Building Air Quality: A Guide for Building Owners and Facility Managers

Contents iii

Foreword..............................................................................................................................viiNote to Building Owners and Facility Managers .................................................................ixAcknowledgements ............................................................................................................xiii

TAB I: BASICS

Section 1: About This Document .............................................................................1

Section 2: Factors Affecting Indoor Air Quality........................................................ 5Sources of Indoor Air Contaminants .....................................................................................5HVAC System Design and Operation...................................................................................6Pollutant Pathways and Driving Forces ................................................................................9Building Occupants .............................................................................................................10

Section 3: Effective Communication...................................................................... 13Communicating to Prevent IAQ Problems..........................................................................13Communicating to Resolve IAQ Problems .........................................................................15

TAB II: PREVENTING IAQ PROBLEMS

Section 4: Developing an lAQ Profile .................................................................... 19Skills Required to Create an IAQ Profile ............................................................................20Steps in an IAQ Profile........................................................................................................21

Section 5: Managing Buildings for Good IAQ........................................................ 31Developing an IAQ Management Plan................................................................................31

TAB III: RESOLVING IAQ PROBLEMS

Section 6: Diagnosing lAQ Problems .................................................................... 45Overview: Conducting an IAQ Investigation......................................................................46Initial Walkthrough .............................................................................................................47Collecting Additional Information ......................................................................................49Collecting Information about Occupant Complaints...........................................................50Using the Occupant Data.....................................................................................................53Collecting Information about the HVAC System ...............................................................57Using the HVAC System Data ............................................................................................62Collecting Information about Pollutant Pathways and Driving Forces...............................68Using Pollutant Pathway Data.............................................................................................70Collecting Information on Pollutant Sources ......................................................................72Using Pollutant Source Data ...............................................................................................74

Contents

iv Contents

Sampling Air for Contaminants and Indicators...................................................................74Complaints Due to Conditions Other Than Poor Air Quality .............................................77Forming and Testing Hypotheses........................................................................................78

Section 7: Mitigating lAQ Problems .......................................................................81Background: Controlling Indoor Air Problems ...................................................................81Sample Problems and Solutions ..........................................................................................86Judging Proposed Mitigation Designs and Their Success.................................................102

Section 8: Hiring Professional Assistance to Solve an lAQ Problem .................. 105Make Sure That Their Approach Fits Your Needs............................................................105Selection Criteria ...............................................................................................................106

TAB IV: APPENDICES

Appendix A: Common lAQ Measurements - A General Guide ........................... 109Overview of Sampling Devices.........................................................................................109Simple Ventilation/Comfort Indications ...........................................................................110Air Contaminant Concentrations.......................................................................................115

Appendix B: HVAC Systems and Indoor Air Quality ........................................... 121Background........................................................................................................................121Types of HVAC Systems ..................................................................................................122Basic Components of an HVAC System...........................................................................123ASHRAE Standards and Guidelines .................................................................................137

Appendix C: Moisture, Mold and Mildew ............................................................. 141Background on Relative Humidity, Vapor Pressure, and Condensation...........................141Taking Steps to Reduce Moisture......................................................................................143Identifying and Correcting Common Problems From Mold and Mildew.........................145

Appendix D: Asbestos .........................................................................................147EPA and NIOSH Positions on Asbestos ...........................................................................148Programs for Managing Asbestos In-Place .......................................................................149Where to Go for Additional Information...........................................................................150

Appendix E: Radon..............................................................................................151Building Measurement, Diagnosis and Remediation ........................................................151Where To Go for Additional Information .........................................................................152

Appendix F: Glossary and Acronyms ..................................................................153

Appendix G: Resources.......................................................................................157Federal Agencies with Major IAQ Responsibilities..........................................................157Other Federal Agencies with Indoor Air Responsibilities.................................................160State and Local Agencies ..................................................................................................160Private Sector Contacts......................................................................................................161Publications .......................................................................................................................164Training .............................................................................................................................167

Contents v

TAB V: INDOOR AIR QUALITY FORMSIAQ Management Checklist ..............................................................................................171Pollutant Pathway Record For IAQ Profiles .....................................................................175Zone/Room Record ...........................................................................................................177Ventilation Worksheet.......................................................................................................179Indoor Air Quality Complaint Form..................................................................................181Incident Log.......................................................................................................................183Occupant Interview ...........................................................................................................185Occupant Diary..................................................................................................................187Log of Activities and System Operation ...........................................................................189HVAC Checklist-Short Form ............................................................................................191HVAC Checklist-Long Form ............................................................................................195Pollutant Pathway Form For Investigations ......................................................................211Pollutant and Source Inventory .........................................................................................213Chemical Inventory ...........................................................................................................221Hypothesis Form ...............................................................................................................223

This document is in the public domain. It may he reproduced in whole or in part by an individual or organization without permission. If itis reproduced, however, EPA and NIOSH would appreciate knowing how it is used. Write the Indoor Air Division (ANR-445W), Officeof Air and Radiation, U.S. Environmental Protection Agency, Washington, DC 20460.

Foreword vii

Foreword

oriented" approach to these investigations.This document draws extensively on theexperience of NIOSH in investigating andcorrecting indoor air quality problems inthese types of buildings.

In 1986, Congress mandated that EPAconduct research and develop informationon indoor air quality. To carry out itsinformation dissemination responsibilities,EPA's Indoor Air Division has produced anumber of publications which have beendistributed to a wide range of audiencesand will launch an indoor air qualityinformation clearinghouse in 1992. Inaddition, the Indoor Air Division isdeveloping several guidance documents onbuilding design and management practices.This publication is part of that effort.

The guidance presented here is basedon what is known and generally acceptedat this time in the relevant fields ofbuilding science and indoor air quality.EPA and NIOSH anticipate that thisdocument may later be revised to includemore detailed guidance as researchcontinues and our knowledge grows. Inthe meantime, building owners and facilitymanagers can use the Resources section tosupplement and update the informationpresented here.

In the past two decades, the number ofpeople requesting information and assis-tance on health and comfort concernsrelated to indoor air quality from the U.S.Environmental Protection Agency (EPA)and the National Institute for OccupationalSafety and Health (NIOSH) has risensteadily. Although many studies on indoorair quality have been reported in technicalpublications and proceedings during theseyears, little indoor air-related informationhas been targeted at owners and facilitymanagers of public and commercialbuildings who are the people in the bestposition to prevent and resolve indoor airproblems.

In recognition of the need for practicalindoor air quality advice for buildingowners and facility managers, EPA andNIOSH decided to work jointly to producewritten guidance on preventing, identify-ing, and correcting indoor air qualityproblems. The distinct perspectives of thetwo agencies are reflected in this docu-ment.

Since 1971, NIOSH has conductedmore than 600 indoor air quality investiga-tions in the office (non-industrial, non-residential) buildings under the HealthHazard Evaluation Program. Over time,NIOSH has developed a "solution-

Note to Building Owners and Facilities Managers ix

From marketing and negotiating leasesand maintenance contracts to planning forfuture expansion, operating a commercialor public building is a complex processthat leaves you little time for unnecessaryactivities. Working with your facility staff,you make an effort to provide a pleasantsetting and are accustomed to dealingwith occupant complaints about roomtemperature, noise, plumbing systemproblems, and other elements of thebuilding environment.

A healthy indoor environment is one inwhich the surroundings contribute toproductivity, comfort, and a sense of healthand well being. The indoor air is free fromsignificant levels of odors, dust and con-taminants and circulates to preventstuffiness without creating drafts. Tem-perature and humidity are appropriate tothe season and to the clothing and activityof the building occupants. There is enoughlight to illuminate work surfaces withoutcreating glare and noise levels do notinterfere with activities. Sanitation,drinking water, fire protection, and otherfactors affecting health and safety are well-planned and properly managed.

Good air quality is an importantcomponent of a healthy indoor environ-ment. For the purposes of this document,the definition of good indoor air qualityincludes:

■ introduction and distribution of adequateventilation air

■ control of airborne contaminants■ maintenance of acceptable temperature

and relative humidity

A practical guide to indoor air quality(IAQ) cannot overlook temperature andhumidity, because thermal comfort

Note to Building Owners andFacility Managers

concerns underlie many complaints about“poor air quality.” Furthermore, tempera-ture and humidity are among the manyfactors that affect indoor contaminantlevels.

It is important to remember that whileoccupant complaints may be related totime at work, they may not necessarily bedue to the quality of the air. Other factorssuch as noise, lighting, ergonomic stressors(work station and task design), and job-related psychosocial stressors can —individually and in combination —contribute to the complaints. Theseproblems are briefly addressed in thisdocument.

Good indoor air quality enhancesoccupant health, comfort, and workplaceproductivity. Rental properties can gain amarketing advantage if they are known tooffer a healthy and pleasant indoor envi-ronment. Failure to respond promptly andeffectively to IAQ problems can haveconsequences such as:

■ increasing health problems such ascough, eye irritation, headache, andallergic reactions, and, in some rarecases, resulting in life-threateningconditions (e.g., Legionnaire’s disease,carbon monoxide poisoning)

■ reducing productivity due to discomfortor increased absenteeism

■ accelerating deterioration of furnishingsand equipment

■ straining relations between landlords andtenants, employers and employees

■ creating negative publicity that could putrental properties at a competitivedisadvantage

■ opening potential liability problems(Note: Insurance policies tend to excludepollution-related claims)

x Note to Building Owners and Facilities Managers

problems has sometimes led to reducedenergy use due to the efficiency associatedwith a cleaner, and better controlledheating, ventilation, and air conditioning(HVAC) system. The energy needed tocondition and distribute ventilation air isonly a small part of total building energyconsumption and is far overshadowed byother operating costs (such as personnel).Attempting to limit operating costs byreducing ventilation can be a falseeconomy, if it leads to problems such asincreased occupant complaints, reducedproductivity, and absenteeism.

Every complaint merits a response.

Many indoor air quality problems are notdifficult to correct and can be solved within-house expertise. However, gatheringrelevant information about the problemand identifying appropriate correctiveactions is likely to require a coordinatedeffort by people with a variety of skills.

An indoor air quality problem maybe the direct or indirect result of anapparently minor modification.

Actions such as the placement of interiorroom dividers, the introduction of newoffice equipment, and personal activitiessuch as cooking can have an impact onindoor air quality. Communicationbetween building management andbuilding occupants regarding their respec-tive responsibilities is a critical element inthe management of indoor air quality.

Indoor air quality in a large building isthe product of multiple influences, andattempts to bring problems under controldo not always produce the expected result.

Some indoor air quality problems arecomplex and may require the assistance ofoutside professionals. When contractingfor services, you need to be an informedclient to avoid unnecessary costs anddelays in solving the problem.

Provision of good air quality requiresconscientious effort by both building staffand occupants. The commitment toaddress IAQ problems starts with thebuilding owner or facility manager, theperson who has an overview of theorganization, sets policy, and assigns staffresponsibilities. You have the authority tosee that an IAQ policy is articulated andcarried out, the ability to identify staff withskills that enable them to react promptlyand effectively to complaints, and theincentive to initiate a program that willprevent indoor air problems in the future.As you decide how best to respond to thechallenge of preventing and resolvingindoor air quality problems in yourbuilding, it will be helpful to keep in mindthe following thoughts:

It is important to establish a processthat encourages an active exchange ofinformation.

Without an open communications policy,an atmosphere of distrust may be createdthat complicates your efforts to diagnoseand correct problems.

Facility staff are in a position to noticemalfunctioning equipment or accidentalevents that could produce indoor airquality problems.

They can play a critical role in identifyingproblem situations and averting IAQcrises. On the other hand, if staff are notaware of IAQ issues, their activities canalso create indoor air quality problems.

Facility staff are often instructed to keepenergy costs to a minimum.

Changes in building operation intended tosave energy have sometimes contributed toIAQ problems (for example, by reducingthe flow of outdoor ventilation air withouttaking action to maintain the quality of therecirculated air). The correction of IAQ

Note to Building Owners and Facilities Managers xi

If there is reason to believe that an IAQproblem may have serious health implica-tions, appropriate experts such as occupa-tional physicians, industrial hygienists,and mechanical engineers should becalled in as soon as possible.

In-house investigations by non-profession-als are not recommended in such cases(e.g., if individuals are being hospitalizedbecause of exposure inside the building).

Public and commercial buildings canpresent a wide range of IAQ problems.

The variety of unique features in theirdesign and usage (e.g., apartment build-ings, hospitals, schools, shopping malls)make a wide range of IAQ problems pos-sible. In apartment buildings, for example,each residential unit can produce cookingodors and the operation of kitchen exhaustfans is generally outside the control ofbuilding management. The basic informa-

tion and problem-solving processes in thisguide can be applied, with necessary adap-tations, to a wide range of building types.

This document was written to be a use-ful resource for you and your staff in pre-venting and resolving occupants’ com-plaints that may be related in some way tothe quality of the indoor air. It providesbackground information followed by“how-to” guidance for you and your in-house staff. The practical problem-solvingtechniques it describes have been appliedsuccessfully by NIOSH and other investi-gators. If complaints are not resolved aftercareful application of this guidance, out-side help will probably be needed. Infor-mation on possible sources of outside helpis included. As you read this document, orturn it over to your staff to implement,EPA and NIOSH urge you to maintain apersonal involvement in this issue.

xii Note to Building Owners and Facilities Managers

This box is provided to help building owners and facility managers get ac-quainted with examples of IAQ problem indicators and associated responses.Some IAQ problem situations require immediate action. Other problems areless urgent, but all merit a response.

Carbon monoxide poisoning is apossibility. Investigate sources ofcombustion gases right away.

This is a potentially life-threateningillness. Request Health Departmentassistance in determining whether yourbuilding may be the source of theinfection.

If damp carpeting cannot be lifted andthoroughly dried within a short time, itmight need to be discarded. Propercleaning and disinfection proceduresmust be used to prevent the growth ofmold and bacteria that could causeserious indoor air quality problems.

Inadequately maintained humidifiers canpromote the growth of biologicalcontaminants. Clean equipmentthoroughly, and consider modifyingmaintenance practices.

The symptoms described suggest anIAQ problem that is not life-threatening,but it would be wise to respondpromptly.

Volatile compounds emitted by the newfurnishings could be causing thecomplaints.

The only way to determine the indoorradon concentration in a givenstructure is to test in appropriatelocations.

Asbestos can be positively identifiedonly by laboratory analysis.

There have been complaints of head-aches, nausea, and combustion odors.

One or more occupants of your buildinghave been diagnosed as havingLegionnaire’s disease.

Staff report that water from a roof leakhas flooded a portion of the carpeting.

Inspection of the humidification systemreveals an accumulation of slime andmold. There have been no healthcomplaints suggesting IAQ problems.

A group of occupants has discoveredthat they share common symptoms ofheadaches, eye irritation, and respira-tory complaints and decided that theirproblems are due to conditions in thebuilding.

Immediately after delivery of newfurnishings (furniture or carpeting),occupants complain of odors anddiscomfort.

Local news articles suggest that somebuildings in the area have high indoorradon levels.

You wonder whether some old pipeinsulation contains asbestos.

Problems RequiringImmediate Action

Problems ThatRequire AResponse, ButAre NotEmergencies

SELECTED INDOORAIR QUALITYPROBLEMS

Acknowledgements xiii

The development of this document,Building Air Quality: A Guide forBuilding Owners and Facility Managers,has been a joint undertaking of theIndoor Air Division in the Office ofAtmospheric and Indoor Air Programs ofthe United States EnvironmentalProtection Agency and the NationalInstitute for Occupational Safety andHealth. The document was preparedunder the direction of Robert Axelrad,Director, EPA Indoor Air Division andPhilip J. Bierbaum, Director, NIOSHDivision of Physical Sciences andEngineering.

EPA and NIOSH appreciate the timethat many organizations and individualstook to share ideas, discuss their ownpractical experiences, and review manydrafts of this document. Many of theideas raised by these reviewers havebeen incorporated into this document.

Two people had primary responsibilityfor developing the content and format ofthe document. Elizabeth Agle, the EPAproject manager, developed the structureof the document, assembled the teams ofcontributors and reviewers, and provideddirection and untiring support as the pro-ject came to fruition. Susan Galbraith,Cogito Technical Services, served as theprincipal writer. She brought to the taskboth considerable writing skills and abasic understanding of how buildingsoperate that proved invaluable through-out the process of conceptualizing andcreating this document.

EPA and NIOSH gratefully acknowl-edge the important contribution of TerryBrennan, Camroden Associates; EdLight, Pathway Diagnostics; and WilliamA. Turner, The W.L. Turner Group, who

served as the team of core technicaladvisors for this document. These indi-viduals contributed a substantial amount ofwritten material and thoughtful commentson the many drafts and, most importantly,their considerable practical experience inidentifying and resolving indoor air qualityproblems. Joseph Lstiburek, BuildingScience Corporation, contributed much ofthe material on the problem of moisture.EPA and NIOSH particularly wish to thankthe staff of The Charles E. Smith Compa-nies who reviewed numerous drafts of thedocument and made invaluable commentsfrom a building management perspective.

The photographs were donated by: TerryBrennan, Camroden Associates; MichaelCrandall, NIOSH; Ed Light, PathwayDiagnostics; Joseph Lstiburek, BuildingScience Corporation; Phil Morey, ClaytonEnvironmental Services; Tedd Nathanson,Public Works Canada; Robert Olcerst,Brujos Scientific Inc.; Stan Salisbury,NIOSH; William A. Turner, The H.L.Turner Group; and Kenneth Wallingford,NIOSH. Additional slides came from theNIOSH Health Hazard Evaluation Programand from the Occupational Safety andHealth Administration.

A large number of people within bothEPA and NIOSH commented on the draftsof the document. EPA and NIOSHrecognize the following staff for theirparticular contributions: John Girman,Elissa Feldman, Pauline Johnston, SuePerlin, David Mudarri, Jack Primack, BobThompson, Kevin Teichman, CharlesTruchillo, and Jim Wilson, EPA; andMichael Crandall, Jerome Flesh, RichardGorman, Joseph Hurrell, Pantelis Rentos,and Mitchell Singal, NIOSH.

Acknowledgements

xiv Acknowledgements

The draft document was widely circu-lated for review outside these agencies.EPA and NIOSH thank the followingindividuals who reviewed all or part of thedocument and submitted comments:

Allen C. AbendMaryland Department of Education

Charles A. AchillesInstitute of Real Estate Management

Henry A. AndersonWisconsin Department of Health andSocial Services

David W. BeargLife Energy Associates

W. David BevirtSheet Metal and Air ConditioningContractors Association

Barbara BillauerInternational Council of Shopping Centers

Bob BockholtNational Apartment Association

H.E. BurroughsH. E. Burroughs & Associates, Inc.

Harriet BurgeUniversity of Michigan Medical Center

Paul A. CammerBusiness Council on Indoor Air

James L. CogginsEnergy Applications, Inc.

Geraldine V. CoxChemical Manufacturers Association

Earon S. DavisEnvironmental Heath Consultant

John E. DiFazio, Jr.Chemical Specialties ManufacturersAssociation

James C. DinegarBuilding Owners and ManagersAssociation, International

Stephen D. DrieslerNational Association of Realtors

Sandra EberleU.S. Consumer Product SafetyCommission

Paul C. FiducciaInternational Council of Shopping Centers

Richard B. GammageOak Ridge National Laboratory

Matthew GillenOccupational Health Foundation

William H. GroahHardwood Plywood ManufacturersAssociation

Shirley J. HansenHansen Associates

Steven B. HaywardIndoor Air Quality Program, CaliforniaDepartment of Health Services

John HenshawAmerican Industrial Hygiene Association

Bion HowardAlliance to Save Energy

W. T. IrwinCertainTeed Corporation

Paul JacobetzBrüel & Kjaer Instruments, Inc.

William D. KelleyAmerican Conference of GovernmentalIndustrial Hygienists, Inc.

Jay KiriharaThe Trane Company

Daniel A. La HartMaryland Department of the Environment

Mary LamielleNational Center for EnvironmentalHealth Strategies

Ellen LarsonAir Conditioning Contractors of America

David LeeAssociation of Local Air PollutionControl Officials

Eugene L. LehrU.S. Department of Transportation

Hal LevinIndoor Air Bulletin

William H. McCredieNational Particleboard Association

Jean F. MatesonMateson Environmental Management, Inc.

Keith MestrichFood and Allied Service Trades

Eugene M. MoreauIndoor Air Program,Maine Department of Human Services

Niren L. NagdaGEOMET Technologies, Inc.

Fred NelsonNational Foundation for theChemically Hypersensitive

Acknowledgements xv

Laura OatmanIndoor Air Quality Program,Minnesota Department of Health

Andrew PersilyNational Institute for Standards andTechnology

George R. PhelpsThermal Insulation ManufacturersAssociation, Inc.

Wiliam A. PugsleyLincoln-Lancaster County HealthDepartment (Nebraska)

G.S. RajhansOntario Ministry of Labour

Susan RoseU.S. Department of Energy

Steven A. ScalaU.S. Public Health Service

James SharpeThe Charles E. Smith Companies

Richard J. Shaughnessy, IIIIndoor Air Program, University of Tulsa

Thomas J. ShepichOccupational Safety and HealthAdministration

Henry J. SingerGeneral Services Administration

Philip A. SquairAir-Conditioning and RefrigerationInstitute

John H. StrattonSheet Metal and Air ConditioningContractors Association

Kenneth M. SufkaAssociated Air Balance Council

John M. TalbottU.S. Department of Energy

Simon TurnerHealthy Buildings International, Inc.

Richard A. VersenManville Technical Center

Davidge WarfieldNational Air Duct Cleaners Association

Lewis WeinstockForsyth County Environmental AffairsDepartment (Georgia)

John F. WelchSafe Buildings Alliance

Arthur E. WheelerWheeler Engineering Company

Jim H. WhiteCanada Mortgage and HousingCorporation

W. Curtis WhiteAegis Environmental Management, Inc.

Alexander J. WillmanNational Energy Management Institute

Myra WinfieldVeterans Administration (Texas)

James E. WoodsCollege of Architecture and Urban Studies,Virginia Polytechnic Institute

Rita Cohen, of ICF, Inc., assisted in theproject management for the developmentof this document. Marie O’Neill, of TheBruce Company, provided editorial andcoordination assistance. EPA and NIOSHextend special thanks to Linda Berns,Terry Savage, and others at the firm ofBerns & Kay, Ltd. for their effort andenthusiasm in designing and producing thedocument under tight deadlines.

. .

BASICS

About This Document 1

1About This Document

BEFORE YOU BEGIN

The goal of this guidance document is tohelp you prevent indoor air qualityproblems in your building and resolve suchproblems promptly if they do arise. Itrecommends practical actions that can becarried out by facility staff, outsidecontractors, or both. The document willhelp you to integrate IAQ-related activitiesinto your existing organization and identifywhich of your staff have the necessaryskills to carry out those activities.

This is a long document. It would beconvenient if all of the ideas it containscould be summed up in a few shortrecommendations, such as: “check forunderventilation” and “isolate pollutantsources.” However, such statementswould only be helpful to people who arealready familiar with indoor air qualityconcerns. If the owner’s manual for yourcar said to check your pollution controlvalves every year, but didn’t say how tofind out whether they were workingproperly, you would need either a moredetailed manual or the money to hire amechanic. Don’t be discouraged by thenumber of pages in your hands. Once youbegin to understand the factors thatinfluence indoor air quality in yourbuilding, you can move from section tosection, reading what you need to know atthe moment and leaving the rest until later.

Some Basic Assumptions

EPA and NIOSH recognize that manyfactors influence how an individual owneror manager can put the information in thisguide to use. The skills of facility staff andthe uses of the building can vary widely,

affecting the types of IAQ problems thatare likely to arise and the most effectiveapproach to resolving those problems.

The assumptions used in preparing thisguide include:

■ The expense and effort required toprevent most IAQ problems is much lessthan the expense and effort required toresolve problems after they develop.

■ Many IAQ problems can be preventedby educating facility management, staff,and occupants about the factors thatcreate such problems. When IAQproblems do arise, they can often beresolved using skills that are availablein-house.

■ The basic issues and activities involvedin preventing and resolving IAQ prob-lems are similar for buildings of manydifferent designs and uses.

■ If outside assistance is needed to solvean IAQ problem, the best results will beachieved if building owners and manag-ers are informed consumers.

How this Guide is Organized

This guide is divided into topic areasmarked by tabs. Tab I marks introductorymaterial directed toward all users of thedocument. Tab II is directed to buildingowners and facility managers who do nothave a current IAQ problem and want toprevent such problems from arising. If youcurrently have an indoor air qualityproblem, Tab III provides guidance tohelp resolve that problem. The appendicesmarked by Tab IV present informationthat may not be critical to resolving mostindoor air quality problems but could beuseful reading for additional background

2 Section 1

on major IAQ topics. Abbreviated sampleforms are included throughout the text sothat readers can see what types of informa-tion can be collected using the forms pro-vided in this document. Tab V containsthe complete forms discussed in the text.These can be photocopied for use by youand your staff.

As you read this document, you will findthat some guidance points are repeated.This was intentional, as it allows you touse the sections on prevention, diagnosis,and mitigation as “stand-alone” guides.

Tab I: Basics

Section 2: Factors Affecting Indoor AirQuality

Indoor air quality is not a simple, easilydefined concept like a desk or a leakyfaucet. It is a constantly changing interac-tion of a complex set of factors. Four ofthe most important elements involved inthe development of indoor air qualityproblems are: a source of odors orcontaminants; a problem with the design oroperation of the HVAC system; a pathwaybetween the source and the location of thecomplaint; and the building occupants.

Read Section 2 for an introduction to thefactors that influence indoor air quality. Abasic understanding of these factors iscritical to investigating and resolving IAQproblems.

Section 3: Effective Communication

An effective communication system helpsfacility managers, staff, contractors, andoccupants to clarify their responsibilitiesand cooperate in identifying potential IAQproblems. Building occupants can bevaluable allies in resolving indoor air qual-ity problems. On the other hand, evensmall problems can have disruptive andpotentially costly consequences if occu-pants become frustrated and mistrustful.Effective communications are the key tocooperative problem-solving.

Good communications can be promotedthrough a group that represents all of theinterested parties in the building. Manyorganizations have health and safety com-mittees that can fill this role. Section 3suggests ways to work productively withbuilding occupants to prevent IAQ prob-lems and to maintain good communica-tions during IAQ investigations.

Tab II: Preventing IAQProblems

Section 4: Developing an IAQ Profile

An IAQ profile is a “picture” of buildingconditions from the perspective of indoorair quality. A review of construction andoperating records, combined with aninspection of building conditions, helps toreveal potential indoor air problems andidentify building areas that require specialattention to prevent problems in the future.Baseline data collected for the IAQ profilecan facilitate later investigations, shouldproblems arise. Section 4 suggests a three-stage approach to developing an IAQprofile and describes the products of eachstage.

Section 5: Managing Buildings for GoodIAQ

Many indoor air problems can be pre-vented by following common senserecommendations, such as: maintain goodsanitation, provide adequate ventilation,and isolate pollutant sources. Otherpreventive measures may require a carefulreview of job descriptions, contracts,supplies, and schedules. It is important todesignate an IAQ manager to bear respon-sibility for coordinating the effort in yourbuilding. Section 5 discusses key elementsto include in your IAQ management plan.

Tab III: Resolving IAQProblems

Section 6: Diagnosing IAQ Problems

Most IAQ investigations begin in response

About This Document 3

to a complaint from one or more buildingoccupants. IAQ complaints can affectentire buildings or be limited to areas assmall as an individual work station. Thegoal of the investigation is to resolve thecomplaint without causing other problems.

Section 6 describes a variety of informa-tion-gathering strategies used to identifythe cause of an IAQ problem. This sectionprovides suggestions for in-house staffwho have been given the responsibility ofinvestigating the problem. It will also helpbuilding management to understand andoversee the activities of any outsideprofessionals who may be brought in toassist in the investigation.

Section 7: Mitigating IAQ Problems

The basic approaches to mitigating indoorair quality problems are: control ofpollutant sources; modifications to theventilation system; air cleaning; andcontrol of exposures to occupants. Suc-cessful mitigation often involves a combi-nation of these techniques.

Section 7 provides criteria for judgingpotential mitigation strategies and fordetermining whether a problem has beensolved. It includes brief descriptions ofcommon indoor air quality problems andpossible solutions.

Section 8: Hiring Professional Assis-tance to Solve an IAQ Problem

Indoor air quality is an emerging andinterdisciplinary field. Section 8 providesguidance in hiring professional assistanceif you decide that outside expertise isneeded to determine the cause of an IAQproblem.

Tab IV: Appendices

Appendix A: Common IAQMeasurements – A General Guide

Appendix A describes measurementtechniques that are commonly used for

IAQ investigations. If you are responsiblefor developing an IAQ profile or investi-gating an IAQ complaint, Appendix Aprovides suggestions for collecting andinterpreting information on: temperatureand humidity; airflow patterns; carbondioxide; ventilation (outdoor) air quanti-ties; and commonly measured environmen-tal contaminants.

Appendix B: HVAC Systems and IAQ

Appendix B presents basic information onHVAC system designs and componentsand their effects on indoor air quality.This appendix is designed to accompanythe HVAC Checklists in Tab V.

Appendix C: Moisture, Mold andMildew

Appendix C discusses indoor moisture andits relationship to mold and mildewgrowth. The role of humidity in creatingmold and mildew problems is oftenmisunderstood because relative humidityreadings taken in the breathing zone of anoccupied space give little indication ofconditions at the wall and ceiling surfacesor in the wall cavities. This appendixdescribes ways in which to evaluate howmoisture may be causing indoor air qualityproblems and how successful differentmitigation measures may be in reducingthose problems.

Appendix D: Asbestos

Appendix D is a brief discussion ofasbestos. If asbestos is a concern in yourbuilding, this appendix and the Appendix Gsection will direct you to sources ofdetailed guidance.

Appendix E: Radon

Appendix E is a brief discussion of radon.To learn more about how to check forradon in your building, refer to thisappendix. Appendix G will direct you to

4 Section 1

other sources of information.

Appendix F: Glossary and Acronyms

Appendix F explains scientific andengineering terminology that may beunfamiliar to some readers.

Appendix G: Resources

Appendix G is intended for readers whowant to pursue more detailed informationabout indoor air quality. It includes thenames, addresses, and telephone numbersof Federal, State, and private sector organi-zations with interests related to IAQ, aswell as a list of selected publications.

Contaminant emission and movement inbuildings is an emerging field of study.Building owners, facility managers, andengineers are urged to keep abreast of newinformation through professional journalsand seminars in addition to relying on theguidance presented in this document.

Tab V: Indoor Air Quality Forms

Tab V contains a full set of the formsdescribed in Tabs II and III. Buildingmanagers are encouraged to reproduce anduse these blank forms. You may want tomodify elements of these forms to reflectconditions in your particular building.

WARNING

Please note the following as you prepare touse this manual:

■ Modification of building functions toremedy air quality complaints may createother problems. A thorough understand-ing of all of the factors that interact tocreate indoor quality problems can helpto avoid this undesirable outcome.

■ The guidance in this document is notintended as a substitute for appropriateemergency action in the event of ahazardous situation that may beimminently threatening to life or safety.

■ The implementation of mitigationrecommendations reached as a result ofan indoor air quality evaluation shouldalways be done in accordance with locallaws and good practice. Changes to theoverall design and operation of thebuilding may necessitate the involve-ment of a registered professional engi-neer or other registered or certifiedprofessionals.

■ In the event that medical records areutilized in the course of evaluating anIAQ problem, appropriate legal confi-dentiality must be maintained.

Factors Affecting Indoor Air Quality 5

2The indoor environment in any buildingis a result of the interaction between thesite, climate, building system (originaldesign and later modifications in thestructure and mechanical systems), con-struction techniques, contaminant sources(building materials and furnishings,moisture, processes and activities within thebuilding, and outdoor sources), andbuilding occupants. The following four elements are involvedin the development of indoor air qualityproblems:

Source: there is a source of contaminationor discomfort indoors, outdoors, or withinthe mechanical systems of the building.

HVAC: the HVAC system is not able tocontrol existing air contaminants and ensurethermal comfort (temperature and humidityconditions that are comfortable for mostoccupants).

Pathways: one or more pollutant pathwaysconnect the pollutant source to the occu-pants and a driving force exists to movepollutants along the pathway(s).

Occupants: building occupants are present.

It is important to understand the role thateach of these factors may play in order toprevent, investigate, and resolve indoor airquality problems.

SOURCES OF INDOOR AIRCONTAMINANTS

Indoor air contaminants can originatewithin the building or be drawn in fromoutdoors. If contaminant sources are notcontrolled, IAQ problems can arise, even ifthe HVAC system is properly designed andwell-maintained. It may be helpful to thinkof air pollutant sources as fitting into one of

the categories that follow. The examplesgiven for each category are not intended tobe a complete list.

Sources Outside Building

Contaminated outdoor air■ pollen, dust, fungal spores■ industrial pollutants■ general vehicle exhaust

Emissions from nearby sources■ exhaust from vehicles on nearby roads

or in parking lots, or garages■ loading docks■ odors from dumpsters■ re-entrained (drawn back into the

building) exhaust from the buildingitself or from neighboring buildings

■ unsanitary debris near the outdoor airintake

Soil gas■ radon■ leakage from underground fuel tanks■ contaminants from previous uses of the

site (e.g., landfills)■ pesticides

Moisture or standing water promotingexcess microbial growth■ rooftops after rainfall■ crawlspace

Equipment

HVAC system■ dust or dirt in ductwork or other

components■ microbiological growth in drip pans,

humidifiers, ductwork, coils■ improper use of biocides, sealants, and/

or cleaning compounds■ improper venting of combustion

products■ refrigerant leakage

Factors Affecting Indoor Air Quality

Four elements—sources, the HVACsystem, pollutantpathways, andoccupants—areinvolved in thedevelopment of IAQproblems.

6 Section 2

Non-HVAC equipment■ emissions from office equipment (vola-

tile organic compounds, ozone)■ supplies (solvents, toners, ammonia)■ emissions from shops, labs, cleaning

processes■ elevator motors and other mechanical

systems

Human Activities

Personal activities■ smoking■ cooking■ body odor■ cosmetic odorsHousekeeping activities■ cleaning materials and procedures■ emissions from stored supplies or trash■ use of deodorizers and fragrances■ airborne dust or dirt (e.g., circulated by

sweeping and vacuuming)

Maintenance activities■ microorganisms in mist from improp-

erly maintained cooling towers■ airborne dust or dirt■ volatile organic compounds from use of

paint, caulk, adhesives, and otherproducts

■ pesticides from pest control activities■ emissions from stored supplies

Building Components and Furnishings

Locations that produce or collect dust orfibers■ textured surfaces such as carpeting,

curtains, and other textiles■ open shelving■ old or deteriorated furnishings■ materials containing damaged asbestos

Unsanitary conditions and water damage■ microbiological growth on or in soiled

or water-damaged furnishings■ microbiological growth in areas of

surface condensation■ standing water from clogged or poorly

designed drains■ dry traps that allow the passage of

sewer gas

Given our presentknowledge, it isdifficult to relatecomplaints ofspecific healtheffects to exposuresto specific pollutantconcentrations,especially since thesignificant exposuresmay be to low levelsof pollutant mixtures.

Chemicals released from buildingcomponents or furnishings■ volatile organic compounds or■ inorganic compounds

Other Sources

Accidental events■ spills of water 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/remodeling/repair activities■ emissions from new furnishings■ dust and fibers from demolition■ odors and volatile organic and inorganic

compounds from paint, caulk, adhesives■ microbiologicals released from demoli-

tion or remodeling activities

Indoor air often contains a variety ofcontaminants at concentrations that are farbelow any standards or guidelines foroccupational exposure. Given our presentknowledge, it is difficult to relate com-plaints of specific health effects to expo-sures to specific pollutant concentrations,especially since the significant exposuresmay be to low levels of pollutant mixtures.

HVAC SYSTEM DESIGN ANDOPERATION

The HVAC system includes all heating,cooling, and ventilation equipment servinga building: furnaces or boilers, chillers,cooling towers, air handling units, exhaustfans, ductwork, filters, steam (or heatingwater) piping. Most of the HVAC discus-sion in this document applies both to centralHVAC systems and to individual compo-nents used as stand-alone units.


