problem is likely to be
the building. They may be building-related, though not necessarily due
relieved immediately, overnight, or to air quality.
(in some cases) after extended
periods away from the building.
• Symptoms never relieved, - the problem may not be building-related
even after extended absence from
building (e.g. vacations)
Look for patterns in the types of symptoms or discomfort
IAQ investigations often fail to conclusively prove that any particular pollutant or
group of pollutants are the cause of the problem. Such causal relationships are
extremely difficult to establish because the typical levels of pollutants found indoors
are much lower than the levels at which traditional toxicology has linked pollutants to
spec ic health effects. Instead of reviewing occupant health and discomfort data for
specific pollutant and health effect relationships, it may be more useful to look for
patterns of symptoms that suggest the possible occurrence of general medical
syndromes. Note that the confidentiality of medical information may be protected by
law in some jurisdictions.
The following chart lists some syndromes that can be related to indoor air quality,
their typical symptoms, and possible sources or causes of those syndromes. Building
managers are cautioned that this is only a partial listing of a few common symptom
groups and their potential causes. Investigators who are not medically trained cannot
make a diagnosis and should not attempt to interpret medical records.
31
-------
SYMPTOM PATTERNS
SUGGESTIONS
• Thermal discomfort
(overheating, overcooling)
• Health syndromes
- Headache, lethargy, drowsiness,
dizziness
- congestion; swelling, itching or
irritation of eyes, nose, or throat;
sore or dry throat; watering or
burning eyes; may also be
accompanied by other non-
specific symptoms such as
headache, fatigue and nausea
- cough; shortness of breath; fever,
chills +/or fatigue follow re-
exposure to the building
- diagnosed infection such as
Legionnaires or histoplasmosis,
related to bacteria or fungi found
in the environment
• Other stresses: Discomfort or
health complaints which cannot be
readily ascribed to air contaminants
or thermal conditions
- check HVAC condition and operation
- measure temperature and humidity (see
chart of comfort range - page 33)
- check for drafts and stagnant areas
- check for excessive radiant heat gain or
loss (e.g. locations by windows)
If onset was acute, arrange for medical
evaluation, as the problem may be carbon
monoxide poisoning.
-check combustion sources for uncontrolled
emissions; check outside air intakes for
nearby sources of combustion fumes.
- consider other pollutant sources
- check overall ventilation; see if areas of
poor ventilation coincide with complaints
May be allergic, if only a small number or
percentage of people are affected; more
likely to be irritational response if a large
number of people are affected.
- urge medical attention for allergies
- check for dust or microbial contamination
due to sanitation problems, water damage or
contaminated ventilation system
- check outdoor allergen levels
• check closely for sources of irritating
chemicals such as solvents or formaldehyde
May be hypersensi:ivuy illness. A medical
evaluation can help identify possible causes.
- check for microbial contamination due to
sanitation problems, water damage or
contaminated ventilation system
Contact your local or state Health
Department for guidance.
May be due to other environmental stressors
• check for problems with lighting, noise,
vibration, ergonomics, human relations as
needed.
32
DE AFT
-------
BREAK FOR ILLUSTRATION 3-2
ACCEPTABLE RANGES OF OPERA11VE TEMPERATURE AND HUMiDITY
(ASHRAE 55-198 1)
Sc
20 15
w
I5
w
0
w
t-. 10
z
0
0.
w
0
0
-5
-10
55
50
45
I I
20
OPERATIVE
0.
90’F
Flprt 2 Acc tib ri. n if epirid’, Ie.p.iil.r, 1.4 iuldft) 1w pen... doth.d I. fypksl....
f 1.4 1SWV d tWsg. St h$ I SIuPy si4e . r sc i ( 1.3
Reprinted with permission from ASHRAE 55-198 1, “Thermal Environmental Conditions for
Human Occupancy”
Note to reviewers: There is considerable debate among researchers, lAO
professionals and health professionals concerning recommended levels of relative
humidity. In general, the range of humidity levels recommended by different
organizations seems to run from 30% to 60%. However, some professionals
concerned with biologicals are reluctant to support any recommendations that would
foster the use of mechanical humidification systems. EPA is particularly interested in
receiving comments concerning appropriate guidance on relative humidity.
33
r
0
0
0
0
lo
0
I—
4
>.
I—
52
I
.
70
65
60
40
35
30
25
20
IS
5
60 70 80
I I I I I I I I i i i i I i
25 30C
TEMPERATURE
-------
Do you have a hypothesis that might explain the complaints?
Use the HYPOTBISIS FORM on page 66 to make notes on what you have learned.
If you have enough information to suggest a potential explanation for the lAO
complaints, it may be valuable to use that information to:
• direct further investigation
• test a hypothesis by manipulating the apparent pollutant source, ventilation,
or pathways of contaminant movement and observing the effects of
the manipulation.
What additional information is needed at this point?
If you need addttional data that is more detailed or more quantitative, consider
whether in-house expertise and instruments can supply that information or whether
outside assistance is needed.
34
DRAFT
-------
Collecting Information about the Ventilation Sgstem
Strategies and Tools:
• Review existing documentation on HVAC design, installation, and operation
existing documentation: design documents, testing and balancing reports
• Talk to facilities staff
LOG OF ACTIVITIES AND SYSTEM OPERATIONS
• Inspect system layout, condition, and operation
HVAC CHECKLIST
thermometer
a device to measure pressure differentials
qualitative: chemical smoke tubes (with squeeze bulb and tube snapper)
Note: The smoke should not be inhaled and should be used in small
quantities, as it is toxic. Also note that chemical smoke can set off smoke
detectors.
quantitative: manometer (sensitivity 0 - 100 pascals)
a device to measure humidity. e.g. sling psychrometer
a device to assess airflow from diffusers
qualitative: strip of tissue paper
rough quantitative: plastic bag of known volume (e.g. garbage bag), clock;
anemometer; velometer
precise quantitative: flow hood
Other instruments may be needed as the investigation progresses, such as:
carbon dioxide measuring devices
detector tubes with a hand pump
direct reading meter
tracer gases and equipment to release and measure them
IAQ complaints often arise because the quantity or distribution of outside air is
inadequate to serve the ventilation needs of building occupants. Problems also may
be traced to air distribution systems which are introducing outdoor contaminants or
transporting pollutants within the building.
The design, condition, and operation of the HVAC system should be investigated to
see if it fits the current usage of the building and should also be compared to existing
ventilation standards (e.g. ASHRAE 62-1989, see pages 42-44). Increasing
ventilation to the rates contained in ASHRAE 62-1989 is likely to improve indoor air
quality; however,
35
-------
achieving these rates will not guarantee healthful indoor air quality if strong
contaminant sources are present. In particular, in EPA’s view these rates are not
sufficient if smoking is taking place.
The investigation should begin with the HVAC system(s) that serve the complaint
area and surrounding rooms, but will need to expand if connections to other areas are
discovered. Your goal is to understand the system’s design and operation well
enough to answer the following questions:
• Should the definition of the complaint area be expanded based upon the HVAC
layout and operating characteristics?
• is the HVAC system functioning adequately to serve the use of the building?
• U there are ventilation (or thermal comfort) deficiencies, are they caused by
operating and maintenance problems or by a system design that does not fit
current needs?
Sources of information for the ventilation evaluation include: discussions with
operating personnel, onsite inspection, and review of available documents. Limited
temperature, humidity, air flow, CO 2 measurements, and smoke tube observations may
be necessary. Complex investigations may require more extensive or sophisticated
measurements of the same variables (e.g. repeated CO 2 measurements taken at the
same location under different operating conditions).
Note: Biological contamination in the HVAC system can pose a serious
health hazard for building investigators. The array of potential
contaminants makes it difficult to know what sort of personal protection
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. II there is reason to suspect biological
contamination (e.g. visible mold growth), protective equipment such as a
positive pressure air mask may be needed.
Steps in Collecting Information about the Ventilation System
1) review documentation on HVAC design, installation, and operation
A review of existing documentation (e.g. plans, specifications, testing and
balancing reports) should provide information about the original design, particularly:
• the HVAC system type (e.g. constant volume, VAV)
• locations and capacities of HVAC equipment serving the complaint area
• the planned use of each building area
36
DRAFT
-------
• supply and exhaust air quantities
• location of the outside air intake and supply and return diffusers and grilles
serving the complaint area
The most useful way to record this information is to make a floor plan of the
complaint area and surrounthng rooms. You may be able to copy an existing floor
plan from architectural or mechanical drawings, fire evacuation plans, or some other
source.
If there is no documentation on the mechanical system design, on-site inspection
(including airflow and/or pressure measurements) will be needed to reach an
understanding of the HVAC system.
2) talk to lacilities staff
Facilities staff can provide important current information about equipment operating
and maintenance schedules and breakdowns or other incidents. There may be
inspection reports or other written records available for review. Some facilities
operators have extensive preventive maintenance programs.
lAO 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. A LOG OF ACTIVI11FS AND SYSTEM
OPERATIONS such as the example shown on page 38 can be helpful, particularly if
occupants are asked to keep an occupant diary at the same time.
The sample LOG OF ACTIVITIES ANI) SYSTEM OPERATIONS (reproduced in
the I Iank Icrms section) should be adapted to reflect personnel responsibilities
and equipment in your specitic building. You may want to have input from more than
one person or department. Naming the air handlers and other equipment items of
interest will help staff to focus their attention. Critical equipment includes air handlers
and exhaust fans serving the immediate area of the lAO complaint and its surrounding
rooms. The staff may have theories about the cause of the problem that can be helpful
in selecting equipment and activities to include in the log, such as:
• air handling units may be drawing in fumes from exhaust fans (record wind
direction and the times of operation of exhaust fans and air handling units)
• exhaust fumes from delivery trucks may be entering the building (record
delivery dates and the times that trucks arrive and depart; compare to the timing
of complaints as recorded in an OCCUPANT DIARY)
37
DRAFT
-------
LOG OF ACTJVHTES AND SYSTEM OPERATIONS
Name________________ Position________________ Pbone_
On the form below, please record your observations of HVAC system operation, maintenance activities,
weather events, and any other information that you think might be helpful in identifying the cause of LAC
complaints in this building. The items of equipment listed below are of particular interest; however, any othe
observations you think may be important should be reported as well.
Feel free to attach additional pages or use more than one line for each event.
Equipment of interest :
AirHandler_______________ Area Served:
Air Handler:________________ Area Served:.
Air Handler:________________ Area Served:.
Exhaust Fan: ___________________ Area Served:
Exhaust Fan: ___________________ Area Served:
Exhaust Fan: ___________________ Area Served:,
Exhaust Fan: _________________ Area Served
Fiwe/Date Item of Equipment Observation Comments: (weather. other associated events)
WWWW\ ’W /N’
38 DRAFT
-------
3) inspect system layout, condition, and operation
If the building is new or if there is a preventive maintenance program with recent
testing and balancing reports available for inspection, it is possible that the HVAC
system is functioning according to its original design. Otherwise it is likely that one or
more features of building usage or system operation have changed in ways which
could affect indoor air quality.
The HVAC CHECKLIST can be helpful in reminding the investigator about the
elements of the HVAC system that affect air distribution and air quality in the building.
A portion of the form is reproduced below. A full length checklist is reproduced in the
[ lank E rms section. along with a blank form that you can use to create a list for
your specific building.
HVAC CHECKLIST
BuiIchn
Dale Checked ____________________ Inspected by
Component
OK
Needs
Attention
Not
Checked
Comments
Fans
location
fan blades clean?
belts guaided?
belts prop 1y tensioned?
excess vibmtion?
ci mded boi mg?
controls woikii g. calibrated?
cootrol setpoints correct?
no pnewi tic leaks?
39
DRAFT
-------
While you are inspecting the HVAC system, it is important to confirm the accuracy
of reported operating schedules and controls sequences; for example, power outages
may have disrupted time clocks, fans reported as ‘always running’ may have been
accidentally switched off, and controls can be in need of calibration. These may seem
like small departures from normal operation, but they can have a major impact on
indoor air quality.
Elements of the on-site investigation can include (but are not limited to) the
following:
• Compare the current system to the original design. Original equipment may
have been replaced by a different model.
• Check temperature and/or humidity to see that the complaint area is in the
comfort range.
• Check that equipment serving the complaint area is operating properly and that
supplies and returns are unobstructed.
• Observe airflow patterns and/or pressure differentials within the complaint area
and between the complaint area and surrounding spaces (including outdoors).
Look for areas of poor mixing or short-circuiting (supplies and returns too close
together).
• See whether the layout of supplies, returns and exhausts promotes
efficient air distribution to all occupants and isolates or dilutes contaminants.
• Check for equipment malfunction, deterioration or unsanitary conditions in and
around HVAC equipment (e.g. corrosion, water damage or standing water,
mold growth or excessive dust in ductwork)
• Check for indicators of inadequate ventilation.
- A quick evaluation of whether ventilation quantities may be a problem can be
accomplished by comparing design air quantities to the current occupancy.
If the HVAC system performing as designed would not provide enough
ventilation air for current needs, then there is good reason to believe that
actual ventilation rates are inadequate.
- Measure air quantities supplied to and exhausted from the complaint area,
including calculation of outside air quantities. Be aware of damper settings
and equipment cycles when you are measuring (e.g. are you evaluating
minimum outside air, ‘normal’ conditions, or maximum airflow?). Compare
to the recommended minimum ventilation rates from ASHRAE 62-1989,
reproduced on pages 42-44.
40
DRAFT
-------
- Measure carbon dioxide as an indicator of ventilation adequacy in occupied
areas. CO 2 concentrations in the complaint area can reveal ventilation
problems. Practically speaking, CO 2 levels abovel 000 ppm indicate that
airborne contaminants may be accumulating, rather than being diluted by
ventilation air. The higher the C0 2 , the more likely it is that the amount of
outside air provided is insufficient. It is also informative to compare CO 2 in
the complaint area with concentrations in other, similar areas of the building
where there are no lAO complaints. Note that carbon dioxide itself does not
generally reach high enough concentrations to cause significant health
problems. (See Appendk A for a discussion of techniques for
measuring carbon dioxide concentrations.)
41
r
-------
BREAK FOR ILLUSTRATION
OUTDOOR AIR REQUIREMENTS FOR VENTILATION (ASHRAE 62-1989)
Dn Oetiwm. Utodetet
Commercial laundry
Corn rntrttil dry deane?
Storage. pick up
Con.oprrtied Iaundnei
Coen opemsed dry ekarier
Food sad ereru t Steele,
Dte.tn$ roonit
Cafeteria. runt rood
Bars. cocl Lsi1 lounges
Garages. Ripslr. Stir U, Sustious
Encloted p 5rkurii 151*
Auto repair rooms
Bedroom,
I.i’in looms
Bath,
Lobbi es
Conference rooms
Assembly room,
Dormitory lrepirt areas
0mm
QUiet spate
Reception asc i i
Telecommunication cuticle
end data irnr arias
- Conference rooms
PabIk Spares
Corridors and utilities
Public rnsrocms. efnil.e
or urinal
Locker end dressing iooiiii
Smoking lounge
TABLE 2
OUTDOOR AIR REQUIREMENTS FOR VENTILATION
2.1 COMMERCIAL. FACILITIES (offices. seam . shops, botcll aporu .dIl lies)
Outdoor Air Requirements
L s thai
p riot ft ’
25 13
30 15
35 I I
IS I
1 3 $
Cornmeal,
Supptemenury smoke-removal
equipment may be reqaured
Makeup air for hood erhiust msy
require more sentilaling sun The
curs of the outdoor sir arid
trsnsfer air of aecepiable quality
from adjacent tpscm utah be sur.
ricient to proside an eslisust rate
of nor etc than 1.5 cfm/fl (7 3
lJ sm 1 )
ISO 73 Distribution among people must
ISO 3.30 cvrnidcs worker location and conS
centralior of ruitmung cn 5unet.
atinds where engines are run must
rncorporve systems for positive
engine ahauut withdrawal Con
tansinairs sensors stay be used to
control wflhiletiOit
efm/room [ .4-roam lndepend nt of roost size.
30 IS
30 IS
33 II Installed capacity foe tvuceiititCciU uric
005 0.25
See also food and benuatr services,
sneschindususg. barber and beauty
chops, pease’
Supplementary nmobe•eemoval
eqwprnent may be required
Some offles equipment may
require local esitsuat
Mechanical cahauat with no
0.3 2.5 recirculation Ii recommended
Normally supplied by smatter ilr.
local mechanical eshaust. with no
,tdrculatson recommended
100 S 00 Normally supplied by transfer air
• btr 1 prescribes pupal) risen aeeepiibk eutibsee iii reqaked tm acceptable
err quslily These el i tes tm’ .q beet chomu ‘a mental CO sod other coo.
tarn muss witS as adequate rnar su of rainy atud t o aerowu lee S(,tth .s,let ,or ,
a(CO coeuss&hi pretested sa Appeesdie D.
‘NO occvptab4e ipsct
42
DRAFT
Estimated Mulmum”
App liml lo. Occ upa a e7
P/ l000fe’orlOOm 5
Cf i
peenoa
Li ,!
1m’
l0
30
30
20
20
70
100
*00
Dry-cleaning processes may require
more sir
Enchant (COOkufl 5) 20
Hotels, Motels. Resort,, Dornihorien
20 10
20 10
30 I i
IS I
IS S
20 10
IS S
IS $
30 iS
20 10
IS S
20 tO
20 10
30 25
60 30
30
30
120
20
Gambling casinos $20
. 7
60
60
SO
70
eqtnpmcns may be required
-------
OUTDOOR AIR REQUIREMENTS FOR VENTILATION (ASHRAE 62.1989)
(con’t)
RatiO Storm. Sales floon. sad
Sbow Room floors
Basement and arrest
Uppee floors
Stomgt rooms
Dressing rooms
Malls and arcades
Shipping and rtcsiving
azehousn
Smoksng lounge
— S_
Barbe,
Bcauiy
Rrducing islosu
P l o i is i s
ClothieT . Furni lurt
Hardware. drugs, fabric
SupetmarLess
Psi shops
Sports and Amusement
Speciatos areas
Game room,
Ice arenas (pla)sng areas)
Swimming pools (pool and
dech area)
Pla 5 ,n floors (gymnasium)
Ballrooms and discos
Bowling alley, (leasing
SrU s)
Tbeuters
Ticket booths
Lobbies
Audutorwm
Sign, iludios
T ranspontsilon
5 aiting morn,
platforrsu
Vehicici
o etrooms
Meat pmcmaizlg
30
20
IS
20
l0
S
70
25
23
20
I
IS I
25 I i
IS S
Is I
is I
Ii I
IS I
25 13
20 $0
25 13
25 13
is e
IS I
is I
IS I
030 ISO
020 100
013 015
020 100
020 100
015 015
005 025
Normally supplied by rrangfer air.
local mechanical exhaust, exhausi
wish no recirtulation recommended
Ventilation so optimize plant growth
may dictate requirements
Special esniulutson will be needed
toelumisate special stage effects
(e.g ,dry ice vapors, miss,, etc.)
Ventilation within vehicles may
require special considerations
Spaces maintained at low tcmpcra•
tures(—lO Fto • 50F.or —23C
to. iO’C) are not covered by
three requirements unless the cccii
pancy is continuous Ventilation
from adjoining spaces is permissi-
ble. When the occupancy is sister.
existent, infiltration will normally
exceed the ventilation requirement
(See Ref IS)
TABLE 2
OUTDOOR AIR REQUIREMENTh FOR VENTILATION (Continued)
LI COMMERCIAL FACILmES (offices, sieves, shops, hotels, spoils I.clllslea)
Outdoor Alt Requlreneusts
Us ef m i
pemo. It ’
Estimated Mazimum’
AppUextloa Oncapancy
P/I000li’sellOm’
LIs Comments
.n it
cf m/
60 30
030 130
100 500
When internal combustion engines
are operated for maintenance of
0.50 2 50 playing surfaces, increased ventila
lion mien may be required
0 50 2 50 Higher values may be required for
humidity control
I
$
ISO
70
30
l x
70
60
ISO
IS O
70
100
$00
I SO
10
20 tO
20 10
IS S
I$ I
• TabSe 2 preumlbes svpp t earn of ucnpabue ouldoos air inqatred foe accaptabte
.done air quilluup Tbeso ‘iluet s ues been shows to control CO 1 and c di i i ceo ’
ieeeeaaia vuih an adequate margin of safety arid in aceouiu foe stealth en,vas,onu
43
among people, varied activity leesla . mdi mod.n.te attiogat of smebing. Iai,oral
of CO, eunituf is presented in Appridis D
“Ni l cceupuabts apace.
-------
OUTDOOR AIR REQUIREMENTS FOR VENTILATION (ASHRAE 62.1989)
(con’t)
a an a t.