A properly designed and functioningHVAC system:■ provides thermal comfort■ distributes adequate amounts of outdoor

air to meet ventilation needs of allbuilding occupants

■ isolates and removes odors and con-taminants through pressure control,filtration, and exhaust fans

Thermal Comfort

A number of variables interact to deter-mine whether people are comfortable withthe temperature of the indoor air. Theactivity level, age, and physiology of eachperson affect the thermal comfort require-ments of that individual. The AmericanSociety of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)Standard 55-1981 describes the tempera-ture and humidity ranges that are comfort-able for most people engaged in largelysedentary activities. That information issummarized on page 57. The ASHRAEstandard assumes “normal” indoorclothing. Added layers of clothing reducethe rate of heat loss.

Uniformity of temperature is importantto comfort. When the heating and coolingneeds of rooms within a single zonechange at different rates, rooms that areserved by a single thermostat may be atdifferent temperatures. Temperaturestratification is a common problem causedby convection, the tendency of light, warmair to rise and heavier, cooler air to sink. Ifair is not properly mixed by the ventilationsystem, the temperature near the ceilingcan be several degrees warmer than atfloor level. Even if air is properly mixed,uninsulated floors over unheated spacescan create discomfort in some climatezones. Large fluctuations of indoortemperature can also occur when controlshave a wide “dead band” (a temperaturerange within which neither heating norcooling takes place).

A number ofvariables, includingpersonal activitylevels, uniformity oftemperature, radiantheat gain or loss, andhumidity, interact todetermine whetherpeople arecomfortable with thetemperature of theindoor air.

Radiant heat transfer may cause peoplelocated near very hot or very cold surfacesto be uncomfortable even though thethermostat setting and the measured airtemperature are within the comfort range.Buildings with large window areas some-times have acute problems of discomfortdue to radiant heat gains and losses, withthe locations of complaints shifting duringthe day as the sun angle changes. Largevertical surfaces can also produce asignificant flow of naturally-convecting air,producing complaints of draftiness.Adding insulation to walls helps tomoderate the temperature of interior wallsurfaces. Closing curtains reduces heatingfrom direct sunlight and isolates buildingoccupants from exposure to windowsurfaces (which, lacking insulation, arelikely to be much hotter or colder than thewalls).

Humidity is a factor in thermal comfort.Raising relative humidity reduces theability to lose heat through perspiration andevaporation, so that the effect is similar toraising the temperature. Humidity ex-tremes can also create other IAQ problems.Excessively high or low relative humiditiescan produce discomfort, while high relativehumidities can promote the growth of moldand mildew (see Appendix C).

Ventilation to Meet OccupantNeeds

Most air handling units distribute a blendof outdoor air and recirculated indoor air.HVAC designs may also include units thatintroduce 100% outdoor air or that simplytransfer air within the building. Uncon-trolled quantities of outdoor air enterbuildings by infiltration through windows,doors, and gaps in the exterior construc-tion. Thermal comfort and ventilationneeds are met by supplying “conditioned”air (a blend of outdoor and recirculated airthat has been filtered, heated or cooled, andsometimes humidified or dehumidified).

8 Section 2

Large buildings often have interior(“core”) spaces in which constant coolingis required to compensate for heat gener-ated by occupants, equipment, andlighting, while perimeter rooms mayrequire heating or cooling depending onoutdoor conditions.

Two of the most common HVACdesigns used in modern public andcommercial buildings are constant volumeand variable air volume systems. Con-stant volume systems are designed toprovide a constant airflow and to vary theair temperature to meet heating andcooling needs. The percentage of outdoorair may be held constant, but is oftencontrolled either manually or automaticallyto vary with outdoor temperature andhumidity. Controls may include a mini-mum setting that should allow the systemto meet ventilation guidelines for outdoorair quantities under design conditions.

Variable air volume (VAV) systemscondition supply air to a constant tempera-ture and ensure thermal comfort by varyingthe airflow to occupied spaces. Most earlyVAV systems did not allow control of theoutdoor air quantity, so that a decreasingamount of outdoor air was provided as theflow of supply air was reduced. Somemore recent designs ensure a minimumsupply of outdoor air with static pressuredevices in the outdoor air stream. Addi-tional energy-conserving features such aseconomizer control or heat recovery arealso found in some buildings.

Good quality design, installation, andtesting and balancing are critically impor-tant to the proper operation of all typesof HVAC systems, especially VAVsystems, as are regular inspections andmaintenance. (See Appendix B for furtherdiscussion of HVAC system types.)

The amount of outdoor air consideredadequate for proper ventilation has variedsubstantially over time. The currentguideline issued by ASHRAE is ASHRAEStandard 62-1989. The building code thatwas in force when your building HVAC

system was designed may well haveestablished a lower amount of ventilation(in cubic feet of outdoor air per minute perperson) than is currently recommended.(A table of outdoor air quantities recom-mended by ASHRAE is reproduced onpage 136 in Appendix B. Note that otherimportant aspects of the standard are notincluded in this table.)

Control of Odors andContaminants

One technique for controlling odors andcontaminants is to dilute them withoutdoor air. Dilution can work only ifthere is a consistent and appropriate flowof supply air that mixes effectively withroom air. The term “ventilation effi-ciency” is used to describe the ability ofthe ventilation system to distribute supplyair and remove internally generatedpollutants. Researchers are currentlystudying ways to measure ventilationefficiency and interpret the results of thosemeasurements.

Another technique for isolating odorsand contaminants is to design and operatethe HVAC system so that pressurerelationships between rooms are con-trolled. This control is accomplished byadjusting the air quantities that aresupplied to and removed from each room.If more air is supplied to a room than isexhausted, the excess air leaks out of thespace and the room is said to be underpositive pressure. If less air is suppliedthan is exhausted, air is pulled into thespace and the room is said to be undernegative pressure.

Control of pressure relationships iscritically important in mixed use buildingsor buildings with special use areas.Lobbies and buildings in general are oftendesigned to operate under positive pressureto prevent or minimize the infiltration ofunconditioned air, with its potential tocause drafts and introduce dust, dirt, andthermal discomfort. Without properoperation and maintenance, these pressure

The amount ofoutdoor airconsidered adequatefor proper ventilationhas variedsubstantially overtime. The currentguideline issued byASHRAE is Standard62-1989.


Chases, crawlspaces, andother hidden spaces can beboth sources and pathwaysfor pollutants.

differences are not likely to remain asoriginally designed.

A third technique is to use local exhaustsystems (sometimes known as dedicatedexhaust ventilation systems) to isolate andremove contaminants by maintainingnegative pressure in the area around thecontaminant source. Local exhaust can belinked to the operation of a particular pieceof equipment (such as a kitchen range) orused to treat an entire room (such as asmoking lounge or custodial closet). Airshould be exhausted to the outdoors, notrecirculated, from locations which producesignificant odors and high concentrationsof contaminants (such as copy rooms,bathrooms, kitchens, and beauty salons).

Spaces where local exhaust is used mustbe provided with make-up air and the localexhaust must function in coordination withthe rest of the ventilation system. Undersome circumstances, it may be acceptableto transfer conditioned air from relativelyclean parts of a building to comparativelydirty areas and use it as make-up air for alocal exhaust system. Such a transfer canachieve significant energy savings.

Air cleaning and filtration devicesdesigned to control contaminants are foundas components of HVAC systems (forexample, filter boxes in ductwork) and canalso be installed as independent units. Theeffectiveness of air cleaning depends uponproper equipment selection, installation,operation, and maintenance. Cautionshould be used in evaluating the many newtechnological developments in the field ofair cleaning and filtration.

POLLUTANT PATHWAYS ANDDRIVING FORCES

Airflow patterns in buildings result fromthe combined action of mechanicalventilation systems, human activity, andnatural forces. Pressure differentialscreated by these forces move airbornecontaminants from areas of relativelyhigher pressure to areas of relatively lowerpressure through any available openings.

The HVAC system is generally thepredominant pathway and driving force forair movement in buildings. However, allof a building’s components (walls, ceilings,floors, penetrations, HVAC equipment, andoccupants) interact to affect the distributionof contaminants.

For example, as air moves from supplyregisters or diffusers to return air grilles, itis diverted or obstructed by partitions,walls, and furnishings, and redirected byopenings that provide pathways for airmovement. On a localized basis, themovement of people has a major impact onthe movement of pollutants. Some of thepathways change as doors and windowsopen and close. It is useful to think of theentire building — the rooms and theconnections (e.g., chases, corridors,stairways, elevator shafts) between them —as part of the air distribution system.

Natural forces exert an importantinfluence on air movement between zonesand between the building’s interior andexterior. Both the stack effect and windcan overpower a building’s mechanicalsystem and disrupt air circulation andventilation, especially if the buildingenvelope is leaky.

Stack effect is the pressure driven flowproduced by convection (the tendency of

10 Section 2

warm air to rise). The stack effect existswhenever there is an indoor-outdoortemperature difference and becomesstronger as the temperature differenceincreases. As heated air escapes fromupper levels of the building, indoor airmoves from lower to upper floors, andreplacement outdoor air is drawn intoopenings at the lower levels of buildings.Stack effect airflow can transport contami-nants between floors by way of stairwells,elevator shafts, utility chases, or otheropenings.

Wind effects are transient, creating localareas of high pressure (on the windwardside) and low pressure (on the leewardside) of buildings. Depending on theleakage openings in the building exterior,wind can affect the pressure relationshipswithin and between rooms.

The basic principle of air movement fromareas of relatively higher pressure to areasof relatively lower pressure can producemany patterns of contaminant distribution,including:

■ local circulation in the room containingthe pollutant source

■ air movement into adjacent spaces thatare under lower pressure (Note: Even iftwo rooms are both under positivepressure compared to the outdoors, oneroom is usually at a lower pressure thanthe other.)

■ recirculation of air within the zonecontaining the pollutant source or inadjacent zones where return systemsoverlap

■ movement from lower to upper levels ofthe building

■ air movement into the building througheither infiltration of outdoor air orreentry of exhaust air

Air moves from areas of higher pressureto areas of lower pressure through anyavailable openings. A small crack or holecan admit significant amounts of air if thepressure differentials are high enough(which may be very difficult to assess.)

Even when the building as a whole ismaintained under positive pressure, there isalways some location (for example, theoutdoor air intake) that is under negativepressure relative to the outdoors. Entry ofcontaminants may be intermittent, occur-ring only when the wind blows from thedirection of the pollutant source. Theinteraction between pollutant pathways andintermittent or variable driving forces canlead to a single source causing IAQcomplaints in areas of the building that aredistant from each other and from thesource.

BUILDING OCCUPANTS

The term “building occupants” is generallyused in this document to describe peoplewho spend extended time periods (e.g., afull workday) in the building. Clients andvisitors are also occupants; they may havedifferent tolerances and expectations fromthose who spend their entire workdays inthe building, and are likely to be moresensitive to odors.

Groups that may be particularly suscep-tible to effects of indoor air contaminantsinclude, but are not limited to:

■ allergic or asthmatic individuals■ people with respiratory disease■ people whose immune systems are

suppressed due to chemotherapy,radiation therapy, disease, or othercauses

■ contact lens wearers

Some other groups are particularlyvulnerable to exposures of certainpollutants or pollutant mixtures. Forexample, people with heart disease may bemore affected by exposure at lower levelsof carbon monoxide than healthyindividuals. Children exposed to environ-mental tobacco smoke have been shown tobe at higher risk of respiratory illnessesand those exposed to nitrogen dioxide havebeen shown to be at higher risk fromrespiratory infections.

The basic principle ofair movement fromareas of relativelyhigher pressure toareas of relativelylower pressure canproduce manypatterns ofcontaminantdistribution.


Because of varying sensitivity amongpeople, one individual may react to aparticular IAQ problem while surroundingoccupants have no ill effects. (Symptomsthat are limited to a single person can alsooccur when only one work station receivesthe bulk of the pollutant dose.) In othercases, complaints may be widespread.

A single indoor air pollutant or problemcan trigger different reactions in differentpeople. Some may not be affected at all.Information about the types of symptomscan sometimes lead directly to solutions.However, symptom information is morelikely to be useful for identifying the timingand conditions under which problemsoccur.

Types of Symptoms andComplaints

The effects of IAQ problems are often non-specific symptoms rather than clearlydefined illnesses. Symptoms commonlyattributed to IAQ problems include:

■ headache■ fatigue■ shortness of breath■ sinus congestion■ cough■ sneezing■ eye, nose, and throat irritation■ skin irritation■ dizziness■ nausea

All of these symptoms, however, may alsobe caused by other factors, and are notnecessarily due to air quality deficiencies.

“Health” and “comfort” are used todescribe a spectrum of physical sensations.For example, when the air in a room isslightly too warm for a person’s activitylevel, that person may experience milddiscomfort. If the temperature continues torise, discomfort increases and symptomssuch as fatigue, stuffiness, and headachescan appear.

Some complaints by building occupantsare clearly related to the discomfort end ofthe spectrum. One of the most commonIAQ complaints is that “there’s a funnysmell in here.” Odors are often associatedwith a perception of poor air quality,whether or not they cause symptoms.Environmental stressors such as improperlighting, noise, vibration, overcrowding,ergonomic stressors, and job-relatedpsychosocial problems (such as job stress)can produce symptoms that are similar tothose associated with poor air quality.

The term sick building syndrome (SBS)is sometimes used to describe cases inwhich building occupants experience acutehealth and comfort effects that are appar-ently linked to the time they spend in thebuilding, but in which no specific illness orcause can be identified. The complaintsmay be localized in a particular room orzone or may be widespread throughout thebuilding. Many different symptoms havebeen associated with SBS, includingrespiratory complaints, irritation, andfatigue. Analysis of air samples often failsto detect high concentrations of specificcontaminants. The problem may be causedby any or all of the following:

■ the combined effects of multiplepollutants at low concentrations

■ other environmental stressors(e.g., overheating, poor lighting, noise)

■ ergonomic stressors■ job-related psychosocial stressors

(e.g., overcrowding, labor-managementproblems)

■ unknown factors

Building-related illness (BRI) is a termreferring to illness brought on by exposureto the building air, where symptoms ofdiagnosable illness are identified (e.g.,certain allergies or infections) and can bedirectly attributed to environmental agentsin the air. Legionnaire’s disease andhypersensitivity pneumonitis are examplesof BRI that can have serious, even life-threatening consequences.

Environmentalstressors such asimproper lighting,noise, vibration,overcrowding,ergonomic stressors,and job-relatedpsychosocialproblems (such as jobstress) can producesymptoms that aresimilar to thoseassociated with poorair quality.

12 Section 2

A small percentage of the populationmay be sensitive to a number of chemicalsin indoor air, each of which may occur atvery low concentrations. The existence ofthis condition, which is known as multiplechemical sensitivity (MCS), is a matter ofconsiderable controversy. MCS is notcurrently recognized by the major medicalorganizations, but medical opinion isdivided, and further research is needed.The applicability of access for the disabledand worker’s compensation regulations topeople who believe they are chemicallysensitive may become concerns for facilitymanagers.

Sometimes several building occupantsexperience rare or serious health problems(e.g., cancer, miscarriages, Lou Gehrig’sdisease) over a relatively short time period.These clusters of health problems areoccasionally blamed on indoor air quality,and can produce tremendous anxietyamong building occupants. State or localHealth Departments can provide adviceand assistance if clusters are suspected.They may be able to help answer keyquestions such as whether the apparentcluster is actually unusual and whether theunderlying cause could be related to IAQ.

Effective Communication 13

Effective Communication

3potential problems to the attention ofbuilding staff and management, and fostera sense of shared responsibility formaintaining a safe and comfortable indoorenvironment.

The group will be most successful if itrepresents the diverse interests in thebuilding, including:

■ building owner■ building manager■ facility personnel■ health and safety officials■ tenants and/or other occupants who are

not facility staff■ union representatives (or other worker

representatives)

Clarify Responsibilities

It is important to define the responsibilitiesof building management, staff, andoccupants in relation to indoor air quality.These responsibilities can be formalized byincorporating them into documents such asemployee manuals or lease agreements.

This section discusses establishing andmaintaining a communication system thatcan help prevent indoor air qualityproblems and resolve problems coopera-tively if they do arise. If you are currentlyresponding to an indoor air qualitycomplaint, you may want to skip ahead tothe discussion of Communicating toResolve IAQ Problems on page 15.

COMMUNICATING TO PREVENTIAQ PROBLEMS

Effective communication can encouragebuilding occupants to improve their workenvironment through positive contribu-tions. The following objectives should bekept in mind while reviewing and revisingyour current approach to communicatingwith occupants:

■ provide accurate information aboutfactors that affect indoor air quality

■ clarify the responsibilities of each party(e.g., building management, staff, ten-ants, contractors)

■ establish an effective system for loggingand responding to complaints shouldthey occur

Provide Accurate Information

Many indoor air quality problems can beprevented if staff and building occupantsunderstand how their activities affect IAQ.You may already have a health and safetycommittee functioning to promote goodworking conditions. If so, it is easy to addindoor air quality to their list of concerns.If you do not have a health and safetycommittee, consider establishing one orsetting up a joint management-tenant IAQtask force. Whatever its official designa-tion, such a group can help to disseminateinformation about indoor air quality, bring

The occupant in this roomcovered the supply air ventswith papers. Whether thiswas done to reduce uncom-fortable drafts or to providemore shelf space, the resultcan disrupt the air flow, notonly through this room butelsewhere in the building. Bytampering with the air han-dling system, occupants canunintentionally cause com-plaints in other areas.

14 Section 3

projected ranges of occupants. If theoccupancy rate becomes a problem, it maybe helpful to refer to a standard referencesuch as ASHRAE Standard 62-1989 toshow occupants that keeping occupancywithin the ventilation capacity serves thegoal of providing a quality work environ-ment and is not an arbitrary decision bybuilding management.

Modifications: Review plans that mayinvolve increases in the number of occu-pants, relocation of walls or partitions,installation of new equipment, or changesin the use of space. Building owners,facility managers, and occupants shareresponsibility for monitoring new equip-ment installation and changes in the use ofspace. The review process allows potentialindoor air quality problems to be identifiedso that the HVAC system can be modifiedas needed. Only authorized maintenancepersonnel should adjust air supply orexhaust vents; however, if occupants areexpected to follow such a “hands-off”policy, facility management must respondpromptly to IAQ complaints.

Notification of planned activities:Establish a procedure for informing tenantsbefore the start of activities that produceodors or contaminants (e.g., maintenance,pest control, repair, remodeling,redecorating).

Establish a System forResponding to Complaints

Many organizations have establishedprocedures for responding to occupantcomplaints that can be modified to includeindoor air quality concerns. To avoidfrustrating delays, building occupants needto know how to express their complaintsabout IAQ. More importantly, they need toknow how to locate responsible staff andwhere to obtain complaint forms. Thisinformation can be posted on bulletinboards, circulated in memos or newsletters,or publicized by some other means.

Use of Space: Educate occupants about thepermitted uses and maximum occupancy ofdifferent areas within the building andmake sure that appropriate ventilation isprovided for the activities that are permit-ted. Indoor air quality complaints oftenarise in mixed-use buildings. For example,kitchen staff expect food odors as part oftheir work, but nearby office workers mayfind cooking odors distracting and unpleas-ant. Problems can also arise when oldtenants leave and new arrivals introducenew uses of the building.

Occupancy Rate: Inform occupants aboutthe importance of keeping the buildingmanagement informed about significantchanges in the number of people regularlyusing particular areas of the building. Theventilation systems in buildings aredesigned and operated to supply air to

MANAGEMENT AND OCCUPANT COOPERATIONON INDOOR AIR QUALITY

The State of Wisconsin’s “Quality Building Management” system hashelped to unite the diverse interests involved in operating and usingState office buildings. Tenants and facility personnel volunteers toserve on teams, working cooperatively to improve the quality of theindoor environment.

Each team was assigned a specific area for which it drafted “IdealBuilding Standards.” Air quality was one such area; others includedelevators, rest rooms, and work spaces. The IAQ teams were trainedin conducting research; toured mechanical rooms to achieve a betterunderstanding of building operations; read articles; and listened topresentations on IAQ, ventilation, and related topics.

The proposed “Ideal Building Standards” were reviewed with othertenants and then used as a basis for Quality Improvement Plans.Some elements of the Quality Improvement Plans identify responsi-bilities of the tenants, such as adopting good housekeeping practicesto improve the work environment and facilitate cleaning. Responsi-bilities identified as belonging to building management are reflected inwork plans and budget decisions.

Since implementation of this management system, interactionsbetween building management and tenants have improved. Tenantsactively seek out management staff to discuss concerns. However,they are also more willing to review their own actions when lookingfor potential causes of IAQ problems.


Complaints should be handledpromptly, with every incident givenserious attention. It is advisable toestablish a recordkeeping system thatcross-references documentation oncomplaints with records of equipmentoperation and maintenance. Therecordkeeping system can help to resolvecomplaints by collecting information in aform that highlights patterns of problems(for example, complaints that occur at aregular time of day or in the same area ofthe building). The IAQ Complaint Formand Incident Log shown here and on thefollowing page (and also reproduced inTab V) can be used to track complaintsrelated to the indoor environment.

COMMUNICATING TO RESOLVEIAQ PROBLEMS

In many cases, building managers may bealerted to potential indoor air qualityproblems by complaints from occupants.The complaints can be vague, to the effectthat one or more people feel “sick” or“uncomfortable” or that someone hasnoticed an unusual odor. They may bespecific, blaming a particular material asthe cause of discomfort or health problems.People are usually reacting to a realproblem, so their complaints should betaken seriously. However, they mayattribute their symptoms to the wrongcause, so their theories about the problemshould be heard respectfully but weighedcautiously.

Indoor air quality problems cansometimes be identified and resolvedquickly. On other occasions, complaintsoriginate from the interaction of severalvariables, and detailed investigation maybe necessary in order to resolve theproblem.

The Importance of Respondingto IAQ Complaints

Listening and responding to buildingoccupants is critical to achieving a

successful resolution of indoor air qualitycomplaints. IAQ complaints may begrounded in poor indoor air quality,thermal conditions, noise, glare, or evenjob stresses. However, it is in the buildingmanager’s best interest to respond to allcomplaints about the indoor environmentpromptly and seriously and to establishcredibility through open communicationwith building occupants. The biggestmistake that building managers can makein the face of an IAQ complaint is tounderestimate the problems that can resultif building occupants believe that no actionis being taken or that important informa-tion is being withheld. Without opencommunication, any IAQ problem canbecome complicated by anxiety, frustra-tion, and distrust, delaying its resolution.

Paying attention to communication, aswell as problem-solving, helps to ensure

Sample FormIndoor Air Quality Complaint Form

This form should be used if your complaint may be related to indoor airquality. Indoor air quality problems include concerns with temperaturecontrol, ventilation, and air pollutants. Your observations can help toresolve the problem as quickly as possible. Please use the space belowto describe the nature of the complaint and any potential causes.

We may need to contact you to discuss your complaint. What is the besttime to reach you?

So that we can respond promptly, please return this form to:

IAQ Manager or Contact Person

SEECOMPLETEFORMPAGE 181

16 Section 3

the support and cooperation of buildingoccupants as the complaint is investigatedand resolved. The messages to convey arethat management believes it is important toprovide a healthy and safe building, thatgood indoor air quality is an essentialcomponent of a healthful indoor environ-ment, and that complaints about indoor airquality are taken seriously.

Communications, whether they occur inconversations or in writing, should includethe following information:

■ what types of complaints managementhas received

■ management’s policy in regard toproviding a healthy and safe environ-ment and responding to occupantcomplaints

■ what management has done to date (e.g.,collecting data, responding to theproblem)

■ what management plans to do in order tofurther investigate and correct theproblem (including the fact that outsideconsultants have been called in, if theyhave been)

■ the names and telephone numbers ofappropriate facility management,

medical, or health and safety staff towhom the occupants should turn if theyhave additional complaints or questions,or if they have information that may helpin resolving the complaints

Maintaining the Lines ofCommunication

Make certain that occupants know how tocontact the responsible personnel who canreceive and respond to IAQ complaints.Tenants may also have an internal systemfor channeling complaints, for examplethrough a health and safety representative,supervisor, or company doctor.

Indoor air quality complaints that canbe resolved quickly and that involve smallnumbers of people (e.g., annoying butharmless odors from an easily-identifiedsource) can be handled matter-of-factlylike other minor problems without riskingconfusion and bad feeling among otherbuilding occupants. Communicationbecomes a more critical issue when thereare delays in identifying and resolving theproblem and when serious health concernsare involved.

Sample FormIncident Log

Investigation Record(check the forms that were used)

DateFileNumber

Outcome /Comments

Log Entry By(initials)

Problem Location

The messages toconvey are thatmanagement believesit is important toprovide a healthy andsafe building, thatgood indoor airquality is an essentialcomponent of ahealthful indoorenvironment, andthat complaintsabout indoor airquality are takenseriously.



If the problem seems to be widespreador potentially serious, it is advisable towork with your health and safety commit-tee. If you do not have a health and safetycommittee, consider forming one, orestablishing a joint management-tenantIAQ task force. (See the discussion onpage 13.)

Productive relations will be enhanced ifoccupants are given basic informationduring the process of investigation andmitigation. Potential critics can becomeallies if they are invited to be part of theproblem-solving process and becomebetter educated about IAQ and buildingoperations. Building managers may beunderstandably reluctant to share testresults or consultants’ reports with theirtenants or employees, but secrecy in suchmatters can backfire if information leaksout at a later time.

Building management staff can beencouraged to talk directly with occupantsboth at the time a complaint occurs andlater during a diagnostic investigation.Their observations about patterns ofsymptoms or building conditions mayprovide helpful information.

Confidentiality of records can beimportant to occupants, especially if theyare concerned that IAQ complaints willlead to negative reactions from theiremployers. There may be legal penaltiesfor violating confidentiality of medicalrecords. By reassuring occupants thatprivacy will be respected, investigators aremore likely to obtain honest and completeinformation.

It is advisable to explain the nature ofinvestigative activities, so that rumors andsuspicions can be countered with factualinformation. Notices or memoranda canbe delivered directly to selected occupantsor posted in general use areas. Newsletterarticles or other established communica-tion channels can also be used to keepbuilding occupants up-to-date.

Problems can arise from saying eithertoo little or too much. Premature releaseof information when data-gathering is stillincomplete can produce confusion,frustration, and mistrust at a later date.Similar problems can result from incorrectrepresentation of risk — assuming theworst case (or the best). However, ifprogress reports are not given, people maythink nothing (or something terrible) ishappening. It is good practice to cleareach piece of information with the facilitymanager, building owner, or legal counsel.Management should attempt to be factualand to the point when presenting informa-tion such as:

■ the definition of the complaint areabased upon the location and distributionof complaints (this may be revised as theinvestigation progresses)

■ the progress of the investigation,including the types of information thatare being gathered and ways thatoccupants can help

■ factors that have been evaluated andfound not to be causing or contributingto the problem

■ how long the investigation might take■ attempts that are being made to improve

indoor air quality■ work that remains to be done and the

schedule for its completion

Vague discomfort, intermittent symp-toms, and complex interactions of jobstress with environmental factors, whichmake IAQ problems difficult to investi-gate, can also obscure the effects ofmitigation efforts. Even after the propermitigation strategy is in place, it may takedays or weeks for contaminants to dissi-pate and symptoms to disappear. Ifbuilding occupants are informed that theirsymptoms may persist for some time aftermitigation, the inability to bring instantrelief is less likely to be seen as a failure.

If the problem seemsto be widespread orpotentially serious, itis advisable to workwith your health andsafety committee. Ifyou do not have ahealth and safetycommittee, considerforming one, orestablishing a jointmanagement-tenantIAQ task force.

. .

PREVENTING IAQ PROBLEMS

. .

. .

Developing an IAQ Profile 19

After reading this manual to develop afeel for the issues involved in maintaininggood indoor air quality in a building, thedevelopment of an IAQ profile shouldbecome a priority. The process ofdeveloping an IAQ profile should requireonly a modest effort, from a few days to afew weeks of staff time, depending on thecomplexity of your building and theamount of detailed information collected.The work can be done in pieces over alonger period, if necessary, to fit into abuilding manager’s busy schedule.

Over time, it is desirable to make someactual measurements of airflow, tempera-ture, relative humidity, carbon dioxide(CO

2), and/or pressure differentials (e.g., in

each of the air handling zones or other sub-areas of the building). These measure-ments provide far better information oncurrent conditions than can be obtainedfrom the plans and specifications, even ifas-built records are available.

In addition, few buildings have beenadequately commissioned, so the systemmay never have delivered the airflowsshown on the design drawings. In theevent of litigation around future IAQcomplaints, the value of the IAQ profile asa resource document will be enhanced byreal-world measurements. (Refer toAppendix G and the ASHRAE standard oncommissioning. The EPA document ondesigning for good indoor air quality,which is due to be published in 1992, willcontain a more complete discussion of theprocess of commissioning buildings.)

4Developing an IAQ Profile

An IAQ profile is a description of thefeatures of the building structure, function,and occupancy that impact indoor airquality. When you have completed theIAQ profile, you should have an under-standing of the current status of air qualityin the building and baseline information onthe factors that have a potential for causingproblems in the future.

The IAQ profile can help buildingmanagement to identify potential problemareas and prioritize budgets for mainte-nance and future modifications. Combinedwith information on lighting, security, andother important systems, it can become anowner’s manual that is specific to yourbuilding and that will serve as a referencein a variety of situations.

The key questions to answer whiledeveloping the IAQ profile are:

■ How was this building originallyintended to function? Consider thebuilding components and furnishings,mechanical equipment (HVAC and non-HVAC), and the occupant populationand associated activities.

■ Is the building functioning as designed?Find out whether it was commissioned.Compare the information from thecommissioning to its current condition.

■ What changes in building layout and usehave occurred since the original designand construction? Find out if the HVACsystem has been reset and retestedto reflect current usage.

■ What changes may be needed to preventIAQ problems from developing in thefuture? Consider potential changes infuture uses of the building.

20 Section 4

■ Description of HVAC systemdesign and operation; set ofoperating instructions, manuals

■ Set of maintenance and calibrationrecords

■ Inventory of locations whereoccupancy, equipment, or buildinghave changed

■ Inventory of complaint locations

■ List of responsible staff and/orcontractors; evidence of training;job descriptions

■ Identification of areas wherepositive or negative pressuresshould be maintained (sketchplan)

■ Record of locations that needmonitoring or correction

■ Inventory of HVAC systemcomponents needing repair,adjustment or replacement

■ Record of control settings andoperating schedules

■ Completed plan showing airflowdirections or pressure differen-tials in significant areas

■ Inventory of significantpollutant sources and theirlocations

■ Set of Material Safety DataSheets for supplies andhazardous substances that arestored or used in the building

■ Zone/Room Record

FIGURE 4-1: Developing an IAQProfile

START

Yes

PRODUCTS

1. Collect andReview ExistingRecords

Review design,construction andoperating documents

Check HVAC mainte-nance records againstequipment lists

Review complaintrecord

2. Conduct aWalkthroughInspection of theBuilding

Talk with staff andother occupants

Look for IAQ problem

3. Collect DetailedInformation

HVAC systemcondition andoperation

Pollutant pathways

Pollutant sources

Occupants

Develop an IAQ management plan (see Section 5)

Go to Section 6

Didyou findany IAQproblems

?

SKILLS REQUIRED TO CREATEAN IAQ PROFILE

Many of the resources necessary for theIAQ profile should already be on handwithin your organization. Additionalinformation can be collected by the staffperson or persons who have the followingskills:

■ basic understanding of HVAC systemoperating principles

■ ability to read architectural and mechani-cal plans and understandmanufacturer’scatalog data on equipment

■ ability to identify items of officeequipment

■ ability to work cooperatively withbuilding occupants and gather informa-tion about space usage

■ ability to collect information aboutHVAC system operation, equipmentcondition, and maintenance schedules

■ authority to collect information fromsubcontractors about work schedulesand materials used (particularly cleaningand pest control activities)

■ ability to understand the practicalmeaning of the information contained inthe Material Safety Data Sheets(MSDSs)

If direct measurements are to beincluded in the IAQ profile, the staffshould have the tools and training to makethe following measurements (see AppendixA for guidance on air sampling):■ air volumes at supply diffusers and

exhaust grilles■ CO

2 concentration

■ temperature■ relative humidity■ pressure differentials■ assessment of thermal and ventilation

load requirements

Section 8 provides guidance on hiringIAQ professionals if you prefer to useoutside expertise to develop your IAQprofile.

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STEPS IN AN IAQ PROFILE

The information needed for an IAQ profileis similar to that which is collected whensolving indoor air quality problems, butincludes the entire building rather thanfocusing on areas that may have caused anidentified problem. The IAQ profileshould be an organized body of recordsthat can be referred to in planning forrenovations, negotiating leases andcontracts, or responding to future com-plaints.

The process of gathering informationfor the IAQ profile can be divided intothree major stages:1. Collect and review existing records.2. Conduct a walkthrough inspection ofthe building.3. Collect detailed information on theHVAC system, pollutant pathways,pollutant sources, and buildingoccupancy.

The first two stages should be carriedout as quickly as possible, but the thirdstage can be handled as time allows so thatit does not interfere with other staffresponsibilities.

1. Collect and Review ExistingRecords

Review construction and operatingdocuments

Collect any available documents thatdescribe the construction and operation ofthe building: architectural and mechanicalplans, specifications, submittals, sheetmetal drawings, commissioning reports,adjusting and balancing reports, inspectionrecords, and operating manuals. Manybuildings may lack some or all of thesedocuments. If there are no commissioningreports or balancing reports, actual venti-lation quantities may be quite differentfrom those indicated on mechanical design

PRODUCTS OF THE REVIEW OF EXISTING RECORDS

■ a description of the HVAC system design and operation(e.g., original plans and specifications with changes indi-cated or new sketch plans and notes, commisioning reports,testing and balancing reports)

■ a set of operating instructions, maintenance and calibra-tion records for HVAC system components (e.g., fans,dampers, filters, chillers, boilers, and control systems)

■ an inventory of locations where architectural or engineeringmodifications have taken place

■ an inventory of locations in which current occupancy orHVAC system operation represents a change from theoriginal design

■ an inventory of locations where complaints have beencommon in the past

drawings. If there are no operating ormaintenance manuals for HVAC equip-ment, it is difficult for staff to carry out anadequate preventive maintenance program.

Study the original architectural andmechanical design so that you understandthe building’s layout and intended func-tions. Identify and note locations in whichchanges in equipment or room usage createa potential for indoor air quality problemsand give them special attention during thewalkthrough inspection.

Items of interest and the questions theysuggest could include the following:

Commissioning reports

■ Was the building properly commissionedwhen it was first constructed, includingtesting and balancing of the HVACsystem?

Operating manuals

■ Do staff members understand how theHVAC equipment is intended to operate?

Remodeled areas

■ Has the HVAC system layout beenchanged to accommodate new walls,rearranged partitions, or similar architec-tural modifications?

22 Section 4

has been installed in inaccessible or out-of-the-way locations is frequently overlookedduring routine maintenance. This isparticularly true of items such as filterboxes and small capacity exhaust fans.

Review records of complaints

If there is an organized record of pastoccupant complaints about the buildingenvironment, review those complaints toidentify building areas that deserveparticular attention.

2. Conduct a WalkthroughInspection of the Building

The intent of the walkthrough inspection isto acquire a good overview of occupantactivities and building functions and tolook for IAQ problem indicators. Nospecific forms are suggested for this stageof IAQ profile development. However,the investigator should have a sketch planof the building, such as a small floor planshowing fire exit, so that his or her notescan be referenced to specific locations.

Detailed measurements of temperature,humidity, airflow, or other parameters aremore appropriate to a later stage of profiledevelopment. However, chemical smokecan be used to observe airflow patterns andpressure relationships between special useareas or other identified pollutant sourcesand surrounding rooms. Odors in inappro-priate locations (e.g., kitchen odors in alobby) may indicate that ventilation systemcomponents require adjustment or repair.(See Appendix A for further discussion ofthe use of chemical smoke.)

The value of IAQ ventilation measure-ment tools to your operation will grow asyou become more familiar with handlingindoor air quality concerns. For example,if you do not own a direct-reading carbondioxide monitor, it is not necessary toacquire one for the IAQ profile. Thosewho already have access to this type ofinstrument can take readings during thewalkthrough as a way to obtain baseline

Addition, removal, or replacement ofHVAC equipment

■ Where the original equipment has beenreplaced, do the newer units have thesame capacity as the originals?

■ Has new equipment been properlyinstalled and tested? Where equipmenthas been removed, is it is no longerneeded?