OUTDOOR AIR REQUIREMENTS FOR VENTILATION (Concluded)
2.1 COMM CIAL FACIUT1!S (offices. IIOr S. IhODI. holds. sports facIlItIes)
A pçfi 11oa
E mat.d Maasm.m ’•
Occopaicy
P 11000 tt’ or 100 in 5
Oaldoo, Ale Requlremeata
Comment,
dm/ L/, dm/
person person It’
1./al
a or’
Photo utudion
10
IS $
Darkroom,
10
0.30
2.30
Pharmacy
20
IS 8
Bank enults
3
IS S
Duplicating. Pt1 1U 5 5I
0.30
2.30
Irsursiled equipment rnusi sncorpo-
rate posh, ’! eshausu and control
(U required) or undesirable con.
taminanha (toxic or otherwise)
2.2 INSTITUTIONAL FACILITIES
Educallos
Classroom
30
IS S
Laboratories
30
20 10
Special Contaminant control
Training shop
30
20 10
systems may be required
Music rooms
Libraries
30
20
IS I
IS S
processes of functions including
Iaboratoryanim a loccupsncy
Lockerruoms
050
250
Corridors
0 10
0 50
Auditoriums
ISO
IS 8
Smoking lounjes
70
60 30
Normally aupplied by transfer air
Local mechanical rrh usI with no
Hospitals. ‘ arsing and
rec,rculai,on recommended
Comalncent Homes
Pattern rooms
10
23 13
Special requirements or code, and
Medical procedure
20
IS I
pressure relationships may
eeniulation rates
Operating rooms
P.ecoser> and ICU
20
20
30 IS
IS S
minimum
and filter efficiency Procedures
geiserstung may
enquire higher rates.
*58005) roomu
0 30
2.30
Mr shall not be mecsrc ialaued into
other spaces.
Pttysitsi Therapy
20
IS 8
Css’reellonsl Iscilitles
Cells
20
20 • 10
Dining halls
100
IS S
Guard stasrons
40
Ii S
Reprinted with permission from ASHR.AE 62-1989, “Ventjlatjon for Acceptable Indoor Air
Quality”
44
DP FT
• lhble 2 prescribes suppi, rain of acceptable out or art requrted f ,i acceptable
indam ma uniai These *ilues host been chosen uo comml CO, and aSh,? con.
sainu runtl ash an adequate macyin of aahoy and to uceoulu for hcskh ,vlailom
smoc 5 prank ,anod uctr ti beet,. osdi modatssur smosco ol oua&.n . laiuoeale
roe CQ control is presented is Appeisdis D
N0t acceptable specs.
-------
Using the HIJAC Sgstem Data
As you review the HVAC system data, remember the critical questions you are
trying to answer:
• Is the HVAC system functioning adequately to serve the use of the building?
• If there are ventilation (or thermal comfort) deficiencies, what is their cause?
(For example, such deficiencies could be due to operating and maintenance
problems or to a system design that does not fit current needs.)
Strategies:
• Consider the original HVAC design and compare it to the current equipment,
layout, and controls.
• Compare the original uses of the complaint area and surrounding rooms to
current uses of those areas.
• Consider whether the HVAC system is reasonably clean and functioning
properly.
Consider the original HVAC design and compare it to the current
equipment, layout, and controls.
A variety of HVAC system designs have been used in public and commercial
buildings. The type of system used in your building affects the control of ventilation air
quantities and distribution, as well as thermal comfort. See AppendIx I for a
discussion of HVAC system types.
45
DRAFT
-------
HVAC SYSTEMS SUGGESTIONS
ALL SYSTEMS
• Ventilation and temperature - Revise definition of complaint area (if
control zones needed) to add spaces linked to the original
complaint area by ductwork or controls.
• Changes in equipment -Note equipment changes that could be
affecting the system’s performance (e.g.
removal or addition of equipment,
replacement by a different model).
• Operating cycles as related to - Compare occupied period to start-up and
timing of complaints shut-down times, and confirm that time
clocks are reading the actual time.
SYSTEM TYPES
• No mechanical ventilation - Identify the source(s) of ventilation air
(e.g. operable windows, doors propped open).
• Exhaust ventilation only - Identify the source(s) of ventilation air.
• Room units (e.g. unit - Are outside air intakes obstructed? Does
ventilators) their location promote the introduction of
odors or contaminants?
- Note design airfiows in the complaint area
and surrounding spaces; compare to ASHRAE
62-1989 and to actual measured airfiows.
• Constant volume - Note design airflows (supply, return, and
exhaust) in the complaint area and
surrounding spaces; compare to ASHRAE 62-
1989 and to actual measured airfiows.
- Are outside air intakes obstructed? Does
their location promote the introduction of
odors or contaminants?
- Check outside air damper controls.
• Variable air volume (VAV) - Note design airfiows (supply, return, and
exhaust) in the complaint area and
surrounding spaces; compare to ASHRAE 62-
1989 and to actual measured airfiows.
- Check outside air controls; confirm
whether the system design allows regulation
of outside air quantities.
- Check outside air intake for possible
unsanitary conditions.
-Are outside air intakes obs ucted? Does
their location promote the introduction of
odors or contaminants?
46
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Compare the original uses of the complaint area and surrounding rooms
to current uses of those areas.
Indoor air quality problems often arise when the usage of rooms changes without
corresponding adjustments to the HVAC system. If ventilation appears to be a
problem despite a properly-functioning HVAC system, the existing system may be
inadequate to meet current needs.
CHANGES IN ROOM USE
• increased occupant density
• change in type of occupant
population
(e.g. introduction of a more
environmentally sensitive
population group such as children or
elderly people)
• additional non-H VAC
equipment
• conversion to or addition of
special uses
(e.g. smoking lounge, print shop,
kitchen facilities)
• rearrangement of work
stations (e.g. relocation of partitions)
SUGGESTIONS
- compare outside air quantities to AS}IRAE
62 -1989 guidelines
- compare outside air quantities to ASHRAE
62 -1989 guidelines
- check for low-level contaminant sources
- consider the need for local exhaust at point
sources of contaminants
- check pressure relationships between
special use areas and surrounding spaces
- consider the need for local exhaust at point
sources of contaminants
- check layout of supplies, returns, and
exhausts
- check to make sure that tops and bottoms of
partitions are not tight to floor and ceiling,
to allow good airflow
Consider whether the HVAC system is clean and functioning properly.
Review the results of the on-site inspection. If you identified sanitary or operating
problems in the HVAC system serving the complaint area, you may want to correct
those problems and see whether the complaints are resolved before continuing with
the investigation.
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HVAC SYSTEM CONDITION
SUGGESTIONS
• Unsanitary conditions
- moisture or standing water
- debris
- dust and/or mold growth
• HVAC malfunctions
- equipment breakdown
- equipment out of calibration or in
need of other adjustment
- leaks in air distribution system
(e.g. leaky ductwork;
unintended openings in
pressurized ceilings)
• HVAC functions properly.
However, there is evidence of
underventila lion
Correct sanitary problems and adopt
necessary measures to prevent their
recurrence.
Correct the malfunction(s), and see whether
complaints are resolved. Review your
maintenance program and revise as needed
to prevent future problems.
Consider what adjustments could be made to
increase the supply of outside air (or
decrease the ventilation demand) in the
complaint area.
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Do you have a hypothesis that might explain the complaints?
Use the HYPOTHESIS FORM on page 66 to make notes on what you have learned.
If you have enough information to suggest a potential explanation for the IAQ
complaints, it may be valuable to use that information to:
• direct further investigation
• test a hypothesis by manipulating the apparent pollutant source, ventilation,
or pathways of contamtriant movement and observing the effects of
the manipulation.
What additional Information is needed at this point?
If you need additional data that is more detailed or more quantitative, consider
whether in-house expertise and instruments can supply that information or whether
outside assistance is needed.
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Collecting Information about Pollutant Pathways
and Orluing Forces
Strategies and Tools:
Identify architectural and mechanical pathways
architectural and mechanical plans
pollutant pathway assessment form and sketch plan of complaint area
• Observe direction of air movement
testing and balancing reports
chemical smoke tubes (with squeeze bulb and tube snapper) or manometer
peppermint oil
tracer gas
Unless the IAQ problem is caused by an obvious contaminant located in the
complainant’s immediate workspace, you will need to understand the patterns of
airflow into and within the complaint area. Correction of IAQ problems often involves
controlling pollutant movement through sealing of pollutant pathways or manipulation
of the pressure relationships.
Identify architectural and mechanical pathways
Architectural and mechanical pathways allow pollutants to enter the complaint area
from surrounding spaces, including the outdoors. An examination of architectural and
mechanical plans can help in developing a list of connections to surrounding areas.
These include:
• doors
• operable windows
• stairways
• utility chases
• ductwork and plenums
• areas served by common HVAC controls (e.g. shared thermostats)
Onsfte inspection is needed to confirm the existence of these connections and to
identity other openings (e.g. accidental openings such as cracks and holes).
The POLLUTANT PATHWAY ASSESSMENT FORM which follows (see the
[ lank ltrms section for a complete copy) can be used along with a sketch ptan of
the complaint area to record pathways and directions of pollutant movement.
50
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POLLUTANT PATHWAY ASSESSMENT FORM
Building name/address__________________________ Investigator
Comp int Area
This form should be accompanied by a sketch plan of the complaint area and surrounding spaces. Doors,
windo diffusers, and other openings should be labelled on the plan so that your observations are clearly
referenced to specific locations.
Date and time of obe vatious:________________________________________
Westl conditions temperature windspeed and direction _____________
humidity _____ other observations____________________
Equipment : List equipment operating in (or servicing) the complaint area and surrounding spaces and
indicate whether it is operating while pressure differentials are being measured. II may be helpful to turn
equipment on and off, open and close doors or windows, or perform other manipulations in an attempt to
simulate conditions at the time that complaints occur.
HVAC equipment Air handleris)___________________________________
Other fans
Other equrpment:
Pathways : Note pathways by which poflutants may be entering the space from surrounding areas. These may
assist in defining the problem area and identifying poUutant sources.
Other moms served by same air handlw _________________________________________________
Surrounding spaces (including outdoors):_________________________________
Use chemical smoke to observe airflow at intentional and accidental openings into the complaint area. A
checklist of typical openings is provided below. Use additions! pages as needed. If a manometer is used,
record the pressure differential in the middle colunm.
Architectural opanngs
— doors (note: open or closed) — tiansoms — windo (note: open or closed) stairways
— utility chases floor drains — cracks and holes
Mechanical openings :
— supply diffusers — return diffusers — exhaust intakes
Opening Direction of smoke movement Comments
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Observe direction of air movement
Although testing and balancing reports can indicate the direction of air movement
intended by the designer, onsite examination is necessary to determine whether air is
actually moving into or out of the complaint area through each available pathway.
Airflow direction is not necessarily constant, but often changes depending upon
weather conditions, windspeed and direction, equipment operation within the building,
traffic through doors, and other factors. Switching air handlers or exhaust fans on and
off, opening and closing doors, and simulating the range of operating conditions in
other ways can help to show how airborne contaminants move within the building.
Airflow patterns and pressure differentials between the complaint area and
surrounding spaces (including the outdoors) can be assessed using chemical smoke
tubes or a manometer and recorded on the POLLUTANT PATHWAY
ASSESSMENT FORM. Chemical smoke can also reveal air circulation patterns
within the complaint area.
If you suspect that a chase or other opening is a pathway for pollutant movement,
you may want to use peppermint oil as a tracer gas. This is done by one person
releasing a small quantity of peppermint oil at the far end of the suspected pathway
while an assistant sniffs for the characteristic peppermint toothpaste” odor in the
complaint area. Investigators with sufficient technical expertise can use an easily-
measured tracer gas such as SF 6 (sulfur hexafluoride) to quantify ventilation rates and
trace pollutant pathways.
Using Pollutant Pathway Data
Strategies:
• Evaluate airflow patterns into and within the complaint area
• Confirm or revise definition of complaint area
Evaluate airflow patterns into and within the complaint area
Because of the complexity and variability of airf’ow patterns, investigators cannot
be expected to understand how air moves within the building under all potential
operating conditions. However, data on pathways and driving forces can help to
locate potential pollutant sources and to understand how contaminants are
transported to building occupants.
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AIRFLOW PATTERNS SUGGESTIONS
On-site observations - look for temporal patterns linking changes
in airflow direction to incidents of
complaints
- look for spatial pauerns linking potential
sources to the locations of complaints
Confirm or revise the boundaries of the complaint area.
The discovery of unexpected pollutant pathways can show a need to study areas of
the building that may be distant from the original complaint area.
COMPLAINT AREA SUGGESTIONS
• Areas connected by Check whether air from other locations
architectural features flows into the complaint area under some
conditions. If so, consider expanding the
• Areas connected by investigation to inventory pollutant sources
mechanical system (and perhaps collect HVAC or occupant data)
in those locations.
• Unintentional pathways (e.g.
cracks, holes)
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Do you have a hypothesis that might explain the complaints?
Use the HYPOIUESIS FORM on page 66 to make notes on what you have learned.
If you have enough information to suggest a potential explanation for the lAO
complaints, it may be valuable to use that information to:
• direct further investigation
• test a hypothesis by manipulating the apparent pollutant source, ventilation,
or pathways of contaminant movement and observing the effects of
the manipulation.
What additional information is needed at this point?
If you need additional data that is more detailed or more quantitative, consider
whether in-house expertise and instruments can supply that information or whether
outside assistance is needed.
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Collecting Information on Pollutant Sources
Strategies and Tools:
• On-site inspection
POLLUTANT AND SOURCE INVENTORY
• Talk with facilities staff and other building occupants (also contractors, if outside
firms are responsible for housekeeping or pest control)
POLLUTANT AND SOURCE INVENTORY
From the beginning of the investigation process, the building investigator begins to
look for pollutant sources which may be causing the occupant complaints. The
POLLUTANT AND SOURCE INVENTORY can be used to record observations.
One page of the multi-page form is reproduced on page 56; the complete form is
shown in the hank Icrms section.
During the investigation, the area included in the pollutant source inventory should
be defined by the investigator’s common sense understanding of the building’s
architectura’ and mechanical layout and by information gathered from the inventory of
pollutant pathways. The inventory can be expanded and potential sources and
pollutants can be examined in more detail if your initial data does not suggest a
hypothesis or if early hypotheses are developed and rejected.
Remember that very few sources of indoor air contaminants are continuous.
Pollutant concentrations often vary in strength over time, and may not be evident at the
time of the site visit. Some sources are subtle and might only be noticed by a trained
eye (or nose). The inventory of pollutant sources may need to be revised as the
investigation progresses.
55
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POLLUTANT ANI) SOURCE INVENTORY
PtLJ.iI.L&Ai _________________________________________ Inve s tigator
Using the list of potential source categories below, record any indications of contamination or suspected pollutants that may
require further investigation or treatment. Sources of contkmrnMlon may be constant or intermittent or may be linked to
single, unrepeated events. For internnttent sources, try to indicate the time of peak activity or contfiminant production.
Source Category
Checked
Attention
Sources outside the building
Contaminated ambient air
- pollen, dust
- industrial contarmnatits
Emissions from nearby sources
- vehicle exhaust ( parking
garages, loading docks, roads)
- ezs
- construction/demolition
- re-entrained exhaust
- debris near O.A. intake
Soil gas
- moisture
-raden
- leaking_umd ground_tanks
- previous use of the site
Other
Equipment
HVAC system equipn it. supplies
-dustordulinducts
- microbial growth in ducts
- microbial growth at chip pans,
chillers, humidifiers
- leaks of treated boiler water
56
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On-site Inspection
The following general indicators may help to call attention to pollutant sources:
• odors
• overcrowding
• unsanitary conditions (e.g. excessive dust)
• moisture problems, visible fungal growth
• staining and discoloration (note that discoloration around diffusers in a room is
usually caused by dust and dirt within the room, pushed against walls and
ceilings by turbulent airflow around the diffusers)
• smoke damage
• presence of hazardous substances
• evidence of soil gas entry (e.g. openings to earth)
Depending upon the nature of the complaint, the investigator may find some of the
f000wing activities to be useful. This list is not intended to be complete.
• Inventory outdoor sources
• Examine the area around the outdoor air intake.
- Observe patterns of traffic, construction activity, and other potential sources in
the neighborhood of the building.
- Inquire about outdoor ambient air problems in the area. (This information may
be available from your local Health Department.)
- Observe soil gas entry points.
• Inventory equipment sources
- Review non-H VAC equipment, particularly large office equipment such as
engineering drawing reproduction machines and wet-process copiers. Learn
about usage patterns and identify items that are not equipped with local
exhaust.
- Review biocides, water treatment, etc. used on HVAC equipment
• Review building components and furnishings
• Check drain traps to make sure they are not dry.
• Identify areas of excessive dust and/or deteriorated furnishings.
- Identify areas of soil or water damage.
- Identify locations of new furnishings.
• Inventory other potential sources
- Identify special use areas such as smoking lounges, laboratories, print shops
- Identify areas where remodelling, repair, or redecorating activites are in
progress or recently completed. Check procedures being used to isolate
demolition dust, paint fumes, and other contaminants related to the process.
57
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Talk with facilities staff and other building occupants
Facilities staff and other building occupants can provide valuable information about
the location and timing of occupant activities such as housekeeping or maintenance
operations which may be releasing contaminants into the air. They may also offer
suggested explanations for the lAO problem which can help in the development of
hypotheses. If outside contractors have been used for housekeeping, pest control, or
remodelling, ft may be necessary to interview them about the materials they use and
their schedule of activities within the building.
The following is a partial list of items to discuss with building occupants:
• Inventory human activities
• Review smoking policy (and actual practice).
- Identify areas of overcrowding.
- Review products used for housekeeping, maintenance, and pest control.
- Inquire about housekeeping, maintenance, and pest control schedules.
- Identify supply storage areas and check for well-sealed containers and proper
ventilation.
• Discuss incidents which could be sources
- inquire about events such as spills, fires or leaks.
- If such events have occurred, learn what remedial actions were taken to clean
up after the incidents and prevent their recurrence.
Using Pollutont Source Onto
Strategies:
• Identify patterns linking emissions from potential sources to the lAO complaints
• Evaluate sources that appear unrelated to the complaints
58
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Identify patterns linking emissions from potential sources to the IAQ
complaints
PATfERNS SUGGESTIONS
Location(s) of sources - compare locations of sources to locations of
complaint(s)
- identify pathways linking potential
sources to the complaint area
- revise definition of complaint area if
necessary
Timing of emissions - identify occasions when source is likely to
be strongest
- compare timing of emissions to timing of
complaints
Effects associated with - compare types of symptoms reported to
exposure to specific pollutants symptoms generally associated with the
identified source
It is not unusual to identify potential contaminant sources that are unrelated to the
IAQ complaint. These should be prioritized for remedial work according to their
potential for causing health problems or complaints in the future.
A detailed study of pollutants and sources may involve an engineering evaluation
of equipment that is releasing IAQ contaminants, diagnostic sampling to assess
sources in operation, or other measurements. These may require skills or
instrumentation that are not available in-house.
59
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0
Do you have a hypothesis that might explain the complaints?
Use the HYPOThESIS FORM on page 66 to make notes on what you have learned.
If you have enough information to suggest a potential explanation for the lAO
complaints, it may be valuable to use that information to:
• direct further investigation
• test a hypothesis by manipulating the apparent pollutant source, ventilation,
or pathways of contaminant movement and observing the effects of
the manipulation.
What additional information is needed at this point?
If you need additional data that is more detailed or more quantitative, consider
whether in-house expertise and instruments can supply that information or whether
outside assistance is needed.
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S mpIing fir for Contuminants ond Indicutors
Although air sampling might seem to be the logical response to an air quality
problem, such an approach may not be required to solve the problem and can even be
misleading. Air sampling should not be undertaken until some or all of the other
investigative activities mentioned above have been used to collect considerable
information. A successful sampling strategy should be based on a comprehensive
understanding of how the building operates and the nature of the complaints.
Air sampling may be needed to help confirm building-related illness (by testing for
site-specific contaminants) or sick building syndrome (by testing for carbon dioxide at
an appropriate time for near peak conditions). High readings from such measuring
may be considered conclusive evidence of a problem. However, low readings are not
sufficient to rule out subtle or intermittent air quality problems, unless they take into
consideration the full range of building operating conditions.
It may be desirable to take certain routine air quality measurements during an
investigation to obtain a snapshot” of current conditions. These tests should be
limited to those which are indicative of very common IAQ concerns such as
temperature, relative humidity, air movement, or CO 2 . Unusual readings may or may
not indicate a problem, and should always be interpreted in perspective, based upon
site-specific conditions and overall patterns.
Measurement of specific chemicals can be very expensive. Before expending time
and money to obtain measurements of indoor air pollutants, you must decide:
• how the results will be used
• what substances(s) should be measured
• where to take samples
• when to take samples
• what sampling and analysis method to use so that the results provide useful
information
How will the results be used?
The intended use of the measurements is critically important in designing an
appropriate sampling strategy. Potential uses of indoor air measurements include:
(1) comparing different areas of the building or comparing indoor to outdoor
conditions
• confirming that a control approach has the desired effect of reducing
pollutant concentrations or improving ventilation
61 DRAFT
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• establishing baseline conditions so that they can be compared to
concentrations at other times or locations
- concentrations in outside air
- concentrations in areas where no symptoms are reported
• testing a hypothesis about the source of the problem (e.g. checking
emissions from a piece of equipment)
(2) testing for ‘indicator compounds associated with particular types of building
conditions (e.g. high concentrations of CO 2 are associated with
underventi lat ion)
• carbon dioxide over 1000 ppm is an indicator of underventilation
• carbon monoxide over several ppm is an indicator for irritating combustion
products
(3) comparing measured concentrations to guidelines or standards
• occupational exposure standards
• public health guidelines for specific pollutants (e.g. World Health
Organization or Canadian guidelines)
Extreme caution must be used in comparing contaminant concentrations to existing
occupational standards and guidelines. Although concentrations of contaminants
above those guidelines are clear problem indications, occupants may still report
heatth complaints at concentrations within the guidelines.
Where specific exposure problems are documented, the development of remedial
measures may require more detailed diagnostic testing to locate or understand major
sources. For example, the control of microbial or pesticide contamination may involve
surface or bulk sampling.
What substance(s) should be measured?
Measurement of ‘indicator” compounds can be a cost-effective investigation
strategy. Carbon dioxide is an indicator associated with underventilation, while
carbon monoxide is associated with combustion gases.
It may be appropriate to sample for the chemical(s) associated with a suspected
source to see whether the concentration of that substance in the complaint area is
higher than in a control location. However, measuring the concentrations of all
potential chemical contaminants would be an extremely expensive way to discover the
cause of an indoor air quality problem. Air sampling for specific pollutants works best
as an investigative tool when it is combined with other types of information-gathering.
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Where should air samples be taken?
The identified problem area is an obvious site for air sampling. It may also be
worthwhile to take measurements in a control location. The conditions experienced by
building occupants are best simulated by sampling air from the breathing zone.
There are several ways to locate sampling sites for an lAO investigation. One
approach first divides the building into homogeneous areas based on key factors
identified in the building inspection and interviews. Examples of how a building might
be divided include:
• by individual HVAC zones
• by types of HVAC zones (e.g. interior vs. perimeter)
• by complaint vs. non-complaint areas
• by relationship to major sources (e.g. spaces directly, indirectly or not impacted
by smoking areas)
• by complaint types
Test sites can then be selected to represent complaints, controls, and potential
sources with a reasonable number of samples.
When should indoor air samples be taken?
Samples may be designed to obtain worSt caseu conditions, such as
measurements during periods of maximum equipment emissions, minimum
ventilation, or disturbance of contaminated surfaces. Worst-case sample results can
be very helpful in characterizing maximum occupant exposures and identifying
sources for corrective measures.
If symptoms or odors only occur occasionally, this generally does not happen
during the lAO investigation. Air samples should not be taken unless an incident is
occuring, unless the purpose of the sample is to establish a baseline for future
comparisons. One cost-effective approach to intermittent lAO problems is for the IAQ
investigator to have appropriate building staff or other occupants document changes
over time (see discussion of the OCCUPANT DiARY, pages 29-30 and LOG OF
ACTiVITIES AND SYSTEM OPERATION, pages 37-38). For example, when an
odor episode does occur, the building engineer could inspect the air handler and
intake area while another staff member documents the status of several potential
sources. Another strategy is to manipulate building conditions to create worst-case
conditions during the building investigation (e.g. arrange for the trash truck to idle at
the loading dock or close outside air dampers to minimum settings). Tracer gases can
be used to assess where emissions may travel under various building conditions.
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What sampling and analysis method should be used so that the results
provide useful information?
Off-the-shelf industrial hygiene procedures may not always be suitable for an IAQ
assessment. Care must always be taken in selecting a meaningful detection limit and
averaging time for the lAO setting. (See Appendk A for a discussion of
measurement techniques commonly used in lAO investigations.)
64
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Using Information to Form and Test Hgpotheses
As the building investigation progresses, you should be developing one or more
hypotheses (educated guesses) that could explain the occupant complaints. The
investigation can then be shaped to collect information that will either support or refute
your hypotheses.
The HYPOIHiSIS form on page 66 summarizes the results of the investigation.
As you review the information, write down any explanation(s) for the IAQ problem that
make sense. Is all of your information consistent with your hypothesis? If not, is there
a reasonable explanation for the inconsistencies? Think of ways to test your
hypotheses. You may want to change ventilation rates, cover suspected sources, seal
pathways, or temporarily relocate sensitive individuals. If your manipulations can
produce an effect on occupant complaints, you have found a reasonable hypothesis.
If you are having difficulty developing hypotheses, review the information you have
collected and the suggestions about how to use that information. For suggestions on
using occupant complaint data, see pages 30-34; on using HVAC system information,
see pages 45-49; on using pollutant pathway information, see pages 52-54; on using
pollutant/source inventory data, see pages 58-60; on using air sampling information,
see pages 61-62.
The changes that are made during hypothesis testing may offer a practical solution
to the lAO problem, or may be only temporary measures. The mitigation chapter
presents a variety of approaches to correction of lAO problems and discusses how to
evaluate those strategies.
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HYPOTHESIS FORM
Building eame/adthess
Invesbgair______________________ Date ___________
Problesn Area: (this can be revised as the investigation progresses):
Complaints: What is the pattern of complaints? (tuning, location. number of people affected)
HVAC:
Does the ventilation system appear to provide adequate outdoor air, efficiently distzibuted to n et occupant needs in the
problem area? If not, what problems do you see?
Is there any apparent pattern connecting the location and tuning of complaints with the HVAC system layout, condition or
op atmg hedule?
Path ys What pathways and driving forces connect the complaint area to locations of potential sources?
Sources: What potential sources have been identified?
• in the problemarea
- in locations associated with the problem area (connected by pathways)
Hypothesis: Using the information you have gathered, what is your best explanation for the problem?
Testing: Can this hypothesis be tested? If so, ho (?
Results: Results of hypothesis testing:
Additional information needed:
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Complaints Due to non-lAO Enulronmental Stressors
Complaints which initially seem to be linked to thermal discomfort or indoor air
pollutants may actually be caused by factors such as:
• lighting
• noise
• vibration
• ergonomics
• human relations factors
In some cases, problems with these environmental factors can reduce tolerance for
other sources of stress, including indoor air pollutants. In other cases, health
complaints produced by extremes of temperature, glare, and other environmental
problems may be mistakenly identified as being due to contaminated indoor air.
The following brief presentation is intended to provide an introduction to
environmental stresses which have been shown to contribute to “lAO” complaints.
While the investigation and resolution of these problems may be critical to resolving
complaints, EPA’s and NIOSH’s ability to provide technical guidance on these issues
cannot be covered in depth in this document. Additional guidance is available in the
Occupational Safety and Health Administration’s Permissible Exposure Limits (PELs),
NIOSH’s Recommended Exposure Umits (RELs) and published “policy statements”,
and the American Conference of Government Industrial Hygienists’ Threshold Limit
Values (TLVs).
Lighting
Stresses from inadequate or poorly-designed lighting (e.g. glare, flicker, poor
illumination of work surfaces) can produce symptoms such as eyestrain and
headaches. These complaints are sometimes interpreted as signs of poor indoor air
quality. Lighting problems may be evident in large areas or localized in particular
workspaces.
Noise
Noisy surroundings can reduce the ability to concentrate and produce stress-
related symptoms such as headaches. Noise can also contribute to job dissatisfaction,
particularly if the problem is caused by overcrowding or other factors likely to produce
a sense of substandard work conditions.
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The ear habituates quickly so it is possible for a complainant to be unaware of a
constant or regular sound. Investigators should recognize that noise can be a source
of stress, even if it is not reported as a problem.
Vibration
Low-frequency vibration is another source of stress that may go unreported by
building occupants or become confused with pollutant problems. Vibration can be
caused by nearby machinery or movement of the building as a whole; motion sickness
has been reported in some high rise buildings which sway in the wind.
Ergonomics
Fatigue, circulatory problems, and other physical problems can be produced by
furniture which is mismatched to the task, such as chairs which are the wrong height
for computer terminals. When IAQ investigators inquire about whether new furniture
has recently been installed in the problem area (i.e. to determine if the furniture could
be contributing to increased contaminant levels), they should also ask about other
changes in the work stations, such as furniture rearrangement, new office equipment,
or new tasks assigned to staff.
Psychosocial Factors
Stresses due to poor labor-management relations, landlord-tenant disputes or
other interpersonal problems can reduce tolerance for inadequacies in the indoor
environment. Complaints may arise over any perceived problem, including indoor air
quahty. Psychosocial factors may be suspected as a complication of the lAO complaint
if the investigator is aware of friction over working conditions, lease arrangements, or
other issues.
Even if interpersonat stresses may be contributing to a perception of poor lAO, the
investigator should not assume that the occupant complaints are unfounded. It is
possible that psychosocial problems have simply produced a heightened sensitMty to
substandard environmental conditions.
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S [ CIIC i - MII1GAII IAI U?CI I [ MS
Over the years many types of mitigation (correction) strategies have been
implemented to solve indoor air quality problems. The purpose of this section is to
provide an understanding of basic approaches to mitigation and the various solutions
which can be effective in treating commonly-encountered lAO problems. It is not
intended to provide detailed instructions for using each type of mitigation but rather to
give guidance in s&ecting a mitigation strategy and in judging proposals that you may
receive from in-house or outside consultants.
Mitigation of indoor air quality problems may require the involvement of building
management and staff representing various areas of responsibility, including:
• HVAC operation
• purchasing
• policymaking
• staff training
Background: Basic Opprooches to Controlling Indoor
fir Problems
Section 2 introduced the idea that indoor air quality problems result from
interactions between contaminant source, building site, building structure, activities
within the building, mechanical equipment, climate, and occupants. Efforts to control
indoor air contaminants change the relationships between these factors. There are
many ways that people can intervene in these relationships to prevent or control
indoor air contaminant problems. All of the control strategies fit into one of the
following categories:
• source control
• ventilation
• air cleaning
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Source control
Source control techniques are effective when point sources of contaminants can be
identified. In the case of a strong source, they may be the only solution that will work.
The following are categories and examples of source control:
I. remove or reduce the source
- prohibit smoking indoors or limit smoking to areas from which air is
exhausted, not recirculated
- modify other occupant activities
- select products which produce fewer or less potent contaminants
- relocate contaminant-producing equipment to an unoccupied or
better-ventilated space
- institute an asbestos management program
• seal or cover the source
- improve storage of materials which produce contaminants
- seal surfaces of building materials that emit VOCs such as formaldehyde
• modify the environment
- after disinfecting an area that is contaminated by fungal or bacterial
growth, control humidity to make conditions inhospitable for reinfestation
- modify cleaning procedures or schedule
Source removal or reduction can sometimes be accomplished by a one-time effort
such as thorough cleaning of a spill. In other cases, it requires an ongoing process
such as establishing and enforcing a non-smoking policy.
Sealing or covering the source can be a semi-permanent solution in some cases;
application of a barrier over formaldehyde-emitting building materials is an example.
Sealing may also involve educating staff or building occupants about the
contaminant-producing features of materials and supplies and inspecting storage
areas to ensure that containers are properly covered.
In some cases, modification of the environment is necessary for effective mitigation.
If the indoor air problem arises from microbiological contaminants, for example,
disinfection of the affected area may not eliminate the problem. Reinfestation could
occur unless humidity control or other steps are taken to make the environment
inhospitable to microbiologicals, such as adding insulation to prevent surface
condensation.
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Ventilation
Ventilation can be used to control indoor air contaminants in three ways:
• increase the flow of outside air
- increase the total quantity of supply air
- increase the proportion of outdoor air to total air
• control air pressure relationships
- install local exhaust at the location of the source
• make sure that doors are closed where necessary to
separate zones
• use air tightening techniques to maintain pressure
differentials and eliminate pollutant pathways
• control source / distribution relationships
- adjust locations of pollutant sources relative to supply, return, and
exhaust diffusers (e.g. keep contaminants away from returns)
- locate building occupants near supply diffusers and away from
contaminant sources as much as possible
- avoid recirculation of air that contains contaminants
BREAK FOR FIGURE
FIGURE Pictured above is a plan view drawing of a room showing walls and ductwork.
Arrows are used to illustrate airflow patterns.
Ventilation modification is often used to correct or prevent indoor air quality
problems. One reason for the popularity of this approach is that it can be effective
even where a specific contaminant source cannot be identified. The most obvious
method of mitigation by ventilation dilutes the contaminant by increasing the flow of
outdoor air. Increasing the total quantity of supply air can be accomplished in the
complaint area (e.g. opening supply diffusers, adjusting dampers) or at the air
handling unit, (e.g. cleaning the finer on the supply fan). An alternative is to increase
the proportion of outdoor air (e.g. adjusting the outside air intake damper, installing
minimum stops on VAV boxes so that they satisfy the outside air requirements of
ASHRAE 62-1989).
Research to date shows that, contrary to popular belief, increasing ventilation in
existing buildings severalfold (e.g. from 5 to 15-20 Cf rn/person) to meet the current
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ASHRAE ventilation guidance for the design of new buildings (Standard 62-1989,
UVentilation for Acceptable Indoor Air Quality ) results in only a small increase in
energy costs. in some buildings, however, HVAC equipment may not have sufficient
capacity to allow successful mitigation using this approach. The cost of modifying the
HVAC system can vary widely depending upon the specific situation.
Note the side-effects of each approach to increased ventilation.
• mitigation by increasing the circulation of outdoor air requires good
outdoor air quality
• increased supply air at the problem location might mean less supply
air in other areas
• increased total air in the system and increased outside air will both
tend to increase energy consumption
• any approach which affects airflow in the building can change
pressure relationships between rooms (or zones) and between
indoors and outdoors
• modifications to the HVAC system may push equipment beyond its capacity
• increasing air in a VAV system may overcool an area to the extent that
terminal reheat units are needed
Ventilation equipment can be used to manage airfiows, thus using air pressure
relationships to contain contaminants within particular areas. This is a more
sophisticated strategy than simple dilution but can be more effective at lowering
concentrations of problem materials in building air. Techniques for controlling air
pressure relationships range from adjustment of dampers to installation of local
exhaust.
Using local exhaust confines the spread of contaminants by captunng them near
the source and exhausting them to the outside. It also dilutes the contaminant by
drawing cleaner air from surrounding areas into the exhaust airstream. If there are
return grilles in a room equipped with local exhaust, the local exhaust should exert
enough suction to prevent recirculation of contaminants. Properly designed and
installed local exhaust results in far lower contaminant levels in the building than could
be accomplished by a general increase in dilution ventilation, with the added benefit of
costing less. Note that it may be necessary to add door or wall louvers to provide a
make-up air supply for the local exhaust. (Make sure that this action does not violate
fire codes.)Further, correct identification of the pollutant source is critically important. If
contaminants are actually infiltrating the space, installation of local exhaust can make
the problem worse.
Elimination of pollutant pathways by air sealing is an approach that can increase
the effectiveness of other control techniques. It can be a difficult technique to
implement because of hidden pathways.
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Control of source/distribution relationships is a strategy for improving ventilation
efficiency. ‘Ventilation efficiency” describes the ability of the air distribution sytem to
control pollutant concentrations. The ventilation efficiency within a room is said to be
100% ii doubling the ventilation rate cuts contaminant concentrations in half.
Ventilation efficiency in a space can be greater or less than 100%. For example, if
supply and return diffusers are too close together, clean supply air may be drawn into
the return before it has mixed with the dirtier room air, so that little or no dilution of
contaminants occurs. This is called “short-circuiting. Ventilation efficiency can vary
at different locations within a space as well. If supply diffusers are all at one end of a
room and returns are all at the other end, the people located near the supplies are
provided with relatively clean air while those located near the returns breathe air
which has already picked up contaminants from all the sources in the room.
Controlling source/distribution relationships involves manipulation of the physical
layout of supply, return, and exhaust grilles relative to the location of sources and
occupants. Relocation of diffusers may be needed if the ventilation system layout does
not sweep the area with supply air. In other cases, moving the pollutant source or
relocating occupants may eliminate IAQ problems. Furnishings can also disrupt
airflow patterns. In open offices with movable partitions, elevating the partitions to
create a 2.4M gap at the bottom often helps to improve air circulation.
Air Cleaning
The third lAO control strategy is to clean the air. Air cleaning is usually most
effective when used in conjunction with either source control or ventilation; however, it
may be the only approach when the source of pollution is outside the building. Most
air cleaning in large buildings is aimed primarily at preventing contaminant buildup in
HVAC equipment and enhancing equipment efficiency. Keeping mechanical systems
clean by filtering the air that moves through them can help in detering microbiological
growth.
Air cleaning equipment must be properly selected and designed for the particular
pollutants of interest (for example, gaseous contaminants can only be removed by gas
sorption). Once installed, the equipment requires regular maintenance in order to
ensure good performance. There are three technologies that remove contaminants
from the air.
• particulate filtration
• electrostatic precipitation
• gas sorption
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BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows three filters commonly used in HVAC
applications.
Air filtration equipment is usually installed in central station air handlers to protect
the entire system and all zones. Self-contained filtering equipment is also available
using all three filtering technologies. This allows for specific space or sub-zone control
and facilitates mitigation when room or performance is not available at the air handler.
Particulate filtration removes solid materials whose size, shape and mass allow
them to remain airborne for the air velocity conditions present. Higher efficiency filters
work by collecting or ‘straining” the particles as air passes through a permeable
material. Filters are available in a range of efficiencies, with higher efficiency
indicating removal of a greater proportion of particles and of smaller particles. The
higher efficiency the filter, the more it will increase the pressure drop within the air
distribution system and reduce total airflow (unless other adjustments are made to
compensate). It is important to select an appropriate filter for the specific application
and to make sure that the HVAC system will continue to perform as designed.
Electrostatic precipitation is another type of particulate control. It uses the attraction
of charged particles to oppositely charged surfaces to collect airborne particulates. In
this process, the particles are charged by ionizing the air with an electric field. The
charged particles are then collected by a strong electric field generated between
oppositely charged electrodes. This provides relatively high efficiency filtration of
small respirable particles at low air pressure losses. Electrostatic precipitators may be
installed in air distribution equipment or in specific usage areas. As with other filters,
they must be serviced regularly. Large buildings may require many room units
because of the large volumes of air in circulation. If room units are used, the
installation should be designed for proper air recirculation. Note, however, that some
electrostatic precipitators produce ozone. Ozone is in itself a harmful air contaminant
for which EPA has set exposure limits in the outdoor air and OSHA has set exposure
limits in the workplace. The amount of ozone emitted varies from model to model.
Gas sorption is used to control compounds that behave as gases rather than as
particles (e.g. water vapor, gaseous contaminants such as HCHO - formaldehyde, SO 2 -
sulfur dioxide, 03- ozone, NO - oxides of nitrogen, or odors). The process is most
nearly like diffusion of a contaminant from areas of higher concentration to areas of
lower concentration. The gas clings to the surface or is wicked into the high surface
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area sorption material (e.g. activated carbon, chemically treated active clays) when the
airstream passes through it. Gas sorption units are installed as part of the air
distribution system. Each type of sorption material performs differently with different
gases.
Sample Problems and Solutions
In the investigation section you were introduced to a variety of problems that are
often found in buildings. This section presents common problems and strategies that
have been used to correct them. Reading these examples may help you to think about
the best way to solve your indoor air quality problems. You will note that some
solutions are simple and low-cost, while others are complex and expensive.
Remember that these are brief sketches, and apparent parallels to your building could
be misleading. It is better to carry out a building investigation and learn the specific
facts in your own case, rather than adopt a mitigation approach that might not be
appropriate. Attempting to correct IAQ problems without understanding the cause of
those problems can be ineffective and expensive.
Most of the problems presented here are common and do not have serious, life-
threatening consequences. At the end of the section is a brief description of less
common problems which can have severe health impacts. The basic correction
principles that apply to these serious problems are similar to those used in less critical
situations.
IAQ professionals generally prefer mitigation based upon source control or
ventilation; however, filtration, electrostatic precipitation, or gas sorption may be the
best practical alternative in specific cases. In the following section, recommendations
about filters generally refer to maintenance of the original HVAC system, rather than to
installation of special filters designed for removal of contaminants.