Changes in room use

■ Is there a need for additional ventilation(supply and/or exhaust) due to increasedoccupant population or new activitieswithin any area of the building?

■ Have new items of equipment (non-HVAC) been provided with local exhaustwhere needed? Look for unusual typesor quantities of equipment such as copymachines or computer terminals.

Check HVAC maintenance recordsagainst equipment lists

Collect your existing maintenance andcalibration records and check them againstthe construction documents (e.g., equip-ment lists and mechanical plans). Seewhether all components appear to bereceiving regular attention. Equipment that

PRODUCTS OF THE WALKTHROUGH INSPECTION

At the end of the walkthrough inspection, you should have:

■ List of staff (and contractors) with responsibilities that could affectIAQ, including contact information:

•names, telephone numbers job descriptions

•notes on training and experience of building staff

■ Notes on the schedules and procedures used in:

•facilities operation and maintenance

•housekeeping

•pest control

■ Sketch plan with notes showing:

•pressure relationships between special use areas and surrounding rooms

•locations in which general indicators of IAQ problems showthe need for close monitoring or corrective action


information about normal operatingconditions or identify problem locations.If you begin to suspect that underventila-tion is a consistent problem, you maydecide that it would be helpful to obtainmore ventilation monitoring equipment.(See Appendix A for further discussion ofcarbon dioxide and other ventilationmeasurements.)

Talk with staff and other occupants

A walkthrough inspection provides anopportunity to introduce facility staff andother building occupants to the topic ofindoor air quality and to understand currentstaff (and contractor) responsibilities inrelation to housekeeping and maintenanceactivities. Advance notice of the inspec-tion will make it seem less intrusive andmay encourage staff and other occupants toremember important information.

Discussion of routine activities in thebuilding will help to clarify elements thatshould be included in the IAQ manage-ment plan. Ask staff members about theirjob responsibilities, training and experi-ence. It will be helpful to meet withresponsible staff and contractors todiscuss:

Facility operation and maintenance(e.g., HVAC, plumbing, electric, interiormaintenance)

■ HVAC operating schedule (e.g., occu-pied/unoccupied cycles)

■ HVAC maintenance schedule (e.g., filterchanges, drain pan maintenance)

■ use and storage of chemicals■ schedule of shipping and receiving,

handling of vehicles at loading dock■ scheduling and other procedures for

isolating odors, dust, and emissions frompainting, roof repair, and other contami-nant-producing activities

■ budgeting (i.e., how do staff membersinfluence budget decisions?)

Housekeeping

■ cleaning schedule

■ trash storage and schedule of refuseremoval

■ use and storage of chemicals

Pest control

■ schedule and location of pesticideapplications

■ use and storage of chemicals■ pest control activities other than use of

pesticides

Look for IAQ problem indicators

The walkthrough inspection can be used toidentify areas with a high potential for IAQproblems. The following are generalindicators of IAQ problems:

■ odors■ dirty or unsanitary conditions (e.g.,

excessive dust)■ visible fungal growth or moldy odors

(often associated with problem of toomuch moisture)

■ sanitary conditions at equipment such asdrain pans and cooling towers

Maintenance is more likely tobe performed on a routinebasis when there is goodaccess to HVAC equipmentsuch as that shown in thisphoto.

24 Section 4

Inadequate maintenance: Look for leaksof oil, water, or refrigerants around HVACequipment. Also be aware of signals suchas unreplaced burned-out light bulbs in fanchambers and staff members who havedifficulty locating specific pieces ofequipment. Dry drain traps can also causeindoor air quality problems. If traps arenot kept charged with liquid, they could beallowing sewer gas to enter occupiedspaces.

Signs of occupant discomfort: Noticeuneven temperatures, persistent odors(including tobacco smoke), drafts, sensa-tions of stuffiness. You may find thatoccupants are attempting to compensatefor an HVAC system that doesn’t meettheir needs. Look for propped-opencorridor doors, blocked or taped updiffusers, popped-up ceiling tiles, peopleusing individual fans/ heaters or wearingheavier (or lighter) clothing than normal.

Overcrowding: Future occupant density isestimated when the ventilation system for abuilding is designed. When the actualnumber of occupants approaches orexceeds this occupant design capacity,managers may find that IAQ complaintsincrease. At that point, the outdoor airventilation rate will have to be increased.However, the ventilation and coolingsystems may not have sufficient capacityto handle the increased loads from thecurrent use of the space.

Blocked airflow: Check for under-ventilation caused by obstructed vents,faulty dampers or other HVAC systemmalfunctions, or from problems within theoccupied space. Furniture, papers, or othermaterials can interfere with air movementaround thermostats or block airflow fromwall or floor-mounted registers. If officecubicles are used, a small space (i.e., twoto four inches) between the bottom of thepartitions and the floor may improve aircirculation.

Ceiling plenums: Lift a ceiling tile andexamine the plenum for potential prob-

■ sanitary conditions in equipment such asdrain pans and cooling towers

■ poorly-maintained filters■ signs of mold or moisture damage at

walls (e.g., below windows, at columns,at exterior corners), ceilings, and floors

■ staining and discoloration (Note: Makesure that stains are removed after leaksare repaired so that there will be visibleevidence if the leak recurs.)

■ smoke damage (Note: If a fire hasoccurred involving electrical equipment,determine whether PCBs (polychlori-nated biphenyls) may have been releasedfrom the equipment.)

■ presence of hazardous substances■ potential for soil gas entry (e.g., unsealed

openings to earth, wet earth smells)■ unsanitary mechanical room, or trash or

stored chemicals in mechanical room■ unusual noises from light fixtures or

mechanical equipment

In addition to these general indications,some common problems deserve mention:

Building occupants who areuncomfortable may try toimprove the situation bythemselves. The small fansshown above indicate an aircirculation or thermaldiscomfort problem. The ironyof this situation is that the fanmotors add heat to the air.


lems. Walls or full-height partitions thatextend to the floor above can obstruct ordivert air movement in ceiling plenumsunless transfer grilles have been provided.If fire dampers have been installed toallow air circulation through walls orpartitions, confirm that the dampers areopen. Construction debris and damaged orloose material in the plenum area maybecome covered with dust and can releaseparticles and fibers.

Heat sources: Be aware of areas thatcontain unusual types or quantities ofequipment such as copy machines orcomputer terminals. Also look forinstances of over-illumination. Highconcentrations of electrical fixtures andequipment can overwhelm the ventilationand cooling systems.

Special use areas: Confirm that theHVAC system maintains appropriatepressure relationships to isolate andcontain odors and contaminants in mixed-use buildings and around special use areas.Examples of special use areas includeattached parking garages, loading docks,print shops, smoking lounges, janitorialclosets, storage areas, and kitchens.

Improperly located vents, exhausts andair intakes: Check the outdoor air intakesto see whether they are located nearcontaminant sources (e.g., plumbing vents,exhaust outlets, dumpsters, loading docks,or other locations where vehicles idle).

Unsanitary mechanical rooms: See if thespace containing the HVAC system isclean and dry. Examples of problemsinclude: cleaning or other maintenancesupplies stored in mechanical room; dustand dirt buildup on floors and equipment;moisture in mechanical room because ofinadequate insulation, lack of conditionedair, or failure to provide for air movement.Unsanitary conditions in the mechanicalroom are particularly a problem ifunducted return air is dumped into andcirculated through the mechanical room.

Occupants or staff sometimesopen ceiling tiles into returnplenums when attempting toeliminate odors. Buildingmanagers should be alert tosuch signs of occupantdissatisfaction in order toremedy the original problemand prevent additionalproblems, such as the short-circuiting of supply air.

PRODUCTS OF COLLECTING DETAILED INFORMATION

■ an inventory of HVAC system components that need to berepaired, adjusted, or replaced

■ a current record of control settings and operating schedules■ a floor plan of the building showing airflow directions or

pressure differentials around areas intended to run positive or negative(e.g., special use areas)

■ an inventory of pollutant sources and their locations■ Material Safety Data Sheets for products used or stored within

the building■ a record of usage for each zone or room, including the source of outside

air and the presence of local exhaust (if any)

Collect Detailed Information

The collection of detailed information forthe IAQ profile can be handled as time isavailable. Areas that have been identifiedas presenting potential IAQ problemsshould be given the highest priority. Youmay want to review Section 2 for back-ground information on the factors thatcontribute to indoor air quality.

Inspect HVAC system condition andoperation

Use your current maintenance records incombination with one or both of theHVAC Checklists to inspect HVAC

26 Section 4

equipment and make sure that it is in goodoperating condition. A portion of theHVAC Checklist - Short Form is shownon this page, with the entire form repro-duced in Tab V. The HVAC Checklist -Long Form (also reproduced in Tab V) isrecommended where a more detailedexamination is needed. You may want tocreate a new form incorporating elementsfrom your existing inspection forms.

Identify items of equipment that need tobe repaired, adjusted, or replaced. Recordcontrol settings and operating schedules forHVAC equipment for comparison tooccupancy schedules and current uses ofspace.

Inventory pollutant pathways

Using the sketch plan of the buildingthat was begun during the walkthroughinspection, indicate architectural connec-tions (e.g., chases) and mechanical connec-tions (e.g., ductwork, temperature controlzones). Observe and record airflowbetween spaces intended to run positive ornegative and the areas that surround them(including airflow between perimeterrooms and outdoors). Note that hiddenpathways such as chases may travel bothvertically and horizontally and transportpollutants over long distances. Record theresults on the Pollutant Pathway Recordfor IAQ Profiles, the sketch plan, or both.The form is shown at the left (and in TabV), and a sample sketch plan is shown onthe opposite page.

Inventory pollutant sources

Use the Pollutant and SourceInventory (shown in part on page 28 andreproduced in full in Tab V) to recordpotential pollutant sources in the building.As you fill out the inventory form, note thelocations of major sources. Major sourcessuch as large items of equipment can berecorded on the floor plan. The ChemicalInventory Form (shown on page 28 andreproduced in Tab V) can be used to recordthe names and locations of chemicals orhazardous substances used or stored within

SEECOMPLETEFORMSPAGES 97AND 81

Sample Form

HVAC Checklist — Short Form

Mechanical Room

■ Clean and dry?

(describe items in need of attention)

■ Stored refuse or chemicals?

Mechanical Equipment

■ Preventative maintenance (PM) plan in use?

Control System Type

■ System operation

Building Area Use Intended Pressure Needs (zone, room) Positive Negative Attention? Comments

(+) (-) (Y/N)

Pollutant Pathway Record For IAQ ProfileSample Form

28 Section 4

the building, such as those that may becontained in cleaning materials, biocides,paints, caulks, and adhesives. Ask yoursuppliers to provide you with MaterialSafety Data Sheets.

You may be unaware of the potentialhazards of some materials that are com-monly used in public and commercialbuildings. For example:■ In 1990, EPA eliminated the sale of

mercury-containing interior latex paint.(Enamel paints do not contain mercury.)People are urged not to use exterior latexpaint indoors, as it may contain mercury.If you have paint in storage that mayhave been manufactured before August20, 1990, you may contact the manufac-turer, the National Pesticide Telecommu-nication Network (1-800-858-7378), oryour State Health

Department for guidance.■ In 1990, EPA banned the use of

hexavalent chromium chemicals incooling towers, because the chemicalshave been shown to be carcinogenic.

■ Heating system steam should not be usedin the HVAC humidification system, asit may contain potentially harmfulchemicals such as corrosion inhibitors.

Collect information on building occu-pancy

The Zone/Room Record shown on thefollowing page (and also reproduced inTab V) can be used during IAQ profiledevelopment to maintain an up-to-daterecord of the way each area of the buildingis used, its source of outdoor air, andwhether or not it is equipped with localexhaust. If underventilation is suspected,the form can be used to estimate ventila-tion rates in cubic feet per minute perperson or per square foot floor area, forcomparison to guidelines such as designdocuments, applicable building codes, orthe recommendations of ASHRAE 62-1989 (see the table that is reproduced inAppendix B).

Sample FormPollutant and Source Inventory Form

Using the list of potential source categories below, record anyindications of contamination or suspected pollutants that may requirefurther investigation or treatment.

Source Category Checked Needs Attention Location Comments

SOURCES OUTSIDE THE BUILDING

Contaminated Ambient Air

Pollen, dust

Industrialcontaminants

General vehicularcontaminants

The inventory should include chemicals stored or used in the buildingfor cleaning, maintenance, operations, and pest control. If you have anMSDS (Material Safety Data Sheet) for the chemical, put a check markin the right-hand column. If not, ask the chemical supplier to providethe MSDS, if one is available.

Date Chemical/ Use Storage MSDSBrand Name Location(s) on File?


Sample FormChemical Inventory Form


Underventilation problems can occureven in areas where ventilation ratesapparently meet ASHRAE guidelines;proper distribution and mixing of supplyair with room air are also essential forgood ventilation.

If the information collected as youdevelop the IAQ profile indicates that youhave one or more IAQ problems, Sections6-8 provide guidance to help you deal withthem. If you need to prioritize these prob-lems, consider the apparent seriousness oftheir consequences. For example, combus-tion gas odors demand a more rapidrespons than thermostats that are out ofcalibration.

This form is to be used differently depending on whether the goal is to prevent or diagnose IAQ problems.During development of a profile, this form should be used to record more general information about the entirebuilding; during an investigation, the form should be used to record more detailed information about thecomplaint area and areas surrounding the complaint area or connected to it by pathways.

Zone/Room RecordSample Form


PROFILE AND DIAGNOSIS INFORMATION DIAGNOSIS INFORMATION ONLY

Building Area(Zone/Room)

Use** Source ofOutdoor Air*

MechanicalExhaust?

(Write “No”or estimatecfm airflow)

Comments Total AirSupplied

(in cfm)***

Peak Number ofOccupants or

Sq. Ft. Floor Area**

Outdoor AirSupplied

per Person orper 150 sq.Ft. Area****

Managing Buildings for Good IAQ 31

5Managing Buildings for Good IAQ

■ keep interior of equipment and ductworkclean and dry

Oversee activities of staff, tenants, contrac-tors, and other building occupants thatimpact indoor air quality

■ smoking■ housekeeping■ building maintenance■ shipping and receiving■ pest control■ food preparation and other special uses

Maintain communications with occupantsso that management will be informed ofcomplaints about the indoor environmentin a timely way

■ identify building management and staffwith IAQ responsibilities

■ use health and safety committees

Educate staff, occupants, and contractorsabout their responsibilities in relation toindoor air quality

■ staff training■ lease arrangements■ contracts

Identify aspects of planned projects thatcould affect indoor air quality andmanage projects so that good air qualityis maintained■ redecorating, renovation, or remodeling■ relocation of personnel or functions

within the building■ new construction

DEVELOPING AN IAQMANAGEMENT PLAN

The chart on page 32 shows the elementsof an IAQ management plan. Develop-ment of the management plan involvesreviewing and revising staff responsibili-ties so that IAQ considerations becomeincorporated into routine procedures.

The relationships among buildingowners, management, staff, and occupantsare an important factor in decisions thataffect indoor air quality. The objectives ofthe major players in these relationshipsmay be very different. Occupants want thebuilding to be pleasant, safe, and attractive;if they are paying tenants, they also wantto get the maximum use out of the spacethey rent for the least cost. Buildingowners and management want to maintaina reputation for providing quality propertyat reasonable cost, but also need to derive aprofit. Facility staff are often caught in themiddle, trying to control operating andmaintenance costs while still keepingoccupants satisfied.

Regardless of the points on which theymay disagree, building occupants, staff,and management share the goal of provid-ing a healthy indoor environment. Recog-nition of this common goal may help avoidconflict when discussing IAQ-relatedpolicies.

Any IAQ management system will besuccessful only if it is organized to fit yourspecific building. It would not be appropri-ate for this document to prescribe anysingle approach. However, the skillsassociated with IAQ management activitieswill be identified to help building manage-ment decide who will be best able to carrythem out. Education and training programsfor staff and building occupants should beprovided to ensure that new procedures areunderstood and adopted.

Managing a building for good indoor airquality involves reviewing and amendingcurrent practice (and establishing newprocedures, if necessary) to:

Operate and maintain HVAC equipment

■ keep all equipment and controls in properworking order

IAQ managementsystems will only besuccessful if they areorganized to fit yourspecific building.

32 Section 5

Facilities Operationand Maintenance

Housekeeping

Pest Control

Tenant Relations

RenovationRedecoratingRemodeling

Smoking

Select an IAQ Manager

Review IAQ Profileand Existing Records

Assign StaffResponsibilities/Train Staff

START

FIGURE 5-1: Developing an IAQ Management Plan

Organizations may assign responsibility foroperations, recordkeeping, purchasing,communications, planning, and policy-making in many different ways. However,the key elements of good IAQ managementremain the same:

Reach an understanding of the funda-mental influences that affect indoor airquality in your building by:

■ becoming familiar with literature on IAQ■ keeping abreast of new information

Select an IAQ manager with:

■ clearly defined responsibilities■ adequate authority and resources

Use the IAQ profile and other availableinformation to:

■ evaluate the design, operation, and usageof the building

■ identify potential IAQ problem locations■ identify staff and contractors whose

activities affect indoor air quality

Review and revise staff responsibilities toensure that responsibilities that may affectindoor air quality are clearly assigned. Inaddition, establish lines of communicationfor sharing information pertaining to:

■ equipment in need of repair orreplacement

■ plans to remodel, renovate, or redecorate■ new uses of building space or increases in

occupant population■ installation of new equipment

Review standard procedures and makenecessary revisions to promote goodindoor air quality, such as:

■ terms of contracts (e.g., pest control,leases)

■ scheduling of activities that produce dust,emissions, odors

■ scheduling of equipment operation,inspection, and maintenance

■ specifications for supplies (e.g., cleaningproducts, construction materials, furnish-ings)

■ policy regarding tobacco smoking withinthe building

Review the existing recordkeeping systemand make necessary revisions to:

■ establish a system for logging IAQ-related complaints

■ obtain Material Safety Data Sheets forhazardous materials used and stored in thebuilding

Educate building staff, occupants, andcontractors about their influence onindoor air quality by:

■ establishing a health and safety committee■ instituting training programs as needed

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IAQ problems may occur even inbuildings whose owners and managersconscientiously apply the best availableinformation to avoid such problems.Those who can demonstrate their ongoingefforts to provide a safe indoor environ-ment are in a strong legal and ethicalposition if problems do arise.

Select an IAQ ManagerIAQ management will be facilitated if oneindividual is given overall responsibilityfor IAQ. Whether or not this person isgiven the title of “IAQ Manager,” he orshe should have a good understanding ofthe building’s structure and function andshould be able to communicate withtenants, facility personnel, and buildingowners or their representatives about IAQissues.

The IAQ manager’s ongoing responsi-bilities might include:

■ developing the IAQ profile■ overseeing the adoption of new

procedures■ establishing a system for communicating

with occupants about IAQ issues■ coordinating staff efforts that affect

indoor air quality, and making sure thatstaff have the information (e.g., operat-ing manuals, training) and authority tocarry out their responsibilities

■ reviewing all major projects in thebuilding for their IAQ implications

■ reviewing contracts and negotiating withcontractors (e.g., cleaning services, pestcontrol contractors) whose routineactivities in the building could createIAQ problems

■ periodically inspecting the building forindicators of IAQ problems

■ managing IAQ-related records■ responding to complaints or observations

regarding potential IAQ problems■ conducting an initial walkthrough

investigation of any IAQ complaints

PRODUCTS OF THE REVIEW OF THE IAQ PROFILEAND OTHER EXISTING RECORDS

■ a priority list of locations and activities within the building that willrequire special attention in order to prevent indoor air quality problems

■ a list of staff and contractors whose responsibilities need to beincluded in the IAQ management plan

Review IAQ Profile and OtherExisting Records

If the IAQ manager was not activelyinvolved in developing the IAQ profile,one of the first tasks will be to review theprofile carefully. The manager can start byalso identifying building locations with apotential for IAQ problems, staff andcontractors whose activities impact indoorair quality, and other building occupantswhose activities impact indoor air quality.

In addition to information from the IAQprofile, it may be helpful to review leaseforms and other contractual agreements foran understanding of the respective legalresponsibilities of the building manage-ment, tenants, and contractors. Incorpora-tion of IAQ concerns into legal documentshelps to ensure the use of proper materialsand procedures by contractors and can helpto limit the load placed on ventilationequipment by occupant activities.

Assign Responsibilities/Train Staff

The assignment of responsibilities varieswidely between organizations, dependingupon the routine activities to be carried outand the capabilities of the availablepersonnel. It would not be appropriate forthis document to suggest how IAQ-relatedresponsibilities should be allocated in yourorganization. For example, issues ofaccess in buildings with tenant-occupiedspace highlight the need for cooperationbetween building managers and the

IAQ management willbe facilitated if oneindividual is givenoverall responsibilityfor IAQ.

34 Section 5

Using information from the IAQprofile, the IAQ manager should workwith staff and contractors to ensure thatbuilding operations and planning processesincorporate a concern for indoor airquality. New procedures, recordkeepingrequirements, or staff training programsmay be needed. (Growing interest in IAQis stimulating government agencies andprivate sector organizations to developtraining programs. See Appendix G foradditional information.) The flow ofinformation between the IAQ manager andstaff, occupants, and contractors isparticularly important. Good indoor airquality requires prompt attention tochanging conditions that could cause IAQproblems, such as installation of newequipment or furnishings, increases inoccupant population, or new uses ofrooms.

Facility Operation and Maintenance

Indoor air quality can be affected bothby the quality of maintenance and by thematerials and procedures used in operatingand maintaining the building componentsincluding the HVAC system.

Facility staff who are familiar withbuilding systems in general and with thefeatures of their building in particular arean important resource in preventing andresolving indoor air quality problems.Facility personnel can best respond toindoor air quality concerns if they under-stand how their activities affect indoor airquality. It may be necessary to changeexisting practices or introduce newprocedures in relation to:

Equipment operating schedules: Confirmthat the timing of occupied and unoccu-pied cycles is compatible with actualoccupied periods, and that the building isflushed by the ventilation system beforeoccupants arrive. ASHRAE 62-1989provides guidance on lead and lag timesfor HVAC equipment. In hot, humid

tenants’ office managers. The buildingstaff may be limited in its access to tenantspaces and tenants may not have access tobuilding operations areas such as mechani-cal rooms, yet both tenants and buildingmanagement have responsibilities formaintaining good indoor air quality.

Facility personnel are not generallytrained to think about IAQ issues as theygo about their work. Even though buildingstaff may be observing events and condi-tions that would indicate potential prob-lems to an experienced IAQ investigator,the staff member’s attention may bedirected elsewhere. As new practices areintroduced to prevent indoor air qualityproblems, an organized system ofrecordkeeping will help those practices tobecome part of routine operations and to“flag” decisions that could affect IAQ(e.g., renovations, new tenants). The bestresults can be achieved by taking time tothink about the established channels ofcommunication within your organization,so that new forms can be integrated intodecisionmaking with minimum disruptionof normal procedures.

A clean mechanical room,free of tracked-in dirt andstored chemicals, is animportant element in theprevention of indoor airquality problems. Airbornecontaminants in themechanical room can bedrawn into ductwork throughreturn air openings orunsealed seams in returnducts and circulatedthroughout the building.


climates, ventilation may be needed duringlong unoccupied periods to prevent moldgrowth.

Control of odors and contaminants:Maintain appropriate pressure relationshipsbetween building usage areas. Avoidrecirculating air from areas that are strongsources of contaminants (e.g., smokinglounges, chemical storage areas, beautysalons). Provide adequate local exhaustfor activities that produce odors, dust, orcontaminants, or confine those activities tolocations that are maintained undernegative pressure (relative to adjacentareas). For example, loading docks are afrequent source of combustion odors.Maintain the rooms surrounding loadingdocks under positive pressure to preventvehicle exhaust from being drawn into thebuilding. Make sure that paints, solvents,and other chemicals are stored and handledproperly, with adequate (direct exhaust)ventilation provided. If local filter trapsand adsorbents are used, they requireregular maintenance. Have vendorsprovide Material Safety Data Sheets(MSDSs).

Ventilation quantities: Compare outdoorair quantities to the building design goaland local and State building codes andmake adjustments as necessary. It is alsoinformative to see how your ventilationrate compares to ASHRAE 62-1989,because that guideline was developed withthe goal of preventing IAQ problems.(Note: Increasing ventilation quantities tomeet ASHRAE guidelines may exceed thecapacity of HVAC equipment to conditionthe air.)

HVAC equipment maintenance sched-ules: Inspect all equipment regularly (perrecommended maintenance schedule) toensure that it is in good condition and isoperating as designed (i.e., as close to thedesign setpoints for controls as possible).Most equipment manufacturers providerecommended maintenance schedules for

their products. Components that areexposed to water (e.g., drainage pans,coils, cooling towers, and humidifiers)require scrupulous maintenance to preventmicrobiological growth and the entry ofundesired microbiologicals or chemicalsinto the indoor airstream.

HVAC inspections: Modify the HVACChecklists (reproduced in Tab V) asnecessary so that they are appropriate forinspection of the specific equipment inyour building. Be thorough in conductingthese inspections. Items such as smallexhaust fans may operate independentlyfrom the rest of the HVAC system and areoften ignored during inspections. Asequipment is added, removed, or replaced,document any changes in function,capacity, or operating schedule for futurereference. It may also be helpful to storeequipment manuals and records of equip-ment operation and maintenance in thesame location as records of occupantcomplaints for easy comparison if IAQproblems arise.

Building maintenance schedules: Tryto schedule maintenance activities thatinterfere with HVAC operation or produceodors and emissions (e.g., painting, roofingoperations) so that they occur when thebuilding is unoccupied. Inform occupantswhen such activities are scheduled and, ifpossible, use local ventilation to ensurethat dust and odors are confined to thework area.

Purchasing: Review the general informa-tion provided by MSDS and requestinformation from suppliers about thechemical emissions of materials beingconsidered for purchase.

Note: At present there is no generalsystem for certifying or labeling low-emission products nor is there a standardprocedure for building managers to use ingathering emissions data on products theyare considering for purchase. Limitedinformation on some materials such as

Be thorough inconducting HVACinspections. Itemssuch as small exhaustfans may operateindependently fromthe rest of the systemand are often ignoredduring inspections.

36 Section 5

pressed-wood products is available, andmore may be expected in the future.Public and private sector organizations areworking to develop product testingprocedures for acceptance by such organi-zations as the American Society forTesting and Materials (ASTM).

Preventive maintenance management:Maintenance “indicators” are available tohelp facility staff determine when routinemaintenance is required. For example, airfilters are often neglected (sometimes dueto reasons such as difficult access) and failto receive maintenance at proper intervals.Installation of an inexpensive manometer,an instrument used to monitor the pressureloss across a filter bank, can give animmediate indication of filter conditionwithout having to open the unit to visuallyobserve the actual filter.

Computerized systems are available thatcan prompt your staff to carry out mainte-nance activities at the proper intervals.Some of these programs can be connectedto building equipment so that a signal istransmitted to your staff if a piece ofequipment malfunctions. Individual areascan be monitored for temperature, airmovement, humidity, and carbon dioxide,and new sensors are constantly entering themarket. These sensors can be programmedto record data and to control multipleelements of the HVAC system.

Housekeeping

Indoor air quality complaints can arisefrom inadequate housekeeping that fails toremove dust and other dirt. On the otherhand, cleaning materials themselvesproduce odors and emit a variety ofchemicals.

As they work throughout your building,cleaning staff or contractors may be thefirst to recognize and respond to potentialIAQ problems. Educate them about topicssuch as the following:

PREVENTIVE MAINTENANCEAn HVAC system requires adequate preventive maintenance (PM) andprompt attention to repairs in order to operate correctly and providesuitable comfort conditions and good indoor air quality. The HVACsystem operator(s) must have an adequate understanding of the overallsystem design, its intended function, and its limitations. The preventivemaintenance program must be properly budgeted and implemented, notmerely planned on paper. A well-implemented PM plan will improve the functioning of themechanical systems and usually save money when evaluated on a life-cycle basis. However, in some buildings, because of budgetaryconstraints, maintenance is put off until breakdowns occur or complaintsarise, following the “if it isn’t broken, don’t fix it” philosophy. This type ofprogram represents a false economy and often increases the eventualcost of repairs. Poor filter maintenance is a common example of this phenomenon.Filters that are not changed regularly can become a bed for fungalgrowth, sometimes allowing particles or microorganisms to be distrib-uted within the building. When filters become clogged, the fans usemore energy to operate and move less air. If the filters are an inexpen-sive, low-efficiency type that becomes clogged and then “blows out,” thecoils then accumulate dirt, causing another increase in energy con-sumption. Poor air filter efficiency and poor maintenance may causedirt to build up in ducts and become contaminated with molds, possiblyrequiring an expensive duct cleaning operation.

General elements of a PM plan include:■ periodic inspection, cleaning, and service as warranted■ adjustment and calibration of control system components■ maintenance equipment and replacement parts that are of good

quality and properly selected for the intended function

Critical HVAC system components that require PM in order tomaintain comfort and deliver adequate ventilation air include:■ outdoor air intake opening■ damper controls■ air filters■ drip pans■ cooling and heating coils■ fan belts■ humidification equipment and controls■ distribution systems■ exhaust fans Some private sector organizations have developed guidance onpreventive maintenance. (See discussion in Guidelines of CareDeveloped by Trade Associations on page 43.)


A good preventive maintenance programcan help a facility manager identify andcorrect problems before they occur. If thisfan belt breaks, the area served by the airhandling unit may be without ventilation. Ifit is slipping, it is already reducing theairflow.

A termiticide misapplication resulted in anindoor air quality problem in this school.Detectable levels of chlordane were foundin both wipe (surface) and air samples nearthe injection holes drilled into the groundfloor. Note the small white circles near thewall. (Under an agreement with EPA,manufacturers have withdrawn chlordanefrom sale.) Proper application methods areimportant for all pesticides.

Cleaning schedules: Consider howcleaning activities are scheduled. Manag-ers may want to schedule the use of somecleaning agents that introduce strong odorsor contaminants during unoccupiedperiods. However, make sure that fumesfrom cleaning products are eliminatedbefore air handling systems switch to their“unoccupied” cycles.

Purchasing: Become more familiar withthe chemicals in cleaning and maintenanceproducts and their potential toxicity.Select the safest available materials thatcan achieve your purpose. Review theinformation provided by product labelsand Material Safety Data Sheets. Requestinformation from suppliers about thechemical emissions of products beingconsidered for purchase.

Material handling and storage: Reviewthe use of cleaning materials to ensureproper use and storage.

Trash disposal: Follow proper trashdisposal procedures. If there is a restau-rant in the building, require daily pick-upof perishable refuse. Ensure that thecontainers are covered, pest control iseffective, and that the trash collection areais cleaned at least daily.

Shipping and Receiving

Shipping and receiving areas can createindoor air quality problems regardless ofthe types of materials being handled.Vehicle exhaust fumes can be minimizedby prohibiting idling at the loading dock.This is particularly important if the loadingdock is located upwind of outdoor airintake vents. You can also reduce draftsand pollutant entry by pressurizing interiorspaces (e.g., corridors) and by keepingdoors closed when they are not in use.

38 Section 5

INTEGRATED PEST MANAGEMENT

Integrated Pest Management (IPM) is a coordinated approach to pestcontrol intended to prevent unacceptable levels of pests, while causingthe least possible hazard to people, property, and the environment andusing the most cost-effective means. IPM uses a combination of tactics,including sanitation, monitoring, habitat modification, and the judiciousapplication of pesticides when absolutely necessary.

IPM methods include:

■ improved sanitation (e.g., removing food from desks, cleaning)■ inspection and monitoring of pest population sites■ managing waste (e.g., keeping refuse in tight containers, locating

waste containers away from building if possible)■ maintaining structures (e.g., fixing leaking pipes promptly,sealing cracks)■ adding physical barriers to pest entry and movement (e.g.,screens for chimneys, doors, and windows; air curtains)■ modifying habitats (e.g., removing clutter, relocating outside light

fixtures away from doors)■ using traps (e.g., light traps, snap traps, and glue boards)■ using pesticides judiciously

An efficient IPM program will integrate pest management planningwith preventive maintenance, housekeeping practices, landscaping,occupant education, and staff training.

Pest Control

Pest control activities that depend uponthe use of pesticides involve the storage,handling, and application of materials thatcan have serious health effects. Commonconstruction, maintenance practices, andoccupant activities provide pests with air,moisture, food, warmth, and shelter.Caulking or plastering cracks, crevices, orholes to prevent harborage behind wallscan often be more effective than pesticideapplication at reducing pest populations toa practical minimum.

Integrated Pest Management (IPM) is alow-cost approach to pest control basedupon knowledge of the biology andbehavior of pests. Adoption of an IPMprogram can significantly reduce the needfor pesticides by eliminating conditionsthat provide attractive habitats for pests.

If an outside contractor is used for pestcontrol, it is advisable to review the termsof the contract and include IPM principleswhere possible. The following itemsdeserve particular attention.

Pest control schedule: Schedule pesticideapplications for unoccupied periods, ifpossible, so that the affected area can beflushed with ventilation air before occu-pants return. Pesticides should only beapplied in targeted locations, with mini-mum treatment of exposed surfaces. Theyshould be used in strict conformance withmanufacturers’ instructions and EPAlabels. General periodic spraying may notbe necessary. If occupants are to bepresent, they should be notified prior to thepesticide application. Particularly suscep-tible individuals could develop seriousillness even though they are only mini-mally exposed.

Materials selection, handling, andstorage: Select pesticides that are speciesspecific and attempt to minimize toxicityfor humans and non-target species. Askcontractors or vendors to provide EPAlabels and MSDSs. Make sure thatpesticides are stored and handled properlyconsistent with their EPA labels.

Ventilation of areas where pesticides areapplied: If only limited areas of thebuilding are being treated, adjust theHVAC system so that it does not distributecontaminated air throughout the rest of thebuilding. Consider using temporaryexhaust systems to remove contaminantsduring the work. It may be necessary tomodify HVAC system operation duringand after pest control activities (e.g.,running air handling units on 100%outdoor air for some period of time orrunning the system for several complete airexchanges before occupants re-enter thetreated space).


Possible Uses

■ MSDSs may identify significantairborne contaminants

■ may suggest precautions forconducting source inspection

■ generally presents types of healtheffects that may be expected primarilyat high level (e.g., industrial)exposures

■ odor description may help identifysources

■ volatility may suggest which productsare likely to be airborne

■ contaminants to expect in event of afire or decomposition may be listed

■ reactivity data may suggest potentialproblems with storage or use

■ identifies proper storage and packagingprocedures

■ identifies steps for cleanup of grossspills

Under OSHA regulations, responsible parties are required to document information onpotentially hazardous products. These Material Safety Data Sheets (MSDSs) may be oflimited help in identifying some products that may pose IAQ concerns. However, profes-sional judgment and collection of additional information may be necessary in order to makefull use of the MSDS. The following table summarizes some of the issues to keep in mindwhen deciding whether information from MSDSs is applicable to emission sources andexposures of concern in a building.

MATERIAL SAFETYDATA SHEETS

Item

Substances Covered

Personal Protection/First Aid

Health Effects

Physical Data

Control Measures

Comments

■ MSDSs may not be available onsite for manyproducts

■ some components are listed as proprietaryand are not disclosed

■ MSDSs do not always highlight productsmost likely to be airborne

■ contaminant byproducts inadvertentlyformed during manufacture won't always belisted

■ usually relates only to high-level, worst-caseexposures in general industry

■ symptoms listed may not occur at low-levelconcentrations found in indoor air

■ MSDSs may not include more subtle IAQaspects such as nuisance factors andsensitivity to mixtures

■ reference material on how to use physicaldata information to predict IAQ impactsmay be scarce

■ many office chemicals are kept in muchsmaller amounts than found in industrialsettings

■ spill cleanup may not eliminate airbornecontamination

■ does not specify routine emission controls

A reasonable effort should be made to collect available MSDSs during IAQ profile develop-ment. Care should be taken to consider information that is relevant to IAQ concerns. Otherimportant indicators of how a particular product may affect IAQ are available from direct odorand dust observations, a review of work practices and interviews with operators and occu-pants. The manufacturer is a good source of follow-up information on a given product (phonenumber should be included on each MSDS).