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Common Problem #1: Ventilation rate too low
Examples
• routine odors from occupants and normal office actMties result in
problems (drowsiness, headaches, discomfort)
• measured ventilation rates do not meet ASHRAE 62-1989 guidelines for
outside air supply
• CO 2 concentrations above 1000 ppm indicate inadequate ventilation
• corrosion of fan casing causes air bypassing and reduces airflow in system
Solutions
• open, adjust or repair air distribution system
• outside air intakes
- mixing and relief dampers
- supply diffusers
• increase outside air within the design capacity of
- air handler
- heating and air conditioning equipment
- distribution system
• modify components of the HVAC system as needed to allow
increased outside air
(e.g. increase capacity of heating and cooling coils)
• design and install an updated ventilation system
In addition to these increased ventilation approaches, problems caused by
underventilation can sometimes be corrected by other means. For example:
• remove or reduce the source
- relocate some occupants to other spaces to redistribute the load on the
ventilation system
- relocate or reduce usage of heat-generating equipment
- improve cleaning procedures to eliminate odors
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a blocked fresh air intake
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Common Problem #2: Overall ventilation rate is high enough, but not
effective
Example
• measured outside air meets guidelines, but there are zones where
heat, routine odors from occupants, and normal office activities result in
problems (drowsiness, headaches, comfort complaints)
Solutions
• open, adjust, or repair air distribution system
• supply diffusers
• return diffusers
• seal leaky ductwork
• remove obstructions from return air plenum
• control pressure relationships
- install local exhaust in problem areas
• change source/distribution relationship by changing the
physical arrangement of occupants, point sources of
contaminants, and supply and return diffusers
- move occupants so that they are closer to supply diffusers; move
contaminant sources closer to exhaust or return grilles
- relocate identified sources closer to exhaust intakes
• relocate supply and/or return diffusers to improve ventilation
efficiency
• reduce source by limiting activities or equipment use which
produce heat, odors, or contaminants
• design and install an appropriate ventilation system
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a local exhaust installation
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Common Problem #3: Contaminant entering building from outside
Examples
• soil gases (radon, gasoline from tanks, methane from landfills)
• contaminants from nearby activities (roofing, dumpster, construction)
• outside air intake near source (parking, loading dock, building exhaust)
• outside air contains pollutants or excess moisture
Solutions
• remove the source, if it can be moved easily
• remove debris around outdoor air intake
- relocate dumpster
• reduce source: shift time of activity to avoid occupied periods
• painting
- roofing
- demolition
• housekeeping, pest control
• relocate elements of the ventilation system which contribute to
entry of outside air contaminants
- outdoor air intakes near sources of odors, contaminants
- exhaust f an outlets near operable windows, doors, air intakes
- make rooftop exhaust outlets taller than intakes
• control air pressure relationships
- lower the air pressure in the soil to prevent entry of soil gas contaminants
(radon, gases from landfills and underground tanks)
- pressurize the building interior relative to outside
• add special equipment to HVAC system
- filtration equipment to remove pollutants (select to fit the situation)
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows an inappropriately located fresh air intake.
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Common Problem #4: Occupant activities contribute to air contaminants
or comfort problems
Examples
• smoking
• special activities such as print shops, laboratories
• interference with HVAC system operation
- blockage of supply diffusers to eliminate drafts
- turning off exhaust fans to eliminate noise
- use of space heaters, desktop humidifiers to remedy local discomfort
Solutions
• remove the source by eliminating the activity (this may require a
combination of policy-setting and educational outreach)
- smoking
- use of desktop humidifiers and other personal HVAC equipment
- unsupervised manipulation of HVAC system
• reduce the source: select materials and processes which minimize
release of contaminants
- solvents
- art materials
• install new or improved local exhaust to accomodate the activity
- smoking lounge
- laboratory hoods
- pools and spas
- food preparation
- storage areas which contain contaminant sources
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows an office with small fans on several desks,
illustrating occupant interference with HVAC system operation.
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Common Problem #5: HVAC system Is a source of contaminants
The HVAC system can act as a source of contaminants by providing a nourishing
environment for microbiologicals and by then distributing the biologically-
contaminated air within the building. (Note: the presence of dust in ductwork does not
indicate a microbial problem. In most cases, dust comes from rooms, and better
housekeeping in the building will slow down the rate at which duct accumulates in
ductwork. Special attention should be given to trying to find out if ducts are
contaminated only if microbials are identified in ductwork.)
Examples
• surface contamination by biologicals (mold, fungus, bacteria)
- drain pans
- interior of ductwork
Solutions
• remove source by Improving maintenance procedures
- inspect equipment for signs of corrosion, high humidity
- replace corroded parts
- clean drip pans, outside air intakes, other affected locations
• provide access to all the items that must be cleaned, drained, or
replaced periodically
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a corroded fan casing in an unsanitary
mechanical room.
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Common Problem #6: HVAC system distributes contaminants
Examples
• recirculation of dust
• recirculation of air that contains contaminants
- system recirculates air from rooms containing pollutant sources
- return air plenum draws air from rooms in which ceiling tiles have been
removed (e.g. janitor’s closets)
- return air plenums draw soil gases from interiors of block corridor walls
that terminate above ceilings
Solutions
• modify air distribution system to minimize recirculation of
contaminants
- provide local exhaust at point sources of contaminants
• increase proportion of outside air
- seal unplanned openings into return air plenums
• improve housekeeping and pest control activities to minimize
release of contaminants
• install improved filtration equipment to remove contaminants
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a janitor’s closet with a ceiling tile removed,
so that air is drawn into the ceiling p’enum.
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Common Problem #7: Non-HVAC equipment is a source of contaminants
Examples
• wet process copiers
• engineering drawing reproduction machines
Solutions
• install local exhaust near machines
• remove source
- relocate occupants out of rooms which contain contaminant-generating
equipment
• relocate equipment into special use areas equipped with exhaust
ventilation
• increase ventilation of problem areas
• total air supplied
- proportion of outside air
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a wet-process photocopier with local exhaust.
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Common Problem #8: Surface contamination
Examples
• bological contaminants result in allergy or disease
- fungal, viral, bacterial (whole organism, spores)
- bird, insect or rodent parts or droppings, hair, dander, parts,
microrganisms (in HVAC, crawispace, building shell)
• accidents
- spills of water, beverages, cleansers, paints, varnishes, mastics or
specialized products (printing, chemical art supplies)
- fire damage: soot, odors, chemicals
• corrosion resulting from
- moisture, high humidity, chemical and cleaning supplies
Solutions
• remove source by cleaning
- outside air intakes, mixing plenums
- carpets, furnishings
• modify environment to prevent recurrence of problem
- change filters regularly
- clean and drain drip pans
- control humidity or surface temperatures to prevent condensation
• remove source by installing drip pans that drain
• provide access to all the items that must be cleaned, drained,
or replaced periodically
• use local exhaust where corrosive materials are stored
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows an outside air intake contaminated th bird
droppings.
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Common Problem #9: Mold and mildew growth
Examples
• on interior surfaces of walls near thermal bridges (uninsulated locations
around structural members)
• in carpeting on cold floors
• at any location where high surface humidity promotes condensation
Solution: Clean and disinfect to remove mold and mildew, then act to prevent
re-infestation by treating locations that are subject to condensation
• increase surface temperatures
• insulate thermal bridges
- improve air distribution
• reduce moisture levels
- repair leaks
- increase ventilation (e.g. if outside air is cold and dry)
- dehumidify (e.g. if outside air is warm and humid)
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows mold growth on a wall surface.
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Common Problem #10: Building materials and furnishings produce
contaminants
Examples
• odors from newly installed carpets, furniture, wall coverings resuft in
complaints
• newly drycleaned drapes or other textiles emit odors
Solutions
• remove source with appropriate cleaning methods
- steam clean carpeting and upholstery
- accept only fully dried, odorless drycleaned products
• remove source by covering the materials
- seal surfaces of building materials that contain asbestos
• increase ventilation
- total air supplied
- proportion of fresh air
• remove the materials that are producing the emissions and
replace with lower emission alternatives (Note: Only limited
information is available at this time. Building managers will have access to
more information regarding the emission characteristics of building materials
and furnishings in the future.)
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows an office that is beautiful to look at,but emissions
from its new furnishings could create indoor air quality problems.
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Common Problem #11: Housekeeping or maintenance activities
contribute to problems
Examples
• cleaning products emit chemicals, odors
• particulates become airborne
• contaminants are released from painting, caulking, lubricating
• frequency of maintenance is insufficient to eliminate contaminants
• facilities staff have removed ceiling tile in janitor’s storage closet
so that the return in the ceiling plenum is used as a local exhaust
Solutions
• remove source by modifying standard procedures or frequency
of maintenance (this may require a combination of policy-setting and
training in IAQ impacts of staff actMties)
- improve storage practices
- shift time of painting, cleaning, pest control, other contaminant-producing
activities to avoid periods when occupants are in the building
• reduce source: select products to minimize production of
contaminant emissions
• use local exhaust
- on a temporary basis to remove contaminants from work areas
- as a permanent installation where contaminants are stored
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows painters at work in a building interior.
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Common Problem #12: Specialized use areas as sources of
contaminants
Examples
• food preparation
• art or print rooms
• laboratories
Solutions
• change pressure relationships
- run specialized use area under negative pressure relative to surrounding
areas
- install local exhaust
• remove source by ceasing, relocating, or rescheduling
incompatible activities
• reduce source by selecting materials to minimize production of
contaminants
• reduce source by using proper sealing and storage for materials
which emit contaminants
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a darkroom.
DRAFT
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Common Problem #13: Remodeling or repair activities produce problems
Examples
• VOCs and odors
- paint, caulks, adhesives
- particleboard
- carpet and furnishings
• dust
- demolition
- new construction
• existing HVAC system does not provide adequate ventilation for new
occupancy or arrangement of space
Solutions
• modify ventilation to prevent recirculation of contaminants
• install temporary local exhaust in work area
• seal off air distribution system in work area
• reduce source: schedule work for unoccupied periods
• reduce source: materials selection and installation
- select materials to minimize production of contaminants
- have supplier store new furnishings in a clean, dry area until VOCs
outgas
- request installation procedures (e.g. adhesives) which limit emissions of
contaminants
• modify HVAC or wall partition layout If necessary
- partitions should not interrupt airflow
- relocate supply and return diffusers as necessary
- adjust supply and return air quantities as necessary
- adjust total air supply and/or outside air to serve new occupancy
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows normal commercial activity in a building
continuing while an adjoining area is being remodelled.
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Uncommon but Severe Problem #1: Combustion odors
Combustion odors can indicate the existence of a serious problem. Among
combustion gases may be an odorless gas, carbon monoxide. Carbon monoxide
poisoning can be a life-threatening problem!
Examples
• offices above an underground parking garage
• rooms near a loading dock
• areas near a mechanical room
Solutions
• remove source by sealing
- close unintentional openings between the contaminant source and the
occupied space
- install well-sealed doors with automatic closers between the contaminant
source and the occupied space
• remove source by relocating
- holding area for vehicles
- parking area
• modify ventilation system
- install local exhaust in loading dock, parking garage
- relocate fresh air intake (move away from source of contaminants)
• reduce source by modifying operating procedures
- turn off engines of vehicles that are waiting to be unloaded
• modify pressure relationships
- maintain combustion equipment and/or modify system to avoid
backdrafting
- pressurize building relative to area which contains source of combustion
gases
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a loading dock.
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Uncommon but Severe Problem #2: Serious building-related illness
Some building-related illnesses can be life-threatening. Even a single confirmed
diagnosis should provoke an immediate and vigorous response.
Examples
• Legionnaire’s disease
• Hypersensitivity pneumonitis
Solutions
• remove source
- clean and drain drip pans and other habitats of Legionella
- install drip pans that drain
- provide access to all the items that must be cleaned, drained, or replaced
periodically
• modify schedule and procedures for improved maintenance
• discontinue processes which deposit moisture in air
distribution system
- air washing
- humidification
- cease nighttime shutdown of air handlers during the heating season
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a contaminated drip pan
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Judging Proposed Mitigotion Designs end Their
Success
Mitigation efforts should be assessed at the design stage using the following
criteria:
• permanent or temporary
• operating principle makes sense
• degree to which the size or scope of correction effort fits the job
• makes the solution part of the institutional memory
• durability
• installation and operating costs
• conformity with codes
Permanence
Mitigation efforts which create permanent solutions to indoor air problems are
clearly superior to those which provide temporary solutions (unless the problems are
also temporary). Opening windows or running air handlers on full outside air may be
suitable mitigation strategies for a temporary problem such as outgassing of volatile
compounds from new furnishings, but would not be good ways to deal with emissions
from a print shop. A permanent solution to microbiological contamination involves not
Only cleaning and disinfection, but also modification of the environment to prevent
re-infestation.
Operating Principle
The most economical and successful solutions to lAO problems are those in which
the operating principle of the correction strategy makes sense and is suited to the
problem. If a specific point source of contaminants has been identified, treatment at
the source by removal, sealing, or local exhaust is probably a more appropriate
correction strategy than dilution of the contaminant by increased general ventilation. If
the lAO problem is caused by the introduction of outside air that contains
contaminants, increased general ventilation will only make the situation worse.
Sizing the Strategy to Fit the Job
It is important to make sure that you understand the lAO problem well enough to
select a correction strategy whose size and scope fit the job. If odors from a special
use area such as a kitchen are causing complaints in a nearby office, increasing the
ventilation rate in the office may not be a successful approach. The mitigation strategy
should address the entire area affected.
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If mechanical equipment is needed to correct the IAQ problem, it must be powerful
enough to accomplish the task. For example, a local exhaust system should be strong
enough and close enough to the source so that none of the contaminant is drawn into
nearby returns and recirculated.
Institutionalizing the Solution
A mitigation strategy will be most successful when it is institutionalized as part of
normal building operations. Solutions which do not require exotic equipment are
more likely to be successful in the long run than approaches which involve unfamiliar
concepts or delicately-maintained systems. If maintenance or housekeeping
procedures or supplies must change as part of the mitigation, it may be necessary to
plan for additional staff training, new inspection checklists, or modified purchasing
practices. Operating schedules for HVAC equipment may also require modification.
Durability
lAO mitigation strategies which are durable and low maintenance are more
attractive to owners and building staff than approaches which require frequent
adjustment or specialized maintenance skills.
Installation and Operating Costs
The approach with the lowest initial cost may not be the least expensive over the
long run. Other economic considerations include: energy costs for equipment
operation, increased staff time for maintenance, differential cost of alternative materials
and supplies, higher hourly rates if odor-producing activities (e.g. cleaning) must be
scheduled for unoccupied periods.
Conformity with Codes
Any modification to building components or mechanical systems should be
designed and installed in keeping with applicable fire, electrical, and other building
codes.
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Judging the Success of a Mitigation Effort
Two kinds of criteria can be used to judge the success of an effort to correct an
indoor air problem:
• reduced complaints
• measurement of properties of the indoor air
Reduction or elimination of complaints appear to be a clear indication of success,
but that is not necessarily the case. Occupants who see that their concerns are being
heard may temporarily stop reporting discomfort or health symptoms, even if the actual
cause of their complaints has not been addressed. Lingering complaints may
continue after mitigation if people have become upset over the handling of the
problem. Ongoing (but reduced) complaints could also indicate that there were
multiple lAO problems and that one or more problems are still unresolved.
However, it can be very difficutt to use measurements of contaminant levels as a
means of determining whether air quatity has improved. The concentrations of indoor
air pollutants can vary greatly over time. If air samples are taken, it is important that the
•before and after conditions are as identical as possible, except for the operation of
the control strategy. For example, the same HVAC operation, building occupancy and
climatic conditions should apply during both measurement periods.
Measurements of airf lows, ventilation rates, and air distribution patterns are more
reliable methods of assessing the results of control efforts. Airflow measurements
taken during the building investigation can identify areas with poor ventilation; later
they can be used to evaluate attempts to improve the ventilation rate or distribution.
Studying air distribution patterns will show whether a mitigation strategy has
successfully prevented a contaminant from being transported by airflow.
Persistent Problems
Solving an indoor air quality problem is a repetitive process of data collection and
hypothesis testing. Deeper and more detailed investigation is needed to suggest new
hypotheses after any unsuccessful or partially-successful control attempt.
Even the best-planned investigations and mitigation actions may not produce a
resolution to the problem. You may have made a careful investigation, found one or
more apparent causes for the problem, and implemented a control system.
Nonetheless, your correction strategy may not have caused a noticeable reduction in
the concentration of the contaminant or improvement in ventilation rates or efficiency.
Worse, the complaints may persist even though you have been successful at
improving ventilation and controlling all of the contaminants you could identify. At
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some point you may have pursued the source control options and increased
ventilation rates and efficiency to the limits of your expertise. Then you must decide
how important it is to pursue the problem further.
If you have made several unsuccessful efforts to control a problem, then it may be
advisable to seek outside assistance. The problem is probably fairly complex; it may
occur only intermittently or cross the borders that divide traditional fields of knowledge.
It is even possible that indoor air quality is not the actual cause of the complaints.
However, you should be careful not to jump to this conclusion, as it could have an
inflammatory effect on building occupants. Bringing in a new perspective at this point
can be very effective.
The next section provides guidance on hiring professional indoor air quality
assistance. An interdisciplinary team (such as people with engineering and medical
or heatth backgrounds) may be needed to solve particularly difficult problems.
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SICIIO 5 - ItIII G I I I [ SSIONAL
ASSISTANCE 10 SOLVE AN IA I I0I LIM
Many IAQ problems are simple to resotve when facilities staff have been educated
about the investigation process. In other cases, a time comes when outside
assistance is needed. Professional help might be necessary or desirable in the
following situations, among others:
• Mistakes or delays could have serious consequences (e.g. health hazards,
liability exposure, regulatory sanctions).
• Building management feels that an independent investigation would be better
received or more effectively documented than an in-house investigation.
• Investigation and mitigation efforts by facilities staff have not relieved the
IAQ problem.
• Preliminary findings by staff suggest the need for measurements which
require specialized equipment and training beyond in-house capabilities.
You may not be able to find help in solving your indoor air quality problem by
looking in the yellow pages of your telephone book (e.g. under “Engineers or
industrial Hygienists ). It may be helpful to consult a copy of the U.S. EPA’s Survey of
Indoor Air Quality Diagnostic and Mitigation Firms (EPA 400/1-89/004, November
1989), which is available through the National Technical Information Service (NTIS),
5285 Port Royal Road, Springfield, VA 22161 (7030-487-4850.
Local, State, or federal government agencies may be able to provide expert
assistance or direction in solving IAQ problems. It is important to contact your
State or local Health Department If you suspect that you have a serious
building-related illness ‘potentially linked to biological contamination in
your building. If available government agencies do not have personnel with the
appropriate skills to assist in solving your lAO problem, they may be able to direct you
to firms in your area with experience in indoor air quality work. Note that even certified
professionals from disciplines closely related to IAQ issues (such as industrial
hygienists, ventilation engineers, and toxicologists) may not have the specific
expertise needed to investigate and resolve indoor air problems. Individuals or groups
that offer services in this evoMng field should be questioned closely about their
related experience and their proposed approach to your problem.
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As with any hiring process, the better you know your own needs, the happier you
are likely to be with the result. Firms and individuals working in IAQ may come from a
variety of disciplines. Typically, the skills of HVAC engineers and industrial hygienists
are needed for this type of investigation, aRhough input from other disciplines such as
chemistry, architecture, microbiology, or medicine may be required to solve some lAO
problems. If problems other than indoor air quality are involved, experts in lighting,
acoustic design, interior design, psychology, or other fields may be helpful in resolving
occupant complaints about the indoor environment.
Make Sure that the Opproach Fits Your Needs
As you prepare to hire professional services in the area of indoor air quality, be
aware it is a developing area of knowledge. Most consultants working in the field
received their primary training in other areas. A variety of investigative methods may
be employed, many of which are ineffective for resolving any but the most obvious
situations. Inappropriately-designed studies may lead to conclusions that are either
false negative (e.g. fails to identify illness that is actually caused by the building) or
false positive (e.g. complaints are incorrectly attributed to building conditions).
Investigative outcomes to avoid include:
• an evaluation that is limited to listing measured concentrations for pollutants
and comparing those concentrations to numerical standards
• a report that lists a series of major and minor building deficiencies and links all
the deficiencies to the problem without considering their actual association with
the complaints
Considerable care should be exercised when interviewing potential consultants to
avoid those subscribing to these strategies. An understanding of sick building
syndrome and building related illness and the conditions which can lead to them,
along with appropriate experience and a phased investigative approach, is the best
way to Kientify a quaJified IAQ investigator.
Selection Criteria
Most of the criteria used in selecting a professional to provide indoor air quality
services are similar to those used for other professionals:
• company experience in solving similar problems; training and experience of the
individuals who wo d be responsible for the work;
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• quality of interview and proposal;
• company reputation; licensing and certification
• knowledge of local codes and climate, and
• cost
Experience
An EPA survey of firms providing IAQ services found that almost half had been
providing lAO diagnostic or mitigation services in non-industrial settings for ten or
fewer years.
• Ask how much lAO work and what type of IAQ work the firm has done.
• Have the firm identify the personnel who would be responsible for your case,
their specific experience, and related qualifications.
Quality of interview and proposal
The following guidelines may be of assistance in hiring IAQ professionals:
• Competent professionals will ask questions about your situation to see whether
they feel they can offer services that will assist you.
• A competent firm will emphasize observations rather than measurements and
should not provide non-routine measurements without site-specific justification.
• The staff responsible for building investigation should have a good
understanding of the relationship between lAO and the building structure,
mechanical systems, and human activities (see Section 2 of this document).
Frequently th%s means they will have to be able to call on multidisciplinary skills.
In some cases building investigators may have accumulated a breadth of
knowledge. For example, a mechanical engineer and an industrial hygienist
see buildings differently. However, a mechanical engineer with several years of
experience in building problem investigations will have seen enough health-
related problems to cross the gap, as will an industrial hygienist with years of
experience studying prob’ems in an office setting.
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• Either in the proposal or in discussion, the consultant should:
- describe the goal(s), methodology, and sequence of the investigation, the
information to be obtained, and the process of hypothesis development and
testing, including criteria for decisionmaking about further data gathering.
This should include an explanation of the need for any proposed
measurements. The goal is to reach a successful resolution of the
complaints, not simply to generate data.
- identify any elements of the work which will require a time commitment from
the client’s own staff, including information to be collected by the client.
- identify additional tasks (and costs) which are part of solving the fAQ problem
but are outside the scope of the contract. Examples might include medical
examination of complainants, laboratory fees, contractor’s fees for mitigation
work
- describe the schedule, cost and work product(s), such as: written report,
specifications and plans for mitigation work, supervision of mitigation work,
training program for building staff.
- discuss communication between the lAO professional and the client: How
often will the contractor discuss the progress of the work with the client?
Who will be notified of test results and other data? Will communications be
in writing, by telephone, or face-to-face? Will the consultant be meeting with
building occupants?
Reputation, licensing and certification
There are no regulations covering professional services in the field of indoor air
quality, although some disciplines (e.g. engineers, industrial hygienists) whose
practitioners work with fAQ problems have licensing and certification requirements. A
few specific pollutants (e.g. asbestos) have been a matter for regulatory concern so
that training programs or certification requirements have been developed; local and
State heatth departments may be able to provide information on firms which are
qualified in this way.
Firms should be asked to provide references from clients who have received
comparable services. In exploring references, it is useful to ask about long-term follow-
up. After the contract was completed, did the contractor remain in contact with the
client to ensure that problems did not recur?
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Location, local knowledge
Familiarity with State and local regulations and codes helps to avoid problems
during mitigation, and regional climate conditions can affect indoor air quality.
However, because of the complexities which may be involved in evaluating lAO
problems, it may be necessary to seek expertise from outside the local area.
Cost
ft is impossible for this document to give specific guidance on the cost of
professional services. However, if projected costs jump suddenly during the
investigation process, the consultants should be able to justify that added cost by
explaining the hypothesis they are testing.
The budget will be influenced by a number of factors, including:
• the size and complexity of the building and its HVAC system(s)
• the quality and extent of recordkeeping by building staff and management
• the type of report or other product required
• the number of meetings required
• air sampling (e.g. use of instruments, laboratory analysis) if required
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Sectkn 1 I ack n Track
When the problem that stimulated the IAQ investigation has been resolved, it is
timely to think about acting to prevent future indoor air quality problems. Some kinds
of problems can recur if indoor air quality concerns do not receive ongoing attention.
You may also have identified one or more additional problems (e.g. malfunctioning
equipment) thai need to be corrected but are unrelated to the ongirial complaint.
The companion volume of this document, PREVENTING iNDOOR AIR
QUALITY PROBLEMS, can help you to evaluate and modify routine procedures
(e.g. maintenance, housekeeping, tenant relations) and your handling of special
projects (e.g. remodelling) to keep indoor air quality problems to a minimum. The
guide instructs you in communicating with building occupants about indoor air quality,
preparing an IAQ profile and an IAQ management plan.
Building occupants can be valuable partners in promoting a comfortable, healthy
indoor environment. Section 3 of PREVENTING INDOOR AIR QUALITY
PROBLEMS suggests health and safety committees as a way to work cooperatively
to maintain good indoor air quality. It also discusses clarifying the lAO-related
responsibilities of landlords and tenants through the use of lease provisions arid
establishing a complaint Jogging system that can collect valuable information and help
resolve future IAQ problems if they arise.
Section 4 of PREVENTING INDOOR AIR QUALITY PROBLEMS discusses
the process of creating an lAO profile. This is a record of conditions in your building
that affect indoor air quality: the HVAC system, pollutant pathways and driving forces,
pollutant sources and occupants. The IAQ profile includes the same type of
information that is used in resolving IAQ complaints, but looks at the entire building
rather than focussing on a local “complaint area”. The data from the profile serves as
a valuable reference in developing an lAO management plan. Further, it may reveal
potential indoor air quality problems that can be corrected before they cause serious
complaints.
Section 5 of PREVENTING INDOOR AIR QUALITY PROBLEMS describes
how to develop an lAO management plan. Such a plan is most likely to be successful
if it is integrated into your existing organizationai structure and reflected in procedures
such as operations. recordkeeping, purchasing 1 commmunications, and planning and
policymaking. Critical elements of the lAO management plan include:
• facilities maintenance
• housekeeping
• pest control
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• tenant relations
• renovation, redecoration, and remodelling
• smoking
The steps involved in developing the lAO profile and management plan can be
carried out gradually when time is available, without the stress and pressure typical of
problem-solving investigations. The rewards can be substantial: improved relations
with building occupants, a healthier and more comfortable indoor environment, and (in
many cases) better-maintained mechanical equipment and building furnishings. EPA
and N OSH strongly recommend that you invest the effort in reviewing PREVENTING
INDOOR AIR QUALITY PROBLEMS and incorporating its suggestions into your
operations.
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FEDERAL AGENCIES WITH MAJOR INDOOR AIR RESPONSIBILITY FOR
PUBLIC AND COMMERCIAL BUILDINGS
U.S. Environmental Protection National Institute for
Agency: Occupational Safety and Health:
Public Information Center Requests for Field Investigations:
(PM-211B) NIOSH
401 M Street, SW Hazard Evaluations and Technical
Washington, DC 20460 Assistance Branch (R-9)
202-382-2080 4676 Columbia Parkway
(distributes indoor air quality Cincinnati, Ohio 45226
publications) 513-841-4382
National Pesticides Requests for Information:
Telecommunications Network National 1-800-35-N IOSH or
toll-free number: 1 -800-638-2772
1-800-858-PEST
In Texas: 806-743-3091 Occupational Safety and Health
(provides information on pesticides) Administration:
TSCA Hotline U.S. Department of Labor
Service 202-554-1404 200 Constitution Avenue, NW
(provides information on asbestos and Washington, D.C. 20210
other toxic substances)
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EPA Regional Offices
Address inquiries to the Indoor Air
Contacts in the EPA regional offices at
the following addresses:
REGION STATES IN REGION
Region 1 Connecticut, Maine,
EPA Massachusetts, New
John F. Kennedy Hampshire, Rhode Island,
Federal Building Vermont
Boston, MA 02203
617-565-3232
Region 2 New Jersey, New York,
EPA Puerto Rico, Virgin Islands
26 Federal Plaza
New York, NY 10278
212-264-2517
Region 3 Delaware, District of Columbia,
EPA Maryland, Pennsylvania, Virginia, West
841 Chestnut Building Virginia
Philadelphia, PA 19107
215-597-8322
21 5-597-4084(radon)
Region 4 Alabama, Florida, Georgia,
EPA Kentucky, Mississippi, North
345 Courtland Street, N.E. Carolina, South Carolina, Tennessee
Atlanta, GA 30365
404-347-2864
Region 5 Illinois, Indiana, Michigan,
EPA Minnesota, Ohio, Wisconsin
230 South Dearborn Street
Chicago, II 60604
312-886-6054
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REGION STATES IN REGION
RegIon 6 Arkansas, Louisiana,
EPA Oklahoma, New Mexico, Texas
Allied Bank Tower
1445 Ross Avenue
Dallas, TX 75202
214-655-7214
Region 7 Iowa, Kansas, Missouri, Nebraska
EPA
726 Minnesota Avenue
Kansas City, KS 66101
919-236-2893
Region 8 Colorado, Montana, North Dakota,
EPA South Dakota, Utah, Wyoming
999 18th Street,
Suite 1300
Denver, CO 80202
303-293-1692
Region 9 Arizona, California, Hawaii, Nevada,
EPA American Samoa, Guam, Trust
215 Fremont Street Terntories of the Pacific
San Francisco, CA 94105
415-974-8381
Region 10 Alaska, Idaho, Oregon, Washington
EPA
1200 Sixth Avenue
Seattle, WA 98101
206-442-2589
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OTHER FEDERAL AGENCIES WITH INDOOR AIR RESPONSIBILITIES IN
PUBLIC AND COMMERCIAL BUILDINGS
Bonneville Power
Administration
Portland, OR 97208
General Services
Administration
18th and F Streets, N.W.
Washington, D.C. 20450
Office of Conservation
and Renewable Energy
U.S. Department of Energy
1000 Independence Avenue, S.W.
Washington, DC 20585
105
Office on Smoking and Health
Center for Chronic Diseases Prevention
and Health Promotion
Centers for Disease Control
Park Building Room 1-10
5600 Fishers Lane
Rockville, MD 20857
Tennessee Valley Authority
Industry Hygiene Branch
328 Multipurpose Building
Muscle Shoals, AL 35660
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STATE AND LOCAL AGENCIES
Your questions and concerns about indoor air problems can frequently be
answered most readily by the government agencies in your state or locality.
Responsibilities for indoor air quality issues are usually divided among many different
agencies. You will often find that calling or writing the agencies responsible for health
or air quality control is the best way to start getting information from your state or local
government. The EPA and Public Health Foundation publication, Directory of State
indoor Air Contacts, lists state agency contacts. (See publications list for information
about how to order this publication.)
PRIVATE SECTOR CONTACTS
Some of the private sector organizations that have information for the public on
indoor air quality issues in commercial and public buildings:
Building Management Associations:
Association of Physical Plant
Administrators of Universities and
Colleges
1446 Duke Street
Alexandria, VA 22314-3492
Building Owners and Managers
Association, International
1201 New York Ave., NW, Suite 300
Washington, DC 20003
International Council of Shopping
Centers
1199 North Fairfax Street
Suite 204
Alexandria, VA 22314
International Facilities Management
Association
Summit Tower Suite 1710
11 Greenway Plaza
Houston TX 77046
Professional and Standard Setting Organizations:
American Conference of
Governmental Industrial
Hygienists
6500 Glenway Avenue
Building D-7
Cincinnati, OH 45211
106
American Industrial Hygiene
Association
P.O. Box 8390
345 White Pond Drive
Akron, OH 44320
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Professional and Standard Setting Organizations (continued):
American Society of Heating,
Refrigerating, and Air Conditioning
Engineers
1791 Tullie Circle, N.E.
Atlanta, GA 30329
Product Manufacturers:
Adhesive and Sealant Council
1627 K Street NW
Washington, DC 20006
Asbestos Information Association
1745 Jefferson Davis Highway
Room 509
Arlington, VA 22202
Association of Wall and Ceiling
Industries
1600 Cameron Street
Alexandria, VA 22314-2705
Carpet and Rug lnstiti.jte
1155 Connecticut Avenue
Suite 500
Washington, DC 20036
107
American Society of Testing Materials
Subcommittee D22.05 Indoor Air
Quality
1916 Race Street
Philadelphia, PA 19103
Chemical Specialities Manufacturers
Association
1001 Connecticut Avenue NW
Suite 1120
Washington, DC 20005
Formaldehyde Institute
1330 Connecticut Avenue NW
Washington DC 20855
National Paint and Coatings
Association
1500 Rhode Island Avenue NW
Washington, DC 20005
Thermal Insulation Manufacturers
Association
8341 S. Sangre De Cristo Road
Littleton,CO 80127
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Building Service Associations:
Air-Conditioning and Refrigeration
Institute
1501 Wilson Boulevard 6th floor
Arlington, VA 22209
Air-Conditioning Contractors of
America
1513 16th Street NW
Washington DC 20036
American Consulting Engineers
Council
1015 15th Street, NW Suite 802
Washington, DC 20005
Associated Air Balance Council
1518 K Street, NW
Washington, DC 20005
Association of Specialists in Cleaning
and Restoration
10830 Annapolis Junction Road
Suite 312
Annapolis Junction, MD 20701
Unions:
AFL-CIO
Department of Occupational Safety
and Health
815 16th Street
Washington, DC 20006
Amalgamated Clothing and Textile
Workers Union
15 Union Square
New York, NY 10003
108
National Air Duct Cleaner Association
1518 K Street, NW
Washington, DC 20005
National Association of Power
Engineers
4470 MacArthur Blvd.
Washington, DC 20007
National Environmental
Bureau
8224 Old Courthouse Rd.
Vienna, VA 22182
Balancing
National Pest Control Association
8100 Oak Street
Dunn Loring, VA 20027
Sheet Metal & Conditioning
Contractors National Association
8224 Old Courthouse Rd.
Vienna, VA 22182
American Federation of Government
Workers
1325 Massachusetts Avenue NW
Washington, DC 20005
American Federation of State, County,
and Municipal Employees
1625 L Street NW
Washington, DC 20036
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Unions (continued):
American Federation of Teachers
555 New Jersey Avenue NW
Washington, DC 20001
Communication Workers of America
1925 K Street NW
Washington, DC 20006
International Brotherhood of
Teamsters, Chauffeurs,
Warehousemen, and Helpers of
America
25 Louisiana Avenue NW
Washington, DC 20001
International Union of Operating
Engineers
1125 17th Street, NW, 4th Floor
Washington, DC 20036
Service Employees International
Union
1313 L Street, NW
Washington, DC 20005
EnvironmentallHealth Organizations
Your local lung association or
American Lung Association
1740 Broadway
New York, NY 10019
109
Sheet Metal Workers International
Association
1750 New York Avenue NW
Washington, DC 20006
The Newspaper Guild
1125 15th Street NW
Washington, DC 20005
United Food and Commercial
Workers International Union
1775 K Street NW
Washington, DC 20006
Utility Workers Union of America
815 16th Street NW
Washington DC 20006
National Environmental Health
Association
720 South Colorado Blvd.
South Tower Suite 970
Denver, CO 80222
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PUBLICATIONS AND WRITTEN MATERIAL
• items are available from EPA Public Information Center (PM-21 1B), 401 M Street
SW, Washington, DC 20460
General Information:
Bazerghi, Hani and Catherine Arnoult. Practical Manual for Good Indoor Air Quality.
1989. Quebec Association for Energy Management. 1259 Bern Street, Suite 510,
Montreal, Quebec. Canada. H2L4C7.
Cone, James E. and Michael J. Hodgson, MD, MPH. Problem Buildings: Building-
Associated Illness and the Sick Building Syndrome. Occupational Medicine: State of
the Art Reviews. Hanley & Belfus, Inc., 210 South 13th Street, Philadelphia, PA
19107.
Indoor Air Quality Update. Cutter Information Corp. 1100 Massachusetts Avenue,
Arlington, MA 02174. (Monthly newsletter covering technical indoor air issues.)
US EPA. Ventilation and Air Quality in Offices. Indoor Air Quality Fact Sheet #3.
Revised 1990.
US EPA. Sick Buildings. Indoor Air Quality Fact Sheet #4. Revised 1990. Revised
1990.
US EPA. Project Summaries: Indoor Air Quality in Public Buildings. 1988.
Description and findings of research project.
US EPA and the U.S. Consumer Product Safety Commission. The Inside Story: A
Guide to Indoor Air Quality. 1988. Addresses residential indoor air quality primarily,
but contains a section on offices.
US EPA and the Public Health Foundation. Directory of State Indoor Air Contacts.
1990. (In revision)
Ventilation:
ASHRAE Standard 62-1989. 1989. Ventilation for Acceptable Indoor Air Quality.
1989. American Society of Heating, Refrigerating and Air-Conditioning Engineers,
Inc., 1791 Tullie Circle, N.E. Atlanta, GA 30329.
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ASHRAE Journal. October 1989. Several articles describing ASHRAE Standard 62-
1989. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.,
1791 Tullie Circle, N.E. Atlanta, GA 30329.
Building Investigation and Remediatlon:
Commission of the European Communities. Sick Building Syndrome: A Practical
Guide. (Report #4). 1989. COST Project 613. Office of Publications of the European
Communities. Luxembourg.
US Department of Health and Human Services. NIOSH. Indoor Air Quality: Selected
References. 1989. 4676 Columbia Parkway, Cincinnati, Ohio 45226.
US Department of Health and Human Services. NIOSH. Guidance for Indoor Air
Quality Investigations. 1987. 4676 Columbia Parkway Cincinnati, Ohio 45226.
Environmental Tobacco Smoke:
US Department of Health and Human Services. The Health Consequences of
Involuntary Smoking, A Report of the Surgeon General. 1986. Office on Smoking and
Health. U.S. Public Health Service 5600 Fishers Lane, Roomi-lO, Rockville, MD
20857.
US Department of Health and Human Services. National Cancer Institute. Office of
Cancer Communications. A series of one-page information sheets on all aspects of
smoking in the workplace. For copies, call 1-800-4-CANCER.
US EPA. Environmental Tobacco Smoke. Indoor Air Quality Fact Sheet #5. *
US EPA. Environmental Tobacco Smoke: A Guide to Workplace Smoking Policies.
1990. (In review) *
US EPA. Health Effects of Passive Smoking: Assessment of Lung Cancer in Adults
and Respiratory Disorders in Children. 1990. (In review.) *
Biologicals:
American Council of Governmental Industrial Hygienists. Guidelines for the
Assessment of Bioaerosols in the Indoor Environment. 1989. 6500 Glenway Avenue,
Building D-7, Cincinnati, OH 45211
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Asbestos:
US EPA. In-Place Asbestos Guidance. 1990. In review. Available from the TSCA
hotline: (202) 554-1404.
US EPA. Tenants’ Guide. 1990. In preparation. Available from the TSCA hotline:
(202) 554-1404.
US EPA. Transmission Electron Microscopy Asbestos Laboratories: Quality
Assurance Guidelines. 1989. EPA 560/5-90-002. Available from the TSCA hotline:
(202) 554-1404.
US EPA. Asbestos Ban and Phaseout Rule. 40 CFR 763.16010 763.179. Federal
Register, July 12, 1989. Available from the TSCA hotline: (202) 554-1404.
US EPA. Guidelines for Conducting the AHERA TEM Clearance Test to Determine
Completion of an Asbestos Abatement Project, EPA 560/5-89-001. Available from the
TSCA hotline: (202) 554-1404.
US EPA. Asbestos Abatement Projects: Worker Protection. Final Rule 40 CFR. 763.
February 1987. Available from the TSCA hotline: (202) 554-1404.
US EPA. A Guide to Respiratory Protection for the Asbestos Abatement Industry.
1986. EPA 560/OTS 86-001. Available from the TSCA hotline: (202) 554-1404.
US EPA. Abatement of Asbestos-Containing Pipe Insulation. 1986. Technical
Bulletin No. 1986-2. Available from the TSCA hotline: (202) 554-1404.
US EPA. Asbestos in Buildings: Guidance for Ser’ice and Maintenance Personnel
(in English and Spanish). 1985. EPA 560/5-85-018. (“Custodial Pamphlet”).
Available from the TSCA hotline: (202) 554-1404.
US EPA. Measuring Airborne Asbestos Following An Abatement Action. 1985. EPA
60014-85-049. (“Silver Book”). Available from the TSCA hotline: (202) 554-1404.
US EPA. Asbestos in Buildings: Simplified Sampling Scheme for Surfacing Materials.
1985. 560/5-85-030A. (“Pink Book”). Available from the TSCA hotline: (202) 554-
1404.
US EPA. Guidance for Controlling Asbesto-Containing Materials in Buildings. 1985.
EPA 560/5-85-024. (“Purple Book”). Available from the TSCA hotline: (202) 554-
1404.
112
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US EPA. National Emission Standards for Hazardous Air Pollutants. 40 CRF 61.
April 1984. Available from the TSCA hotline: (202) 554-1404.
US Department of Labor. OSHA Regulations. 29 CFA 191 0.1001 “General Industry
Ash stos Standard” and 29 CFR 1926.58 “Construction Industry Asbestos Standard”.
Ju. 1986; Amended September 1988.
US Department of Labor. OSHA Regulations. 29 CFR 1910.134 “Respiratory
Protection Standard. June 1974.
Keyes, Dale L. and Chesson, Jean. A Guide to Monitoring Airborne Asbestos in
Buildings. 1989. Environmental Sciences, Inc., 105 E. Speedway Blvd., Tucson,
Arizona 85705.
Radon:
US EPA. Cumulative Proficiency Report, Round 6 1990. List of laboratories which
have demonstrated competence in radon measurement analysis.
Contact: National Technical Information Service (NTIS), 5285 Port Royal Road,
Springfield, VA 22161 (703)-487-4850
Volatile Organic Compounds:
US EPA. 1988. Project Summary; Indoor Air Quality in Public Buildings:
Volume I. Key findings of air quality monitoring research in four new public and
commercial buildings: two homes for the elderly, an elementary school, and an office
building.
US EPA. 1988. Project Summary; Indoor Air Quality in Public Buildings:
Volume Ill Key findings of air quality monitoring research in six new public and
commercial buildings: one hospital, two office buildings, two homes for the elderly,
and an institute for governmental studies. *
PCBs:
US EPA. 1986. Transformers and the Risk of Fire: A Guide for Building Owners.
0PA186-001. Available from National Toxics Hotline.
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TRAINING
American Industrial Hygiene Association (AIHA). Indoor Air Quality courses held in
conjunction with meetings. Open to AIHA members only. Contact: American Industrial
Hygiene Association, P.O. Box 8390, 345 White Pond Drive, Akron, OH 44320.