40 Section 5

Close monitoring of renovation,redecorating, and remodeling projects isrecommended. The following suggestionsmay be helpful:

Working with professional consultants:Communicate your concern about prevent-ing indoor air quality problems to theengineer, architect, interior designer, orother professionals involved in the project.

Product selection: Specify products andprocesses that minimize odors and emis-sions, while maintaining adequate safetyand efficacy. Review the general informa-tion provided by the product labels andMSDSs. Request information fromsuppliers about the chemical emissions ofproducts being considered for purchase.

Work schedules: Schedule activities thatproduce dust, odors, or emissions forunoccupied periods if possible.

Isolation of work areas: Block off returnregisters so that contaminants are notrecirculated from the demolition/construc-tion area into adjoining areas, and installtemporary barriers to confine dust andnoise. If possible, install temporary localexhaust to remove odors and contaminants,and check to confirm that the temporaryventilation system is operating as planned.

Installation of new furnishings: Asksuppliers to store new furnishings in aclean, dry, ventilated location so thatvolatile organic compounds will be emittedbefore installation. Minimize the use ofadhesives during installation or specifylow-emitting products. After new furnish-ings are installed, increase the ventilationrate to flush the area with outdoor air anddilute emissions.

Smoking

Although there are many potentialsources of indoor air pollution, bothresearch and field studies have shown thatenvironmental tobacco smoke (ETS) is oneof the most widespread and harmful indoorair pollutants. Environmental tobaccosmoke is a combination of sidestream

Occupant Relations

Managing occupant relations to preventIAQ problems involves: allocating spaceand monitoring the use of building areas toisolate odor- and contaminant-producingactivities and avoid re-entrainment; estab-lishing a communication strategy that isresponsive to complaints and providestenants with information about their role inpreventing indoor air quality problems;and modifying employee manuals or leaseagreements as necessary to clarify theresponsibilities of occupants and buildingmanagement. A health and safety commit-tee or joint tenant-management IAQ taskforce that represents all of the major inter-est groups in the building can be veryhelpful in disseminating information andfostering a cooperative approach to IAQmanagement. See Section 3 for a discus-sion of these points.

Renovation, Redecorating, andRemodeling

Renovation, redecorating, and re-modeling activities can create indoor airproblems by producing dust, odors, micro-biologicals and their spores, and emissions.It is difficult to prevent IAQ problems ifsome building areas are undergoing reno-vation while adjoining areas continuenormal operations.

It is important for buildingoccupants to understand thattheir activities can createindoor air quality problems.Smoking releases bothcarcinogenic and irritatingsubstances into the air.


Smoking areas must be separatelyventilated, negatively pressurized inrelation to surrounding interior spaces, andsupplied with much more ventilation thannon-smoking areas. The NIOSH Bulletinalso recommends that the air from thesmoking area should be exhausted directlyoutdoors and not recirculated within thebuilding or vented with the general exhaustfor the building. ASHRAE Standard 62-1989 recommends that smoking areas besupplied with 60 cubic feet per minute (60cfm) per occupant of outdoor air; thestandard also recognized that using transferair, which is pulled in from other parts ofthe building, to meet the standard iscommon practice.

Both EPA and NIOSH advise thatbuilding owners or facility managersconsidering the introduction of smokingrestrictions should implement smokingcessation programs. In addition, employ-ees and labor unions should be involved inthe development of non-smoking policiesin the workplace.

(Refer to Appendix G for citations on allthe publications mentioned in this section.See especially NIOSH Current IntelligenceBulletin (#54), Environmental TobaccoSmoke in the Workplace: Lung Cancerand Other Health Effects. Additionalresources on ETS, including an assessmentof respiratory disorders in children andlung cancer risks in adults, and a guide todeveloping effective smoking policies, willbe available from EPA early in 1992.)

PRODUCTS OF THE ASSIGNMENT OFRESPONSIBILITIES AND REVIEW OF TRAINING

■ job descriptions and/or contracts, work procedures, and schedulesrevised to reflect indoor air quality concerns

■ procedures for reviewing purchases of supplies, new projects,contracts, and policies in relation to indoor air quality

■ smoking policy revisions, if necessary

■ plans for educating occupants and training staff training in relation toindoor air quality

smoke from the burning end of thecigarette, pipe, or cigar and the exhaledmainstream smoke from the smoker. ETScontains over 4,000 chemicals; 43 ofwhich are known animal or humancarcinogens. Many other chemicals inETS are tumor promoters, tumor initiators,co-carcinogens (i.e., chemicals that areable to cause cancer when combined withanother substance), or cancer precursors(i.e., compounds that can make it easier toform other carcinogenic chemicals).

In 1986, The Health Consequences ofInvoluntary Smoking: A Report of theSurgeon General on EnvironmentalTobacco Smoke concluded that ETS was acause of lung cancer in healthy non-smokers and that “the scientific caseagainst involuntary smoking as a publichealth risk is more than sufficient to justifyappropriate remedial action, and the goalof any remedial action must be to protectthe non-smoker from environmentaltobacco smoke.” In the same year, theNational Research Council of the NationalAcademy of Sciences issued a report,Environmental Tobacco Smoke: Measur-ing Exposures and Assessing HealthEffects, which also concluded that passivesmoking increases the risk of lung cancerin adults.

In June 1991, NIOSH issued a CurrentIntelligence Bulletin (#54) on ETS in theworkplace that dealt with lung cancer andother health effects. In its Bulletin,NIOSH concluded that the weight ofevidence is sufficient to conclude that ETScan cause lung cancer in non-smokers (i.e.,those who inhale ETS). It recommendedthat the preferable method to protect non-smokers is the elimination of smokingindoors and that the alternative method isto require that smoking be permitted onlyin separately ventilated smoking areas.The NIOSH Bulletin emphasized thatprovision of such isolated areas should beviewed as an interim measure until ETScan be completely eliminated indoors.

According to a 1986report of the SurgeonGeneral, “the caseagainst involuntarysmoking is more thansufficient to justifyappropriate remedialaction to protect thenon-smoker fromenvironmental to-bacco smoke.”

42 Section 5

Sample FormManagement Checklist

Item

Date Begunor Completed(as applicable)

Responsible Person(name, telephone)

Location("NA" if the item is not

applicable to this building)

IAQ PROFILE

Collect and ReviewExisting Records

HVAC design data, operating instructionsand manuals

HVAC maintenance and calibrationrecords, testing and balancing reports

Inventory of locations whereoccupancy, equipment, or buildinguse has changed

Inventory of complaint locations

Conduct a WalkthroughInspection of the Building

List of responsible staff and/orcontractors, evidence of training,and job descriptions

Identification of areas where positive ornegative pressure should be maintained


The IAQ Management Checklist shownin part here and included in full within TabV can be used to help confirm that youhave accounted for the major factors thatcould cause IAQ problems in yourbuilding.


The following associations have developed guidelines of care that may have a direct orindirect impact on indoor air quality. These standards are described below so thatbuilding management may become aware of them. Neither EPA nor NIOSH endorsethese standards.

GUIDELINES OFCARE DEVELOPEDBY TRADEASSOCIATIONS

Technical Reference Bulletin Series. Indoor air quality is one of the topics coveredin this series of technical bulletins on heating, ventilation and air conditioning(HVAC). Bulletins can be filed in the ACCA Technical Reference Notebook. The AirSide Design tab of the notebook includes bulletins devoted to indoor air qualitycontrol.

Air Conditioning and Refrigeration Equipment General Maintenance Guidelines forImproving the Indoor Environment (1991). General maintenance requirements forheating ventilation, air conditioning,and refrigeration (HVACR) equipment.Specific equipment/component maintenance is given for the following: air cleaningsystems; ducts; registers/diffusers and air terminals; dampers/economizers; drain pans;air handlers; humidifiers; package terminal units; and evaporator, condenser, hydronicand economizer coils. The guidelines do not supersede any maintenance instructionsthat are provided by the manufacturer. In addition, the Institute has issued an Indoor AirQuality Briefing Paper that addresses the interactions between HVACR equipment andthe quality of indoor air.

National Standards for Testing and Balancing Heating,Ventilation, and Air ConditioningSystems (1989). Establishes a minimum set of field testing and balancing standards andprovides comprehensive and current data on testing and balancing HVAC systems.Chapters receiving special attention include Cooling Tower Performance Tests, SoundMeasurements, Vibration Measurements, Fume Hoods, and AABC General Specifica-tions. The book contains a complete index to the technical data provided.

Procedural Standards for Testing, Adjusting, and Balancing of Environmental Systems(1991). A “how-to” set of procedural standards that provide systematic methods fortesting, adjusting, and balancing (TAB) of HVAC systems. Includes sections on TABinstruments and calibration, report forms, sample specifications, and engineering tablesand charts. A valuable innovation is the “Systems Ready to Balance” start-up checklistto help organize jobs systematically. Other features include: additional engineering data,condensed duct design tables/charts, hydronic design tables/charts, and pertinent HVACequations in U.S. and metric units.

Good Practice Statements. Periodically updated, officially approved and adopted by theAssociation’s Board of Directors, these “Good Practice Statements” are designed asguidelines for performing various services rather than standards of operation. Inaddition, the Association produces a self-study series for technicians that covers fiveareas of pest control, management manuals, an encyclopedia of structural pest control,a number of specific subject matter technical reference manuals, and a pamphlet series.

HVAC Duct Construction Standards — Metal and Flexible (1985). Primarily for commer-cial and institutional work, this set of construction standards is a collection of materialfrom earlier editions of SMACNA’s low-pressure, high-pressure, flexible duct, and ductliner standards. In addition, SMACNA has published a manual entitled Indoor Air Qualitythat contains basic information on many aspects of indoor air quality and guidance onconducting building evaluations and indoor air quality audits. Other related SMACNApublications include HVAC Duct Systems Inspection Guide, HVAC Systems—Testing,Adjusting and Balancing, and HVACAir Duct Leakage Test Manual.

Air ConditioningContractors ofAmerica(ACCA)

Air Conditioning andRefrigeration Insti-tute (ARI)

Associated AirBalance Council(AABC)

NationalEnvironmentalBalancing Bureau(NEBB)

National Pest ControlAssociation(NPCA)

Sheet Metal andAir ConditioningContractors’ NationalAssociation(SMACNA)

. .

RESOLVING IAQ PROBLEMS

Diagnosing IAQ Problems 45

Yes

Diagnosing IAQ Problems

The goal of the diagnostic buildinginvestigation is to identify and solve theindoor air quality complaint in a way thatprevents it from recurring and that does notcreate other problems. This sectiondescribes a method for discovering thecause of the complaint and presents a“toolbox” of diagnostic activities to assistyou in collecting information.

Just as a carpenter uses only the toolsthat are needed for any given job, an IAQinvestigator should use only the investiga-tive techniques that are needed. Manyindoor air quality complaints can beresolved without using all of the diagnostictools described in this chapter. Forexample, it may be easy to identify thesource of cooking odors that are annoyingnearby office workers and solve theproblem by controlling pressure relation-ships (e.g., installing exhaust fans) in thefood preparation area. Similarly, mostmechanical or carpentry problems prob-ably require only a few of the many toolsyou have available and are easily accom-plished with in-house expertise.

The use of in-house personnel buildsskills that will be helpful in minimizingand resolving future problems. On theother hand, some jobs may be best handledby contractors who have specializedknowledge and experience. In the sameway, diagnosing some indoor air qualityproblems may require equipment and skillsthat are complex and unfamiliar. Yourknowledge of your organization andbuilding operations will help in selectingthe right tools and deciding whether in-house personnel or outside professionalsshould be used in responding to thespecific IAQ problem.

6Start (reason for concern)

Initial walkthrough■ preparation■ visual inspection■ talk with occupants and staff

Collect additionalinformation about■ building occupants■ the HVAC system■ pollutant pathways■ pollutant sources

(sample contaminants if needed)

Develop one or more hypothesesto explain the problem. Test bymanipulating building conditionsor exposure, or by performingappropriate tests.

Is theproblemsolved ?

Make necessarychanges so thatthe problem willnot recur.

Finish

Yes

No

No

No Yes

▼

▼

▼

▼

▼

▼

▼

▼

Note: Outside assistance may be needed at anypoint in the investigation, depending upon thecomplexity of the problem, the skills available in-house, time pressures, or other factors.

FIGURE 6-1:Conducting an IAQ Investigation

Do you havean explanation

for the complaint ?

Do resultssupport yourhypothesis ?

Attempta controlstrategy

▼

Follow-upvalidation

46 Section 6

OVERVIEW: CONDUCTING ANIAQ INVESTIGATION

An IAQ investigation begins with one ormore reasons for concern, such as occu-pant complaints. Some complaints can beresolved very simply (e.g., by asking a fewcommon sense questions of occupants andfacility staff during the walkthrough). Atthe other extreme, some problems couldrequire detailed testing by an experiencedIAQ professional. In this section “theinvestigator” refers to in-house staffresponsible for conducting the IAQinvestigation.

The flowchart on page 45 shows thatthe IAQ investigation is a cycle of infor-mation-gathering, hypothesis formation,and hypothesis testing. The goal of theinvestigation is to understand the IAQproblem well enough so that you can solveit. Many IAQ problems have more thanone cause and may respond to (or require)several corrective actions.

Initial Walkthrough

An initial walkthrough of the problem areaprovides information about all four of thebasic factors influencing indoor air quality(occupants, HVAC system, pollutantpathways, and contaminant sources). Theinitial walkthrough may provide enoughinformation to resolve the problem. At theleast, it will direct further investigation.For example, if the complaint concerns anodor from an easily-identified source (e.g.,cooking odors from a kitchen), you maywant to study pollutant pathways as a nextstep, rather than interviewing occupantsabout their patterns of discomfort.

Developing and TestingHypotheses

As you develop an understanding of howthe building functions, where pollutantsources are located, and how pollutantsmove within the building, you may thinkof many “hypotheses,” potential explana-

tions of the IAQ complaint. Buildingoccupants and operating staff are often agood source of ideas about the causes ofthe problem. For example, they candescribe changes in the building that mayhave occurred shortly before the IAQproblem was noticed (e.g., relocatedpartitions, new furniture or equipment).

Hypothesis development is a processof identifying and narrowing downpossibilities by comparing them with yourobservations. Whenever a hypothesissuggests itself, it is reasonable to pauseand consider it. Is the hypothesisconsistent with the facts collected so far?

You may be able to test your hypothesisby modifying the HVAC system orattempting to control the potential sourceor pollutant pathway to see whether youcan relieve the symptoms or other condi-tions in the building. If your hypothesissuccessfully predicts the results of yourmanipulations, then you may be ready totake corrective action. Sometimes it isdifficult or impossible to manipulate thefactors you think are causing the IAQproblem; in that case, you may be able totest the hypothesis by trying to predict howbuilding conditions will change over time(e.g., in response to extreme outdoortemperatures).

Collecting AdditionalInformation

If your hypothesis does not seem to be agood predictor of what is happening in thebuilding, you probably need to collectmore information about the occupants,HVAC system, pollutant pathways, orcontaminant sources. Under somecircumstances, detailed or sophisticatedmeasurements of pollutant concentrationsor ventilation quantities may be required.Outside assistance may be needed ifrepeated efforts fail to produce a successfulhypothesis or if the information requiredcalls for instruments and procedures thatare not available in-house.

The IAQ investigationis often a repetitivecycle of information-gathering, hypothesisformation, andhypothesis testing.


Results of the Investigation

Analysis of the information collectedduring your IAQ investigation couldproduce any of the following results:

The apparent cause(s) of the complaint(s)are identified.

Remedial action and follow-up evaluationwill confirm whether the hypothesis iscorrect.

Other IAQ problems are identified thatare not related to the original complaints.

These problems (e.g., HVAC malfunc-tions, strong pollutant sources) should becorrected when appropriate.

A better understanding of potential IAQproblems is needed in order to develop aplan for corrective action.

It may be necessary to collect moredetailed information and/or to expand thescope of the investigation to includebuilding areas that were previouslyoverlooked. Outside assistance may beneeded.

The cause of the original complaintcannot be identified.

A thorough investigation has found nodeficiencies in HVAC design or operationor in the control of pollutant sources, andthere have been no further complaints. Inthe absence of new complaints, the originalcomplaint may have been due to a single,unrepeated event or to causes not directlyrelated to IAQ.

Using Outside Assistance

Some indoor air quality problems may bedifficult or impossible for in-houseinvestigators to resolve. Special skills orinstruments may be needed. Other factorscan also be important, such as the benefitof having an impartial outside opinion orthe need to reduce potential liability from a

serious IAQ problem. You are best able tomake the judgment of when to bring in anoutside consultant. See Section 8 for adiscussion of hiring professional assistanceto solve an IAQ problem.

INITIAL WALKTHROUGH

An investigation may require one or manyvisits to the complaint area. The amountof preparatory work needed before theinitial walkthrough varies with the natureand scope of the complaint and theexpertise of the investigator, among otherfactors. For example, an in-house investi-gator who is already familiar with thelayout and mechanical system in thebuilding may begin responding to acomplaint about discomfort by goingdirectly to the complaint area to check thethermostat setting and see whether air isflowing from the supply outlets.

If the investigator is not familiar withthe building or is responding to complaintsthat suggest a serious health problem, morepreparation may be needed before theinitial walkthrough. The activities listedbelow can be directed at a localized“problem area” or extended to include theentire building:

Collect easily-available information aboutthe history of the building and of thecomplaints.

Identify known HVAC zones and com-plaint areas.

Begin to identify potential sources andpollutants (e.g., special use areas near thecomplaint location). Having a copy ofmechanical and floor plans can be helpfulat this stage, especially if they arereasonably up-to-date.

Notify the building occupants of theupcoming investigation.

Tell them what it means and what toexpect.

48 Section 6

to describe the operating schedule ofequipment. Obvious problems (e.g.,blocked diffusers, malfunctioning airhandlers) can be corrected to see if thecomplaints disappear. The walkthroughcan solve many routine IAQ problems andwill suggest directions for a more complexinvestigation, should one be necessary.

Some investigators avoid taking anymeasurements during the initial walk-through so that they are not distracted from“getting the big picture.” Others find thatusing smoke sticks, digital thermometers,and direct reading CO

2 meters or detector

tubes to take occasional measurementshelps them develop a feel for the building.

It may help to keep the followingquestions in mind during the initialwalkthrough:

Are there obvious pollutant sources? Dothey appear to be adequately controlled?

■ Are pollutant indicators present, such asodors, excessive dust, or staining?

■ Are there sanitation problems (e.g.,debris near outdoor air intake, visiblemold growth, major water damage) thatcould be introducing air contaminants?

■ Are there any conditions or activitiesoccurring in or near the building thatcould be related in timing, location andhealth effects to the complaints?

Are there any deficiencies in the HVACsystem that serves the complaint area?

■ Does equipment serving the area (e.g.,thermostats, diffusers, fans, dampers,filters) appear to be operating, clean, andin good condition?

■ Do operating procedures exist, and doesthe staff follow them?

■ Do records indicate that the system wascommissioned (set, tested, and balanced)after construction?

■ Do records indicate that system compo-nents are regularly inspected, calibrated,and adjusted?

This improvised catch basinis intended to collect waterseeping into the building frombelow grade. Although thecatch basin “solves” the prob-lem of uncontrolled waterleakage, it also provides anindoor location that couldsupport the growth ofmicrobiologicals and createIAQ problems.

Identify key individuals needed for accessand information.

A person familiar with the HVAC systemsin the building should be available to assistthe investigator at any time during theonsite phase. Individuals who havecomplained or who are in charge ofpotential sources (e.g., housekeeping, non-HVAC equipment) should be aware thattheir information is important and shouldbe contacted for appointments or telephoneinterviews if they will not be availableduring the onsite visit.

The initial walkthrough provides anopportunity to question complainants aboutthe nature and timing of their symptomsand to briefly examine the immediate areaof the complaint. The investigatorattempts to identify pollutant sources andtypes and observes the condition andlayout of the HVAC system serving thecomplaint area. Facility staff can be asked


Are there pathways and pressure differ-ences which could be moving contami-nants into the complaint area from theoutdoors or from other parts of thebuilding?

COLLECTING ADDITIONALINFORMATION

Additional information will be needed ifthe initial walkthrough does not identifythe cause of the problem. The followingpages present techniques for collectinginformation about the occupant com-plaints, HVAC system, pollutant pathways,and pollutant sources and using thatinformation to develop a hypothesis thatcould explain the problem. Common sensewill suggest the appropriate sequence ofsteps during this part of the investigation.For example, if the complaint is limited toa single room, it makes sense to evaluatepollutant pathways into that room beforeattempting to inventory sources in loca-tions outside of, but connected to, thecomplaint area. On the other hand, if thecomplaint involves a recognizable odor(e.g., exhaust fumes), it may be morepractical to begin by locating the potentialsource(s) of the odor before trying toidentify pollutant pathways.

Forms and checklists such as thesamples provided in this document (modi-fied if needed) can help investigators torecord information in an organized way.Small copies of basic floor plans, such asfire evacuation plans, are convenient fornoting locations of observations.

Any instruments that will be usedshould be inspected to make sure they arein working order and calibrated. IAQinvestigations generally include the use of,at a minimum: heatless chemical smokedevices and instruments for measuringtemperature and humidity.

Carbon dioxide measuring devices(detector tubes with a hand pump or adirect reading meter) are helpful for mostinvestigations. Other instruments may beneeded as the investigation progresses.See Appendix A for additional guidance oncommon IAQ measurements.

Tools for Collecting Information

The following pages present strategies,tools, and forms for the investigator to useduring an in-depth investigation. TheIncident Log shown below (and in Tab V)can be used to track the course of an inves-tigation from the receipt of the originalcomplaint.

Sample FormIncident Log


DateFileNumber

Outcome /Comments

Log Entry By(initials)

Problem Location


50 Section 6

buildings. They are intended to present aproblem-solving approach that can helpfacility staff to understand and resolvemany common indoor air quality prob-lems. If you decide to hire outsideprofessionals to resolve your IAQ com-plaint, this discussion of strategies andtools should help you to understand andoversee their investigative work.

COLLECTING INFORMATIONABOUT OCCUPANTCOMPLAINTS

Occupant data falls into two categories:complaints of discomfort or other symp-toms (e.g., teary eyes, chills) and percep-tions of building conditions (e.g., odors,draftiness). Investigators can gathervaluable information about potentialindoor air problems from listening tooccupants, and use that information for:

■ defining the complaint area within thebuilding

■ suggesting directions for further investi-gation, either by identifying other eventsthat seem to happen at the same time asthe incidents of symptoms or discomfort,or by identifying possible causes for thetypes of symptoms or discomfort that areoccurring

■ indicating potential measures to reduceor eliminate the problem

Review Existing Records ofComplaints

If there is a record of occupant complaints,a review of that record can help to definethe location of the IAQ problem andidentify people who should be interviewedas part of the investigation. Informationabout the history of complaints could alsostimulate theories about potential causes ofthe problem.

Interview Occupants

The most obvious way to collect informa-tion from building occupants is to talk to

COLLECTING OCCUPANT INFORMATION

Strategies Tools

Review existinginformation aboutcomplaints

Collect additionalinformation fromoccupants

■ Existing Records■ IAQ Complaint Form■ Incident Log

■ Occupant Interview■ Occupant Diary

An initial walkthrough mayuncover problems such asthis unsanitary condition inthe HVAC system. Birddroppings have collected inan air supply plenum near anoutdoor air intake that wasnot protected by a birdscreen.

The discussion that follows has beendivided into categories of occupant data,HVAC system data, pollutant pathwaydata, and source data. However, thesuggestions for collecting and usinginformation reflect the interdependence ofthese factors. For example, the operationof the air distribution system affectspollutant pathways, and the air distributionsystem can also be a source of pollutants.

Indoor air quality-related complaintsmay develop from a variety of causes.Neither the discussion of strategies forcollecting information nor the suggestionsfor interpreting data can present the fullrange of possible situations encountered in


Sample FormOccupant Interview


them in person. If it is not possible tointerview everyone who has complainedabout building conditions, the investigatorshould attempt to interview a group ofindividuals that reflect the concerns of theaffected areas.

The investigation may also includeoccupant interviews with building occu-pants who do not have complaints. Thenconditions in the complaint area can becompared to conditions in similar buildinglocations where there are no complaints.

A sample Occupant Interview form isshown here (there is another copy inTab V). It can also be presented in awritten form in order to get informationfrom more people than can be interviewed.The following key points will helpinterviews to be productive:

■ Read the discussion of evaluatingoccupant data before you conductinterviews, to be certain that youunderstand what sort of information isneeded.

■ Make a copy of the interview form foreach person you speak with, and use theform to record the answers to yourquestions.

■ Choose a location in which the personyou are interviewing feels comfortable tospeak freely.

■ Explain that the interview is intended tohelp discover and correct the cause of thecomplaints. Encourage the person youare interviewing to join in this coopera-tive problem-solving effort.

■ Give the person you are interviewingenough time to think about your ques-tions.

■ If complainants are reluctant to answerquestions about health symptoms,respect their desire for privacy. Planningfor how to maintain this privacy iswarranted, and in some cases may bemandated.

■ Feel free to expand the interview byadding questions that help to improveyour understanding or explore their

hypotheses (or your own) about whatmay be causing the problem. Always beopen to answers that may not fit yourhypotheses.

■ You may sometimes need to clarify aquestion by giving examples of the sortof information you are interested in. Tryto provide more than one example so thatyou don’t seem to be telling the personthe answer you want. Be particularlycautious about mentioning specifichealth effects.

The Occupant Interview includesmany basic points that are found inquestionnaires used by professional IAQinvestigators. It is important to note,however, that this form is not called a“questionnaire.” Formal questionnairesmay be useful for quantitative epidemiol-ogy, IAQ research, complex IAQ investi-gations, or when litigation is a possibility.In these cases, questionnaires must becarefully designed and executed by peoplewith an understanding of representativesampling and expertise in public health,industrial hygiene, or medicine. Use ofquestionnaires for such purposes is beyondthe scope or expertise of most in-houseinvestigations; if such questionnaire data is

SYMPTOM PATTERNSWhat kind of symptoms or discomfort are you experiencing?

Are you aware of other people with similar symptoms or concerns?Yes____ No____

If so, what are their names and locations?

Do you have any health conditions that may make you particularlysusceptible to environmental problems?

TIMING PATTERNSWhen did your symptoms start?

52 Section 6

On the form below, please record each occasion when you experiencea symptom of ill-health or discomfort that you think may be related toan environmental condition in the building.

Sample FormOccupant Diary

Time/Date Location Symptom Severity/Duration Comments

Sample FormLog of Activities and System Operations

On the form below, please record your observations of HVAC systemoperation, maintenance activities, and any other information that youthink may be helpful in identifying the cause of IAQ complaints in thisbuilding. Please report any other observations (e.g., weather, otherassociated events) that you think may be important as well.

Equipment and activities of particular interest:Air Handler(s):Exhaust Fan(s):Other Equipment or Activities:

Date/Time Day of Week Equipment Item/Activity Comments


needed, building owners and managersshould use professionals.

Ask Occupants and FacilityStaff to Keep More DetailedRecords

Many events occur simultaneously in andaround a complex building, and it can bevery difficult to judge which of thoseevents might be related to the IAQcomplaints. In trying to resolve stubbornproblems, professional investigatorssometimes ask occupants and facility staffto keep day-by-day records. Occupants areasked to record the date and time ofsymptoms, where they are when thesymptoms appear, and any other informa-tion that might be useful. Such informa-tion could include observations about theseverity and duration of symptoms andcomments on weather conditions, events,and activities that are happening at thesame time. Facility staff are asked torecord the date and time of events such asmaintenance work, equipment cycles, ordeliveries. If symptoms seem to occur atparticular times of day, staff can focustheir attentions on recording events thatoccur before and during those periods.Such records are likely to produce moreaccurate and detailed information than canbe obtained by relying on memory. (Usethe Occupant Diary and the Log ofActivities and System Operations shownhere and included in Tab V.)


Exhaust fumes are drawn intothis building’s outdoor airintake when trucks are idlingat the nearby loading dock.Tools such as the OccupantDiary and Log of Activitiesand System Operation canhelp to identify intermittentpollutant sources such as thisone.

USING THE OCCUPANT DATA

The pattern of complaints within thebuilding helps to define the complaint area.The timing of symptoms and the types ofsymptoms reported may provide cluesabout the cause of the problem.

Strategies for Using Occupant Data

■ Define the complaint area■ Look for timing patterns■ Look for symptom patterns

54 Section 6

SPATIAL PATTERNS

Widespread, no apparent spatialpattern

Localized (e.g., affecting indi-vidual rooms, zones, orair handling systems)

Individual(s)

SUGGESTIONS

■ Check ventilation and tem-perature control for entirebuilding.

■ Check outdoor air quality.■ Review sources that are spread

throughout building (e.g.,cleaning materials).

■ Consider explanation other thanair contaminants.

■ Check ventilation and tempera-ture control within the complaintarea.

■ Review pollutant sourcesaffecting the complaint area.

■ Check local HVAC systemcomponents that may be actingas sources or distributors ofpollutants.

■ Check for drafts, radiant heat(gain or loss), and otherlocalized temperature control orventilation problems near theaffected individual(s).

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

■ Consider that common back-ground sources may affect onlysusceptible individuals.

■ Consider the possibility thatindividual complaints may havedifferent causes that are notnecessarily related to thebuilding (particularly if symp-toms differ among the individu-als).

Define the Complaint Area

Use the spatial pattern (locations) ofcomplaints to define the complaint area.Building locations where symptoms ordiscomfort occur define the rooms or zonesthat should be given particular attentionduring the initial investigation. However,the complaint area may need to be revisedas the investigation progresses. Pollutantpathways can cause occupant complaintsin parts of the building that are farremoved from the source of the problems.


Look for Timing Patterns

Look for patterns in the timing of com-plaints. The timing of symptoms andcomplaints can indicate potential causesfor the complaints and provide directionsfor further investigation. Review the datafor cyclic patterns of symptoms (e.g.,worst during periods of minimum ventila-tion or when specific sources are mostactive) that may be related to HVACsystem operation or to other activities inand around the building.

TIMING PATTERNS SUGGESTIONS

■ Review HVAC operating cycles.Emissions from buildingmaterials, or from the HVACsystem itself, may build upduring unoccupied periods.

■ Consider that ventilation maynot be adequate to handleroutine activities or equipmentoperation within the building.

■ Look for daily, weekly, orseasonal cycles or weather-related patterns, and checklinkage to other events in andaround the building.

■ Consider spills, otherunrepeated events as sources.

■ Ask staff and occupants todescribe recent changes orevents (e.g., remodeling,renovation, redecorating, HVACsystem adjustments, leaks, orspills).

■ Consider that the problem islikely to be building-related,though not necessarily due to airquality. Other stressors (e.g.,lighting, noise) may be involved.

■ Consider that the problem maynot be building-related.

Symptoms begin and/orare worst at the start ofthe occupied period

Symptoms worsen overcourse of occupied period

Intermittent symptoms

Single event of symptoms

Recent onset of symptoms

Symptoms relieved on leaving thebuilding, either immediately,overnight, or (in some cases) afterextended periods away from thebuilding

Symptoms never relieved,even after extended absence frombuilding (e.g., vacations)

56 Section 6

which toxicology has found specificeffects. Therefore, it may be more usefulto look for patterns of symptoms thanfor specific pollutant and health effectrelationships.

Investigators who are not medicallytrained cannot make a diagnosis and shouldnot attempt to interpret medical records.Also, confidentiality of medical informa-tion is protected by law in some jurisdic-tions and is a prudent practice everywhere.

Look for Symptom Patterns

Look for patterns in the types of symptomsor discomfort. IAQ investigations oftenfail to prove that any particular pollutantor group of pollutants are the cause of theproblem. Such causal relationships areextremely difficult to establish. There islittle information available about the healtheffects of many chemicals. Typical indoorlevels are much lower than the levels at

The following chart lists somecommon symptom groupsthat can be related to indoorair quality, along with possiblesources or causes of thosesymptoms. Buildingmanagers are cautioned thatthis is only a partial listing.

SYMPTOM PATTERNS

THERMAL DISCOMFORT

COMMON SYMPTOM GROUPSHeadache, lethargy, nausea,drowsiness, dizziness

Congestion; swelling, itching orirritation of eyes, nose, orthroat; dry throat; may beaccompanied by non-specificsymptoms (e.g. headache,fatigue, nausea)

Cough; shortness of breath;fever, chills and/or fatigue afterreturn to the building

Diagnosed infection

Suspected cluster of rare orserious health problems suchas cancer, miscarriages

OTHER STRESSORSDiscomfort and/or healthcomplaints that cannot bereadily ascribed to air contami-nants or thermal conditions

SUGGESTIONS

■ Check HVAC condition and operation.■ Measure indoor and outdoor temperature and humidity (see Figure 6-2 on

page 57). See if extreme conditions exceed design capacity of HVAC equip-ment.

■ Check for drafts and stagnant areas.■ Check for excessive radiant heat gain or loss.

If onset was acute, arrange for medical evaluation, as the problem may be carbonmonoxide poisoning.■ Check combustion sources for uncontrolled emissions or spillage. Check

outdoor air intakes for nearby sources of combustion fumes.■ Consider evacuation/medical evaluation if problem isn’t corrected quickly.■ Consider other pollutant sources.■ Check overall ventilation; see if areas of poor ventilation coincide with com-

plaints.

May be allergic, if only small number affected; more likely to be irritationalresponse if large number are affected.■ Urge medical attention for allergies.■ Check for dust or gross microbial contamination due to sanitation problems,

water damage, contaminated ventilation system.■ Check outdoor allergen levels (e.g., pollen counts).■ Check closely for sources of irritating chemicals such as formaldehyde or those

found in some solvents.

May be hypersensitivity pneumonitis or humidifier fever. A medical evaluationcan help identify possible causes.■ Check for gross microbial contamination due to sanitation problems, water

damage, or contaminated HVAC system.

May be Legionnaire’s disease or histoplasmosis, related to bacteria or fungi foundin the environment.■ Contact your local or State Health Department for guidance.

■ Contact your local or State Health Department for guidance.

■ Check for problems with environmental, ergonomic, and job-relatedpsychosocial stressors.


FIGURE 6-2: Acceptable Ranges of Temperature and RelativeHumidity During Summer and Winter 1

Relative Humidity Winter Temperature Summer Temperature

30% 68.5°F - 76.0°F 74.0°F - 80.0°F

40% 68.5°F - 75.5°F 73.5°F - 79.5°F

50%2 68.5°F - 74.5°F 73.0°F - 79.0°F

60% 68.0°F - 74.0°F 72.5°F - 78.0°F

1 Applies for persons clothed in typical summer and winter clothing, at light,mainly sedentary activity.2 See left for discussion of relative humidities.

SOURCE: Adapted from ASHRAE Standard 55-1981, Thermal EnvironmentalConditions for Human Occupancy

Figure 6-2 shows the range of tempera-tures and relative humidities that fallwithin the comfort zone for most individu-als dressed in “typical” clothing andinvolved in light, mostly sedentaryactivity. Recent research suggests thatindoor air quality is judged to be worse astemperatures rise above 76°F, regardless ofthe actual air quality.

There is considerable debate amongresearchers, IAQ professionals, and healthprofessionals concerning recommendedlevels of relative humidity. In general, therange of humidity levels recommended bydifferent organizations seems to be 30% to60%. Relative humidities below thislevel may produce discomfort fromdryness. On the other hand, maintainingrelative humidities at the lowest possiblelevel helps to restrict the growth of moldand mildew. The concerns (comfort forthe most part) associated with dry air mustbe balanced against the risks (enhancedmicrobiological growth) associated withhumidification. If temperatures aremaintained at the lower end of the comfortrange (68 - 70°F) during heating periods,relative humidity in most climates will notfall much below 30% (also within thecomfort range) in occupied buildings.

COLLECTING INFORMATIONABOUT THE HVAC SYSTEM

IAQ complaints often arise because thequantity or distribution of outdoor air isinadequate to serve the ventilation needs ofbuilding occupants. Problems may also betraced to air distribution systems that areintroducing outdoor contaminants ortransporting pollutants within the building.

The investigation should begin with thecomponents of the HVAC system(s) thatserve the complaint area and surroundingrooms, but may need to expand if connec-tions to other areas are discovered. Yourgoal is to understand the design andoperation of the HVAC system well

enough to answer the following questions:

■ Are the components that serve theimmediate complaint area functioningproperly?

■ Is the HVAC system adequate for thecurrent use of the building?

■ Are there ventilation (or thermal com-fort) deficiencies?