ASHRAE Professional Development Seminars on Indoor Air Quality. Contact:
Education Coordinator, ASHRAE, 1791 Tullie Circle NE, Atlanta, GA, 30329.
Honeywell, Inc. Indoor Air Quality Diagnostics Professional Training Course. offered
two-three times annually. Contact: Honeywell Indoor Air Quality Diagnostics, MNO8-
2123, 82 Normandale Boulevard, Bloomington, MN 55437. (612)-921-3509.
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AppendIx A
Ccmmcn IA Liaencstlc Measurements:
a eneraI guIde
The following is a brief introduction to making measurements that might be needed
in the course of a detailed lAO study. Emphasis has been placed on the parameters
most commonly of interest in non-research studies, highlighting the more practical
methods and noting some inappropriate tests to avoid. Consult the guidance on
pages 61-64 (Section 4) before determining whether to proceed with air sampling.
Simple ljentilotlon/Comfort Indicotlons
Carbon Dioxide (C0 2 ) as an Indicator of Ventilation
CO 2 is a normal constituent of the atmosphere, but its concentration in indoor air
can, under some test conditions, provide a good indication of the adequacy of
ventilation. Comparison of peak CO 2 readings between rooms, between air handler
zones, and at varying heights above the floor, may help to identify and diagnose
various building ventilation deficiencies.
Methodology:
CO 2 can be measured with either a direct reading meter or a detector tube kit. CO 2
instrumentation for lAO use should have a range of at least 200 - 4000 ppm and an
accuracy of within ± 10% at 1000 ppm.
CO 2 measurements for ventilation should be collected away from any direct source
(e.g. at least two feet from the investigator’s or an occupant’s face). Individual
measurements should be short-term (e.g. a 60-second averaging time).
Measurements should be made when concentrations are expected to peak. If the
occupant population is fairly stable during normal business hours, sampling in the mid-
to-late-afternoon is recommended. Other sampling times may be necessary for
differing occupancy patterns.
Using the Results:
Peak CO 2 values below 1000 ppm generally suggest adequate air exchange for
the present occupancy and HVAC settings. This addresses only routine products of
human occupancy and not unusual contaminants. The relative occupancy and air
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damper settings should be noted for each period of CO 2 testing. Higher
concentrations can generally be expected if the space would become more crowded
or the HVAC systems would adjust to provide a lower ventilation rate.
Use of Smoke Tubes to Track Air Movement
The release of heatless smoke from an air current tube kit can be helpful in
evaluating HVAC systems. Smoke tubes can also help track potential contaminant
movement and identify pressure differentials. Heatless smoke moves from a relatively
positive room to a relatively negative room if there is an opening between them (e.g.
door, utility penetration)
Methodology:
The air current tube kit consists of a tube which chemically generates smoke and a
squeeze bulb. A small amount of smoke is released and its movement is observed.
The smoke is extremely sensitive to air currents.
Using the Results:
Smoke released mid-room : Observation of a few puffs of smoke released in mid-room
or mid-cubicle can help to visualize air circulation within the space. Dispersal of
smoke in several seconds suggests good air circulation, while smoke that stays
essentially still for several seconds suggests poor circulation. Poor air circulation may
contribute to sick building syndrome (if it is accompanied by high peak CO 2 levels) or
may contribute to comfort complaints even if there is sufficient overall air exchange.
Smoke released near diffusers, grilles : Puffs of smoke released by HVAC vents give a
general idea of airflow (is it in or out? vigorous, sluggish, or no flow?). This is helpful
in evaluating the supply and return system and determining whether ventilation air
actually reaches the breathing zone (for a VAV system, be sure to take into account
how it is designed to modulate).
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above illustrates the use of heatless chemica] smoke
tubes to observe airflow patterns.
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Temperature and Relative Humidity as an Indicator of Comfort
thodology: Measurements can be made with a simple thermometer and sling
thrometer or with electronic sensors (e.g. a thermohygrometer). For each
asurement, time should be allowed for the reading to stabilize to room conditions.
Using the Results: Measure next to thermostats to confirm calibration. Measure at
the location of complaints to evaluate whether or not temperature and humidity at that
location are within the comfort zone. (See the chart on page 33 for guidance on
interpreting temperature and relative humidity readings.)
Highly variable readings may indicate control or balance problems with the HVAC
systems. Note also that warmer indoor temperatures may generate higher airborne
levels of some contaminants.
Thermal Mass Balance as an Indicator of Outside Air Quantity
Thermal mass balance measurements allow calculation of the amount of outside air
that is introduced by a particular air handling unit. Use of this test requires the
following conditions:
1) Air streams representing return air, outside air and mixed air (supply air before it
has been heated or cooled) are accessible for separate measurement. This is
easy in some large units, impossible in very large units and in many smaller
units.
2) There is at least a several degree temperature difference between the building
interior and the outside air.
3) Total air flow in the air handling system can be estimated.
Methodology: The required temperature measurements can be made with a simple
thermometer or an electronic sensor. Several measurements should be taken across
each air stream and averaged. It is generally easy to obtain a good temperature
reading in the outside air and return air streams. The mixed air stream, however,
requires that a large number of measurements be taken and averaged. In large
systems, it may be impossible to get a good average temperature reading for the
mixed air.
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Using the Results: The percentage or quantity of outside air is calculated from
average temperatures as foflows:
Outside a (percent) nnxed air - ti aii
air - T ietwn an’
Outside (in ) fliiX vd - T X HVAC capacity (in cfm)
-T rtwnair
Where: I = temperature (degrees Fahrenheit)
cfm = cubic feet per minute
HVAC capacity refers to the total air supplied by the air handling unit being
measureL
fir Contaminant Concentrations
Overview of Sampling Devices
Air contaminants of concern in IAQ can be measured by one or more of the
following methods:
Vacuum Pump: A vacuum pump with a known airflow rate draws air through
collection devices, such as a filter (catches airborne particles), a sorbent tube (a
tube filled with a powder such as carbon which attracts certain chemical
vapors), or an impinger (air bubbles through solution in a test tube). Tests
originated for industrial environments typically need to be adjusted to a lower
detection limit for lAO work. This can be achieved by an increase in sample air
volume and/or adjustments in lab technique. Also, for lAO work, labs can be
asked to report when trace levels of an identifiable contaminant are present
below the quantification (Rdetection ) limit.
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a vacuum pump with attachments for
sampling with a filter, a sorbent tube, and an impinger.
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Direct Reading Meter: Direct reading meters estimate air concentrations
through one of several detection principles. These may report specific
chemicals (e.g. CO 2 by infrared light), chemical groups (e.g. certain volatile
organics by photolonization potential) or broad pollutant categories (e.g. all
respirable particles by scattered light). Detection limits and averaging time
developed for industrial use may or may not be appropriate for lAO.
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a direct reading meter.
Detector tube kit: Detector tube kits generally include a hand pump which
draws a known volume of air through a chemically treated tube intended to
react with certain contaminants. The length of color stain resulting in the tube
correlates to chemical concentration. A variety of tubes are available, although
only a limited number have detection limits sensitive enough for lAO.
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a detector tube kit.
Passive dosimeter: Passive dosimeters are badgesu which react with or
collect chemicals at a predictable rate over a period of time. Dosimeters are
available for formaldehyde, nitrogen oxides, and other lAO contaminants. Long
collection times are generally required, which tends to mask any peak
exposures occuring during the measurement period.
BREAK FOR PHOTOGRAPH
PHOTOGRAPH The photograph above shows a passive dosimeter.
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Formaldehyde
Small amounts of formaldehyde are present in most indoor environments.
Sampling may be helpful when relatively new suspect materials are present. A
pungent odor often indicates an elevated concentration.
Methodology: A number of measurement methods are available. Sensitivity and
sampling time are very important issues in selecting a method. A detection limit not
exceeding 0.05 ppm is recommended for lAO applications. Measurement of short-
term peaks (around a two-hour sample time) is ideal for evaluating acute irritation.
Dosimeters may accurately record long-term exposure but may miss these peaks.
Two commonly-used methods that are generally acceptable for lAO screening
involve impingers (NIOSH 3500) and sorbent tubes (OSHA 52). Other appropriate
methods are available but tend to cost more or are not as easily available.
Using the Results: Various guidelines are available for formaldehyde exposure.
Several organizations have adopted 0.1 ppm as a reasonable protection against
irritational effects in the normal population. Hypersensitivity reactions may occur at
lower levels of exposure. Worst-case conditions are created by minimum ventilation,
maximum temperatures, and high-source loadings.
Other Organic Compounds
In addition to formaldehyde, hundreds of other organic (carbon-containing)
chemicals can be found in indoor air at trace levels. Organics may present an lAO
problem when the mixture exceeds normal background levels or when individual
chemicals are released in harmful amounts.
Methodology: Although there are numerous methods available to test for airborne
organics, they generally fall into one of three categories:
1) An estimate of total volatile organic compounds (low sensitivity)
Several direct-reading instruments are available that provide a total M
reading for some organics present in the air. Such estimates are usually
presented in parts per million and are calculated with the assumption that all
chemicals detected are the same as the one used to calibrate the instrument.
An example of this would be a photoionization detector.
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In a related approach, an estimate of total solvents in the air can also be
obtained from lab analysis of a charcoal sorbent tube. Although methods in this
category report “total volatile organic compounds” TVOCs) or “total
hydrocarbons” (THC), each differs in its ability to respond to the different types
of organics. Results of one method should generally not be compared to
another. Direct-reading instruments don’t provide sufficient sensitivity to
differentiate normal from problematic mixtures of organics. However,
instantaneous readouts may help to identify “hot spots,” sources and pathways.
TVOCs or THC determined from sorbent tubes provide more accurate readings,
but will tend to miss worst-case peak exposures due to the longer averaging
time.
2) Measurement of individual organics (medium sensitivity)
Individual organic compounds can be measured in indoor air with a
moderate degree of sensitivity through adaptations of existing industrial air
monitoring technology. Examples of such IAQ tests include nicotine (with XAD-
4 sorbent tubes), solvents (with charcoal tubes), and pesticides (with
chromosorb tubes). After a sufficient volume of air is pumped through these
tubes, they are sent to a lab for extraction and analysis by gas chromatography.
Variations use a passive dosimeter (charcoal badge) to collect the sample or a
portable gas chromatograph onsite for direct injection of building air. These
methods may not be sensitive enough to detect many trace level organics
present in building air.
In adapting an industrial hygiene sorbent tube sampling method for lAO, the
investigator must consider at least two important questions. First: are the
emissions to be measured from a products’ end use the same as those of
concern during manufacturing? For example, the NIOSH method for chiordane
in the workplace tests for volatile components, while the Air Force method for
chiordane in housing tests for the less volatile, longer-lasting components. The
second question involves the volume of air needed to meet a lower detection
limit for IAQ. For example, an investigator might have to increase sampling time
from 30 minutes to five hours in order to detect whether the concentration of a
substance exceeds a public health guideline that is significantly lower than
occupational standards.
3) Characterization of trace organics (high sensitivity)
The third category of monitoring for organics involves highly sensitive
collection media (i.e. Tenax sorbent tubes) analyzed by gas chromatography
followed by mass spectroscopy. This approach can identify most orgariics in
the parts per billion range or less. Disadvantages include very high cost, the
possibility of identification error and difficulty in interpreting the voluminous data
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produced. Distinguishing normal, background concentrations from unusual and
potentially harmful levels may be very difficult, if not impossible.
Bioaerosols
Bioaerosols include material that is or was living such as airborne mold and
bacteria. Direct sampling results can be misleading; thus inspection of building
sanitary conditions is generally preferred over air monitoring.
Methodology: Where air sampling is desired, several approaches are available.
The most common type of air sampler uses a pump to blow air onto nutrient agar,
which is then incubated. Any bacterial or fungal colonies which subsequently grow
can be counted by a qualified analyst. Different types of agar and incubation
temperatures can be used to culture different types of organisms. Only living spores in
the air are counted by this method. One sampling approach to be avoided is settling
plates which are simply opened to room air and then incubated. This does not provide
an accurate representation of air quality.
Interpreting the Results: Bioaerosols can vary greatly over time in any given
building, making sampling results difficult to interpret. No absolute guidelines are
available. Comparison of relative numbers and types betwen inside and outside or
between complaint areas and background sites can help to establish trends. Low
bioaerosol results by themselves are not considered proof that a problem does not
exist. Any sampling should be accompanied by observations of building sanitary
conditions and a determination as to whether any health problems appear likely to be
related to bioaerosols.
Other Contaminants
Other lAO tests tend to follow the same basic principles discussed above.
Examples of other commonly-employed sampling methods include:
• Dust can be measured either by drawing air through a filter and weighing it or
by direct reading with a “scattered light” meter.
• Combustion products are indicated by the measurement of either carbon
monoxide (using detector tubes or direct reading meter) or nitrogen oxides
(using a passive dosimeter).
• Inorganic compounds such as ammonia or ozone can be measured by
impinger sampling or by detector tubes.
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Appendix I - 1-IVAC Systems and Indccr
Air uaIlt
The term ‘HVAC system’ is used to refer to the equipment that provides heat,
cooling, fresh air, and humidity control to maintain comfort conditions in a building.
Not all HVAC systems fill all of these functions. Some buildings rely on natural
ventilation, others lack mechanical heating or cooling equipment, and many function
without humidity control. This appendix provides a brief introduction for building
owners and managers who may be unfamiliar with the terminology and concepts
associated with HVAC system design.
HVAC systems range in complexity from independently-functioning units serving
individual rooms to centrally-controlled systems serving entire large buildings. Some
buildings use only natural ventilation or exhaust fans to remove odors and
contaminants. In these buildings, indoor air quality problems may be associated with
insufficient outdoor air or low air exchange rates, particularly during the heating
season (when occupants tend to keep windows closed).
Interior spaces often require year-round cooling to counteract the heat introduced
by lighting, people, and equipment. Rooms with exterior wall or roof surfaces need to
be heated or cooled as outdoor weather conditions change.
Large, modern public and commercial buildings generally use a mechanical
ventilation system to introduce outdoor air. Thermal comfort is maintained by
mechanical equipment that distributes ‘conditioned’ (heated or cooled) air, sometimes
supplemented by piping systems that carry steam, hot water, or chilled water to
perimeter areas of the building. As this document is concerned with HVAC systems in
reference to indoor air quality, the remainder of this discussion will focus on air
systems.
The basic components of an HVAC system that uses air to condition space are:
• ductwork to convey the circulated air
• one or more fans to move the air
• a filter to remove particles from the air
• terminal devices to distribute relatively clean supply air (e.g. grille, diffuser, etc.)
and withdraw contaminated air
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heating and cooling coils to control air temperature
controls that direct the operation of the system
The illustration below shows the general relationship
however, many variations are possible.
between these components;
piping
supply
ductwork
heating coil served
by hot water or steam
piping (could also be
electric resistance)
Schematic of an Air Circulation System with Heating and Cooling
Ductwork
Air circulation systems can move air through ducts that are constructed to be
relatively airtight. Airflow in ductwork is determined by the size of the duct opening
and the velocity of the air through the duct. HVAC designs may also utilize elements of
the building construction as part of the air distribution system.
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return air
return
wall
exhaust
to outside
supply air
air
chilled water
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If a ceiling plenum is used for the collection of return air, openings into the
ceiling plenum created by the removal of ceiling tiles can disrupt airflow patterns. It is
particularly important to maintain the integrity of the ceiling over areas that should be
exhausted 1 such as supply closets, bathrooms, and chemical storage areas.
Dampers are used as controls to restrict airflow. Damper positions may be
relatively fixed (e.g. set manually during system testing and balancing) or may change
in response to signals from the control system.
When dampers that regulate the intake of outdoor air are arranged to modulate,
they are usually designed to bring in a minimum amount of outside air under extreme
temperature conditions and to open as outdoor temperatures approach the design
(goal) indoor temperature. Indoor air quality problems may result if the outside air
damper is not operating properly, if the system is not arranged to allow the introduction
of sufficient outdoor air for the current use of the building, or if the location of the
outdoor air intake promotes the introduction of contaminants (e.g. from dumpsters or
loading docks).
Fans
Effective air delivery by a mechanical system requires proper coordination between
fan selection and duct layout. Fan performance is expressed as the ability to move a
given quantity of air at a given resistance or static pressure (measured in inches of
water gauge). The static pressure in a system is calculated using factors for duct
length, speed of air movement and changes in direction of air movement.
It is typical to find some differences between the original design and the final
installation, as ductwork must share limited space with structural members and other
‘hidden elements of the building system such as electrical conduit and plumbing
piping. Air distribution problems can occur, particularly at the end of duct runs, if
departures from the original design increase the friction in the system to a point that
approaches the limit of fan performance.
Terminal Devices
Thermal comfort and effective contaminant removal demand that air delivered into
a conditioned space be well-distributed within that space. Terminal devices are the
supply diffusers, return and exhaust grilles, and associated dampers and controls that
are designed to distribute air within a room and collect ft from that room.
The number, design, and location of terminal devices are very important. They can
cause a system with adequate capacity to produce unsatisfactory results, such as
drafts, stagnant areas, or short-circuiting (i.e. air that fails to blend with room air as it
rr- ‘ s from the supply diffuser to the return grille). Occupants who are uncomfortable
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because of drafts, stagnant air, or uneven temperature distribution may try to
compensate by adjusting or blocking the flow of air from supply outlets. Problems can
also be produced if the arrangement of movable partitions, shelving, or other
furnishings interferes with airflow.
Filters
Filters are used to remove particles from the air. The type of filter used determines
its efficiency at removing particles of a given size. To maintain clean air in occupied
spaces, filters must remove bacteria, pollens, insects, soot, dust, and dirt with an
efficiency suited to the use of the building. It is recommended that filters used in office
areas be 85% efficient.
Filters require regular maintenance (cleaning or replacement). As a filter loads up
with particles, it becomes more efficient at particle removal but increases the pressure
drop through the system, therefore reducing airflow.
Heating and Cooling Coils
Heating and cooling coils are placed in the airstream to regulate the temperature of
the air delivered to the conditioned space. Malfunctions in the coils can result in
thermal discomfort, and leakage in piped systems can create moist conditions
conducive to the growth of molds and fungus.
Controls
HVAC systems can be controlled manually or automatically. The control system
can be used to switch fans on and off, regulate the temperature of air (or piped liquid)
delivered to the conditioned space or modulate airflow by controlling fan speed and
damper settings. Most large buildings use automatic controls, and many have very
complex and sophisticated systems. Regular maintenance and calibration are
required to keep controls in good operating order.
A single air handling unit can serve more than one building area, if the areas
served have similar heating, cooling, and ventilation needs or the control system
compensates for differences in heating, cooling, and ventilation needs between the
areas served. Areas regulated by a common control (e.g. a single thermostat) are
referred to as zones. Thermal comfort problems can result if the design does not
account for differences in heating and cooling loads between rooms that are in the
same zone. This can easily occur if:
• the cooling load in some area(s) within a zone changes due to an increased
occupant population, increased lighting, or the introduction of new heat-
producing equipment (e.g. computers, copiers)
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• areas within a zone have different solar exposures. This can produce radiant
heat gains and losses that, in turn, create unevenly distributed heating or
cooling needs (e.g. as the sun angle changes daily and seasonally).
Multiple zone systems can provide each zone with air at a different temperature by
heating or cooling the airsiream in each zone. An alternative approach is to deliver air
at a constant temperature while either varying the volume of airflow or modulating
room temperature with a supplementary system (e.g. perimeter hot water piping).
Constant volume systems, as their name suggests, deliver a constant airflow to
each space. These systems often operate with a fixed minimum percentage of outside
air. If return and outdoor air are well-blended, it is possible to estimate the minimum
flow of outdoor air to each space and compare it to ventilation guidelines such as
ASHRAE 62-1989.
Variable volume systems maintain thermal comfort by varying the amount of air
delivered to each space. Underventilation can result if the system is not arranged to
introduce at least a minimum quantity (as opposed to percentage) of outdoor air.
Modern HVAC systems ncorpo rate many additional components which have not
been included in this brief introduction, even though they can affect indoor air quality.
Further information can be obtained through using the Fes urces section of this
document or through discussion with your facilities engineer.
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AppendI C - Ccmmcn IAC I iIutants
arni IndIcators
A wide range of contaminants can contribute to IAQ problems. Building
investigators may measure one or more of the following substances based upon initial
hypotheses pointing to a problem:
Substances that are indicators of lAO problems
• moisture (associated with biological growth)
• carbon dioxide (associated with underventilation)
• carbon monoxide (associated with improperly vented or re-entrained
combustion gases)
Pollutants
• formaldehyde
• tobacco smoke and other respirable particulates
• nitrogen dioxide
• ozone
• total VOCs
• radon
• asbestos
A pollutant and source inventory is likely to discover material which is not on the
above lists. The variety of possible indoor processes and associated chemicals
prevents any manageable list from being comprehensive.
Moisture
Moisture can be considered an lAO contaminant in the sense that the presence of
moisture promotes the growth of microorganisms such as mold and mildew. In
addition to obvious reservoirs for microbiological growth (e.g. stagnant water in drip
pans), microorganism growth occurs where water vapor condenses onto surfaces.