■ Should the definition of the complaintarea be expanded based upon the HVAClayout and operating characteristics?

An evaluation of the HVAC systemmay include limited measurements oftemperature, humidity, air flow, and CO

2,

as well as smoke tube observations.Complex investigations may require moreextensive or sophisticated measurements ofthe same variables (e.g., repeated CO

2

measurements taken at the same locationunder different operating conditions,continuous temperature and relativehumidity measurements recorded with adata logger). A detailed engineering studymay be needed if the investigation discov-ers problems such as the following:

■ airflows are low■ HVAC controls are not working or are

working according to inappropriatestrategies

■ building operators do not understand (orare unfamiliar with) the HVAC system

WHAT DO YOUKNOW SO FAR?

■ Use the HypothesisForm on page 223 tomake brief notes afterreviewing the occupantdata.

■ Decide whether youhave a hypothesis thatmight explain thecomplaints. If so, test it.(See page 78 for adiscussion ofhypothesis testing.

■ Decide what else youneed to know.Consider whetherin-house expertise issufficient or outsideassistance is needed(See Section 8 forguidance on hiringoutside assistance.)

58 Section 6

COLLECTING HVAC SYSTEM INFORMATION

Strategies

Review existing documen-tation on HVAC design,installation, and operation

Talk to facilities staff

Inspect system layout,condition, and operation

Use additional instrumentsas appropriate

Tools

Collect:■ design documents, testing and

balancing reports■ operating instructions, control

manufacturer’s installation data

Ask facilities staff to record their observa-tions of equipment cycles, weatherconditions, and other events usingLog of Activities and System Operations

Use:■ Zone/Room Record■ HVAC Checklist - Short Form and/or■ HVAC Checklist - Long Form■ thermometer and sling psychrometer

(or electronic equivalent) to measuretemperature and humidity

■ micromanometer (or equivalent) tomeasure pressure differentials● 0-2" and 0-10" water gauge (w.g.)

to measure at fans and intakes

● 0-.25" w.g. with pitot tube to checkairflow in ducts

■ chemical smoke for observing airflowpatterns

■ a device to assess airflow fromdiffusers● rough quantitative: anemometer;

velometer● accurate quantitative: flow hood

■ carbon dioxide measurement devices● detector tubes with a hand pump● direct reading meter

Instruments often used by professionalIAQ consultants include:■ a hygrothermograph to log temperature

and humidity■ tracer gas and measurement equip-

ment■ a device to measure airborne particu-

lates■ measurement devices for carbon

monoxide and other contaminantsof interest

Review Documentation onHVAC Design, Installation, andOperation

A review of existing documentation (e.g.,plans, specifications, testing and balancingreports) should provide information aboutthe original design and later modifications,particularly:■ the type of HVAC system (e.g., constant

volume, VAV)■ locations and capacities of HVAC

equipment serving the complaint area■ the planned use of each building area■ supply, return, and exhaust air quantities■ location of the outdoor air intake and of

the supply, return, and exhaust registers,diffusers, and grilles that serve thecomplaint area

The most useful way to record thisinformation is to make a floor plan of thecomplaint area and surrounding rooms.You may be able to copy an existing floorplan from architectural or mechanicaldrawings, fire evacuation plans, or someother source.

If there is no documentation on themechanical system design, much more on-site inspection will be required to under-stand the HVAC system. The HVACsystem may have been installed ormodified without being commissioned,so that it may never have performedaccording to design. In such cases, goodobservations of airflow and pressuredifferentials are essential. In addition, loadanalyses may be required.

Talk to Facility Staff

Facility staff can provide important currentinformation about equipment operating andmaintenance schedules and breakdowns orother incidents. There may be inspectionreports or other written records availablefor review. Staff members who arefamiliar with building systems in generaland with the specific features of the


building under investigation can be veryhelpful in identifying conditions that mayexplain the indoor air quality complaints.Some facility operators have extensivepreventive maintenance programs. On theother hand, discussion could reveal thatfacility staff are not operating the buildingaccording to its design, because:■ they do not understand the design logic

of the HVAC system■ they have been asked to run the HVAC

system at the lowest possible energy cost■ they do not have the manpower to

operate the building properly■ the HVAC system has not been modified

to accommodate changes in the use ofspace or increases in the occupantpopulation

Staff may have noticed occupantactivities that are indicators of inadequateventilation or poorly-controlled tempera-tures, such as:■ desktop fans, heaters, or humidifiers■ supply diffusers blocked off with tape or

cardboard■ popped-up ceiling tiles■ interference with thermostat settings

IAQ complaints are often intermittent.Discussions with staff may reveal patternsthat relate the timing of complaints to thecycles of equipment operation or to otherevents in the building such as painting,installation of new carpeting, or pestcontrol. These patterns are not necessarilyobvious. Keeping a day-to-day record mayhelp to clarify subtle relationships betweenoccupant symptoms, equipment operation,and activities in and around the building.(See Occupant Diary and Log of Activi-ties and System Operations on page 52and in Tab V.) Staff members may havetheories about the cause ofthe problem.

Inspect System Layout,Condition, and Operation

If the building is new or if there is a pre-ventive maintenance program with recent

Above: An investigation of this buildingrevealed no problems with the HVAC sys-tem, although the amount of outdoor air wasvery low. In a more thorough inspection ofthe HVAC system, investigators found thatthe wiring to this outdoor air damper motorhad never been connected. No outdoor airwas entering the building through the intakecontrolled by this damper. Below: Theseinvestigators are examining a perimeter fan-coil unit. Self-contained heating or coolingunits such as this one are often overlookedduring routine maintenance. There may bemany such units in a single building, some-times in remote or inaccessible locations.

60 Section 6

test and balance reports, it is possible (butnot necessarily likely) that the HVACsystem is functioning according to itsoriginal design. Otherwise it is probablethat one or more features of building usageor system operation have changed in waysthat could affect indoor air quality.

Elements of the on-site investigationcan include (but are not limited to) thefollowing:

Check temperature and/or humidity to seewhether the complaint area is in the com-fort range.

Take more than one measurement to ac-count for variability over time and fromplace to place. Compare to Figure 6-2 onpage 57 (see also Appendix B ).

■ Check thermostat operation.■ Check whether the supply air tempera-

ture corresponds to the design criteria.■ Use a hygrothermograph (if available) to

log temperature and humidity changes inthe complaint area.

The design specifications forthis building called for a mini-mum 20% setting on theoutdoor air damper control.Facility staff lowered theminimum outdoor air settingto 10% in order to save en-ergy and reduce operatingcosts. As a result, the build-ing was underventilatedwhenever outdoor tempera-tures were either very hot orvery cold.

Check for indicators of inadequateventilation.

■ Check supply diffusers to see if air ismoving (using chemical smoke). If it isnot, confirm that the fan system is operat-ing, and then look for closed dampers,clogged filters, or signs of leaks.

■ Compare design air quantities (if avail-able) to building codes for the currentoccupancy or ventilation guidelines (e.g.,ASHRAE 62-1989, see Appendix B). Ifthe HVAC system, performing as de-signed, would not provide enough venti-lation air for current needs, then there isgood reason to believe that actual ventila-tion rates are inadequate.

■ Measure carbon dioxide (CO2) in the

complaint area to see whether it indicatesventilation problems. (See Appendix Afor a discussion of techniques for measur-ing and interpreting CO

2 concentrations.)

■ Measure air quantities supplied to andexhausted from the complaint area, in-cluding calculation of outdoor air quanti-ties (see Appendix A for further guid-ance). Be aware of damper settings andequipment cycles when you are measur-ing (e.g., are you evaluating minimumoutdoor air, “normal” conditions, ormaximum airflow?). Note that evalua-tion of variable air volume (VAV) sys-tems requires considerable expertise.Compare the measured air quantities toyour mechanical system design specifica-tions and applicable building codes. Alsocompare ventilation rates to ASHRAE62-1989. Some of the ventilation recom-mendations of ASHRAE 62-1989 arereproduced in Appendix B.

Check that equipment serving the com-plaint area (e.g., grilles, diffusers, fans) isoperating properly.

■ Confirm the accuracy of reported operat-ing schedules and controls sequences; forexample, power outages may have dis-rupted time clocks, fans reported as“always running” may have been acci-dentally switched off, and controls can bein need of calibration.


The dark streaks at theoutlet of this supply diffusercould indicate a filtration prob-lem. Poorly maintained or im-properly sized filterscan allow dirt to be distrib-utedthrough the building.

■ Check to see that equipment is properlyinstalled. For example, look for shippingscrews that were never removed or fansthat were reversed during installation, sothat they move air in the wrong direc-tion.

Compare the current system to theoriginal design.

■ Check to see that all equipment calledfor in the original design was actuallyinstalled.

■ See whether original equipment mayhave been replaced by a different model(i.e., a model with less capacity or differ-ent operating characteristics).

See whether the layout of air supplies,returns, and exhausts promotes efficientair distribution to all occupants and iso-lates or dilutes contaminants.

(See Appendix A for guidance on usingchemical smoke to study airflow and mix-ing patterns and CO

2 to help determine the

adequacy of ventilation.)

■ If supplies and returns are close together,heatless chemical smoke can be used tocheck for short-circuiting (supply air thatdoes not mix properly with air in thebreathing zone, but moves directly to thereturn grille). CO

2 can also be used to

evaluate air mixing.■ Use heatless chemical smoke to observe

airflow patterns within the complaintarea and between the complaint area andsurrounding spaces, including outdoors.Compare airflow directions under vari-ous operating conditions.

■ If the system layout includes ceilingplenums, look above the ceiling for inter-ruptions such as walls or full-heightpartitions.

Consider whether the HVAC system itselfmay be a source of contaminants.

■ Check for deterioration or unsanitaryconditions (e.g., corrosion, water damageor standing water, mold growth or exces-

sive dust in ductwork, debris or damagedbuilding materials in ceiling plenums).

■ If the mechanical room serves as a mix-ing plenum (i.e., return and outdoor airare drawn through the room into the airhandler), check very carefully for poten-tial contaminants such as stored solventsand deteriorated insulation.

Use the forms provided in this documentto inspect the HVAC system.

■ Use the Zone/Room Record to describethe ventilation system serving the com-plaint area and surrounding rooms orzones. The Zone/Room Record isreproduced on page 62 and in Tab V.

■ Use the HVAC Checklist (short and/orlong form) to evaluate the condition ofHVAC system components that affect airdistribution and IAQ in the complaintarea. A portion of the HVAC Checklist-Short Form is reproduced on page 62.The HVAC Checklist - Long Form isuseful for more detailed examination ofthe system. Complete copies of bothforms can be found in Tab V.

62 Section 6

This form is to be used differently depending on whether the goal is to prevent or diagnose IAQ problems.During development of a profile, this form should be used to record more general information about the entirebuilding; during an investigation, the form should be used to record more detailed information about thecomplaint area and areas surrounding the complaint area or connected to it by pathways.

Zone/Room RecordSample Form




MechanicalExhaust?


Comments Peak Number ofOccupants or

Sq. Ft. Floor Area*

Total AirSupplied(in cfm)**

Outdoor AirSupplied

per Person orper 150 sq.Ft. Area****

Sample Form

HVAC Checklist — Short Form

Sections 2, 4 and 6 and Appendix B discuss the relationships between theHVAC system and indoor air quality.

MECHANICAL ROOM

■ Clean and dry? Stored refuse or chemicals?

■ Describe items in need of attention

MAJOR MECHANICAL EQUIPMENT

■ Preventive maintenance (PM) plan in use?

Control System

Type

System operation

USING THE HVAC SYSTEMDATA

As you review the HVAC data, considerwhether the system is adequate to servethe use of the building and whether thetiming, location, and impact of apparentdeficiencies appear related to the IAQcomplaint. Deficiencies in HVACdesign, operation, or maintenance mayexist without producing the complaintunder investigation; some defects maynot cause any apparent IAQ problems.

Strategies for Using the HVACSystem Data

■ Compare the original design to thecurrent system.

■ Compare the original uses of space tocurrent uses.

■ Consider the condition of the HVACsystem.



HEALTH AND SAFETY CONSIDERATIONS FORIAQ INVESTIGATORS

Normal safety precautions observed during routine operation of the building must befollowed closely during IAQ inspections. When the IAQ investigator is not familiar withthe mechanical equipment in that particular facility, an operator or engineer should bepresent at all times in equipment areas. Potential safety hazards include:

■ electrocution■ injury from contacting fans, belts, dampers or slamming doors■ burns from steam or hot water lines■ falls in ventilation shafts or from ladders or roofs

Investigators evaluating building IAQ generally do not encounter situations in whichspecific personal protection measures (e.g., protective garments and respirators) arerequired. However, safety shoes and eyeglasses are generally recommended forworking around mechanical equipment. When severe contamination is present (e.g.,microbiological, chemical, or asbestos), IAQ investigators may need additionalprotection in the vicinity of certain building areas or equipment. Such decisions aresite specific and should be made in consultation with an experienced industrialhygienist. General considerations include the following:

Microbiological: Care must be taken when serious building related illness (e.g.,Legionnaire’s disease) is under investigation or when extensive microbiological growthhas occurred. Investigators with allergy problems should be especially cautious. Thearray of potential contaminants makes it difficult to know what sort of personal protec-tion will be effective. At a minimum, investigators should minimize their exposure to airin the interior of ducts or other HVAC equipment unless respiratory protection is used.If there is reason to suspect biological contamination (e.g., visible mold growth), expertadvice should be obtained about the kind of respiratory protection to use and how touse it. Possible protective measures against severe microbiological contaminationinclude disposable coveralls and properly fitted respirators.

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

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

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

When the IAQ investi-gator is not familiarwith the mechanicalequipment in thatparticular facility, anoperator or engineershould be present atall times in equip-ment areas.

64 Section 6

Compare the Original Design tothe Current HVAC System

Consider the original HVAC design andcompare it to the current equipment,layout, and controls. A variety of HVACsystem designs have been used in publicand commercial buildings. The type ofsystem used in your building affects thecontrol of ventilation air quantities anddistribution, as well as thermal comfort.See Appendix B for a discussion of HVACsystem types.

SUGGESTIONS

■ Revise definition of complaint area (ifneeded) to add spaces linked to theoriginal complaint area by ductwork orcontrols.

■ Check to see that thermostatsare properly located and functionproperly.

■ Note equipment changes thatcould be affecting the system’sperformance (e.g., removal or additionof equipment, replacement by a differ-ent model).

■ Review operating procedures for oc-cupied and unoccupied periods.

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

ALL SYSTEMS

Ventilation andtemperaturecontrol zones

Changes inequipment

Operatingcycles


Use HVAC Data to EvaluateMitigation Measures

As you use the HVAC data to evaluatepotential mitigation measures, review thesuggestions made in both the box on thefacing page for all HVAC systems and inthe box on this page for the type of HVACsystem in your building.

SUGGESTIONS

■ Identify the source(s) of ventilation air(e.g., operable windows, doorspropped open).

■ Check whether the location of openwindows, doors, or other openingspromotes the introduction of odors orcontaminants.

■ Check whether outdoor air intakes areobstructed. Does their location pro-mote the introduction of odors or con-taminants?

■ Note design airflows in the complaintarea (outdoor air, supply, return, andexhaust) and surrounding spaces;compare to ASHRAE 62-1989 and to actual measuredairflows.

■ Note design airflows in the complaintarea (outdoor air, supply, return, andexhaust) and surrounding spaces;compare to applicable building codes,ASHRAE 62-1989, and to actual mea-sured airflows.

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

■ Check outdoor air damper controls.

In addition to all suggestions made forconstant volume systems:

■ Confirm whether the system design al-lows regulation of outdoor air quanti-ties. Do VAV boxes have stops to en-sure that minimum amounts of out-door air are delivered at all times dur-ing occupied periods? Are the systemcontrols providing a constant ventila-tion rate per person regardless of totalsystem airflows?

■ Observe changes (if any) in airflowpatterns within and around the com-plaint area as the VAV systemthrottles from maximum tominimum flow.

SYSTEM TYPES

No mechanicalventilation orexhaust only

Room units(e.g., unitventilators)

Constantvolume

Variableair volume(VAV)

66 Section 6

Compare the Original Uses ofSpace to Current Uses

Compare the original uses of the complaintarea and surrounding rooms to currentuses of those areas. Indoor air qualityproblems often arise when the usage ofrooms changes without correspondingadjustments to the HVAC system. Forexample, if ventilation appears to be aproblem despite a properly-functioningHVAC system, the existing system maybe inadequate to meet current needs.

SUGGESTIONS

■ Compare temperature and humidity tocomfort zone in ASHRAE 55-1981guidelines.

■ Compare minimum outdoor airquantities to the original design,applicable building codes, andASHRAE 62-1989 guidelines.

For example introduction of a morephysically active group of occupants canchange thermal comfort requirements.


■ Compare minimum outdoor airquantities to the original design,applicable building codes, andASHRAE 62-1989 guidelines.

■ Check for low-level contaminantsources.


■ Consider the need for local exhaust atpoint sources of contaminants.

Example: Modifications that convert oradd such special uses as smokinglounges, print shops, or kitchen facilitiesmay also require changes in theoperation of the HVAC system.

■ Check pressure relationships betweenspecial use areas and surroundingspaces.

■ Consider the need for local exhaust atpoint sources of contaminants.

■ Check that thermostats are properlylocated. Compare temperature andhumidity to comfort zone in ASHRAE55-1981 guidelines.

■ Check layout of supplies, returns, andexhausts.

■ Check to make sure that partitions donot block proper air circulation.

ROOM USE CHANGES

Increased occupantdensity

Change in type of occu-pant population

Additional non-HVACequipment

Conversion to or additionof special uses

Rearrangement of workstations (e.g., relocation ofpartitions)


SYSTEM CONDITIONS

Unsanitary conditions■ Moisture or standing water■ Debris■ Dust and/or mold growth

HVAC malfunctions■ Equipment breakdown■ Obstructed diffusers or grilles■ Air distribution or mixing problems:

(e.g., equipment isout of balance, requirescalibration, or needs other adjust-ment)

■ Air bypasses filters (due toloose filter tracks, incorrect filtersize, or filter overloaded with dirt)

■ Air distribution system leaks (e.g.,leaky ductwork; unin-tendedopenings in pressurized ceilings orin return air plenums)

HVAC functions properly.However, there is evidence ofunderventilation.

SUGGESTIONS

■ Correct sanitary problems andadopt necessary measures toprevent recurrence of problems.

■ Evaluate whether the HVACdefect could have caused theIAQ complaint.

■ Correct the malfunction(s), andsee whether complaints areresolved.

■ Review maintenance programand revise as needed to preventfuture problems.

■ Consider what adjustmentscould be made to increase thesupply of outdoor air (ordecrease the ventilationdemand) in the complaint area.

Consider the Condition of theHVAC System

Consider whether the HVAC system isreasonably clean and functioning properly.Review the results of the onsite inspection.If you identified sanitary or operatingproblems in the HVAC system serving thecomplaint area, you may want to correctthose problems and see whether thecomplaints are resolved before continuingwith the investigation.


■ Use the HypothesisForm on page 223 tomake brief notes.

■ Decide whether youhave a hypothesisthat might explain thecomplaints. If so, testit. (See page 78 for adiscussion of hypoth-esis testing.)

■ Decide what else youneed to know.Consider whether in-house expertise issufficient or outsideassistance is needed(See Section 8 forguidance on hiringoutside assistance.)

68 Section 6

COLLECTING INFORMATIONABOUT POLLUTANT PATHWAYSAND DRIVING FORCES

Unless the IAQ problem is caused by anobvious contaminant located in thecomplainant’s immediate workspace, youwill need to understand the patterns ofairflow into and within the complaint area.Correction of IAQ problems often involvescontrolling pollutant movement throughsealing of pollutant pathways or manipula-tion of the pressure relationships.

If the complaints being investigated arelimited to a few areas of the building, pollut-ant pathways can be evaluated so that thecomplaint area is properly defined beforeconducting the source inventory. If com-plaints are spread throughout the building,

evaluation of pathways could be a verytime-consuming process, and it may bemore practical to look for major contami-nant sources before trying to discover howthe contaminants move within the building.

Identify Pollutant Pathways

Architectural and mechanical pathwaysallow pollutants to enter the complaint areafrom surrounding spaces, including theoutdoors. An examination of architecturaland mechanical plans can help in develop-ing a list of connections to surroundingareas. These include:

■ doors■ operable windows■ stairways■ elevator shafts■ utility chases■ ductwork and plenums■ areas served by common HVAC controls

(e.g., shared thermostats)

Onsite inspection is needed to confirmthe existence of these connections and toidentify other openings (e.g., accidentalopenings such as cracks and holes). Firecodes usually require that chases and hid-den openings be firestopped. Check for theexistence and condition of firestops inchases, especially those that connect bothvertically and horizontally.

Chemical smoke is beingused to detect the directionand amount of airflow throughthis closed doorway. Abuilding investigator mustknow how the ventilation inthe building is designed tooperate in order to decidewhether the observed flow ofsmoke is appropriate.

Identify pollutantpathways

Observe directionof air movement

■ Architectural and mechanicaldrawings

■ Pollutant Pathway Form for Investigations■ Sketch plan of complaint area

■ Testing and balancing reports■ Chemical smoke tests■ Micromanometer or equivalent

COLLECTING PATHWAY INFORMATION

Strategies Tools


Building Name File Number

Address:

Completed By (name):

The Pollutant Pathway Form forInvestigations shown to the right can beused along with a sketch plan of thecomplaint area (similar to the example onpage 70) to record pathways and directionsof pollutant movement. A blank copy ofthe form is included in Tab V.

Observe Air MovementDirection

The airflow quantities shown in mechani-cal plans or in testing and balancingreports can be used to determine thedirection of air movement intended by thedesigner. Onsite examination is necessaryto determine the actual direction of airflowat each available pathway.

Chemical smoke tubes can be used todetermine airflow directions between thecomplaint area and surrounding spaces(including the outdoors), and to reveal aircirculation patterns within the complaintarea. A micromanometer (or equivalent)can measure the magnitude of pressuredifferences between these areas. Thesketch plan and the Pollutant PathwayForm for Investigations can be used torecord the results.

It may be necessary to make observa-tions under different conditions, as airflowdirection can change depending uponweather conditions, windspeed anddirection, equipment operation within thebuilding, traffic through doors, and otherfactors (e.g., as VAV systems throttleback). Switching air handlers or exhaustfans on and off, opening and closing doors,and simulating the range of operatingconditions in other ways can help to showthe different ways that airborne contami-nants move within the building. Dusttracking patterns around door frames canreveal the dominant direction of air andpollutant movement.

Some investigators study air movementby releasing a small amount of peppermintoil at the opening to a suspected pathwayand asking an assistant to sniff for the

Pollutant Pathway for Investigations FormSample Form

“toothpaste” smell. If this technique isused, it is important that the assistant havean acute sense of smell. If the building isin use during the investigation, occupantsmay also notice the odor and could find itdistracting. Some investigators prefer touse methods that release an odor duringunoccupied periods. Investigators shouldnote two common causes of false negativeresults (falsely concluding that no pathwayexists):

■ The nose quickly becomes tolerant ofstrong odors, so that the assistant mayneed to take a long rest (breathing freshair) between tests.

■ If there is substantial airflow through thepathway, the peppermint oil odor couldbe diluted so that it is imperceptible.

Tracer gases such as sulfur hexafluo-ride (SF

6) can provide qualitative and

quantitative information on pollutant path-ways and ventilation rates. Use of tracergases to obtain quantitative results re-quires considerable technical expertise. Ifit appears that a sophisticated study ofpathways (or ventilation rates) is required,you need to use trained investigators.

Rooms or ZonesConnected to the

Complaint Area byPathways

Pressure Relative toComplaint AreaUse

Comments(e.g., potential

polluntantsources)+/- date/time



Evaluate Airflow Patterns

Evaluate airflow patterns into andwithin the complaint area. Because ofthe complexity and variability of air-flow patterns, investigators cannot beexpected to understand how air moveswithin the building under all potentialoperating conditions. However, dataon pathways and driving forces canhelp to locate potential pollutantsources and to understand how con-taminants are transported to buildingoccupants.

SUGGESTIONS

■ Look for temporal patternslinking changes in airflowdirection to incidents ofcomplaints.

■ Look for spatial patternslinking potential sources tothe locations of complaints.


■ Use the HypothesisForm on page 223 tomake brief notes afterreviewing the pollutantpathway data.

■ Decide whether youhave a hypothesis thatmight explain thecomplaints. If so, test it.(See page 78 for adiscussion of hypothesistesting.)

■ Decide what else youneed to know. Considerwhether in-houseexpertise is sufficient oroutside assistance isneeded. (See Section 8for guidance on hiringoutside assistance.)

AIRFLOW PATTERNS

■ Onsite observations

Confirm or Revise Bound-aries of the Complaint Area

The discovery of unexpected pollutantpathways can show a need to studyareas of the building that may bedistant from the original complaintarea.

COMPLAINT AREA

■ Complaint area connectedby architectural features toother areas

■ Complaint area connectedby mechanical system toother areas

■ Unintentional pathways(e.g., cracks, holes)

SUGGESTIONS

■ Check whether pressure relationshipsbetween complaint area and sur-rounding locations follows intent ofventilation design.

■ Check whether air from otherlocations flows into the complaintarea under some conditions. If so,consider expanding the investigationto inventory pollutant sources (andperhaps collect HVAC or occupantdata) in those locations.

72 Section 6

COLLECTING SOURCE INFORMATION

Strategies Tools

Conduct onsiteinspection

Talk with buildingoccupants, facilitiesstaff, and contractors

■ Pollutant and Source Inventory■ Chemical Inventory

■ Pollutant and Source Inventory■ Chemical Inventory

COLLECTING INFORMATIONON POLLUTANT SOURCESThroughout the investigation, the buildinginvestigator will try to identify pollutantsources that may be causing the occupantcomplaints. Any public or commercialbuilding is likely to contain a number ofsources that produce odors, contaminants,or both. The investigator’s task is toidentify the source(s) that may be respon-sible for the complaint(s).

The area included in the pollutant sourceinventory should be defined by the invest-igator’s understanding of the building’sarchitectural and mechanical layout andpollutant pathways. Common sense willhelp to differentiate unusual sources (e.g.,spills, strong odors from new furnishingsor equipment) from those that are normallyfound within or near the building.

Remember that very few sources ofindoor air contaminants are both continu-ous and constant in volume over time.Pollutant concentrations often vary instrength over time, and may not be evidentat the time of the site visit. Some sourcesare subtle and might only be noticed by atrained investigator. As the investigationprogresses, the inventory of pollutantsources may need to be revised by expand-ing the definition of the complaint area orexamining specific locations more closely(e.g., under various operating conditions).

Onsite InspectionDepending upon the nature of the com-plaint, the investigator may find some ofthe following activities to be useful. Thislist is not intended to be complete.

Inventory outdoor sources■ Examine the area around the outdoor air

intake for unsanitary conditions, standingwater, or nearby pollutant sources suchas exhaust vents or motor vehicles.

■ Observe patterns of traffic, constructionactivity, and other potential sources inthe neighborhood of the building.

Sample FormPollutant and Source Inventory Form

Using the list of potential source categories below, record anyindications of contamination or suspected pollutants that may requirefurther investigation or treatment.

Source Category Checked Needs Attention Location Comments

SOURCES OUTSIDE THE BUILDING


Pollen, dust

Industrialcontaminants

General vehicularcontaminants

The inventory should include chemicals stored or used in the buildingfor cleaning, maintenance, operations, and pest control.

Date Chemical/ Use Storage MSDS Brand Name Location(s) on File?

Sample FormChemical Inventory



■ Inquire about outdoor ambient airproblems in the area. (This informationmay be available from your local HealthDepartment.)

■ Observe soil gas entry points.

Inventory equipment sources■ Review non-HVAC equipment, particu-

larly large office equipment such asengineering drawing reproductionmachines and wet-process copiers.Learn about usage patterns and identifyitems that are not equipped with localexhaust.

■ Review biocides, water treatment usedon HVAC equipment.

Review building components andfurnishings■ 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, printshops.

■ Identify areas where remodeling, repair,or redecorating activities are in progressor recently completed. Check proce-dures being used to isolate demolitiondust, paint fumes, and other contami-nants related to the process.

■ Inventory cleaning materials used in thebuilding.

(See Section 4 for another discussion ofproblem indicators and common problemsthat may become obvious during awalkthrough of the building.)

The Pollutant and Source Inventorycan be used to record your observations.The Chemical Inventory form is intendedto serve as a record of materials such assolvents, biocides, pesticides, and cleaningcompounds that may require special care instorage and handling. Material SafetyData Sheets (MSDSs) should be collected

on these materials whenever possible.(See Section 4 for further discussion ofMSDSs.) Portions of both forms areshown on the poopsite page; the completeform is included in Tab V.

Talk With Building Occupantsand Facility StaffBuilding occupants and facility staff canprovide valuable information about thelocation and timing of activities thatproduce odors or contaminants (e.g.,smoking, cooking, housekeeping, mainte-nance). They may also suggest explana-tions for the IAQ problem that can help inthe development of hypotheses. Facilitystaff and outside contractors (e.g., personsinvolved in housekeeping, pest control, orremodeling) should be interviewed orasked to provide a current list of materials,procedures, and schedules used forcleaning and pest control.

It may be useful to discuss the followingitems with building occupants:

Inventory activities■ Review smoking policy (and actual

practice; cleaning staff may know wheresmoking occurs in violation of policy,especially in private offices).

■ Identify areas of overcrowding.■ Review products used for housekeeping,

maintenance, and pest control and theschedules of their use.

■ Inquire about housekeeping schedulesand procedures.

■ Identify supply storage areas and checkfor well-sealed containers and properventilation.

Discuss incidents that could be sources■ Inquire about prior and neighboring uses

of land (e.g., landfills, underground fueltanks).

■ Inquire about events such as spills, fires,or leaks.

■ If such events have occurred, learn whatremedial actions were taken to clean upafter the incidents and to prevent theirrecurrence.

74 Section 6

PATTERNS

Location(s)of sources

Timingof emissions

SUGGESTIONS

■ Compare locations of sources to locations ofcomplaint(s).

■ Identify pathways linking potential sources to thecomplaint area.

■ Revise definition of complaint area if necessary.

■ Note whether the sources emit on a continuousor intermittent basis.

■ Compare the timing of emissions to the timingof complaints.

■ Identify occasions when the source is likely to bestrongest.

■ Determine whether pathways between thesource(s) and the complaint location couldaccount for the occasions of complaints.


■ Use the HypothesisForm on page 223 tomake brief notes afterreviewing the pollutantsource data.

■ Decide whether youhave a hypothesisthat might explain thecomplaints. If so, testit. (See page 78 for adiscussion of hypoth-esis testing.)

■ Decide what else youneed to know.Consider whether in-house expertise issufficient or outsideassistance is needed.(See Section 8 forguidance on hiringoutside assistance.)

USING POLLUTANT SOURCEDATA

If a strong pollutant source is identified inthe immediate vicinity of the complaint, asimple test (e.g., sealing, covering, orremoving the source) can sometimes revealwhether or not it is the cause of the IAQproblem. If a number of potential sourceshave been found in and around thecomplaint area, other data (e.g., the patternof symptoms, the HVAC system designand operation, and pollutant pathways)may be needed in order to determine whichsource(s), if any, may be related to thecomplaint.

Strategies for Using SourceInformation

■ Identify patterns linking emissions tocomplaints

■ Evaluate unrelated sources

Identify Patterns LinkingEmissions to Complaints

Look for patterns linking emissions frompotential sources to the IAQ complaints.

Evaluate Unrelated Sources

Evaluate sources that appear unrelated tothe complaints. It is not unusual to

identify potential contaminant sources thatare unrelated to the present IAQ complaint(i.e., either the location of the source, thetiming of emissions, or both fit poorly withthe pattern of complaints). These shouldbe prioritized for remedial work accordingto their potential for causing healthproblems or complaints in the future.

A detailed study of pollutants andsources may involve an engineeringevaluation of equipment that is releasingIAQ contaminants, diagnostic sampling toassess sources in operation, or othermeasurements. These may require skills orinstruments that are not available in-house.

SAMPLING AIR FORCONTAMINANTS ANDINDICATORS

Although air sampling might seem to bethe logical response to an air qualityproblem, such an approach may not berequired to solve the problem and can evenbe misleading. Air sampling should not beundertaken until some or all of the otherinvestigative activities mentioned previ-ously have been used to collect consider-able information. Before beginning to takeair samples, investigators should develop asampling strategy that is based on acomprehensive understanding of how thebuilding operates, the nature of thecomplaints, and a plan for interpreting theresults.

It may be desirable to take certainroutine air quality measurements during aninvestigation to obtain a “snapshot” ofcurrent conditions. These tests should belimited to those that are indicative of verycommon IAQ concerns such as tempera-ture, relative humidity, air movement, orcarbon dioxide (CO

2). Unusual readings

may or may not indicate a problem, andshould always be interpreted in perspec-tive, based upon site-specific conditions.

Measurement of specific chemical orbiological contaminants can be veryexpensive. Before expending time and


money to obtain measurements of indoorair pollutants, you must decide:

■ how the results will be used(e.g., comparison to standards orguidelines, comparison to levels incomplaint-free areas)

■ 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 usefulinformation

It is often worthwhile for building staffto develop skills in making temperature,humidity, airflow, and CO

2 measurements

and assessing patterns of air movement(e.g., using chemical smoke). Appendix Aprovides a brief introduction to ventilationand thermal measurement strategies and tomethods of sampling for specific aircontaminants.

How Will the Results Be Used?

Although air sampling will generatenumbers, it will not necessarily helpresolve the IAQ problem. Many IAQcomplaints are resolved without samplingor with inconclusive sampling results.

The design of an air sampling strategyshould fit the intended use of the measure-ments. Potential uses of indoor airmeasurements include:

1. Comparing different areas of the buildingor comparing indoor to outdoor condi-tions in order to:

Confirm that a control approach hasthe desired effect of reducing pollutantconcentrations or improving ventilation

Establish baseline conditions so thatthey can be compared to concentrationsat other times or locations, such as

■ concentrations in outdoor air■ concentrations in areas where no

symptoms are reported

■ expected “background” range fortypical buildings without perceivedIAQ problems

Test a hypothesis about the source of theproblem, such as■ checking emissions from a piece of

equipment

2. Testing for “indicator” compoundsassociated with particular types ofbuilding conditions:

Peak carbon dioxide (CO2 ) concentra-tions over 1000 ppm (parts per million)are an indicator of underventilation

Carbon monoxide (CO) over severalppm indicates inappropriate presenceof combustion by-products (which mayalso account for high CO2 readings)

3. Comparing measured concentrationsto guidelines or standards

Occupational exposure standards andguidelines, such as■ OSHA PELs (Occupational Safety and

Health Administration’s PermissibleExposure Limits)

■ NIOSH RELs (National Institute forOccupational Safety and Health’sRecommended Exposure Limits)

■ ACGIH TLVs (American Conferenceof Governmental Industrial Hygienists’Threshold Limit Values)

Occupants in this one-storyoffice building were complain-ing of intermittent gasolineodors. Exhausts from under-ground gasoline storage tankvent pipes (visible in thelower right portion of thisphotograph) were beingdrawn into the office buildingthrough outdoor air intakes onthis roof. The gasoline stor-age tanks belonged to anadjacent service station.

76 Section 6

Public health guidelines for specificpollutants■ EPA National Ambient Air Quality

Standards■ World Health Organization Air Quality

Guidelines■ Canadian Exposure Guidelines for

Residential Air Quality

There are no widely accepted proceduresto define whether IAQ test results are ac-ceptable. Extreme caution must be used incomparing contaminant concentrations toexisting occupational standards and guide-lines. Although a contaminant concentra-tion above those guidelines is a clear prob-lem indicator, occupants may still experi-ence health and comfort problems at con-centrations well within those guidelines. Itis extremely rare for occupational stan-dards to be exceeded — or even ap-proached — in public and commercialbuildings, including those experiencingindoor air quality problems.

Where specific exposure problems aresuspected, more detailed diagnostic testingmay be needed to locate or understandmajor sources, confirm the exposure, andto develop appropriate remedial actions.For example, the control of microbial orpesticide contamination may involve sur-face or bulk sampling. (Surface samplinginvolves wiping a measured surface areaand analyzing the swab to see what organ-isms are present, while bulk samplinginvolves analyzing a sample of suspectmaterial.) Specialized skills, experience,and equipment may be needed to obtain,analyze, and interpret such measurements.