Problem sites include the relatively cool surfaces (and sometimes the interiors) of
underinsulated exterior walls and areas around thermal breaks (e.g. beams above
windows, balconies). Carpeting is also a common site of biological growth.
See AppendIx I for a discussion of indoor moisture.
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Carbon Dioxide
Carbon dioxide, a product of respiration and combustion processes, is not a
pollutant that is harmful at levels found in non-industrial setting; rather it is an indicator
of inadequate ventilation. Reports of ustaleu air or body odor are common complaints
associated with underventilation. If the HVAC system is not removing the carbon
dioxide associated with respiration by building occupants, other contaminants are also
likely to be accumulating. Carbon dioxide measurements for the purpose of assessing
ventilation are generally taken during periods of peak occupancy. See AppendIx
A for a discussion of carbon dioxide measurement.
Carbon Monoxide
Carbon monoxide pollution occurs where combustion gases are not properly
exhausted or are re-entrained into the building. The presence of carbon dioxide is
often associated with other combustion gases.
Carbon monoxide should be measured if there are complaints of exhaust odors or if
there is some other reason to suspect a problem with combustion gases.
Formaldehyde
Formaldehyde is a volatile organic compound (VOC) that is frequently emitted by
new furnishings as well as by a wide variety of cleaning compounds, deodorants,
hesives, and other materials used in maintenance and housekeeping. lAO
complaints associated with formaldehyde or other VOCs are most commonly found
under the following conditions:
• new construction or new furnishings
• underventilation
See AppendIx A for a discussion of formaldehyde measurement.
Tobacco smoke and other respirable particulates
Tobacco smoke, dust-producing processes (e.g. renovation work), or inefficient
fillers can result in high levels of respirable particulates. Investigators should find out
the smoking policy for the building and identify other internal sources of excessive
r t. Examination of filters and dust accumulation in ductwork will reveal whether
ficient filtration seems to be a problem.
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Nitrogen Dioxide
Nitrogen dioxide, like carbon monoxide, is an air pollutant associated with
combustion processes. It should be measured if outdoor sources of combustion gases
are suspected (e.g. if the exhaust plume from a nearby power plant may be polluting
air outside the building).
Ozone
Ozone problems may occur if the outdoor ambient air quality is a problem or if
where there are unvented indoor sources such as some types of photocopiers or
electrostatic precipitators. Ozone should be measured if the investigator notices its
characteristic odor or suspects its presence due to identified sources.
Volatile organic compounds (VOCs)
Formaldehyde is the best-known VOC in relation to indoor air quality problems, but
many other related compounds are also emitted by building materials, furnishings, and
supplies. If specific sources are identified, measurements of styrene,
paradichlorobenzene, perchioroethylene, trichloroethylerie, or other VOCs may be
indicated.
Radon
Radon is a naturally-occurring odorless, colorless radioactive gas. Indoor radon
problems generally occur where all of the following conditions are met:
• radium levels in soils and bedrock near the building foundation provide a
source of radon
• there are cracks and openings below grade through which the gas can enter
• pressure differentials between the building interior and exterior act to draw
in soil gas
It is also possible for indoor radon levels to be elevated due to emissions from
groundwater (e.g. water from a private well) or building materials.
Radon’s health effects are associated with long-term exposure and therefore will
not come to the investigator s attention as lAO complaints. Radon measurements are
recommended if indoor radon levels in the geographic area of the building suggest a
potential problem. See AppendIx F and the Fes urces section for further
information on radon.
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Asbestos
You may suspect the presence of asbestos in pipe or equipment insulation or other
building materials noted during the onsite investigation. EPA urges building owners
and managers to become familiar with the array of EPA guidance documents on
asbestos before they decide what action to take with respect to with asbestos-
containing materials.
See AppendI F and the I escurces section for further information about
asbestos.
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Appendix l - Mcisture, Mcld and Mildew
Molds and mildew are simple plants that grow on the surfaces of objects. Mold
can discolor surfaces, lead to odor problems, deteriorate building materials and lead
to allergic reactions in susceptible individuals as well as other potential health
problems.
The following conditions are necessary for mold growth to occur on surfaces:
• mold spores must be present
• nutrient base must be available (most surfaces contain nutrients)
• temperature range above 40 degrees and below 100 degrees
• relative humidity at surface above 70 per cent
Of these condftions, relative humidity is the most practical to control. Spores are
almost always present in outdoor and indoor air. Almost all of the commonly used
construction materials can support mold growth, therefore control of available nutrients
is limited. Human comfort constraints limit the use of temperature control.
Relative humidity, although a common term, is often misunderstood.
Furthermore, the factors which govern relative humidity are also typically
misunderstood. The purpose of this appendix is to give building managers an
understanding of the factors which govern relative humidity and to describe common
moisture problems and their solutions.
Background on Vapor Pressure, Relatlue Humiditg, and
Condensation
Air is capable of holding moisture in the vapor or gas phase. The amount of
moisture contained in a unit of air, or the water vapor density, is referred to as the
“absolute humidity” of the air.
The amount of moisture air can hold, the air’s “vapor pressure” or “absolute
humidity”, is dependent on the temperature of the air. The warmer air is, the greater
the amount of moisture it can hold. The cooler air is, the less moisture it can hold.
When air is holding the maximum amount its moisture it can hold, it is said to be
saturated, or 100 percent filled with moisture. When air is holding one half of the
maximum capacity of moisture, the relative humidity of the air is said to be 50 percent.
“Relative humidity” is defined as the amount of moisture contained in a unit of air
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compared to (or relative to), the maximum amount of moisture the unit of air can hold at
a specific temperature.
The relationship between temperature, relative humidity and vapor pressure
can often be counter-intuitive. For example, cold air is not capable of holding very
much moisture, and therefore has a low vapor pressure. However, some moisture in
the air is usually present, and this small amount of moisture is often very close to the
maximum amount of moisture the air can hold at that temperature. Frequently,
therefore, cold and ‘dry” air has a low vapor pressure but a high relative humidity.
A relative humidity reading taken inside an enclosure will not give an accurate
indication of the actual amount of moisture present unless a temperature reading is
taken at the same time. For example, the amount of moisture contained in air at 50
percent relative humidity at 70 degrees Fahrenheit is almost twice the amount of
moisture contained in air at 50 percent relative humidity at 50 degrees Fahrenheit.
The relationship between temperature, relative humidity and vapor pressure is
typically presented graphically on a psychometric chart.
To further complicate matters, relative humidity and temperature often vary
within a room. Usually, the vapor pressure in room can be assumed to be uniform.
However, one side of the room may be warm and the other side may be cool. The
warm side of the room will therefore have a lower relative humidity than the cool side.
If accurate measurement of moisture levels in enclosures are desired, temperature
and relative humidity readings need to be taken simultaneously in same location.
When the relative humidity at a surface reaches 100 per cent, condensation
occurs. The colder the surface, the higher the relative humidity at that surface. The
coldest surfaces in a room always have the highest relative humidities. The coldest
surface in a room will likely be the location where condensation happens first, should
the surface relative humidity rise to 100 percent. The coldest surface in a room is
therefore referred to as the “first condensing surface”. The temperature of the first
condensing surface is important because it usually sets the limit for the maximum
vapor pressure which can exist in the enclosure.
Taking Steps to Heduce Moisture
Where surface relative humidities are maintained below 70 percent, mold and
mildew growth can be controlled. Since relative humidities are dependant on both
temperature and vapor pressure, mold and mildew control will be dependant on
controlling both temperature and vapor pressure at surfaces.
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Controlling surface temperature dominated mold and mildew is best
accomplished by increasing the temperature. Temperature can be increased by:
• increasing the heat flow to the room; and/or
• decreasing the heat flow out the room.
Increasing the heat flow to the room can be as simple as leaving the room door
open. The open door will promote air circulation, and the air circulation will carry heat
into the room, warming the room and thereby reducing its relative humidity. Heating
the room by installing an additional heat register in the room will also reduce room
relative humidity.
Reducing heat flow out of a room can be accomplished by insulating the
exterior walls and by preventing the wind from short circuiting the thermal insulation as
ft blows into the wall cavities. This air flow, sometimes called Nwind washing,R is
distinct from infiltration. Infiltration involves through-the-wall” air movement, whereas
wind.washing typically involves air flows entering a wall at one location at the
exterior and exiting at some other location at the exterior. Wind-washing can be
controlled by installing a tight building paper or tight sheathing on the exterior of the
wall.
Controlling vapor pressure dominated mold and mildew can be
accomplished by actions aimed at:
• source control
• dilution and/or
• dehumidification
Source control involves controlling interior airborne levels through the control of
moisture sources. Common example of source control are the direct venting of
moisture generating activities to the exterior (e.g. washroom, laundry rooms).
Dilution involves controlling interior airborne moisture levels by exchange of
interior moisture-leaden air with exterior air which is drier. Dilution, which can occur
through natural air change (uncontrolled infiltration and ext iltration) and/or through
mechanical ventilation (controlied air change) utilizing fans or blowers, as a control
strategy is Iimfted to heating climates during heating seasons and is not available in
cooling climates or during cooling periods. A common example of dilution control of
interior moisture levels is the installation of an exhaust fan that operates on a timer or
by dehumidistat control (when the moisture levels rise, the fan swftches on).
Dehumidification involves the removal of moisture from a space and usually
involves the cooling of warm, moisture-laden air to reduce its ability to hold moisture.
The air gives up moisture in the form of condensation. Dehumidification is often
1 34
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coupled with air conditioning and common in cooling climates or during the cooling
season. A common example of dehumidification control of interior moisture levels is
the installation of a dehumidifier in a room.
Importance of Distinguishing Detween Causes of
Mold and Mildew
A surface temperature related mold problem may not respond very well to
increasing ventilation or air change, whereas a vapor pressure related mold problem
may not respond well to increasing temperatures. Understanding which factor
dominates, surface temperature or vapor pressure, will encourage the choice of
effective control strategies.
Consider an old, leaky, poorly insulated building in a heating climate which is
suffering from mold and mildew. Since the building is leaky, it has a very high natural
air change which dilutes interior airborne moisture levels and therefore maintains a
very low interior vapor pressure. Providing mechanical ventilation in this building by
installing a fan in an attempt to control interior mold and mildew will likely not be
effective since the interior moisture levels are already low. Increasing surface
temperatures by insulating the exterior walls, and thereby reducing surface relative
humidities, would be a better strategy to control mold and mildew in this instance.
BREAK FOR SIDEBAR
SIDEBAR How To Identify The Cause of A Mold and Mildew Problem
A classic example of relative humidity-caused biological contamination occurs when mold
and mildew grow on the exterior wall surfaces of a room at the building perimeter at heating
climate location. This example to illustrate how to identify whether a mold and mildew problem is
caused by temperature or by water vapor.
The heat loss in this exposed room is likely to be high and the room is likely to be
significantly colder than adjoining rooms. If the vapor pressure in this room is the same as that in
an adjacent room and the room is colder, then the relative humidity in the room will be much higher
than the relative humidity in the adjacent room. If the room experiences mold and mildew growth,
we can conclude that the relative humidity on the surface of the room is greater than 70 percent.
However, is the relative humidity above 70 percent because the room is too cold, or is it because
there is too much moisture present (high vapor pressure) in the room?
To answer this question, the amount of moisture (i.e. vapor pressure) in the enclosures
needs to be determined. This can be done by measuring both the temperature and relative humidity
intheroomatthesameplaceandatthesametime. Let us assume that in this casearelative
humidity of 30 percent is measured at a temperature of 70 degrees Fahrenheit. This indicates that
a relatively low amount of moisture (i.e. a relative low vapor pressure) exists in the room.
Therefore we can conclude that since the amount of moisture in the room or vapor pressure is low,
the reason the high relative humidity exists on the room surfaces (at least above 70 percent since
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mold is present) is due to the fact the room is “too” cold. This can of course be confirmed by
taking a temperature reading in the room.
Considering the same room previously described, let us now assume in the second instance
that a relative humidity of 50 percent at a temperature of 70 degrees Fahrenheit is measured. This
indicates that a relatively high amount of moisture, or relatively high vapor pressure, exists in the
room. Therefore we can conclude that since the amount of moisture in the room or vapor pressure
is high, the reason the high relative humidity exists on the room surfaces (at least above 70 percent
since mold is present) is due to the fact that there is “too much” moisture in the room.
identilging and Correcting Common EHamples al
Mold and Mildew
Exterior Corners
Exterior corners are common locations for mold arid mildew growth in heating
climates because there are higher relative humidities at exterior corner surfaces than
other parts of the envelope surface. Higher surface ref ative humidities at corners are
caused by the fact that corners are colder than other parts of the building surface for
one or more of the following reasons:
• poor circulation
• wind blowing through corner assemblies (“wind-washing”)
• low insulation levels
• greater surface area of heat loss.
Sometimes rearranging furniture (removing obstructions) is all that is required
to increase airflow at corners and control mold and mildew growth. Buildings with
forced air heating systems and/or room ceiling fans have lower incidence of mold and
mildew growth than buildings with low levels of air movement.
Wind typically increases in velocity at corners and this often results in greater
heat loss at corner surfaces. When this wind enters corner assemblies and blows
through the thermal insulation (wind-washing the insulation), significant cooling of
interior surfaces can occur.
“Set Back’ Thermostats
Set back thermostats are commonly utilized in heating climates to reduce
energy consumption during the heating season. Building temperatures are dropped at
night when occupants are absent and raised to “normar comfort levels shortly before
occupants arrive. The set back thermostat does not alter the vapor pressure (moisture
136
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levels do not go up), but the set back thermostat does increases the relative humidity
by cooling the air in the enclosure. This increase in relative humidity can result in
mold and mildew growth at cool surfaces.
Maintaining a building enclosure at too low a temperature can have the same
effect as a set back thermostat. Heating climate mold and mildew can be controlled in
may instances by increasing interior temperatures during heating periods.
Unfortunately, raising the temperature during the heating season also increases
energy consumption.
Air Conditioned Spaces
The problems of mold and mildew can be as extensive in cooling climates as in
heating climates. The same principles apply: either surfaces are too cold or the
moisture levels are too high. When exterior hot air is cooled, its relative humidity
increases. If the exterior hot air is also humid, cooling this air will typically raise its
relative humidity above the point at which mold growth can occur (70 percent).
A common example of mold growth can be found in rooms in cooling climates
where air conditioned coldN air is blownN against the interior surface of an exterior
wall due to poor duct design, diffuser location, or diffuser performance. This creates a
cold spot at the interior gypsum board. Although this cold air is typically dehumidified
before it is supplied to the conditioned space, it can create a mold problem within the
wall cavity. Exterior humid air comes in contact with the cavity side of the cooled
interior gypsum board. Cooling this exterior hot, humid air raises its relative humidity
above 70 percent and mold growth occurs. This is a particular a problem in rooms
decorated with low maintenance interior finishes (e.g. impermeable wall coverings
such as vinyl wallpaper) which can trap moisture between the interior finish and the
gypsum board. When these interior finishes are coupled with cold spots and exterior
moisture, mold growth can be rampant.
Several solutions are possible, such as preventing the hot, humid exterior air
from contacting the cold gypsum board (i.e., controlling the vapor pressure at the
surface) or eliminating the cold spots (i.e., elevating the temperature of the surface),
relocating ducts and diffusers. Increasing the room temperature so as to avoid
overcooling 1 is also a solution. Fortunately, this time increasing temperature
decreases energy consumption.
Thermal Bridges
The cooling of any surface leads to an increase in surface relative humidity
which can lead to mold and mildew growth. Localized cooling of surfaces commonly
occurs as a result of 0 thermal bridges”. Common examples of thermal bridges include
uninsulated window lintels, edges of concrete floor slabs in commercial construction,
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and steel studs in a typical exterior frame walls. The steel studs have a greater
conductivity to heat flow than the insulation in the exterior frame wall and therefore
provide an easy path for heat to ebridgeu the wall. The result is a cold spot at the
interior face of the gypsum board where it is in contact with the stud. Higher surface
relative humidity can occur at the cold spot and can lead to mold and mildew growth.
Sometimes marks on gypsum board are not due to mold and mildew growth but
rather to dust. The higher the temperature of the dust particles, the faster they vibrate;
the lower the temperature, the slower the movement. Dust particles are more likely to
adhere to the cold spots on surfaces where the studs are in contact with the gypsum
board than nearby warmer surfaces, hence leading to dust markings at thermal
bridges.
The use of insulating sheathings significantly reduces the impact of thermal
bridges in building envelopes.
Windows
Windows are typically the coldest surfaces in a room and are therefore the
location where condensation is most likely to occur, due to an increase in the interior
airborne moisture level or a decrease in the exterior air temperature. (The exterior air
temperature determines the temperature of the interior surface of the interior pane of
glass.) The interior surface of a window in a room is often the first condensing surface
in that room.
Historically, to control condensation on window surfaces, window surface
temperatures were raised with the use of storm windows or with the replacement of
single glazed windows either by double glazed windows or by selective surface gas-
fifled windows. The colder the climate, the greater the thermal resistance of window
surfaces, and the greater the sophistication of the glazing systems.
As owners and occupants in heating climates began to humidify building
enclosures during the heating season for comfort reasons, window surface
temperatures have had to be raised to control condensation, hence the trends towards
higher performance glazing systems. The advent of higher performance glazing
systems has led to a greater incidence of moisture problems in heating climate
building enclosures because these building enclosures can now be operated at
higher interior vapor pressures (moisture levels) without visible surface condensation
windows, which are the usual first condensing surfaces. In older building enclosures
with less advanced glazing systems, visible condensation on the windows often
alerted occupants to the need for ventilation to flush out interior moisture and so they
opened the windows. The windows acted as canariesN for moisture and other indoor
air pollutants.
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Concealed Condensation in or on Wall Cavities
The use of thermal insulation in wall cavities increases interior surface
temperatures in heating climates and therefore reduces the likelihood of interior
surface mold, mildew and condensation. However, the use of thermal insulation
reduces the heat loss from the conditioned space into the wall cavities and therefore
increases the temperatures of the wall cavities and therefore also increases the
likelihood of concealed condensation within the wall cavities. The first condensing
surface in a wall cavity in a heating climate is typically the interior surface of the
exterior sheathing, namely the “back side” of plywood, or fiberboard. As the insulation
value is increased in the wall cavities, so the potential for condensation.
Concealed condensation can be controlled either by reducing the entry of
moisture into the wall cavities (controlling vapor pressure at condensing surfaces) or
by elevating the temperature of the first condensing surface or a combination of the
two. Elevating the temperature of the first condensing surface in a heating climate wall
assembly can be accomplished by installing insulation to the exterior of the first
condensing surface. When insulating sheathings are installed on the exterior wall
framing, they act like double glazing and warm everything to the interior of them.
The first condensing surface in a cooling climate is typically the interior gypsum
finish. Elevating the temperature of the first condensing surface in a cooling climate
can be accomplished by installing insulating sheathing to the interior of the wall
framing, between the wall framing and the interior gypsum board, rather than on the
extenor ot the wall framing as is done in a heating climate.
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AppendIx F Asbestcs
Asbestosu describes six naturally occurring fibrous minerals found in certain types
of rock formations. When mined and processed, asbestos is typically separated into
very thin fibers that are normally invisible to the naked eye. They may remain in the air
for many hours if released from asbestos-containing material (ACM) and may be
inhaled during this time. Three specific diseases - - asbestosis (a fibrous scarring of
the lungs), lung cancer, and mesothelioma (a cancer of the lining of the chest or
abdominal cavity) - - have been linked to asbestos exposure. It may be twenty years or
more before symptoms of these diseases appear.
Asbestos fibers can be found nearly everywhere in our environment (usually at very
low levels). At the present time, there is insufficient information concerning health
effects resulting from tow-level exposure. Most of the severe health problems resulting
from asbestos exposure have been experienced by workers who held jobs where they
were exposed to high levels of asbestos in the air over a prolonged period without
presently-required worker protections. This makes it difficult to accurately assess the
magnitude of risk for building occupants, tenants, and building maintenance and
custodial workers. Although in general the risk is likely to be negligible for occupants,
health concerns remain, particularly for the building’s custodial and maintenance
workers. Their jobs are likely to bring them into close proximity to ACM and may
sometimes require them to disturb the ACM in the performance of maintenance
activities.
EPA estimates that friable” (easily crumbled) ACM can be found in an estimated
700,000 public and commercial buildings. About 500,000 of those buildings are
believed to contain at least some damaged asbestos. Significantly damaged ACM is
found primarily in building areas not generally accessible to the public, such as boiler
and machinery room, where asbestos exposures generally would be limited to service
and maintenance workers. However, if friable ACM is present in air plenums, it can be
distributed throughout the building, thereby possibly exposing building occupants.
When is asbestos a problem? Intact and undisturbed asbestos materials do not
pose a health risk. The mere presence of asbestos in a building does not mean that
the health of building occupants is endangered. ACM which is in good condition, and
is not somehow damaged or disturbed, is not likely to release asbestos fiber into the
air. When ACM is properly managed, release of asbestos fibers into the air is
prevented or minimized, and the risk of asbestos-related disease can be reduced to a
negligible level.