What Substance(s) Should BeMeasured?

Measurement of “indicator” compoundssuch as CO

2 or CO can be a cost-effective

strategy. Such measurements can help theinvestigator understand the nature of theproblem and define the complaint area.

Air sampling for specific pollutantsworks best as an investigative tool when itis combined with other types of informa-tion-gathering. It is prudent to begin aprogram of chemical sampling only ifsymptoms or observations strongly suggestthat a specific pollutant or a specific sourcemay be the cause of the complaint and ifsampling results are important in determin-ing an appropriate corrective action.

Where Should Air Samples BeTaken?

The identified problem area is an obvioussite for air sampling. Measurements takenoutdoors and in a control location (e.g., acomplaint-free area of the building) arehelpful in interpreting results from thecomplaint area.

The conditions experienced by buildingoccupants are best simulated by samplingair from the “breathing zone” away fromthe influence of any particular individual.However, if an individual sits at a desk allday (except for brief periods), samplersplaced on the desk when the individual iselsewhere can provide a good estimate ofthat person’s exposure.

There are several ways to locate sam-pling sites for an IAQ investigation. Oneapproach first divides the building intohomogeneous areas based on key factorsidentified in the building inspection andinterviews. Examples of how a buildingmight be divided include:

■ control zones (e.g., individual rooms)■ types of HVAC zones (e.g., interior vs.

perimeter)■ complaint vs. non-complaint areas■ relationship to major sources

(e.g., spaces directly, indirectly, or notimpacted by smoking areas)

■ complaint types

Test sites can then be selected to repre-sent complaints, controls, and potentialsources with a reasonable number ofsamples.

It is prudent to begina program of chemi-cal sampling only ifsymptoms or obser-vations stronglysuggest that a spe-cific pollutant or aspecific source maybe the cause of thecomplaint and ifsampling results areimportant in deter-mining an appropriatecorrective action.


When Should Indoor AirSamples Be Taken?

Samples may be designed to obtain “worst-case” conditions, such as measurementsduring periods of maximum equipmentemissions, minimum ventilation, or distur-bance of contaminated surfaces. Worst-case sample results can be very helpful incharacterizing maximum concentrations towhich occupants are exposed and identify-ing sources for corrective measures.

It is also helpful to obtain samples duringaverage or typical conditions as a basis ofcomparison. It may, however, be difficultto know what conditions are typical. Re-search shows that exposure to some pollut-ants may vary dramatically as buildingconditions change. Devices that allowcontinuous measurements of key variablescan be helpful.

Symptoms or odors that only occur occa-sionally will not generally be seen duringthe IAQ investigation. Air samples shouldnot be taken if an incident is not occurring,unless the purpose of the sample is to es-tablish a baseline for future comparisons.

One approach to intermittent IAQ prob-lems is for the IAQ investigator to askappropriate building staff or other occu-pants to document changes over time usingday-to-day records such as the OccupantDiary and Log of Activities and SystemOperation. When an odor episode doesoccur, the building engineer could inspectthe air handler and intake area while an-other staff member documents the status ofseveral potential sources.

Another strategy is to manipulatebuilding conditions to create worst-caseconditions during the building investiga-tion (e.g., arrange for the trash truck to idleat the loading dock or close outdoor airdampers to minimum settings). Chemicalsmoke and tracer gases can be used toassess where emissions may travel undervarious building conditions. (Suchstrategies should be carried out in waysthat minimize occupant exposure.)

Investigators shouldbear in mind thatcomplaints producedby these stressorsare sometimes mis-takenly blamed oncontaminated air. Tocomplicate matters,such stressors alsocan produce a height-ened sensitivity topoor indoor air qual-ity.

What Sampling and AnalysisMethod Should Be Used?

Take care to select appropriate measure-ment techniques and to provide interpreta-tions so that the results provide usefulinformation. Appendix A providesguidance on measurement techniques thatare commonly used in IAQ investigations.

COMPLAINTS DUE TOCONDITIONS OTHER THANPOOR AIR QUALITY

Complaints that initially seem to be linkedto thermal discomfort, underventilation, orindoor air pollutants may actually becaused or complicated by factors such as:

■ environmental stressors (e.g., lighting,noise, vibration)

■ ergonomic stressors■ job-related psychosocial (human rela-

tions) stressors

The following briefly discusses each ofthese three kinds of stressors. Investiga-tors should bear in mind that complaintsproduced by these stressors are sometimesmistakenly blamed on contaminated air.To complicate matters, such stressors alsocan produce a heightened sensitivity topoor indoor air quality. Thus, even whenspecific stressors are obvious, the investi-gator should not assume that they are theonly reason for the complaints.

Lighting

Stresses from inadequate or poorlydesigned lighting (e.g., glare, flicker, poorillumination of work surfaces) can producesymptoms such as eyestrain and head-aches. Lack of natural sunlight can also bea source of stress. These complaints aresometimes mistakenly interpreted as signsof poor indoor air quality. Lightingproblems may be evident in large areas orlocalized in particular workspaces.

78 Section 6

The glare from the windowswas causing a variety ofoccupant complaints in thisbuilding and was disruptingthe workers’ ability to use thevideo display terminals.Complaints such asheadaches are sometimesincorrectly blamed on poorindoor air quality.

Noise

Noisy surroundings can reduce the abilityto concentrate and produce stress-relatedsymptoms such as headaches. Noise canalso contribute to job dissatisfaction,particularly if the problem is caused byovercrowding or other factors likely toproduce a sense of substandard workconditions.

The ear gets used to sounds quickly, so itis possible for a complainant to be unawareof a constant or regular sound. Investiga-tors should recognize that noise can be asource of stress, even if it is not reported asa problem and is within current industrialexposure criteria (which are designedprimarily to prevent hearing loss).

Vibration

Low-frequency vibration is another sourceof stress that may go unreported bybuilding occupants or become confusedwith pollutant problems. Vibration can becaused by nearby machinery or movementof the building as a whole; motion sicknesshas been reported in some high risebuildings that sway in the wind.

Ergonomic Stressors

Fatigue, circulatory problems, and otherphysical problems can be produced byfurniture that is mismatched to the task,such as chairs that are the wrong height forcomputer terminals. If IAQ investigatorsinquire about whether new furniture hasrecently been installed in the problem area(to determine if the furniture could becontributing to increased contaminantlevels), they should also ask aboutwhether the occupant finds the furniturecomfortable.

Job-related PsychosocialStressors

It is well documented that various job-related psychosocial conditions canproduce symptoms in workers. Excessiveworkload and work pressure are easilyrecognized job stressors. Lack of clarityabout what is expected of the worker (roleambiguity) and the presence of conflictingexpectations (role conflict) are alsocommonly encountered stressors inmodern organizations. Poor interpersonalrelations, management styles that allowlittle participation in decision-making, andfactors related to career development arealso thought to be potentially stressful.

FORMING AND TESTINGHYPOTHESES

As the building investigation progresses,you should be developing one or morehypotheses that could explain the occupantcomplaints. The investigation can then beshaped to collect information that willeither support or refute your hypotheses.

The Hypothesis Form on the oppositepage is designed to pull together theseparate pieces of information that havebeen collected by summarizing the resultsof the investigation. More pages can beadded if desired, but the form is designedfor brief notes that can be scanned easily.As you review the information, write down


any explanation(s) for the IAQ problem thatmake sense, and think about how thepieces of the puzzle fit together whenbuilding conditions are compared tooccupant complaints.

Is all (or most) of your informationconsistent with your hypothesis? If not, isthere a reasonable explanation for theinconsistencies? A different hypothesismight provide a better fit with yourinformation.

You may find that there are several IAQproblems (e.g., underventilation in onezone, a strong contaminant source inanother room). If you have discoveredpotential IAQ problems that do not appearrelated to the original complaint, they canbe prioritized and corrected as time andfunding permit.

Think of ways to test your hypotheses.You may want to change ventilation rates,change the pressure relationship betweenspaces, cover or remove suspected sources,seal pathways, or temporarily relocateaffected individuals. If your manipulationscan reduce occupant complaints, you havefound a reasonable hypothesis. Sometimesit is not possible (or not practical) tomanipulate important factors. You can alsotest your hypothesis by seeing how accu-rately you can predict changes in buildingconditions (e.g., as outdoor temperaturechanges).

If you are having difficulty developinghypotheses, review the information youhave collected and the suggestions abouthow to use that information. For sugges-tions on using occupant complaint data, seepages 53-57; on using HVAC systeminformation, see pages 62-67; on usingpollutant pathway information, see pages70-71; on using pollutant/source inventorydata, see page 74; on using air samplinginformation, see pages 75-76.

The changes that are made duringhypothesis testing may offer a practicalsolution to the IAQ problem, or may beonly temporary measures. The mitigationchapter presents a variety of approachesthat have been used in correcting someselected categories of IAQ problems anddiscusses how to evaluate those strategies.


Sample FormHypothesis Form

Complaint Area (may be revised as the investigation progresses):

_______________________________________________________________

_______________________________________________________________

Complaints (e.g., summarize patterns of timing, location, peopleaffected):

_______________________________________________________________

_______________________________________________________________

HVAC: Does the ventilation system appear to provide adequate air,efficiently distributed to meet occupant needs in the complaint area? Ifnot, what problems do you see?

_______________________________________________________________

_______________________________________________________________

Pathways: What pathways and driving forces connect the complaintarea to locations of potential sources?

_______________________________________________________________

_______________________________________________________________

Mitigating IAQ Problems 81

7Mitigating IAQ Problems

Over the years many types of mitigation(correction) strategies have been imple-mented to solve indoor air quality prob-lems. The purpose of this section is toprovide an understanding of basic ap-proaches to mitigation and the varioussolutions that can be effective in treatingcommonly-encountered IAQ problems. Itis not intended to provide detailed instruc-tions for using each type of mitigationapproach but rather to give guidance inselecting a mitigation strategy and injudging proposals from in-house staff oroutside consultants.

Mitigation of indoor air quality prob-lems may require the involvement ofbuilding management and staff represent-ing such areas of responsibility as:

■ facility operation and maintenance■ housekeeping■ shipping and receiving■ purchasing■ policymaking■ staff training

Successful mitigation of IAQ problemsalso requires the cooperation of otherbuilding occupants, including the employ-ees of building tenants. Occupants must beeducated about the cause(s) of the IAQproblems and about actions that must betaken or avoided to prevent a recurrence ofthe problems.

BACKGROUND: CONTROLLINGINDOOR AIR PROBLEMS

Section 2 introduced the idea that indoorair quality problems result from interac-tions between contaminant source,building site, building structure, activitieswithin the building, mechanical equipment,climate, and occupants. Efforts to control

indoor air contaminants change therelationships between these factors. Thereare many ways that people can intervene inthese relationships to prevent or controlindoor air contaminant problems. Controlstrategies can be categorized as:

■ source control■ ventilation■ air cleaning■ exposure control

Successful mitigation often involves acombination of these strategies. Possibleremedies for the other environmentalstressors discussed in Section 6 arediscussed briefly below.

Source Control

All efforts to prevent or correct IAQproblems should include an effort toidentify and control pollutant sources.Source control is generally the most costeffective approach to mitigating IAQproblems in which point sources ofcontaminants can be identified. In the caseof a strong source, source control may bethe only solution that will work.

The following are categories andexamples of source control:

Remove or reduce the source■ prohibit smoking indoors or limit

smoking to areas from which air isexhausted, not recirculated (NIOSHregards smoking areas as an interimsolution)

■ relocate contaminant-producing equip-ment to an unoccupied, better ventilated,or exhaust-only ventilated space

■ select products which produce fewer orless potent contaminants while maintain-ing adequate safety and efficacy

82 Section 7

■ modify other occupant activities

Seal or cover the source■ improve storage of materials that

produce contaminants■ seal surfaces of building materials that

emit VOCs such as formaldehyde

Modify the environment■ after cleaning and disinfecting an area

that is contaminated by fungal orbacterial growth, control humidity tomake conditions inhospitable forregrowth

Source removal or reduction cansometimes be accomplished by a one-timeeffort such as thorough cleaning of a spill.In other cases, it requires an ongoingprocess, such as establishing and enforcinga non-smoking policy.

Sealing or covering the source can be asolution in some cases; application of abarrier over formaldehyde-emittingbuilding materials is an example. Sealingmay also involve educating staff orbuilding occupants about the contaminant-producing features of materials andsupplies and inspecting storage areas toensure that containers are properlycovered.

In some cases, modification of theenvironment is necessary for effectivemitigation. If the indoor air problemarises from microbiological contaminants,for example, disinfection of the affectedarea may not eliminate the problem.Regrowth of microbiologicals couldoccur unless humidity control or othersteps, such as adding insulation to preventsurface condensation, are taken to makethe environment inhospitable to micro-biologicals.

Ventilation

Ventilation modification is often used tocorrect or prevent indoor air qualityproblems. This approach can be effectiveeither where buildings are underventilatedor where a specific contaminant source

cannot be identified. Ventilation can beused to control indoor air contaminants by:

Diluting contaminants with outdoor air■ increase the total quantity of supply air

(including outdoor air)■ increase the proportion of outdoor air to

total air■ improve air distribution

Isolating or removing contaminants bycontrolling air pressure relationships■ install effective local exhaust at the

location of the source■ avoid recirculation of air that contains

contaminants■ locate occupants near supply diffusers

and sources near exhaust registers■ use air-tightening techniques to maintain

pressure differentials and eliminatepollutant pathways

■ make sure that doors are closed wherenecessary to separate zones

Diluting contaminants by increasingthe flow of outdoor air can be accom-plished by increasing the total supplyairflow in the complaint area (e.g., openingsupply diffusers, adjusting dampers) or atthe air handling unit, (e.g., cleaning thefilter on the supply fan). An alternative isto increase the proportion of outdoor air(e.g., adjusting the outdoor air intakedamper, installing minimum stops onvariable air volume (VAV) boxes so thatthey satisfy the outdoor air requirements ofASHRAE 62-1989).

Studies have shown that increasingventilation rates to meet ASHRAEStandard 62-1989 (e.g., from 5 to 15 or 20cfm/person) does not necessarily signifi-cantly increase the total annual energyconsumption. The increase appears to beless than 5% in typical commercialbuildings. The cost of ventilation isgenerally overshadowed by other operatingcosts, such as lighting. Further, improvedmaintenance can produce energy savingsto balance the costs that might otherwiseresult from increased ventilation.


The cost of modifying an existingHVAC system to condition additionaloutdoor air can vary widely dependingupon the specific situation. In somebuildings, HVAC equipment may not havesufficient capacity to allow successfulmitigation using this approach. Originalequipment is often oversized so that it canbe adjusted to handle the increased load,but in some cases additional capacity isrequired.

Most ventilation deficiencies appear tobe linked to inadequate quantities ofoutdoor air. However, inadequate distribu-tion of ventilation air can also produceIAQ problems. Diffusers should beproperly selected, located, installed, andmaintained so that supply air is evenlydistributed and blends thoroughly withroom air in the breathing zone. Short-circuiting occurs when clean supply air isdrawn into the return air plenum before ithas mixed with the dirtier room air andtherefore fails to dilute contaminants.Mixing problems can be aggravated bytemperature stratification. Stratificationcan occur, for example, in a space withhigh ceilings in which ceiling-mountedsupply diffusers distribute heated air.

Note the side effects of increasedventilation:■ mitigation by increasing the circulation

of outdoor air requires good outdoor airquality

■ increased supply air at the problemlocation might mean less supply air inother areas

■ increased total air in the system andincreased outdoor air will both tend toincrease energy consumption and mayrequire increased equipment capacity

■ any approach which affects airflow inthe building can change pressuredifferences between rooms (or zones)and between indoors and outdoors, andmight lead to increased infiltration ofunconditioned outdoor air

■ increasing air in a VAV system mayovercool an area to the extent thatterminal reheat units are needed

Ventilation equipment can be used toisolate or contain contaminants bycontrolling pressure relationships. If thecontaminant source has been identified,this strategy can be more effective thandilution. Techniques for controlling airpressure relationships range from adjust-ment of dampers to installation of localexhaust.

Using local exhaust confines the spreadof contaminants by capturing them near thesource and exhausting them to the out-doors. It also dilutes the contaminant bydrawing cleaner air from surrounding areasinto the exhaust airstream. If there arereturn grilles in a room equipped with localexhaust, the local exhaust should exertenough suction to prevent recirculation ofcontaminants. Properly designed andinstalled local exhaust results in far lowercontaminant levels in the building thancould be accomplished by a generalincrease in dilution ventilation, with theadded benefit of costing less.

Note that replacement air must be ableto flow freely into the area from which theexhaust air is being drawn. It may benecessary to add door or wall louvers inorder to provide a path for the make-up air.(Make sure that this action does not violatefire codes.)

Correct identification of the pollutantsource and installation of the local exhaustis critically important. For example, animproperly designed local exhaust candraw other contaminants through theoccupied space and make the problemworse.

The physical layout of grilles anddiffusers relative to room occupants andpollutant sources can be important. Ifsupply diffusers are all at one end of aroom and returns are all at the other end,the people located near the supplies maybe provided with relatively clean air whilethose located near the returns breathe airthat has already picked up contaminantsfrom all the sources in the room that arenot served by local exhaust.

84 Section 7

Elimination of pollutant pathways by airsealing (e.g., caulking cracks, closingholes) is an approach that can increase theeffectiveness of other control techniques.It can be a difficult technique to implementbecause of hidden pathways (e.g., abovedrop ceilings, under raised flooringagainst brick or block walls). However, itcan have other benefits such as energysavings and more effective pest control (byeliminating paths used by vermin).

Air Cleaning

The third IAQ control strategy is to cleanthe air. Air cleaning is usually most effec-tive when used in conjunction with eithersource control or ventilation; however, itmay be the only approach when the sourceof pollution is outside of the building.Most air cleaning in large buildings isaimed primarily at preventing contaminantbuildup in HVAC equipment and enhanc-ing equipment efficiency.

Air cleaning equipment intended toprovide better indoor air quality for occu-pants must be properly selected and de-signed for the particular pollutants of inter-est (for example, gaseous contaminants canbe removed only by gas sorption). Onceinstalled, the equipment requires regularmaintenance in order to ensure good per-formance; otherwise it may become amajor pollutant source in itself. This main-tenance requirement should be borne inmind if an air cleaning system involving alarge number of units is under consider-ation for a large building. If room units areused, the installation should be designedfor proper air recirculation.

There are four technologies that removecontaminants from the air:

■ particulate filtration■ electrostatic precipitation■ negative ion generation■ gas sorption

The first three approaches are designedto remove particulates, while the fourth isdesigned to remove gases.

Particulate filtration removes sus-pended liquid or solid materials whosesize, shape and mass allow them to remainairborne for the air velocity conditionspresent. Filters are available in a range ofefficiencies, with higher efficiency indicat-ing removal of a greater proportion ofparticles and of smaller particles. Movingto medium efficiency pleated filters isadvisable to improve IAQ and increaseprotection for equipment. However, thehigher the efficiency of the filter, the moreit will increase the pressure drop within theair distribution system and reduce totalairflow (unless other adjustments are madeto compensate). It is important to select anappropriate filter for the specificapplication and to make sure that theHVAC system will continue to perform asdesigned. Filters are rated by differentstandards (e.g., arrestance and dust spot)which measure different aspects ofperformance.

Electrostatic precipitation is anothertype of particulate control. It uses theattraction of charged particles to oppo-sitely charged surfaces to collect airbornepar-ticulates. In this process, the particlesare charged by ionizing the air with anelectric field. The charged particles arethen col-lected by a strong electric fieldgenerated between oppositely-chargedelectrodes. This provides relatively highefficiency filtration of small respirableparticles at low air pressure losses.

Electrostatic precipitators may be in-stalled in air distribution equipment or inspecific usage areas. As with other filters,they must be serviced regularly. Note,however, that electrostatic precipitatorsproduce some ozone. Because ozone isharmful at elevated levels, EPA has setstandards for ozone concentrations in out-door air, and NIOSH and OSHA have


established guidelines and standards, re-spectively, for ozone in indoor air. Theamount of ozone emitted from electrostaticprecipitators varies from model to model.

Negative ion generators use staticcharges to remove particles from the indoorair. When the particles become charged,they are attracted to surfaces such as walls,floors, table tops, draperies, and occupants.Some designs include collectors to attractthe charged particles back to the unit.Negative ion generators are not availablefor installation in ductwork, but are sold asportable or ceiling-mounted units. As withelectrostatic precipitators, negative iongenerators may produce ozone, eitherinten-tionally or as a by-product of use.

Gas sorption is used to control com-pounds that behave as gases rather than asparticles (e.g., gaseous contaminants suchas formaldehyde, sulfur dioxide, ozone, andoxides of nitrogen). Gas sorption involvesone or more of the following processeswith the sorption material (e.g., activatedcarbon, chemically treated active clays): achemical reaction between the pollutantand the sorbent, a binding of the pollutantand the sorbent, or diffusion of the con-taminant from areas of higher concentrationto areas of lower concentration. Gas sorp-tion units are installed as part of the airdistribution system. Each type of sorptionmaterial performs differently with differentgases. Gas sorption is not effective forremoving carbon monoxide. There are nostandards for rating the performance ofgaseous air cleaners, making the design andevaluation of such systems problematic.Operating expenses of these units can bequite high, and the units may not be effec-tive if there is a strong source nearby.

Exposure Control

Exposure control is an administrative ap-proach to mitigation that uses behavioralmethods, such as:

Scheduling contaminant-producing acti-vities to avoid complaints■ schedule contaminant-producing activi-

ties to occur during unoccupied periods■ notify susceptible individuals about up-

coming events (e.g., roofing, pesticideapplication) so that they can avoid contactwith the contaminants

Scheduling contaminant-producing ac-tivities for unoccupied periods wheneverpossible is simple common sense. It maybe the best way to limit complaints aboutactivities (such as roofing or demolition)which unavoidably produce odors or dust.

Relocating susceptible individuals■ move susceptible individuals away from

the area where they experience symptoms

Controlling exposure by relocating sus-ceptible individuals may be the only practi-cal approach in a limited number of cases,but it is probably the least desirable optionand should be used only when all otherstrategies are ineffective in resolving com-plaints.

Remedies for Complaints NotAttributed to Poor Air Quality

Specific lighting deficiencies or localizedsources of noise or vibration can sometimesbe readily identified, and remedial actionmay be fairly straightforward (more orfewer lights on, adjustments for glare; relo-cating, replacing or acoustically insulating anoise or vibration source). Similarly, fla-grant ergonomic stress or blatant psycho-social stress may be apparent even toan untrained observer.

In other cases, however, problems maybe more subtle or solutions more complex.Since specialized knowledge, skills, andinstrumentation are usually needed toevaluate lighting, noise, vibration, ergo-nomic stress, or psychosocial stress, suchevaluations are generally best done by aqualified professional in that particularfield.

86 Section 7

Remedial actions for lighting, noise,and vibration problems might range frommodifications of equipment or furnishingsto renovation of the building. Ergonomicdeficiencies may require furniture orequipment changes or different workpractices. The solution to psychosocialproblems may involve new managementpractices, job redesign, or resolution ofunderlying labor-management problems.

SAMPLE PROBLEMS ANDSOLUTIONSIn the investigation section you wereintroduced to a variety of problems that areoften found in buildings. This sectionpresents fifteen categories of IAQ prob-lems. Specific problem “examples” aregiven, followed by solutions” that havebeen used for that category of problem.Most of the problems presented here arecommon and do not have serious, life-threatening consequences. At the end ofthe section is a brief description ofproblems that can have severe healthimpacts. The basic correction principlesthat apply to these serious problems aresimilar to those used in less criticalsituations.

Reading these examples may help youto think about the best way to solve yourindoor air quality problems. Rememberthat these are brief sketches, and apparentparallels to your building could be mis-leading. It is better to carry out a buildinginvestigation and learn the specific facts inyour own case, rather than adopt a mitiga-tion approach that might not be appropri-ate. Attempting to correct IAQ problemswithout understanding the cause of thoseproblems can be both ineffective andexpensive.

You will note that some solutions aresimple and low-cost, while others arecomplex and expensive. Do not assume

that each solution listed would be aneffective treatment for all of the problemsin its category.

The example problems and solutions arepresented in the following sequence:

Problem #1: Outdoor air ventilation rateis too low

Problem #2: Overall ventilation rate ishigh enough, but poorlydistributed and not sufficientin some areas

Problem #3: Contaminant enters buildingfrom outdoors

Problem #4: Occupant activities contrib-ute to air contaminants or tocomfort problems

Problem #5: HVAC system is a source ofbiological contaminants

Problem #6: HVAC system distributescontaminants

Problem #7: Non-HVAC equipment is asource or distribution mecha-nism for contaminants

Problem #8: Surface contamination due topoor sanitation or accidents

Problem #9: Mold and mildew growthdue to moisture from con-densation

Problem #10: Building materials andfurnishings producecontaminants

Problem #11: Housekeeping or mainte-nance activities contribute toproblems

Problem #12: Specialized use areas assources of contaminants

Problem #13: Remodeling or repair activi-ties produce problems

Problem #14: Combustion gases

Problem #15: Serious building-relatedillness


Problem #1:Outdoor Air VentilationRate is Too Low

Examples

Routine odors from occupants andnormal office activities result in problems(e.g., drowsiness, headaches, discomfort)

Measured outdoor air ventilation rates donot meet guidelines for outdoor air supply(e.g., design specifications, applicablecodes, or ASHRAE 62-1989)

Peak CO2 concentrations above 1000ppm indicate inadequate ventilation

Corrosion of fan casing causes airbypassing and reduces airflow in system

Solutions

Open, adjust or repair air distributionsystem

■ outdoor air intakes■ mixing and relief dampers■ supply diffusers■ fan casings

Increase outdoor air within the designcapacity of

■ air handler■ heating and air conditioning equipment■ distribution system

Modify components of the HVAC systemas needed to allow increased outdoor air

(e.g., increase capacity of heating andcooling coils)

Design and install an updated ventilationsystem

Reduce the pollutant and/or thermal loadon the HVAC system

■ reduce the occupant density: relocatesome occupants to other spaces toredistribute the load on the ventilationsystem

■ relocate or reduce usage of heat-generating equipment

Malfunctioning controls such as this brokendamper linkage can virtually eliminateintake of outdoor air. Such problems maygo undetected for years without a carefulinvestigation of the HVAC systemcomponents.

88 Section 7

Problem #2:Overall Ventilation Rate IsHigh Enough, But PoorlyDistributed and NotSufficient in Some Areas

Examples

Measured outdoor air meets guidelines atbuilding air inlet, but there are zoneswhere heat, routine odors from occu-pants, and normal office activities resultin complaints(e.g., drowsiness, headaches, comfortcomplaints)

Solutions

Open, adjust, or repair air distributionsystem

■ supply diffusers■ return registers

Ensure proper air distribution

■ balance the air handling system■ make sure that there is an air gap at tops

and bottoms of partitions to prevent deadair space

■ relocate supply and/or return diffusers toimprove air distribution

Seal leaky ductwork

Remove obstructions from return airplenum

Control pressure relationships

■ install local exhaust in problem areasand adjust HVAC system to provideadequate make-up air

■ move occupants so that they are closer tosupply diffusers

■ relocate identified contaminant sourcescloser to exhaust intakes

Reduce source by limiting activities orequipment use that produce heat, odors,or contaminants

Design and install an appropriateventilation system

Complaining of discomfort, buildingoccupants blocked air supply diffusers intheir work areas. The HVAC system in thisbuilding was in poor condition and was notbalanced.


Problem #3:Contaminant EnteringBuilding From Outdoors

Examples

Soil gases(e.g., radon, gasoline from tanks, methanefrom landfills)

Contaminants from nearby activities(e.g., roofing, dumpster, construction)

Outdoor air intake near source(e.g., parking, loading dock, buildingexhaust)

Outdoor air contains pollutants or excessmoisture(e.g., cooling tower mist entrained inoutdoor air intake)

Solutions

Remove the source, if it can be movedeasily

■ remove debris around outdoor air intake■ relocate dumpster

Reduce source (for example, shift time ofactivity to avoid occupied periods)

■ painting, roofing, demolition■ housekeeping, pest control

Relocate elements of the ventilationsystem that contribute to entry of outdoorair contaminants

■ separate outdoor air intakes from sourcesof odors, contaminants

■ separate exhaust fan outlets fromoperable windows, doors, air intakes

■ make rooftop exhaust outlets taller thanintakes

Change air pressure relationships tocontrol pollutant pathways

■ install subslab depressurization toprevent entry of soil gas contaminants(radon, gases from landfills and under-ground tanks)

■ pressurize the building interior relative tooutdoors (this will not prevent contami-nant entry at outdoor air intakes)

■ close pollutant pathways (e.g., sealcracks and holes)

Add special equipment to HVAC system

■ filtration equipment to remove pollutants(select to fit the situation)

For cosmetic reasons, airintakes are frequently locatedon rooftops or near theground. This air intake couldbecome a means of drawinglawn cuttings, vehicleexhaust, and pesticides intothe building.

90 Section 7

Problem #4:Occupant ActivitiesContribute to AirContaminants or toComfort Problems

Personal equipment such as humidifiersbrought in by building occupants canbecome a source of contaminants if notproperly maintained. An effectivecommunication strategy can helpoccupants to understand their role incausing indoor air quality problems and incorrecting those problems.

Examples

Smoking

Special activities such as print shops,laboratories, kitchens

Interference with HVAC systemoperation:

■ blockage of supply diffusers to eliminatedrafts

■ turning off exhaust fans to eliminatenoise

■ use of space heaters, desktop humidifiersto remedy local discomfort

(Note: While such interference can causeIAQ problems, it is often initiated inresponse to unresolved ventilation ortemperature control problems.)

Solutions

Remove the source by eliminating theactivity(Note: This may require a combination ofpolicy-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 whilemaintaining adequate safety and efficacy(e.g., solvents, art materials)

Install new or improved local exhaust toaccommodate the activity, adjust HVACsystem to ensure adequate make-up air,and verify effectiveness

■ smoking lounge, storage areas whichcontain contaminant sources

■ laboratory hoods, kitchen range hoods(venting to outdoors, not recirculating)


Problem #5:HVAC System is a Source ofBiological Contaminants

The HVAC system can act as a source ofcontaminants by providing a hospitableenvironment for the growth of microorgan-isms and by then distributing biologically-contaminated air within the building.

Examples

Surface contamination by molds (fungi),bacteria■ drain pans■ interior of ductwork■ air filters and filter media (collected

debris).

Solutions

Remove source by improving mainte-nance procedures■ inspect equipment for signs of corrosion,

high humidity■ replace corroded parts■ clean drip pans, outdoor air intakes,

other affected locations■ use biocides, disinfectants, and sanitizers

with extreme caution and ensure thatoccupant exposure is minimized

(Note: See discussion of duct cleaning inAppendix B.)

Provide access to all the items thatmust be cleaned, drained, or replacedperiodically

This blackish deposit was scraped from apoorly-maintained air handling unit drainpan. The pan contained nutrients causedby poor upstream filtration and stagnantwater that fostered the growth ofmicrobiological contaminants.

92 Section 7

Problem #6:HVAC System DistributesContaminants

Standing water on a roof can cause waterdamage and potential mold growth sitesinside the building as well as providing abreeding area for insects andmicrobiologicals such as Legionella. Theoutside air intake (near the far left of thisphotograph) is located close to thestanding water and could be drawing ininsects and microbiological contaminants.

Examples

Unfiltered air bypasses filters due toproblems

■ filter tracks are loose■ poorly-maintained filters sag when they

become overloaded with dirt■ filters are the wrong size

Recirculation of air that contains dust orother contaminants

■ system recirculates air from roomscontaining pollutant sources

■ return air plenum draws air from roomsthat should be exhausted (e.g. janitor’sclosets)

■ return air plenums draw soil gases frominteriors of block corridor walls thatterminate above ceilings

Solutions

Modify air distribution system tominimize recirculation of contaminants

■ provide local exhaust at point sources ofcontaminants, adjust HVAC system toprovide adequate make-up air, and test toverify performance

■ increase proportion of outdoor air■ seal unplanned openings into return air

plenums and provide alternative localventilation (adjust HVAC system toprovide adequate make-up air and test toverify performance)

Improve housekeeping, pest control,occupant activities, and equipment use tominimize release of contaminants fromall sources

Install improved filtration equipment toremove contaminants

Check filter tracks for any gaps


Problem #7:Non-HVAC Equipment isa Source or DistributionMechanism for Contaminants

This discussion pertains to medium- tolarge-scale pieces of equipment.

Examples

Non-HVAC equipment can producecontaminants, as in the case of:

■ wet process copiers■ large dry process copiers■ engineering drawing reproduction

machines

It can also distribute contaminants, as inthe case of:

■ elevators, which can act as pistons anddraw contaminants from one floor toanother

Solutions

Install local exhaust near machines(Note: Adjust HVAC system to provideadequate make-up air, and test to verifyperformance.)

Reschedule use to occur during periods oflow occupancy

Remove source

■ relocate occupants out of roomsthat contain contaminant-generatingequipment

■ relocate equipment into special useareas equipped with effective exhaustventilation (test to verify control of airpressure relationships)

Change air pressure relationships toprevent contaminants from enteringelevator shaft

Sometimes there are unusual sources ofindoor air quality problems. An inspectionof the HVAC system revealed air filterscovered with a graphite dust deposit from abroken elevator motor generator. Themotor generator was repaired andcorrections were made to prevent thecrossover of ventilation air from the motorgenerator into the HVAC mechanical room.

94 Section 7

Problem #8:Surface ContaminationDue to Poor Sanitation orAccidents

The carpet on this floor was floodedand an outbreak of humidifier feveroccurred. To eliminate microbiologicals,the contaminated carpet was removed andnew carpet was installed.

Examples

Biological contaminants result in aller-gies or other diseases

■ fungal, viral, bacterial (whole organismsor spores)

■ bird, insect, or rodent parts or droppings,hair, dander (in HVAC, crawlspace,building shell, or near outdoor airintakes)

Accidents

■ spills of water, beverages, cleansers,paints, varnishes, mastics or specializedproducts (printing, chemical art supplies)

■ fire damage: soot, odors, chemicals

Solutions

Clean

■ HVAC system components■ some materials and furnishings (others

may have to be discarded)(Note: Use biocides, disinfectants, andsanitizers with caution and ensure thatoccupant exposure is minimized.)

Remove sources of microbiologicalcontamination

■ water-damaged carpet, furnishings, orbuilding materials

Modify environment to prevent recur-rence of microbiological growth

■ improve HVAC system maintenance■ control humidity or surface temperatures

to prevent condensation

Provide access to all items that requireperiodic maintenance

Use local exhaust where corrosivematerials are stored

Adjust HVAC system to provide adequatemake-up air, and test to verify perfor-mance


Problem #9:Mold and Mildew GrowthDue to Moisture fromCondensation

Examples

Interior surfaces of walls near thermalbridges(e.g., uninsulated locations around struc-tural members)

Carpeting on cold floors

Locations where high surface humiditypromotes condensation

Solutions

Clean and disinfect to remove mold andmildew.(Note: Follow up by taking actions toprevent recurrence of microbiologicalcontamination. Use biocides, disinfec-tants, and sanitizers with caution andensure that occupant exposure is mini-mized.)

Increase surface temperatures to treatlocations that are subject to condensation

■ insulate thermal bridges■ improve air distribution

Reduce moisture levels in locations thatare subject to condensation

■ repair leaks■ increase ventilation (in cases where

outdoor air is cold and dry)■ dehumidify (in cases where outdoor air

is warm and humid)

Dry carpet or other textiles promptly aftersteam cleaning(Note: Increase ventilation to acceleratedrying.)

Discard contaminated materials

This is a school crawlspace in whichmoisture should be controlled. The fungusis Fusarium, some species of which aretoxigenic and should not be inside. Thespores were distributed by the air handlerbecause the return plenum was open to thecrawlspace.

96 Section 7

Low levels of contaminants are emittedfrom many of the building materialsand furnishings in an office. Dust canaccumulate on stacks of papers andopen shelves. Depending on howthey are cared for, plants potentiallyadd moisture, soil microbiologicals,and pesticides.