In an effort to calm unwarranted fears that a number of people seem to have about
the mere presence of asbestos in their buildings and to discourage the spontaneous
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decisions by some building owners to remove all ACM regardless of its condition, EPA
is urging owners and occupants to keep in mind the following five facts:
Although asbestos j hazardous, the risk of asbestos-related
ease depends upon exposure to airborne asbestos fibers.
Based upon available data, the average airborne asbestos levels in
buildings seem to be very low. Accordingly, the health risk to most
building occupants also appears to be very low.
o Removal Is often a building owner’s best course of action to
reduce asbestos exposure. In fact, an improper removal can create a
dangerous situation where none previously existed.
o EPA only requires asbestos removal in order to prevent significant
public exposure to airborne asbestos fibers during building demolition
or renovation activities.
o EPA does recommend a pro-active, in-place management program
whenever asbestos-containing material is discovered.
An in-place management program ensures that the day-to-day management of the
building is carried out in a manner that minimizes the release of asbestos fibers into
the air, and ensures that when asbestos fibers are released, either accidentally or
intentionally, proper control and cleanup procedures are implemented. Such a
program may be all that is necessary to control the release of asbestos fibers until the
ACM in a building is scheduled to be disturbed by renovation or demolition activities.
In some cases, an asbestos operation and maintenance program is more appropriate
than other asbestos control strategies, including removal.
For guidance on asbestos, building owners and managers are urged to become
familiar with two EPA documents: Managing Asbestos in Place (published in 1990)
and Guidance for Controlling Asbestos-Containing Materials in Buildings (published in
1985 and also known as the Purple Book). To obtain copies of these publications, call
the TSCA Hotline: (202)-554-1404. For further information or to get guidance on
technical issues, call or write:
Environmental Assistance Division, Office of Toxic Substances
U.S. EPA - TS 799
401 M Street S.W.
Washington D.C. 20460 Telephone: (202) 382-3949
Fo iore complete listing of publications concerning asbestos, refer to the
Fe .urces Sectlcn in this document.
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Appen4lI% F - F?adcn
Radon is a radioactive gas produced by the decay of radium. It occurs naturally in
almost all soil and rock. Radon migrates through the soil and can enter buildngs
through cracks or other openings in their foundations. Radon and its radioactive
decay products can cause lung cancer.
Data collected through radon surveys conducted jointly by EPA and 25 States have
shown that radon is a widespread national health problem, affecting millions of homes
nationwide. Initial studies in schools and large buildings indicate that a number of
large buildings in the United States also have elevated radon levels. Citing resufts
from numerous statewide studies, the EPA and the Surgeon General’s office have
warned the public that radon is second only to smoking as a cause of lung cancer in
America.
In addition to informing the public about radon and encouraging citizens to take
action to reduce risk, the EPA has worked to develop nationwide State and private
sector capabilities to measure radon, and has also developed radon mitigation and
prevention techniques. EPA technical guidance is currently being used successfully in
homes, and more recently, in schools. The EPA has also worked extensively with
builders, building inspectors, and Federal, State, and local code authorities to promote
the adoption of radon prevention measures in new construction.
As part of its effort to develop widespread State and private sector capability, the
Environmental Protection Agency developed a voluntary proficiency program (Radon
Measurement Proficiency Program, RMPP) for radon laboratories and commercial
measurement firms. Since 1986, the radon measurement industry has grown from
only 35 companies to more than 5,000 in 1989. The Agency is also providing
technical assistance to State school officials on radon measurement, mitigation, and
prevention in the nation’s schools.
A listing of firms that are proficient in radon measurement is available through the
National Technical Information Service (NTIS) in Springfield, VA. The NTIS order
number for the Cumulative Prnficiency Rerxwt, Round 6 is P6-90-187949. The report
is available in microfiche and printed paper. To order, write or call:
NatioriaJ Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703)-487-4850
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fl A tc l©I MS
This section of the document is a collection of the forms presented in the text.
Some or all of them may require adaptation to meet your specific needs. Blank
formatted sheets are included for preparing your own IIVAC CHECKLIST and
POLLUTANT AND SOURCE INVENTORY.
The forms are not numbered, but appear in the following sequence:
COMPLAINT LOG
OCCUPANT INTERVIEW
OCCUPANT DIARY
LOG OF ACTIVITIES AND SYSTEM OPERATIONS
HVAC CHECKLIST (7 page form, followed by one blank formatted sheet)
POLLUTANT PATHWAY ASSESSMENT FORM (2 pages)
POLLUTANT AND SOURCE INVENTORY (3 page form, followed by one
blank formatted sheet)
HYPOTHESIS FORM
QUESTIONNAIRE FOR BUILDING OCCUPANTS
The last item, the QUESTIONNAIRE FOR BUILDING OCCUPANTS, is
included as an example of a detailed questionnaire to be filled out by building
occupants. This particular questionnaire has been used by professional IAQ
investigators. As discussed in Section 3, most in-house investigators would not
benefit from using this questionnaire, as they do not have the medical or industrial
hygiene needed to rnterpret the results.
-------
D*te
Lo tia i
Comp1*int
Complainant
Comments
kenft
nitiuls
COMPLAINF LOG
Building nante/addre!s________________________ Dates from to
-------
OCCUPANT INTERVIEW
Building name/address____
Work Location __________________________________________
Date of Interview _______________________ Interviewer _________
1) Where do you spend most of your time in the building?
Where are you when you experience symptoms (or discomfort)?
2) What kind of symptoms or discomfort are you experiencing?
3) When did your symptoms start?
When are they generally worst?
Have you noticed any other events (such as weather events or activities in the building) that tend to occur around
the me time as yow symptoms?
/hen are your symptoms relieved?
5) Do you have allergies or other health problems that may make you particularly sensitive to environmental problems?
Do you wear contact lenses?
6) Do you have any complaints about building conditions?
i !
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Name Position
Primary Location in the building
OCCUPANT DIARY
Phone
Oct the form below, please record each occasion that you experience a symptom of ill-health or discomfort
that you think may be linked to environmental conditions in the building.
It is important that you record the time and date and your location within the building as accurately as
possible, because that will help to identify conditions (e.g. equipment operation) that may be associated with
your problem. Also, please try to describe the severity of your symptoms (e.g. mild, severe) and their
duration , the length of time that they persist. Any other observations that you think may help in identifying
the cause of the problem should be noted in the column marked comments . Feel free to attach additional
pages or use more than one line for each event if you need more room to record your observations.
Time/Date Location Symptom Sevent’ Duratioi Comments
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LOG OF ACTIVITIES AND SYSTEM OPERATIONS
Name _________________________ ________________________ Phone
On the form below, please record your observations of HVAC system operation, maintenance activities,
weather events, and any other information that you think might be helpful in identifying the cause of JAQ
complaints in this building. The items of equipment listed be!ow are of pathcular interest; however, any
other observations you think may be important should be reported as well.
Feel fine to attach additional pages or use more than one line for each event.
Eaujnment of Interest :
Exhaust Fan:
Exhaust Fan:
Exhaust Fan:
Exhaust Fan:
Area Served:
Area Served:,
Area Served:
Area Served:
L i 1
Ailiandler
Air Handler
Air Handler
Area Served:
Area Serve
Area Served:
Time/Dale Hem of Equipmenl Observation Comments: (weather. other associated events
-------
Building HVAC CHECKLIST page 1 of 7
Date Checked Inspected by
Component
OK
Nee
Attention
Not
Checked
Comments
Fans
location
fan blades clean?
belts guarded?
belts properly tensioned 9
excess vibration’
corroded housing’
controls working, calibrated 9
control setpoints correct 9
no pneumatic leaks’
Outside Air Intake
location
open during occupied hours
unobstructed 9
standing waler, trash, pigeon
droppings in vicinity’
re-entrainment of odor?
(describe)
carryover of exhaust heat’
cooling towerwithin 25 ft 9
exhaust within 25 ft?
trash compactor within 25 ft 9
near parking facility, busy
road, loading dock?
For VAV systems
Is OA reset as total system
air is throttled?
Bird screen
unobstructed 9
good condition’
minimum 1t2’ mesh?
Dampers
open and close freely?
seal when closed’
actuators working’
D c
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. w e•—
HVAC CHECKLIST page 2 of 7 —
Building
Date Checked________________ Inspected by
C eat OK Nee Not Comments
Attention Checked
Fan Chambers
clean 1
no trash or storage’
no standing waxer?
floor drain traps are wet
(liquid seal)?
no air leak’
rs close tIy, kept closed’
sing Plenum
clean?
airt ightness
- of outside air dampers’
- of retarn air dampers
- of exhaust air dampers’
all dampe onnected 9
all dampe operational’
air or opposed blades 1
inixeu air temp control set —
freeze stat?
Outside Air Quantity
minimum percentage
cfm/person at mininlum
iximum percentage —
uormal operation mode —
is minimum O.A. a separate
damper?
Filters
correct type?
complete cove rage 9
correct pressura drop’
bypassing?
conLamin nts visible 1
washable?
odor noticeable?
Eli rs
clean, straight, no carry-over?
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HVAC CHECKLIST page 3of7
Builthng
Date Checked_______________ Inspected by
Component
OK
Needs
Aftentlon
Not
Checked
Comments
Heating Coil
inspection access?
clean’
control (describe)
______
supply water temperature —
____
Reheat Coils
clean 9
obstructed 9
operational’
Ductwork
clean’
sealed 9
no leaks, tight connectio&
fire dampers open’
access doors closed’
lined ducts’
flex duct connected, no tears?
_____
light troffer supply’
balanced (approx date)
recent renovations’
supply in ceding’
height of ceiling
short circuiting 9 (note
location)
Pressurized ceiling
no unintentional openings,
tiles in place?
supply diffusers open’
supply diffusers balanced 9
exhaust diffusers open’
noticeable flow of air’
no short-circuiting?
Return Air Shafts
no unintentional openings’
pits clean and dry’
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Building HVAC CHECKLIST page 4 of 7
D;- Checked_______________ Inspected by
scent OK Nee Not Comments
Attention Chacked
Condensate Drip Pans
accessible to inspect and clean
clean
no standing water, no leaks
noticeable odor’
visible growth’
drains and traps clear, working
trapped to a gap
water carryover
Cooling Coil
inspection access
clean?
trol (describe)_____
supply water temperature —
Thrc. ,, ,
a des working
complete coil coverage
pans clean, no overflow
drains trapped
biocide treatment working
Humidifier
pe
clean’
treated boiler water 9
standing water
visible growth
mineral deposits
control setpoint
high limit setpoint
duct liner within 12 feet?
Room Partitions
full height dividers’
p ’ ‘ ‘onstofloor?
-, return each room 9
open office 9
• - - -
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HVAC CHECKLIST pageS of 7
Checked________________ Inspected by________________________
OK
Nee
Attention
Not
Ch ked
Comments
clean?
volume 9
clean, drain
operational?
posted?
tight’
leaks 9
air source 9
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HVACCHECKLIS1’ page6of7
Building
becked Inspected by
- onen OK Nee Not Comments
—_____ Attention Checked
Exhaust Fah
cenhal
distributed
describe location
0—na’
aake-up &
,ilet exhaust only?
wity relief’
powered exhaust cfm
toilet exhausts
-fans working occupied hours’
-registers open, clean 9
- make-up path adequate’
• volume according to code 9
drain traps kept wet 9
- 4rooms run slightly
negative relative to building?
garage ventilation
-operates during peak traffic’
-fans, controls, dampers all
operate?
- shafts clean, drain freely’
- garage slightly negative
relative to building’
- doors to building close tight’
Stairwells
doors close and latch?
no unintentional openings?
clean, dry’
Chillers
no refrigerant leaks’
purge cycle normal’
oil, refligerant properly
t osed of and spare
refrigerant properly stored’
• 1•’
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HVAC CHECKLIST page 7 of 7
Building
Date Checked_______________ Inspected by
Component
OK
Needs
Attention
Not
Checked
Comments
Cooling Tower
su p clean?
no leaks, no overfiow’
eliminators working, no
carryover?
no slime or algae’
biocide treatment working 9
diii separator working?
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- HVAC CHECKLIST page — of_
B’ : 1mg
Date Checked_______________ Inspected by
iponent
OK
Nee
Attention
Not
Checked
Comments
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POLLUTANT PATHWAY ASSESSMENT FORM page 1 of 2
Building name/address nvestifator__________________
Complaint Area
This form should be accompanied by a sketch plan of the complaint area and surrounding spaces. Doors,
windows, diffusers, and other openings should be labelled on the plan so that your observations are clearly
referenced to specific locations.
Date and time of observations:________________________________________________
Weather conditions: temperature windspeed and direction__________
humidity ______ other observations____________________
Equipment List equipment operating in (or servicing) the complaint area and surrounding spaces and
indicate whether it is operating while pressure differentials are being measured. It may be helpful to turn
equipment on and off, open and close doors or windows, or perform other manipulations in an attempt to
simulate conditions at the time that complaints occur.
HVAC equipment: Air handler(s)
Other fans
Other equipment:
Pathways : Note pathways by which pollutants may be entenng the space from surrounding areas. These may
assist in defining the problem area and identifying pollutant sources.
Other rooms served by same air handler:_________________________________
Surrounding spaces (including outdoors):
Use chemical smoke to observe airflow at intentional and accidental openings into the complaint area. A
checklist of typical openings is provided below. Use additional pages as needed. If a manometer is used,
record the pressure differential in the middle column.
Architectural openings :
— doors (note: open or closed) — transoms — windows (note: open or closed) stairways
— utility chases — floor drains — cracks and holes
Mechanical openings :
— supply diffusers — return diffusers — exhaust intakes
Opening Direction of smoke movement Comments
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POLLUTANT PATHWAY ASSESSMENT FORM page 2 of 2
BmIdin name/address________________________ Inveshgatof
Complaint Area
Opening Direction of smoke movement Comments
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D..;1A..... ..... iAA.. .. . .
POLLUTANT AND SOURCE INVENTORY
_______________ Date _________ Investigator
page 1 of 3
Using the list of potential sowce categones below, record any indications of contRmlnRtlon or suspected pollutants that may
require further investigation or treatment. Sources of contam ination may be constant or intermittent or may be linked to single,
unrepeated events. For intermittent sources, try to mdicate the time of peak activity or contaminant production.
Source Category
Checked
Needs
Attention
Comments
Sources outside the building
Contaminated ambient air
-pc llen,dust
- industnal contaminants
Emissions from nearby sources
- vehicle exhaust_(_parking
gamges, loading docks, roads)
- dumpsters
- constructionldemobtion
• re-entrained exhaust
- debns near O.A. intake
Soil_gas
• moisture
-radon
- leaking underground tanks
• previous use of the site
Other
Equipment
HVAC system equipment, supphes
- dust or dut in ducts
- microbial growth in ducts
• microbial growth at dnp pans,
chillers, humidifiers
- leaks of treated boiler water
Non-HVAC system eqwpment
and/or supplies (e.g office
equipment such as wet-process
cop
Other
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POLLUTANT AND SOURCE INVENTORY
________________ Date __________ Investigator —
‘ç the list of potential source categories below, record any indications of contamination or suspected pollutants that may
re further investigation or treatment. Sources of contamination may be constant or intermittent or may be linked to single,
wirepeated events. For intermittent sources, try to indicate the time of peak activity or contaminant production.
Source Category
Checked
Needs
Comments
Attention
Human activities
Smoking
Personal activities
- overcrowding (e.g. body odor)
- cosmetics
Housekeeping activities
- cleaning materials
- cleaning procedures
- stored supplies
- stored refuse
Maintenance activities
- volatile compounds
(e.g. paint, caulk, adhesives)
itocides (pest control)
- stored supplies
Other
Bldg ConiponentsfFurnlshings
Dust and fibers
- dust-catching areas (e.g. shelves)
- deteriorated furnishings
Unsanitary conditions/water damage
-in crobial growth on orin soiled
or water-damaged_furnishings
Chemicals released from building
components or furnishings
volatile compounds
- asbestos-contaming materials
o
Building name/address
page 2 of 3
I
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Bwlding name/address
POLLUTANT AND SOURCE INVENTORY
______________ Date _________ Investigator —
page 3 of 3
Using the list of potential source categories below, record any indications of contamination or suspected pollutants that may
require further investigation or treatment. Sources of contamination may be constant or intermittent or may be linked to single,
unrepeated events. For intermittent sources, try to indicate the tune of peak activity or contaminant production.
- - -
.- ‘I.
LJ -L .
A . -
Source Category
Checked
Needs
Attention
Comments
Other Sources
Accidental events
- spills (e.g. water, chemicals,
beverages)
- water leaks or flooding
- fire damage
Special use/Mixed use areas
• smoking_lounges
- laboratories
- — shops, art rooms
- exercise rooms
- beauty salons
-_food preparation areas
RedecoratingfRepairlRemodelhng
- emissions from new furnishings
- dust, fibers from demolition
- odors, volatile compounds
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POLLUTANT AND SOURCE INVENTORY
Building name/address.
Date _________ Invesugator
the list of potential source categones below, record any indications of contaminAtion or suspected pollutants that may
- further investigation or treatment. Sources of contamlnRtjOn may be constant or intermittent or may be linked to single,
unrepeated events. For intermittent sources, try to indicate the time of peak activity or contamirnLnt production.
.otwce egory
-
Checked
Needs
Attention
Comments
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HYPOTHESIS FORM
Building nameladdress
Investigator________________________________ Date ________________
Problem Area: (this can be revised as the investigation progresses):
Complaints: What is the pattern of complaints? (tuning, location, number of people affected)
HVAC:
Does the ventilation system appear to provide adequate outdoor air, efficiently distributed to meet occupant needs in the
problem area? If not, what problems do you see?
Is there any apparent pattern connecting the location and timing of complaints with the HVAC system layout, condition or
operating schedule?
Path ys: What pathways and driving forces connect the complaint area to locations of potential sources?
Sources: What potential sources have been identified?
- in the problem area
- in locations associated with the problem area (connected by pathways)
Hypothesis: Using the information you have gathered, what is your best explanation for the problem?
Testing: Can this hypothesis be tested? If so, how?
Results: Results of hypothesis testing:
Additional information needed:
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Ouestionnaire for Building Occupants
Note : The parpose of this questionnaiie is to help evaluate environmental conditions in this building. Please
complete the form accurately and return it to your supervisor as soon as possible. Use of your name of other
identifying ñfonnaflon is optional .
Name _______________________ Position____ Phone___________
Primai7 location in the building___________________________________________
Date staited in building________ At current location since___________
Equipment i d regularly in job_________________________________________
I. Do any of the following apply to you? If so, please describe in the space provided:
(a) llist of allergies___________________________________
(b) }liitory of respuatoiy diseases?__________________________________________
(c) Other pre-existing health conditions causing increased sensitivity to environmental pollution?
( Wear contact lenses?__________ for how long?
(e) Eye swain at wcwk? __________________________________________________
2. Check the best answers in this section as they apply Qfljy to the main symptoms you have experienced
which you feel may be related to the building. Include only those symptoms which generally occur at the
seme time. Other symptoms should be noted in questIon 3 (below).
relief
date relief during never
( symptom itailed overnight vacation clears up
- dl7zness ___ ___ ___ ___
bosiscness ___ ___ ___ ____
- _ _ _ __
— amgestion ___ ___ ___ ____
— itching _______ _______ _______ ________
h eailbwn ___ ___ ___ ___
l he ____ ____ ____ _____
- thynxnith __ __ __ __
chest tightness ____ ____ ____ _____
- ocughing _ _ _ _
— swelling ______ ______ _______ _______
- __ __ __ __
- _ _ _
— eyeirritation ______ ______ ______ _______
— ninny nose ______ _______ _______ ________
rash __ __ __ __
— hearing loss ______ _______
— nose irritation ___ ___ ___ ____
— muscle aches ______ ______ _______ ________
— sinus problems ____ ____
— finoat irritation ___ ____
— sne mg _______ ________
- (other) __ __
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Occupant Ouestionnaire - page two
(b) Symptoms occur (check best answer):
almost every day when in building
aboW half the ume____
several days per month_____
other_________
(c) When are symptoms generally worst ? (circle best answers)
Daily: morning afternoon all day no pattern
Weekly: beginning middle end all week no pattern
Yearly wring summer fall winter all year no pattern
(d) Worst events may be associated th:
Ock,rs (descnbe)
Dust (describe)
ActivityfEvent (descnbe) _________
Weather (describe)
Specific Dates___________
(e) Physician consulted? (circle) Yes No
If yes, what was the physician’s opinion regarding the symptoms?
— not building-related (descnbe diagnosis)
— building-related (describe diagnosis)
— no e
(f) Further comments on main symptoms
3. Complete this section for other symptoms which may also be related to the building but do not always
occur at the same time as the symptoms mentioned in question #2.
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cupant Ouesflonnawe - page three
4. Check any complaints you have about building conditions:
poor ventilation? ______ tobacco smoke? ______
too hot? — too cold? ____ dual?_____
noise? — poor hghtmg? —
Other (descTibe)________________________________
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