Examples

Odors from newly installed carpets,furniture, wall coverings

Newly drycleaned drapes or other textiles

Solutions

Remove source with appropriate cleaningmethods

■ steam clean carpeting and upholstery,then dry quickly, ventilating to acceler-ate the drying process

■ accept only fully dried, odorlessdrycleaned products

Encapsulate source

■ seal surfaces of building materials thatemit formaldehyde

Reduce source

■ schedule installation of carpet, furniture,and wall coverings to occur duringperiods when the building is unoccupied

■ have supplier store new furnishings in aclean, dry, well-ventilated area untilVOC outgassing has diminished

Increase outdoor air ventilation

■ total air supplied■ proportion of fresh air

Remove the materials that are producingthe emissions and replace with loweremission alternatives(Note: Only limited information onemissions from materials is available atthis time. Purchasers can request thatsuppliers provide emissions test data, butshould use caution in interpreting the testresults.)

Problem #10:Building Materials andFurnishings ProduceContaminants


Problem #11:Housekeeping or MaintenanceActivities Contribute toProblems

Examples

Cleaning products emit chemicals, odors

Particulates become airborne duringcleaning (e.g., sweeping, vacuuming)

Contaminants are released from painting,caulking, lubricating

Frequency of maintenance is insufficientto eliminate contaminants

Solutions

Remove source by modifying standardprocedures or frequency of maintenance(Note: Changing procedures may require acombination of policy-setting and trainingin IAQ impacts of staff activities.)

■ improve storage practices■ shift time of painting, cleaning, pest

control, other contaminant-producingactivities to avoid occupied periods

■ make maintenance easier by improvingaccess to filters, coils, and other compo-nents

Reduce source

■ select materials to minimize emissions ofcontaminants while maintaining ad-equate safety and efficacy

■ use portable HEPA (high efficiencyparticulate arrestance”) vacuums vs. low-efficiency paper-bag collectors

Use local exhaust

■ on a temporary basis to remove contami-nants from work areas

■ as a permanent installation wherecontaminants are stored

Indoor air quality problems can be causedby lack of adequate house-keepingpractices. On the other hand, deodorizers,cleansers and other products can alsoproduce odors and contaminants.

98 Section 7

Problem #12:Specialized Use Areas asSources of Contaminants

This chemical storage room should bemaintained under negative pressure.Properly designed and maintained localexhaust will achieve the proper air pressurerelationship with surrounding areas.Otherwise, such storage areas can be asource of occupant exposure to manyairborne contaminants.

Examples

Food preparationArt or print roomsLaboratories

Solutions

Change pollutant pathway relationships

■ run specialized use area under negativepressure relative to surrounding areas

■ install local exhaust, adjust HVACsystem to provide make-up air, and testto verify performance

Remove source by ceasing, relocating, orrescheduling incompatible activities

Reduce source by selecting materials tominimize emissions of contaminantswhile maintaining adequate safety andefficacy

Reduce source by using proper sealingand storage for materials that emitcontaminants


Problem #13:Remodeling or RepairActivities Produce Problems

Examples

Temporary activities produce odors andcontaminants

■ installation of new particleboard,partitions, carpet, or furnishings

■ painting■ reroofing■ demolition

Existing HVAC system does not provideadequate ventilation for new occupancyor arrangement of space

Solutions

Modify ventilation to prevent recircula-tion of contaminants

■ install temporary local exhaust inwork area, adjust HVAC system toprovide make-up air, and test toverify performance

■ seal off returns in work area■ close outdoor air damper during

re-roofing

Reduce source by scheduling work forunoccupied periods and keeping ventila-tion system in operation to remove odorsand contaminants

Reduce source by careful materialsselection and installation

■ select materials to minimize emissionsof contaminants while maintainingadequate safety and efficacy

■ have supplier store new furnishings in aclean, dry, well-ventilated area untilVOC outgassing has diminished

■ request installation procedures (e.g.,adhesives) that limit emissions ofcontaminants

Remodeling may involvemany activities that cancause IAQ problems.Ventilation modifications canbe used to isolate the workarea and prevent pollutantbuild-up in occupied spaces.Proper storage practices canminimize the release ofcontaminants.

Modify HVAC or wall partition layout ifnecessary

■ partitions should not interrupt airflow■ relocate supply and return diffusers■ adjust supply and return air quantities■ adjust total air and/or outdoor air supply

to serve new occupancy

100 Section 7

Problem #14:Combustion Gases

Combustion odors can indicate theexistence of a serious problem. Onecombustion product, carbon monoxide, isan odorless gas. Carbon monoxidepoisoning can be life-threatening.

Examples

Vehicle exhaust

■ offices above (or connected to) anunderground parking garage

■ rooms near (or connected by pathwaysto) a loading dock or service garage

Combustion gases from equipment(e.g., spillage from inadequately ventedappliances, cracked heat exchanger, re-entrainment because local chimney is toolow)

■ areas near a mechanical room■ distributed throughout zone or entire

building

Solutions

Seal to remove pollutant pathway

■ close openings between the contaminantsource and the occupied space

■ install well-sealed doors with automaticclosers between the contaminant sourceand the occupied space

Remove source

■ improve maintenance of combustionequipment

■ modify venting or HVAC system toprevent backdrafting

■ relocate holding area for vehicles atloading dock, parking area

■ turn off engines of vehicles that arewaiting to be unloaded

Modify ventilation system

■ install local exhaust in undergroundparking garage (adjust HVAC system toprovide make-up air and test to verifyperformance)

■ relocate fresh air intake (move awayfrom source of contaminants

Modify pressure relationships

■ pressurize spaces around area containingsource of combustion gases

Air intakes are frequently located near theloading dock for aesthetic reasons.Unfortunately, this air intake placement candraw car and truck exhaust into thebuilding, causing a variety of indoor airquality complaints.


Problem #15:Serious Building-RelatedIllness

Some building-related illnesses can be life-threatening. Even a single confirmeddiagnosis (which involves results fromspecific medical tests) should provoke animmediate and vigorous response.

Examples

Legionnaire’s disease(Note: If you suspect Legionnaire’sdisease, call the local public healthdepartment, check for obvious problemsites, and take corrective action. There isno way to be certain that a single case ofthis disease is associated with buildingoccupancy; therefore, public healthagencies usually do not investigate singlecases. Watch for new cases.)

Hypersensitivity pneumonitis(Note: Affected occupant(s) should beremoved and may not be able to returnunless the causative agent is removed fromthe affected person’s environment.)

Solutions

Work with public health authorities

■ evacuation may be recommended orrequired

Remove source

■ drain, clean, and decontaminate drippans, cooling towers, room unit airconditioners, humidifiers, dehumidifiers,and other habitats of Legionella, fungi,and other organisms using appropriateprotective equipment

■ install drip pans that drain properly■ provide access to all the items that must

be cleaned, drained, or replaced periodi-cally

■ modify schedule and procedures forimproved maintenance

Discontinue processes that depositpotentially contaminated moisture in airdistribution system

■ air washing■ humidification■ cease nighttime shutdown of air handlers

This air intake is locatedbetween the cooling towers.If the water in the coolingtowers becomescontaminated with Legionella,there is potential forLegionnaire’s disease in thebuilding.

102 Section 7

JUDGING PROPOSEDMITIGATION DESIGNSAND THEIR SUCESS

Mitigation efforts should be evaluated atthe planning stage by considering thefollowing criteria:

■ permanence■ operating principle■ degree to which the strategy fits the job■ ability to institutionalize the solution■ durability■ installation and operating costs■ conformity with codes

Permanence

Mitigation efforts that create permanentsolutions to indoor air problems are clearlysuperior to those that provide temporarysolutions (unless the problems are alsotemporary). Opening windows or runningair handlers on full outdoor air may besuitable mitigation strategies for a tempo-rary problem such as outgassing of volatilecompounds from new furnishings, butwould not be good ways to deal withemissions from a print shop. A permanentsolution to microbiological contaminationinvolves not only cleaning and disinfec-tion, but also modification of the environ-ment to prevent regrowth.

Operating Principle

The most economical and successfulsolutions to IAQ problems are those inwhich the operating principle of thecorrection strategy makes sense and issuited to the problem. If a specific pointsource of contaminants has been identified,treatment at the source (e.g., by removal,sealing, or local exhaust) is almost alwaysa more appropriate correction strategy thandilution of the contaminant by increasedgeneral ventilation. If the IAQ problem iscaused by the introduction of outdoor airthat contains contaminants, increasedgeneral ventilation will only make the

situation worse (unless the outdoor air iscleaned).

Degree to Which the StrategyFits the Job

It is important to make sure that youunderstand the IAQ problem well enoughto select a correction strategy whose sizeand scope fit the job. If odors from aspecial use area such as a kitchen arecausing complaints in a nearby office,increasing the ventilation rate in the officemay not be a successful approach. Themitigation strategy should address theentire area affected.

If mechanical equipment is needed tocorrect the IAQ problem, it must bepowerful enough to accomplish the task.For example, a local exhaust systemshould be strong enough and close enoughto the source so that none of the contami-nant is drawn into nearby returns andrecirculated.

Ability to Institutionalizethe Solution

A mitigation strategy will be most success-ful when it is institutionalized as part ofnormal building operations. Solutions thatdo not require exotic equipment are morelikely to be successful in the long run thanapproaches that involve unfamiliarconcepts or delicately maintained systems.If maintenance or housekeeping proce-dures or supplies must change as part ofthe mitigation, it may be necessary to planfor additional staff training, new inspectionchecklists, or modified purchasing prac-tices. Operating schedules for HVACequipment may also require modification.

Durability

IAQ mitigation strategies that are durableand low-maintenance are more attractive toowners and building staff than approachesthat require frequent adjustment or

The most economicaland successfulsolutions to IAQproblems are thosein which the operat-ing principle of thecorrection strategymakes sense and issuited to the prob-lem.


specialized maintenance skills. New itemsof equipment should be quiet, energy-efficient, and durable, so that the operatorsare encouraged to keep them running.

Installation and OperatingCosts

The approach with the lowest initial costmay not be the least expensive over thelong run. Other economic considerationsinclude: energy costs for equipment opera-tion, increased staff time for maintenance;differential cost of alternative materialsand supplies; and higher hourly rates ifodor-producing activities (e.g., cleaning)must be scheduled for unoccupied periods.Although these costs will almost certainlybe less than the cost of letting the problemcontinue, they are more readily identifi-able, so an appropriate presentation tomanagement may be required.

Conformity with Codes

Any modification to building componentsor mechanical systems should be designedand installed in keeping with applicablefire, electrical, and other building codes.

Judging the Success of aMitigation Effort

Two kinds of criteria can be used to judgethe success of an effort to correct an indoorair problem:

■ reduced complaints■ measurement of properties of the indoor

air (often only of limited usefulness)

Reduction or elimination of complaintsappears to be a clear indication of success,but that is not necessarily the case.Occupants who see that their concerns arebeing heard may temporarily stop report-ing discomfort or health symptoms, even ifthe actual cause of their complaints has notbeen addressed. Lingering complaints mayalso continue after successful mitigation ifpeople have become upset over the

MANAGING MITIGATION PROJECTSINVOLVING SEVERE CONTAMINATION

Cautions

Locating the original source of a chemi-cal release or microbiological growthmay only be the tip of the iceberg.Pollutants often tend to migrate througha building and collect in “sinks”, fromwhich they can be resuspended into theair. For example, particles accumulateon horizontal surfaces that are notsubject to regular housekeeping; odorsmay adsorb (stick) to porous materials.Detailed surface and/or bulk samplingmay be needed to locate such “second-ary” sources in order to solve an airquality problem.

Depending on the problem, a detailedknowledge of chemistry, microbiology,building science, and health and safetymay be required.

Include air sampling along with regularinspections if needed. Decontaminationof areas within an occupied building isespecially critical.

In the event of severe contamination,representative air samples should becollected to ensure that key indicatorshave returned to background levels andthat the space can be safely reoccupied.

Elements

Identify the extent of contami-nation

Develop a precise scope ofwork specifying exactly howremediation will be performed

Monitor remediation to ensurework practices are followed

Conduct clearancesampling

Many routine IAQ problems can becorrected by a common sense approachnot requiring special expertise. However,when complex exposure or contaminationissues are involved, more detailed techni-cal assistance may be needed for success-ful remediation. Efforts such as thoseoutlined above are sometimes needed todeal with severe contamination.

104 Section 7

handling of the problem. Ongoing (butreduced) complaints could also indicatethat there were multiple IAQ problems andthat one or more problems are still unre-solved.

However, it can be very difficult to usemeasurements of contaminant levels as ameans of determining whether air qualityhas improved. Concentrations of indoorair pollutants typically vary greatly overtime; further, the specific contaminantmeasured may not be causing the problem.If air samples are taken, readings takenbefore and after mitigation should beinterpreted cautiously. It is important tokeep the “before” and “after” conditions asidentical as possible, except for theoperation of the control strategy. Forexample, the same HVAC operation,building occupancy and climatic condi-tions should apply during both measure-ment periods. “Worst-case” conditionsidentified during the investigation shouldbe used.

Measurements of airflows, ventilationrates, and air distribution patterns are themore reliable methods of assessing theresults of control efforts. Airflow mea-surements taken during the buildinginvestigation can identify areas with poorventilation; later they can be used toevaluate attempts to improve the ventila-tion rate, distribution, or direction of flow.Studying air distribution patterns will showwhether a mitigation strategy has success-fully prevented a contaminant from beingtransported by airflow.

Persistent Problems

Solving an indoor air quality problem is acyclical process of data collection and

hypothesis testing. Deeper and moredetailed investigation is needed to suggestnew hypotheses after any unsuccessful orpartially-successful control attempt.

Even the best-planned investigationsand mitigation actions may not produce aresolution to the problem. You may havemade a careful investigation, found one ormore apparent causes for the problem, andimplemented a control system. Nonethe-less, your correction strategy may not havecaused a noticeable reduction in theconcentration of the contaminant orimprovement in ventilation rates orefficiency. Worse, the complaints maypersist even though you have beensuccessful at improving ventilation andcontrolling all of the contaminants youcould identify. When you have pursuedsource control options and have increasedventilation rates and efficiency to the limitsof your expertise, you must decide howimportant it is to pursue the problemfurther.

If you have made several unsuccessfulefforts to control a problem, then it may beadvisable to seek outside assistance. Theproblem is probably fairly complex, and itmay occur only intermittently or cross theborders that divide traditional fields ofknowledge. It is even possible that poorindoor air quality is not the actual cause ofthe complaints. Bringing in a newperspective at this point can be veryeffective.

The next section provides guidance onhiring professional indoor air qualityassistance. An interdisciplinary team (suchas people with engineering and medical orhealth backgrounds) may be needed tosolve particularly difficult problems.

If you have madeseveral unsuccessfulefforts to control aproblem, then it maybe advisable to seekoutside assistance.

Hiring Professional Assistance to Solve an IAQ Problem 105

Many IAQ problems are simple toresolve when facility staff have beeneducated about the investigation process.In other cases, however, a time comeswhen outside assistance is needed. Profes-sional help might be necessary or desirablein the following situations, among others:

■ Mistakes or delays could have seriousconsequences (e.g., health hazards, li-ability exposure, regulatory sanctions).

■ Building management feels that an inde-pendent investigation would be betterreceived or more effectively documentedthan an in-house investigation.

■ Investigation and mitigation efforts byfacility staff have not relieved theIAQ problem.

■ Preliminary findings by staff suggest theneed for measurements that requirespecialized equipment and trainingbeyond in-house capabilities.

You may be able to find help bylooking in the yellow pages of yourtelephone book (e.g., under “Engineers,”“Environmental Services,” “Laboratories -Testing,” or “Industrial Hygienists”).Local or State health or air pollutionagencies may have lists of firm offeringIAQ services in your area. It may also beuseful to seek out referrals from otherbuilding management firms.

Local, State, or Federal governmentagencies may be able to provide expertassistance or direction in solving IAQproblems. It is particularly important tocontact your local or State HealthDepartment if you suspect that you have aserious building-related illness potentiallylinked to biological contamination in yourbuilding.

If available government agencies do nothave personnel with the appropriate skills

8to assist in solving your IAQ problem, theymay be able to direct you to firms in yourarea with experience in indoor air qualitywork. Note that even certified profession-als from disciplines closely related to IAQissues (such as industrial hygienists,ventilation engineers, and toxicologists)may not have the specific expertise neededto investigate and resolve indoor airproblems. Individuals or groups that offerservices in this evolving field should bequestioned closely about their relatedexperience and their proposed approach toyour problem.

As with any hiring process, the betteryou know your own needs, the easier itwill be to select a firm or individual toservice those needs. Firms and individualsworking in IAQ may come from a varietyof disciplines. Typically, the skills ofHVAC engineers and industrial hygienistsare useful for this type of investigation,although input from other disciplines suchas chemistry, chemical engineering, archi-tecture, microbiology, or medicine mayalso be important. If problems other thanindoor air quality are involved, experts inlighting, acoustic design, interior design,psychology, or other fields may be helpfulin resolving occupant complaints about theindoor environment.

MAKE SURE THAT THEIRAPPROACH FITS YOUR NEEDS

As you prepare to hire professional ser-vices in the area of indoor air quality, beaware it is a developing area of knowledge.Most consultants working in the field re-ceived their primary training in other areas.A variety of investigative methods may beemployed, many of which are ineffectivefor resolving any but the most obvious

As you prepare tohire professionalservices in the areaof indoor air quality,be aware that it is adeveloping area ofknowledge.

Hiring Professional Assistance toSolve an IAQ Problem

106 Section 8

situations. Inappropriately designed studiesmay lead to conclusions that are eitherfalse negative (e.g., falsely concludes thatthere is no problem associated with thebuilding) or false positive (e.g., incorrectlyattributes the cause to building conditions).

Diagnostic outcomes to avoid include:■ an evaluation that overemphasizes

measuring concentrations of pollutantsand comparing those concentrations tonumerical standards, and

■ a report that lists a series of major andminor building deficiencies and links allthe deficiencies to the problem withoutconsidering their actual association withthe complaints.

Considerable care should be exercisedwhen interviewing potential consultants toavoid those subscribing to these strategies.A qualified IAQ investigator should haveappropriate experience, demonstrate abroad understanding of indoor air qualityproblems and the conditions which canlead to them, and use a phased diagnosticapproach.

SELECTION CRITERIA

Most of the criteria used in selecting aprofessional to provide indoor air qualityservices are similar to those used for otherprofessionals:■ company experience in solving similar

problems, including training and experi-ence of the individuals who would beresponsible for the work

■ quality of interview and proposal■ company reputation■ knowledge of local codes and regional

climate conditions■ cost

Diagnostic outcomesto avoid include anevaluation that over-emphasizes measur-ing concentrations ofpollutants and areport that links allthe deficiencies inthe building to theproblem withoutconsidering theiractual associationwith the complaints.

Experience

An EPA survey of firms providing IAQservices found that almost half had beenproviding IAQ diagnostic or mitigationservices in non-industrial settings for ten orfewer years.■ Ask how much IAQ work and what type

of IAQ work the firm has done.■ Have the firm identify the personnel who

would be responsible for your case, theirspecific experience, and related qualifi-cations. Contract only for the services ofthose individuals, or require approval forsubstitutions.

Quality of Interview andProposal

Several guidelines may be of assistance inhiring IAQ professionals.

1. Competent professionals will askquestions about your situation to seewhether they feel they can offer servicesthat will assist you.

The causes and potential remedies forindoor air quality problems vary greatly.A firm needs at least a preliminaryunderstanding of the facts about what isgoing on in your building to evaluate if ithas access to the professional skillsnecessary to address your concerns and tomake effective use of its personnel fromthe outset. Often a multi-disciplinary teamof professionals is needed.

2. The proposal for the investigationshould emphasize observations ratherthan measurements.

Section 6 describes the four types ofinformation that may need to be gatheredin an investigation in order to resolve anindoor air quality problem: the occupantcomplaints, the HVAC system, pollutantpathways, and pollutant sources. There isalso a discussion of the role of monitoring

Hiring Professional Assistance to Solve an IAQ Problem 107

within an investigation. Non-routinemeasurements (such as relatively expen-sive sampling for VOCs) should not beprovided without site-specific justification.

3. The staff responsible for building in-vestigation should have a good under-standing of the relationship between IAQand the building structure, mechanicalsystems, and human activities.

For example, lack of adequate ventila-tion is at least a contributing factor inmany indoor air quality problem situations.Evaluating the performance of the ventila-tion system depends on understanding theinteraction between the mechanical systemand the human activity within the building.

In some cases building investigatorsmay have accumulated a breadth ofknowledge. For example, a mechanicalengineer and an industrial hygienist seebuildings differently. However, a me-chanical engineer with several years ofexperience in IAQ problem investigationsmay have seen enough health-relatedproblems to cross the gap; likewise, anindustrial hygienist with years of experi-ence studying problems in an office settingmay have considerable expertise in HVACand other building mechanical systems.

Either in the proposal or in discussion,the consultant should:■ Describe the goal(s), methodology, and

sequence of the investigation, theinformation to be obtained, and theprocess of hypothesis development andtesting, including criteria for decision-making about further data-gathering.The proposal should include an explana-tion of the need for any proposedmeasurements. The goal is to reach asuccessful resolution of the complaints,not simply to generate data.

■ Identify any elements of the work thatwill require a time commitment from theclient’s own staff, including information

to be collected by the client.■ Identify additional tasks (and costs)

which are part of solving the IAQproblem but are outside the scope of thecontract. Examples might includemedical examination of complainants,laboratory fees, and contractor’s fees formitigation work.

■ Describe the schedule, cost, and workproduct(s), such as a written report,specifications, and plans for mitigationwork; supervision of mitigation work;and training program for building staff.

■ Discuss communication between theIAQ professional and the client: Howoften will the contractor discuss theprogress of the work with the client?Who will be notified of test results andother data? Will communications be inwriting, by telephone, or face-to-face?Will the consultant meet with buildingoccupants to collect information? Willthe consultant meet with occupants todiscuss findings if requested to do so?

Reputation

There are no Federal regulations coveringprofessional services in the general field ofindoor air quality, although some disci-plines (e.g., engineers, industrial hygien-ists) whose practitioners work with IAQproblems have licensing and certificationrequirements.

Building owners and managers whosuspect that they may have a problem witha specific pollutant (such as radon, asbes-tos, or lead) may be able to obtain assis-tance from local and State Health Depart-ments. Government agencies and affectedindustries have developed training pro-grams for contractors who diagnose ormitigate problems with these particularcontaminants.

Firms should be asked to provide refer-ences from clients who have receivedcomparable services. In exploring refer-

The goal of theinvestigative processis to reach a success-ful resolution of thecomplaints, notsimply to generatedata.

108 Section 8

ences, it is useful to ask about long-termfollow-up. After the contract was com-pleted, did the contractor remain in contactwith the client to ensure that problems didnot recur?

Knowledge of Local Codes andRegional Climate Conditions

Familiarity with State and local regulationsand codes helps to avoid problems duringmitigation. For example, in makingchanges to the HVAC system, it is impor-tant to conform to local building codes.Heating, cooling, and humidity controlneeds are different in different geographicregions, and can affect the selection of anappropriate mitigationapproach. Getting assurances that all firmsunder consideration have this knowledgebecomes particularly important if itbecomes necessary to seek expertisefrom outside the local area.

Cost

It is impossible for this document to givespecific guidance on the cost of profes-sional services. If projected costs jumpsuddenly during the investigation process,the consultants should be able to justifythat added cost.

The budget will be influenced by anumber of factors, including:■ complexity of the problem■ size and complexity of the building and

its HVAC system(s)■ quality and extent of recordkeeping by

building staff and management■ type of report or other product required■ number of meetings required (formal

presentations can be quite expensive)■ air sampling (e.g., use of instruments,

laboratory analysis) if required

. .

APPENDICIES

Common IAQ Measurements — A General Guide 109

Appendix A:Common IAQ Measurements - A General Guide

The following is a brief introduction tomaking measurements that might beneeded in the course of developing an IAQprofile or investigating an IAQ complaint.Emphasis has been placed on the param-eters most commonly of interest in non-research studies, highlighting the morepractical methods and noting someinappropriate tests to avoid. Most of theinstruments discussed in this section arerelatively inexpensive and readily availablefrom many local safety supply companies.Consult the guidance in Section 6 on pages72-73 before determining whether toproceed with air sampling.

OVERVIEW OF SAMPLING DEVICES

Air contaminants of concern in IAQ can bemeasured by one or more of the followingmethods:

Vacuum Pump:A vacuum pump with a known airflow ratedraws air through collection devices, suchas a filter (catches airborne particles), asorbent tube (which attracts certainchemical vapors to a powder such ascarbon), or an impinger (bubbles thecontaminants through solution in a testtube). Tests originated for industrialenvironments typically need to be adjustedto a lower detection limit for IAQ work.Labs can be asked to report when tracelevels of an identifiable contaminant arepresent below the limit of quantificationand detection.

In adapting an industrial hygienesorbent tube sampling method for IAQ, theinvestigator must consider at least twoimportant questions. First: are theemissions to be measured from a product’send use the same as those of concern

SELECTING MEASUREMENT DEVICES

The growing interest in indoor air quality is stimulating the development ofinstruments for IAQ research and building investigations. As you evaluatethe available measurement devices, it may be helpful to consider thefollowing criteria:

Ease of use■ portability■ direct-reading vs. analysis required■ ruggedness■ time required for each measurement

Quality assurance■ availability of service and customer support■ maintenance and calibration requirements

Output■ time-averaged vs. instantaneous readings■ sensitivity■ compatibility with computer or data logging accessories

Cost■ single use only vs. reusable■ purchase vs. rental

during manufacturing? Second: is itnecessary to increase the air volumesampled? Such an increase may be neededto detect the presence of contaminants atthe low concentrations usually found innon-industrial settings. For example, aninvestigator might have to increasesampling time from 30 minutes to 5 hoursin order to detect a substance at the lowconcentrations found during IAQ investi-gations. In cases where standard samplingmethods are changed, qualified industrialhygienists and chemists should be con-sulted to ensure that accuracy and preci-sion remain acceptable.

Direct-reading Meter:Direct-reading meters estimate air concen-trations through one of several detectionprinciples. These may report specific

110 Appendix A

chemicals (e.g., CO2 by infrared light),

chemical groups (e.g., certain volatile or-ganics by photoionization potential) orbroad pollutant categories (e.g., all respi-rable particles by scattered light). Detec-tion limits and averaging time developedfor industrial use may or may not be appro-priate for IAQ.

Detector tube kit:Detector tube kits generally include a handpump that draws a known volume of airthrough a chemically treated tube intendedto react with certain contaminants. Thelength of color stain resulting in the tubecorrelates to chemical concentration.

Personal monitoring devices:Personal monitoring devices (sometimesreferred to as “dosimeters”) are carried orworn by individuals and are used to mea-sure that individual’s exposure to particularchemical(s). Devices that include a pumpare called “active” monitors; devices thatdo not include a pump are called “passive”monitors. Such devices are currently usedfor research purposes. It is possible thatsometime in the future they may also behelpful in IAQ investigations in public andcommercial buildings.

SIMPLE VENTILATION/COMFORTINDICATIONS

Thermal Comfort: Temperature andRelative Humidity

The sense of thermal comfort (or discom-fort) results from an interaction betweentemperature, relative humidity, air move-ment, clothing, activity level, and indi-vidual physiology. Temperature andrelative humidity measurements areindicators of thermal comfort.

Methodology

Measurements can be made with a simplethermometer and sling psychrometer orwith electronic sensors (e.g., a thermo-hygrometer). Accuracy of within + or - 1°Fis recommended for temperature measure-

Above: A smoke tube, which is one type ofchemical smoke device. Used to observepatterns of air movement and the direction(negative or positive) of pressure differ-ences. Below: A microman-ometer. Usedfor measuring pressure differentials to learnabout airflow. Provides quantitative data,as compared to the qualitative informationprovided by chemical smoke.


ments. For each measurement, time shouldbe allowed for the reading to stabilize toroom conditions. Refer to the specifica-tions for the measuring device; some takeseveral minutes to stabilize. Electronicrelative humidity (RH) meters must becalibrated frequently.

Indoor relative humidity is influencedby outdoor conditions. A single indoormeasurement may not be a good indicationof long-term relative humidity in the build-ing. Programmable recording sensors canbe used to gain an understanding of tem-perature or humidity conditions as theychange over time.

Using the Results

Temperature and humidity directly affectthermal comfort. They may also provideindirect indications of HVAC conditionand the potential for airborne contamina-tion from biological or organic com-pounds. There is considerable debateamong researchers, IAQ professionals, andhealth professionals concerning recom-mended levels of relative humidity; how-ever, the humidity levels recommended bydifferent organizations generally rangebetween 30% and 60% RH.

Comparison of indoor and outdoortemperature and humidity readings takenduring complaint periods can indicatewhether thermal discomfort might be dueto extreme conditions beyond the designcapacity of HVAC equipment or the build-ing envelope.

Measure next to thermostats to confirmcalibration. Measure at the location ofcomplaints to evaluate whether or nottemperature and humidity at that locationare within the comfort zone (see Figure 6-2on page 57).

Readings that show large variationswithin the space may indicate a room airdistribution or mixing problem. Readingsthat are highly variable over time mayindicate control or balance problems withthe HVAC systems.

Tracking Air Movement withChemical Smoke

Chemical smoke can be helpful in evaluat-ing HVAC systems, tracking potentialcontaminant movement, and identifyingpressure differentials. Chemical smokemoves from areas of higher pressure toareas of lower pressure if there is anopening between them (e.g., door, utilitypenetration). Because it is heatless,chemical smoke is extremely sensitive toair currents. Investigators can learn aboutairflow patterns by observing the directionand speed of smoke movement. Puffs ofsmoke released at the shell of the building(by doors, windows, or gaps) will indicatewhether the HVAC systems are maintain-ing interior spaces under positive pressurerelative to the outdoors.

Methodology

Chemical smoke is available with variousdispensing mechanisms, including smoke“bottles,” “guns,” “pencils,” or “tubes.”The dispensers allow smoke to be releasedin controlled quantities and directed atspecific locations. It is often moreinformative to use a number of small puffsof smoke as you move along an airpathway rather than releasing a large

A psychrometer. Used tomeasure dry bulb and wetbulb temperatures and todetermine relative humiditybased upon a psychometricchart. The NIOSH protocolfor indoor air investigationsalways includes measurementof indoor and outdoor relativehumidity. There are twotypes of psychrometers: aspi-rated (with a fan) or sling(without a fan).

112 Appendix A

amount in a single puff. (Note: Avoiddirect inhalation of chemical smoke,because it can be irritating. Do not releasesmoke directly on smoke detectors.)

Using the Results

Smoke released mid-room: Observationof a few puffs of smoke released in mid-room or mid-cubicle can help to visualizeair circulation within the space. Dispersalof smoke in several seconds suggests goodair circulation, while smoke that staysessentially still for several secondssuggests poor circulation. Poor aircirculation may contribute to sick buildingsyndrome complaints or may contribute tocomfort complaints even if there issufficient overall air exchange.

Smoke released near diffusers, grilles:Puffs of smoke released by HVAC ventsgive a general idea of airflow. (Is it in orout? Vigorous? Sluggish? No flow?)This is helpful in evaluating the supply andreturn system and determining whetherventilation air actually reaches the breath-ing zone. (For a variable air volumesystem, be sure to take into account howthe system is designed to modulate. Itcould be on during the test, but off formuch of the rest of the day.) “Short-circuiting” occurs when air movesrelatively directly from supply diffusers toreturn grilles, instead of mixing with roomair in the breathing zone. When a substan-tial amount of air short-circuits, occupantsmay not receive adequate supplies ofoutdoor air and source emissions may notbe diluted sufficiently.

Carbon Dioxide (CO2) as anIndicator of Ventilation

CO2 is a normal constituent of the atmo-

sphere. Exhaled breath from buildingoccupants is an important indoor CO

2

source. Indoor CO2 concentrations can,

under some test conditions, provide a goodindication of the adequacy of ventilation.

Comparison of peak CO2 readings between

rooms, between air handler zones, and atvarying heights above the floor, may helpto identify and diagnose various buildingventilation deficiencies.

Methodology

CO2 can be measured with either a direct-

reading meter or a detector tube kit. Therelative occupancy, air damper settings,and weather should be noted for eachperiod of CO

2 testing.

CO2 measurements for ventilation

should be collected away from any sourcethat could directly influence the reading(e.g., hold the sampling device away fromexhaled breath). Individual measurementsshould be short-term. As with many othermeasurements of indoor air conditions, it isadvisable to take one or more readings in“control” locations to serve as baselines forcomparison. Readings from outdoors andfrom areas in which there are no apparentIAQ problems are frequently used ascontrols. Outdoor samples should be takennear the outdoor air intake.

Measurements taken to evaluate theadequacy of ventilation should be madewhen concentrations are expected to peak.It may be helpful to compare measure-ments taken at different times of day. Ifthe occupant population is fairly stableduring normal business hours, CO

2 levels

will typically rise during the morning, fallduring the lunch period, then rise again,reaching a peak in mid-afternoon. In thiscase, sampling in the mid- to late-after-noon is recommended. Other samplingtimes may be necessary for differentoccupancy schedules.

Using the Results

Peak CO2 concentrations above 1000 ppm

in the breathing zone indicate ventilationproblems. Carbon dioxide concentrationsbelow 1000 ppm generally indicate thatventilation is adequate to deal with theroutine products of human occupancy.


However, there are several reasons not toconclude too quickly that a low CO

2

reading means no IAQ problem exists.Problems can occur in buildings in whichmeasured CO

2 concentrations are below

1000 ppm. Although CO2 readings

indicate good ventilation, for example, ifstrong contaminant sources are present,some sort of source control may be neededto prevent IAQ problems. Errors inmeasurement and varying CO

2 concentra-

tions over time can also cause low readingsthat may be misleading.

Elevated CO2 may be due to various

causes alone or in combination, such as:increased occupant population, air ex-change rates below ASHRAE guidelines,poor air distribution, and poor air mixing.A higher average CO

2 concentration in the

general breathing zone (at least two feetfrom exhaled breath) than in the airentering return grilles is an indication ofpoor air mixing. Smoke tubes andtemperature profiles will help to clarify aircirculation patterns.

If CO2 measurements taken before the

occupied period begins are higher thanoutdoor readings taken at the same time,there may be an operating problem withthe HVAC system. Potential problemsinclude the following:

■ ventilation terminated too early theevening before (as compared with theoccupancy load on the space)

■ combustion by-products from a nearbyroadway or parking garage are drawninto the building

■ a gas-fired heating appliance in thebuilding has a cracked heat exchanger

Outdoor CO2 concentrations above 400

ppm may indicate an outdoor contamina-tion problem from traffic or other combus-tion sources. Note, however, that detectortubes cannot provide accurate measure-ments of CO

2 in hot or cold weather.

Measuring Airflow

A flow hood. Used tomeasure the total air flow(outdoor plus recirculated air)from a diffuser.

Measurements of airflow allow investiga-tors to estimate the amount of outdoor airthat is entering the building and to evaluateHVAC system operation. The mostappropriate measurement techniquedepends on the characteristics of themeasurement location.

Methodology

Airflow quantities can be calculated bymeasuring the velocity and cross-sectionalarea of the airstream. For example, if air ismoving at 100 feet per minute in a 24” x

114 Appendix A

12” duct, the airflow is:

100 feet/minute x 2 square feet duct area= 200 cubic feet/minute

Air velocity can be measured with a pitottube or anemometer. Air velocity withinan airstream is likely to vary considerably.For example, it is extremely difficult tomeasure air velocity at supply diffusersbecause of turbulence around the mixingvanes. The best estimates of air velocitycan be achieved by averaging the results ofa number of measurements. ASTMStandard Practice D 3154 providesguidance on making such measurements.This method is available from ASTM.(See Appendix G for ASTM’s address andphone number.) The cross-sectional areaof the airstream is sometimes easy tocalculate (e.g., in a straight run of rectan-gular ductwork), but can be very compli-cated at other locations such as mixingboxes or diffusers.

Flow hoods can be used for directmeasurement of airflows at locations suchas grilles, diffusers, and exhaust outlets.They are not designed for use in ductwork.

Using the Results

Airflow measurements can be used todetermine whether the HVAC system isoperating according to design and to

A vacuum pump withattachments for samplingwith a filter, a sorbent tube,and an impinger. Use in anon-industrial setting mayrequire a larger volume of air.Consult with qualifiedindustrial hygienists andchemists if adapting samplingmethods.

identify potential problem locations.Building investigations often includemeasurements of outdoor air quantities,exhaust air quantities, and airflows atsupply diffusers and return grilles.

Estimating Outdoor Air Quantities

Outdoor air quantities can be evaluated bymeasuring airflow directly. Investigatorsoften estimate the proportion of outdoor airquantities using techniques such as thermalmass balance (temperature) or CO

2

measurements. Estimation of outdoor airquantity using temperature measurementsis referred to as “thermal balance” orsometimes “thermal mass balance.”

Thermal Balance: Methodology

Use of this test requires the followingconditions:

1. Airstreams representing return air,outdoor air, and mixed air (supply airbefore it has been heated or cooled) areaccessible for separate measurement.Some systems are already equipped withan averaging thermometer that is strungdiagonally across the mixed air chamber;the temperature is read out continuously onan instrument panel. Some panels read outsupply, return, outdoor, and/or mixed airtemperature.

2. There is at least a several degreetemperature difference between thebuilding interior and the outdoor air.

3. Total air flow in the air handling systemcan be estimated either by using recentbalancing reports or pitot tube measure-ments in ductwork. As an alternative, thesupply air at each diffuser can be estimated(e.g., using a flow measuring hood), andthe results can be summed to calculatetotal system air flow.

Temperature measurements can be madewith a simple thermometer or an electronicsensor. Several measurements should betaken across each airstream and averaged.


It is generally easy to obtain a good tem-perature reading in the outdoor air andreturn airstreams. To obtain a good aver-age temperature reading of the mixed air-stream, a large number of measurementsmust be taken upstream of the point atwhich the airstream is heated or cooled.This may be difficult or impossible insome systems.

The percentage or quantity of outdoor airis calculated using thermal measurementsas shown to the right.

Methodology: Carbon DioxideMeasurements

CO2 readings can be taken at supply outlets

or air handlers to estimate the percentageof outdoor air in the supply airstream. Thepercentage or quantity of outdoor air is cal-culated using CO

2 measurements as shown

to the right.

Using the Results

The results of this calculation can becompared to the building design specifica-tions, applicable building codes, orventilation recommendations such asASHRAE 62-1989 (see page 136 inAppendix B) to see whether under-ventilation appears to be a problem.

AIR CONTAMINANTCONCENTRATIONS

Volatile Organic Compounds (VOCs)

Hundreds of organic (carbon-containing)chemicals are found in indoor air at tracelevels. VOCs may present an IAQproblem when individual organics ormixtures exceed normal backgroundconcentrations.

Methodology: Total Volatile OrganicCompounds (TVOCs)

Several direct-reading instruments are

available that provide a low sensitivity“total” reading for different types oforganics. Such estimates are usuallypresented in parts per million and arecalculated with the assumption that allchemicals detected are the same as the oneused to calibrate the instrument. Aphotoionization detector is an example of adirect-reading instrument used as ascreening tool for measuring TVOCs.

A laboratory analysis of a sorbent tubecan provide an estimate of total solvents inthe air. Although methods in this categoryreport “total volatile organic compounds”(TVOCs) or “total hydrocarbons” (THC),

Using Thermal Mass Balance

Outdoor air (percent) = x100

Where: T = temperature (degrees Farenheit)

Using Carbon Dioxide Measurements

Outdoor air (%) = x 100

Where: CS = ppm CO2 in the supply air (if measured in a room), orCS = ppm of CO2 in the mixed air (if measured at an air

handler)CR = ppm of CO2 in the return airCO = ppm of CO2 in the outdoor air

(All these concentrations must be measured, not assumed.)

Converting Percent To CFM

Outdoor air (in cfm) = x total airflow (cfm)

Where: cfm = cubic feet per minute

The number used for total airflow may be the air quantity supplied to aroom or zone, the capacity of an air handler, or the total airflow of theHVAC system. Note: The actual amount of airflow in an air handler isoften different from the quantity in design documents.

Treturn air - Tmixed air

Treturn air -T

outdoor air

CS-CR

CO-CR

ESTIMATING OUTDOOR AIR QUANTITIES

Outdoor air (percent)100

116 Appendix A

analytical techniques differ in theirsensitivity to the different types of organ-ics. (For discussion of measurementdevices and their sensitivity, see Overviewof Sampling Devices on page 109.)

Using the Results

Different measurement methods are usefulfor different purposes, but their resultsshould generally not be compared to eachother. Direct-reading instruments do notprovide sufficient sensitivity to differenti-ate normal from problematic mixtures oforganics. However, instantaneous readoutsmay help to identify “hot spots,” sources,and pathways. TVOCs or THC deter-mined from sorbent tubes provide moreaccurate average readings, but are unableto distinguish peak exposures. A direct-reading instrument can identify peakexposures if they happen to occur duringthe measurement period.

Methodology: Individual VolatileOrganic Compounds (VOCs)

High concentrations of individual volatileorganic compounds (VOCs) may alsocause IAQ problems. Individual VOCscan be measured in indoor air with amoderate degree of sensitivity (i.e.,measurement in parts per million) throughadaptations of existing industrial airmonitoring technology. Examples ofmedium sensitivity testing devices includeXAD-4 sorbent tubes (for nicotine),charcoal tubes (for solvents), andchromosorb tubes (for pesticides). After asufficient volume of air is pumped throughthese tubes, they are sent to a lab forextraction and analysis by gaschromatography. Variations use a passivedosimeter (charcoal badge) to collect thesample or a portable gas chromatographonsite for direct injection of building air.These methods may not be sensitiveenough to detect many trace level organicspresent in building air.

High sensitivity techniques have

recently become available to measure“trace organics” — VOCs in the air (i.e.measurements in parts per billion.)Sampling may involve Tenax and multiplesorbent tubes, charcoal tubes, evacuatedcanisters, and other technology. Analysisinvolves gas chromatography followed bymass spectroscopy.

Using the Results

Guidelines for public health exposure (asopposed to occupational exposure) for afew VOCs are available in the WorldHealth Organization (WHO) Air QualityGuidelines for Europe. These guidelinesaddress noncarcinogenic and carcinogeniceffects. Occupational exposure standardsexist for many other VOCs. No rule-of-thumb safety factor for applying theseoccupational limits to general IAQ iscurrently endorsed by EPA and NIOSH.

Measurement of trace organics mayidentify the presence of dozens to hundredsof trace VOCs whose significance isdifficult to determine. It may be helpful tocompare levels in complaint areas to levelsin outdoor air or non-complaint areas.

Formaldehyde

Formaldehyde is a VOC that has beenstudied extensively. Small amounts offormaldehyde are present in most indoorenvironments. Itching of the eyes, nose, orthroat may indicate an elevated concentra-tion. Sampling may be helpful whenrelatively new suspect materials arepresent.

Methodology

A number of measurement methods areavailable. Sensitivity and sampling timeare very important issues in selecting amethod; however, many methods allowdetection of concentrations well below0.1 ppm (see Using the Results below).Measurement of short-term peaks (arounda two-hour sample time) is ideal for


evaluating acute irritation. Dosimetersmay accurately record long-term exposurebut may miss these peaks.

Two commonly used methods that aregenerally acceptable for IAQ screeninginvolve impingers and sorbent tubes.Other appropriate methods are alsoavailable.

Using the Results

Various guidelines and standards areavailable for formaldehyde exposure.Several organizations have adopted0.1 ppm as guidance that providesreasonable protection against irritationaleffects in the normal population.Hypersensitivity reactions may occur atlower levels of exposure. Worst-caseconditions are created by minimumventilation, maximum temperatures, andhigh source loadings.

Biological Contaminants

Human health can be affected by exposureto both living and non-living biologicalcontaminants. The term “bioaerosols”describes airborne material that is or wasliving, such as mold and bacteria, parts ofliving organisms (e.g., insect body parts),and animal feces.

Testing for biological contaminantsshould generally be limited to:

■ cases where a walkthrough investigationor human profile study suggests micro-biological involvement

■ cases in which no other pollutant orphysical condition can account forsymptoms

Methodology

Inspection of building sanitary conditionsis generally preferred over sampling,because direct sampling can producemisleading results. Any sampling shouldbe accompanied by observations ofsanitary conditions and a determination asto whether any health problems appearlikely to be related to biological contami-

nation.No single technique is effective for

sampling the many biological contami-nants found in indoor environments. Avariety of specific approaches are used toretrieve, enumerate, and identify each kindof microorganism from water, surfaces,and air. Other specific methods are usedfor materials such as feces or insect parts.The utility of these techniques dependsupon their use by professionals who have athorough understanding of the sample siteand the target organism.

Where air sampling is desired, severalapproaches are available. The mostcommon type of air sampler uses a pumpto pull air across a nutrient agar, which isthen incubated. Any bacterial or fungalcolonies that subsequently grow can becounted and identified by a qualifiedmicrobiologist. Different types of agar andincubation temperatures are used to culturedifferent types of organisms. Only livingorganisms or spores in the air are countedby this method. Settling plates, which aresimply opened to room air and thenincubated, are sometimes used to identifywhich bioaerosols are present in differentlocations. The drawbacks to this techniqueare that it does not indicate the quantity ofbioaerosols present and that only the

A viable impactor. Used tosample for biologicals.Training is required in orderto analyze the results.

118 Appendix A

reactions

Airborne Dust

Particles and fibers suspended in the airgenerally represent a harmless backgroundbut can become a nuisance or cause serioushealth problems under some conditions.

Methodology

A variety of collection and analyticaltechniques are available. Dust can becollected by using a pump to draw airthrough a filter. The filter can then beweighed (gravimetric analysis) or exam-ined under a microscope. Direct readoutsof airborne dust are also available (such asusing meters such as those equipped with a“scattered light” detector).

Using the Results

IAQ measurements for airborne dust willbe well below occupational and ambientair guidelines except under the mostextreme conditions. Unusual types orelevated amounts of particles or fibers canhelp identify potential exposure problems.

Combustion Products

Combustion products are released bymotor vehicle exhaust, tobacco smoke, andother sources, and contain airborne dust(see the previous section) along withpotentially harmful gases such as carbonmonoxide and nitrogen oxides.

Methodology

Direct-reading meters, detector tubes, andpassive dosimeters are among the tech-niques most commonly used to measurecarbon monoxide and nitrogen oxides.

Using the Results

Comparison with occupational standards

bioaerosols that are heavy enough to fallout onto the agar will be recorded.

Using the Results

Quantities and types of bioaerosols canvary greatly over time in any givenbuilding, making sampling results difficultto interpret. Comparison of relativenumbers and types between indoors andoutdoors or between complaint areas andbackground sites can help to establishtrends; however, no tolerance levels orabsolute guidelines have been established.Low bioaerosol results by themselves arenot considered proof that a problem doesnot exist, for a variety of reasons:

■ the sampling and identification tech-niques used may not be suited to thetype(s) of bioaerosols that are present

■ biological growth may have beeninactive during the sampling period

■ the analysis technique used may notreveal non-living bioaerosols (e.g., feces,animal parts) that can cause health

High-flow indoor particulatesampler. Used to measureparticles 10 microns andsmaller that are readilyinhaled.


Methodology

EPA, NIOSH, and ASTM referencesshould be consulted for specific samplingtechniques. Detector tubes or impingermethods are applicable in some cases.

Using the Results

No generalization can be applied to thisdiverse group of substances.

will reveal only whether an imminentdanger exists. Any readings that areelevated above outdoor concentrations orbackground building levels may indicate amixture of potentially irritating combustionproducts, especially if susceptible indi-viduals are exposed.

Other Inorganic Gases

Although they are not routinely sampled inmost IAQ studies, a variety of other gasesmay be evaluated where conditionswarrant. Examples might include ammo-nia, ozone, and mercury.

HVAC Systems and Indoor Air Quality 121

Appendix B:HVAC Systems and Indoor Air Quality

This appendix provides informationabout specific HVAC system designs andcomponents in relation to indoor airquality. It also serves as introductorymaterial for building owners and managerswho may be unfamiliar with the terminol-ogy and concepts associated with HVAC(heating, ventilating, and air conditioning)system design. Further detailed informa-tion can be found in ASHRAE manualsand guides and in some of the guidancedeveloped by other trade and professionalassociations. (See Guidelines of CareDeveloped by Trade Associations inSection 5.) Additional information can beobtained using Appendix G or throughdiscussion with your facility engineer.

BACKGROUND

All occupied buildings require a supply ofoutdoor air. Depending on outdoorconditions, the air may need to be heatedor cooled before it is distributed into theoccupied space. As outdoor air is drawninto the building, indoor air is exhausted orallowed to escape (passive relief), thusremoving air contaminants.

The term “HVAC system” is used torefer to the equipment that can provideheating, cooling, filtered outdoor air, andhumidity control to maintain comfortconditions in a building. Not all HVACsystems are designed to accomplish allof these functions. Some buildings relyon only natural ventilation. Others lackmechanical cooling equipment (AC), andmany function with little or no humiditycontrol. The features of the HVAC systemin a given building will depend on severalvariables, including:

■ age of the design■ climate■ building codes in effect at the time of

the design■ budget that was available for the project■ planned use of the building■ owners’ and designers’ individual

preferences■ subsequent modifications

HVAC systems range in complexityfrom stand-alone units that serveindividual rooms to large, centrallycontrolled systems serving multiple zonesin a building. In large modern officebuildings with heat gains from lighting,people, and equipment, interior spacesoften require year-round cooling. Roomsat the perimeter of the same building (i.e.,rooms with exterior walls, floors, or roofsurfaces) may need to be heated and/orcooled as hourly or daily outdoor weatherconditions change. In buildings over onestory in height, perimeter areas at the lowerlevels also tend to experience the greatestuncontrolled air infiltration.

Working with the electricalcomponents of an HVACsystem involves the risk ofelectrocution and fire. Aknowledgeable member ofthe building staff shouldoversee the inspection of theHVAC controls.

122 Appendix B

Some buildings use only naturalventilation or exhaust fans to remove odorsand contaminants. In these buildings,thermal discomfort and unacceptableindoor air quality are particularly likelywhen occupants keep the windows closedbecause of extreme hot or cold tempera-tures. Problems related to underventilationare also likely when infiltration forces areweakest (i.e., during the “swing seasons”and summer months).

Modern public and commercial build-ings generally use mechanical ventilationsystems to introduce outdoor air during theoccupied mode. Thermal comfort iscommonly maintained by mechanicallydistributing conditioned (heated or cooled)air throughout the building. In somedesigns, air systems are supplemented bypiping systems that carry steam or water tothe building perimeter zones. As thisdocument is concerned with HVACsystems in relation to indoor air quality,the remainder of this discussion will focuson systems that distribute conditioned airto maintain occupant comfort.

Roles of the HVAC System Operatorand Facility Manager

The system operator(s) and facilitymanager(s) (or IAQ manager) are amongthe most significant factors in determiningwhether IAQ problems will occur in aproperly designed, constructed, andcommissioned HVAC system. HVACsystems require preventive maintenance andprompt repairs if they are to operatecorrectly and provide comfortable condi-tions. The operator(s) must have anadequate understanding of the overallsystem design and its limitations. TheHVAC system capacity and distributioncharacteristics should be evaluated beforerenovations to the building, changes in itsoccupancy, or changes in the use of an area.

System operators must be able torespond appropriately to occupant com-plaints. For example, if an occupant

complains that it is too cold or too hot andthe observed (measured) conditions areoutside of the ASHRAE comfort zone,then the HVAC system needs to beevaluated. Sometimes the problem can berelieved by fine tuning or repairing theHVAC system, but in some cases thesystem cannot perform as expected, and along-term solution must be investigated.

TYPES OF HVAC SYSTEMS

Single Zone

A single air handling unit can only servemore than one building area if the areasserved have similar heating, cooling, andventilation requirements, or if the controlsystem compensates for differences inheating, cooling, and ventilation needsamong the spaces served. Areas regulatedby a common control (e.g., a singlethermostat) are referred to as zones.Thermal comfort problems can result if thedesign does not adequately account fordifferences in heating and cooling loadsbetween rooms that are in the same zone.This can easily occur if:

■ The cooling load in some area(s) with-in a zone changes due to an increasedoccupant population, increased lighting,or the introduction of new heat-produc-ing equipment (e.g., computers, copiers).

■ Areas within a zone have different solarexposures. This can produce radiant heatgains and losses that, in turn, createunevenly distributed heating or coolingneeds (e.g., as the sun angle changesdaily and seasonally).

Multiple Zone

Multiple zone systems can provide eachzone with air at a different temperature byheating or cooling the airstream in eachzone. Alternative design strategies involvedelivering air at a constant temperaturewhile varying the volume of airflow, ormodulating room temperature with a


supplementary system (e.g., perimeter hotwater piping).

Constant VolumeConstant volume systems, as their namesuggests, generally deliver a constantairflow to each space. Changes in spacetemperatures are made by heating orcooling the air or switching the air han-dling unit on and off, not by modulatingthe volume of air supplied. These systemsoften operate with a fixed minimumpercentage of outdoor air or with an “aireconomizer” feature (described in theOutdoor Air Control discussion thatfollows).

Variable Air VolumeVariable air volume systems maintainthermal comfort by varying the amount ofheated or cooled air delivered to eachspace, rather than by changing the airtemperature. (However, many VAVsystems also have provisions for resettingthe temperature of the delivery air on aseasonal basis, depending on the severityof the weather). Overcooling oroverheating can occur within a given zoneif the system is not adjusted to respond tothe load. Underventilation frequentlyoccurs if the system is not arranged tointroduce at least a minimum quantity (asopposed to percentage) of outdoor air asthe VAV system throttles back from fullairflow, or if the system supply airtemperature is set too low for the loadspresent in the zone.

BASIC COMPONENTS OF AN HVACSYSTEM

The basic components of an HVAC systemthat delivers conditioned air to maintainthermal comfort and indoor air quality are:

■ outdoor air intake■ mixed-air plenum and outdoor air control■ air filter■ heating and cooling coils■ humidification and/or de-humidification

equipment

TESTING AND BALANCING

Modern HVAC systems typically use sophisticated, automatic controls tosupply the proper amounts of air for heating, cooling, and ventilation incommercial buildings. Problems during installation, operation, mainte-nance, and servicing the HVAC system could prevent it from operating asdesigned. Each system should be tested to ensure its initial and contin-ued performance. In addition to providing acceptable thermal conditionsand ventilation air, a properly adjusted and balanced system can alsoreduce operating costs and increase equipment life.

Testing and balancing involves the testing, adjusting, and balancing ofHVAC system components so that the entire system provides airflows thatare in accordance with the design specifications. Typical componentsand system parameters tested include:

■ all supply, return, exhaust, and outdoor airflow rates■ control settings and operation■ air temperatures■ fan speeds and power consumption■ filter or collector resistance

The typical test and balance agency or contractor coordinates with thecontrol contractor to accomplish three goals: verify and ensure the mosteffective system operation within the design specifications, identify andcorrect any problems, and ensure the safety of the system.

A test and balance report should provide a complete record of thedesign, preliminary measurements, and final test data. The report shouldinclude any discrepancies between the test data and the design specifica-tions, along with reasons for those discrepancies. To facilitate futureperformance checks and adjustments, appropriate records should be kepton all damper positions, equipment capacities, control types and loca-tions, control settings and operating logic, airflow rates, static pressures,fan speeds, and horsepowers.

Testing and balancing of existing building systems should be per-formed whenever there is reason to believe the system is not functioningas designed or when current records do not accurately reflect the actualoperation of the system. The Associated Air Balance Council recom-mends the following guidelines in determining whether testing andbalancing is required:

■ When space has been renovated or changed to provide for new occu-pancy.

■ When HVAC equipment has been replaced or modified.■ When control settings have been readjusted by maintenance or other

personnel.■ After the air conveyance system has been cleaned.■ When accurate records are required to conduct an IAQ investigation.■ When the building owner is unable to obtain design documents or

appropriate air exchange rates for compliance with IAQ standards orguidelines.

Because of the diversity of system types and the interrelationship ofsystem components, effective balancing requires a skilled technician withthe proper experience and instruments. Due to the nature of the work,which involves the detection and remediation of problems, it is recom-mended that an independent test and balance contractor be used andthat this contractor report directly to the building owner, facility manager,or IAQ manager.

124 Appendix B

The illustration above shows thegeneral relationship between many ofthese components; however, manyvariations are possible.

Outdoor Air Intake

Building codes require the introduction ofoutdoor air for ventilation in most build-ings. Most non-residential air handlers aredesigned with an outdoor air intake on thereturn side of the ductwork. Outdoor airintroduced through the air handler can befiltered and conditioned (heated or cooled)before distribution. Other designs mayintroduce outdoor air through air-to-airheat exchangers and operable windows.

■ supply fan■ ducts■ terminal device■ return air system■ exhaust or relief fans and air outlet■ self-contained heating or cooling unit■ control■ boiler■ cooling tower■ water chiller

The following discussion of thesecomponents (each of which may occurmore than once in any total HVAC system)emphasizes features that affect indoor airquality. It may be helpful to refer to thissection when using the HVAC Checklists.

FIGURE B-1: Typical HVAC System Components

Courtesy Terry BrennanCamroden AssociatesOriskny, N.Y.


Indoor air quality problems can beproduced when contaminants enter abuilding with the outdoor air. Rooftop orwall-mounted air intakes are sometimeslocated adjacent to or downwind ofbuilding exhaust outlets or other contami-nant sources. Problems can also result ifdebris (e.g., bird droppings) accumulates atthe intake, obstructing airflow and poten-tially introducing microbiological contami-nants.

If more air is exhausted than isintroduced through the outdoor air intake,then outdoor air will enter the building atany leakage sites in the shell. Indoor airquality problems can occur if the leakagesite is a door to a loading dock, parkinggarage, or some other area associated withpollutants.

Mixed-Air Plenum and Outdoor AirControls

Outdoor air is mixed with return air (airthat has already circulated through theHVAC system) in the mixed-air plenum ofan air handling unit. Indoor air qualityproblems frequently result if the outdoorair damper is not operating properly (e.g.,if the system is not designed or adjusted toallow the introduction of sufficient outdoorair for the current use of the building. Theamount of outdoor air introduced in theoccupied mode should be sufficient tomeet needs for ventilation and exhaustmake-up. It may be fixed at a constantvolume or may vary with the outdoortemperature.

When dampers that regulate the flow ofoutdoor air are arranged to modulate, theyare usually designed to bring in a mini-mum amount of outdoor air (in theoccupied mode) under extreme outdoortemperature conditions and to open asoutdoor temperatures approach the desiredindoor temperature. Systems that useoutdoor air for cooling are called “aireconomizer cooling” systems. Aireconomizer systems have a mixed air

Above: The air intake in the background islocated too close to the sanitary vents (thestraight pipes to the left and in the centerforeground) and the bathroomexhaust vent (next to the sanitary vent onthe right side). Below: The return airdampers in this mixed-air plenum are open(top), but the outdoor air damper (left) is al-most completely closed. Complaints in thebuilding indicate thatunder-ventilation is a problem.

126 Appendix B

temperature controller and thermostatthat are used to blend return air (typicallyat 74°F) with outdoor air to reach a mixedair temperature of 55° to 65°F. (Mixed airtemperature settings above 65°F may leadto the introduction of insufficient quanti-ties of outdoor air for office space use.)The mixed air is then further heated orcooled for delivery to the occupied spaces.

Air economizer systems have a sensibleor enthalpy control that signals the outdoorair damper to go to the minimum positionwhen it is too warm or humid outdoors.Note that economizer cycles which do notprovide dehumidification may producediscomfort even when the indoor tempera-ture is the same as the thermostat setting.

If outdoor air make-up and exhaust arebalanced, and the zones served by each airhandler are separated and well defined, it ispossible to estimate the minimum flow ofoutdoor air to each space and compare it toventilation standards such as ASHRAE 62-1989. Techniques used for this evaluationinclude the direct measurement of the

outdoor air at the intake and the calculationof the percentage of outdoor air by atemperature or CO

2 balance. Carbon

dioxide measured in an occupied space isalso an indicator of ventilation adequacy.Some investigators use tracer gases toassess ventilation quantities and airflowpatterns. There are specific methods foreach of these assessments. See Appendix Afor more information.

Many HVAC designs protect the coilsby closing the outdoor air damper if theairstream temperature falls below thesetpoint of a freezestat. Inadequateventilation can occur if a freezestat tripsand is not reset, or if the freezestat is set totrip at an excessively high temperature.Stratification of the cold outdoor air andwarmer return air in the mixing plenums isa common situation, causing nuisancetripping of the freezestat. Unfortunately,the remedy often employed to prevent thisproblem is to close the outdoor air damper.Obviously, solving the problem in this waycan quickly lead to inadequate outdoor airin occupied parts of the building.

Air Filters

Filters are primarily used to removeparticles from the air. The type and designof filter determine the efficiency atremoving particles of a given size and theamount of energy needed to pull or pushair through the filter. Filters are rated bydifferent standards and test methods suchas dust spot and arrestance which measuredifferent aspects of performance. See thediscussion of ASHRAE Standard 52-76 onpage 138 of this appendix.

Low efficiency filters (ASHRAE DustSpot rating of 10% to 20% or less) areoften used to keep lint and dust fromclogging the heating and cooling coils of asystem. In order to maintain clean air inoccupied spaces, filters must also removebacteria, pollens, insects, soot, dust, anddirt with an efficiency suited to the use ofthe building. Medium efficiency filters(ASHRAE Dust Spot rating of 30% to

Proper air filtration can play an impor-tantrole in protecting the rest of the HVACsystem and in maintaining good indoor airquality in occupied spaces. Air filtersshould be selected and main-tained toprovide maximum filtration, while notovertaxing the supply fan capability orleading to “blow out” situa-tions with no airfiltration. Shown aboveare roll filter (top) and bag, panel, andpleated filters (below).


60%) can provide much better filtrationthan low efficiency filters. To maintain theproper airflow and minimize the amount ofadditional energy required to move airthrough these higher efficiency filters,pleated-type extended surface filters arerecommended. In buildings that aredesigned to be exceptionally clean, thedesigners may specify the equipment toutilize both a medium efficiency pre-filterand a high efficiency extended surfacefilter (ASHRAE Dust Spot rating of 85%to 95%). Some manufacturers recommendhigh efficiency extended surface filters(ASHRAE Dust Spot rating of 85%)without pre-filters as the most costeffective approach to minimizing energyconsumption and maximizing air quality inmodern HVAC VAV systems that serveoffice environments.

Air filters, whatever their design orefficiency rating, require regular mainte-nance (cleaning for some and replacementfor most). As a filter loads up withparticles, it becomes more efficient atparticle removal but increases the pressuredrop through the system, thereforereducing airflow. Filter manufacturers canprovide information on the pressure dropthrough their products under differentconditions. Low efficiency filters, ifloaded to excess, will become deformedand even “blow out” of their filter rack.When filters blow out, bypassing ofunfiltered air can lead to clogged coils anddirty ducts. Filtration efficiency can beseriously reduced if the filter cells are notproperly sealed to prevent air frombypassing.

Filters should be selected for theirability to protect both the HVAC systemcomponents and general indoor air quality.In many buildings, the best choice is amedium efficiency, pleated filter becausethese filters have a higher removalefficiency than low efficiency filters, yetthey will last without clogging for longerthan high efficiency filters.

Choice of an appropriate filter andproper maintenance are important tokeeping the ductwork clean. If dirtaccumulates in ductwork and if the relativehumidity reaches the dewpoint (so thatcondensation occurs), then the nutrientsand moisture may support the growth ofmicrobiologicals. Attention to air filters isparticularly important in HVAC systemswith acoustical duct liner, which isfrequently used in air handler fan housingsand supply ducts to reduce sound transmis-sion and provide thermal insulation. Areasof duct lining that have become contami-nated with microbiological growth must bereplaced. (See later discussion of ductsand duct cleaning .) Sound reduction canalso be accomplished with the use ofspecial duct-mounted devices such asattenuators or with active electronic noisecontrol.

Air handlers that are located in difficult-to-access places (e.g., in places whichrequire ladders for access, have inconve-nient access doors to unbolt, or are locatedon roofs with no roof hatch access) will be

Pleated medium efficiencyfilters are often preferred overlow efficiency filters becausethey offer added protectionto both the HVAC equipmentand to indoor air quality, yetthey do not clog as easily ashigh efficiency filters.Medium efficiency filters doneed routine maintenance,however, which the filter inthis photo did not receive.

128 Appendix B

Without proper installationand maintenance, rust andcorrosion may accumulate incondensate pans underheating and cooling coils.The rust in the pan indi-catesthat it was installed without apitch or was pitched in thewrong direction, so that waterdid not drain out properly.

more likely to suffer from poor air filtermaintenance and overall poor mainte-nance. Quick release and hinged accessdoors for maintenance are more desirablethan bolted access panels.

Filters are available to remove gasesand volatile organic contaminants fromventilation air; however, these systems arenot generally used in normal occupancybuildings. In specially designed HVACsystems, permanganate oxidizers andactivated charcoal may be used for gaseousremoval filters. Some manufacturers offer“partial bypass” carbon filters and carbonimpregnated filters to reduce volatileorganics in the ventilation air of officeenvironments. Gaseous filters must beregularly maintained (replaced or regener-ated) in order for the system to continue tooperate effectively.

Heating and Cooling Coils

Heating and cooling coils are placed in theairstream to regulate the temperature of theair delivered to the space. Malfunctions ofthe coil controls can result in thermaldiscomfort. Condensation on under-insulated pipes and leakage in pipedsystems will often create moist conditionsconducive to the growth of molds, fungus,and bacteria.

During the cooling mode (air condition-ing), the cooling coil provides dehumidifi-cation as water condenses from the air-stream. Dehumidification can only takeplace if the chilled fluid is maintained at acold enough temperature (generally below45°F for water). Condensate collects in thedrain pan under the cooling coil and exitsvia a deep seal trap. Standing water willaccumulate if the drain pan system has notbeen designed to drain completely underall operating conditions (sloped toward thedrain and properly trapped). Under theseconditions, molds and bacteria willproliferate unless the pan is cleanedfrequently.

It is important to verify that condensatelines have been properly trapped and arecharged with liquid. An improperlytrapped line can be a source of contamina-tion, depending on where the line termi-nates. A properly installed trap could alsobe a source, if the water in the trapevaporates and allows air to flow throughthe trap into the conditioned air.

During the heating mode, problems canoccur if the hot water temperature in theheating coil has been set too low in anattempt to reduce energy consumption. Ifenough outdoor air to provide sufficientventilation is brought in, that air may notbe heated sufficiently to maintain thermalcomfort or, in order to adequately condi-tion the outdoor air, the amount of outdoorair may be reduced so that there is insuffi-cient outdoor air to meet ventilation needs.


Humidification and DehumidificationEquipment

In some buildings (or zones withinbuildings), there are special needs thatwarrant the strict control of humidity (e.g.,operating rooms, computer rooms). Thiscontrol is most often accomplished byadding humidification or dehumidificationequipment and controls. In office facili-ties, it is generally preferable to keeprelative humidities above 20% or 30%during the heating season and below 60%during the cooling season. ASHRAEStandard 55-1981 provides guidance onacceptable temperature and humidityconditions. (See also the discussion ofhumidity levels in Section 6.)

The use of a properly designed andoperated air conditioning system willgenerally keep relative humidities below60% RH during the cooling season, inoffice facilities with normal densities andloads. (See the previous discussion of thecooling coil.)

Office buildings in cool climates thathave high interior heat gains, thermallyefficient envelopes (e.g., insulation), andeconomizer cooling may require humidi-fication to maintain relative humiditywithin the comfort zone. When humidi-fication is needed, it must be added in amanner that prevents the growth of micro-biologicals within the ductwork and airhandlers.

Steam humidifiers should utilize cleansteam, rather than treated boiler water, sothat occupants will not be exposed tochemicals. Systems using media otherthan clean steam must be rigorouslymaintained in accordance with themanufacturer’s recommended proceduresto reduce the likelihood of microbiologicalgrowth.

Mold growth problems are more likelyif the humidistat setpoint located in theoccupied space is above 45%. The highlimit humidistat, typically located in theductwork downstream of the point at

Above: Occupants of this buildingcomplained of an inter-mittant fish tank odor.An investigation showed that this water sprayhumidifi-cation system is regularlymaintained. The coils are washed roughlyevery two weeks using fresh tap water,eliminating the need for any use of algacides.Below: Further investigation identified thefact that the maintenance practice wascausing the odor problem. This picture ofthe downstream side of the coils was takenone day after the washing. A high pressurestream of water caused algae in the waterto foam and float for several days,coinciding with the occupant complaints.

130 Appendix B

Fan performance is expressed as theability to move a given quantity of air(cubic feet per minute or cfm) at a givenresistance or static pressure (measured ininches of water column). Airflow inductwork is determined by the size of theduct opening, the resistance of the ductconfiguration, and the velocity of the airthrough the duct. The static pressure in asystem is calculated using factors for ductlength, speed of air movement and changesin the direction of air movement.

It is common to find some differencesbetween the original design and the finalinstallation, as ductwork must sharelimited space with structural members andother “hidden” elements of the buildingsystem (e.g., electrical conduit, plumbingpipes). Air distribution problems canoccur, particularly at the end of duct runs,if departures from the original designincrease the friction in the system to apoint that approaches the limit of fanperformance. Inappropriate use of longruns of flexible ducts with sharp bends alsocauses excessive friction. Poor systembalancing (adjustment) is another commoncause of air distribution problems.

Dampers are used as controls torestrict airflow. Damper positions may berelatively fixed (e.g., set manually duringsystem testing and balancing) or maychange in response to signals from thecontrol system. Fire and smoke damperscan be triggered to respond to indicatorssuch as high temperatures or signals fromsmoke detectors. If a damper is designedto modulate, it should be checked duringinspections to see that it is at the propersetting. ASHRAE and the Associated AirBalance Council both provide guidance onproper intervals for testing and balancing.

Ducts

The same HVAC system that distributesconditioned air throughout a building aircan distribute dust and other pollutants,including biological contaminants. Dirt or

DUCT LEAKAGE

Leakage of air from ducts can cause or exacerbate air quality problems, inaddition to wasting energy. In general, sealed duct systems specified witha leakage rate of less than 3% will have a superior life cycle cost analysisand reduce the likelihood of problems associated with leaky ductwork.Examples of excessive duct leakage leading to problems include:

■ leakage of light troffer-type diffusers at the diffuser/light fixture interfacewhen they are installed in a return plenum. Such leakage has beenknown to cause gross short-circuiting between supply and return,wasting much of the conditioned air. If the “room” thermostat islocated in the return plenum, the room can be very uncomfortable whilethe temperature in the plenum is operating at the control setpoint.

■ leakage of supply ductwork due to loose-fitting joints and connectionsor “blow outs” of improperly fabricated seams

■ leakage of return ducts located in crawl spaces or below slabs, allowingsoil gases and molds to enter the ductwork

which water vapor is added, is generallyset at 70% to avoid condensation (with apotential for subsequent mold growth) inthe ductwork. Adding water vapor to abuilding that was not designed forhumidification can have a negative impacton the building structure and theoccupants’ health, if condensation occurson cold surfaces or in wall or roof cavities.

Supply Fans

After passing through the coil sectionwhere heat is either added or extracted, airmoves through the supply fan chamber andthe distribution system. Air distributionsystems commonly use ducts that areconstructed to be relatively airtight.Elements of the building construction canalso serve as part of the air distributionsystem (e.g., pressurized supply plenumsor return air plenums located in the cavityspace above the ceiling tiles and below thedeck of the floor above). Proper coordina-tion of fan selection and duct layout duringthe building design and construction phaseand ongoing maintenance of mechanicalcomponents, filters, and controls are allnecessary for effective air delivery.


dust accumulation on any components ofan air handling system — its cooling coils,plenums, ducts, and equipment housing —may lead to contamination of the airsupply.

There is widespread agreement thatbuilding owners and managers should takegreat precautions to prevent dirt, highhumidity, or moisture from entering theductwork; there is less agreement atpresent about when measures to clean upare appropriate or how effective cleaningtechniques are at making long-termimprovements to the air supply or atreducing occupant complaints.

The presence of dust in ductwork doesnot necessarily indicate a current microbio-logical problem. A small amount of duston duct surfaces is normal and to beexpected. Special attention should begiven to trying to find out if ducts arecontaminated only where specific prob-lems are present, such as: water damage orbiological growth observed in ducts, debrisin ducts that restricts airflow, or dustdischarging from supply diffusers.

Problems with dust and other contami-nation in the ductwork are a function offiltration efficiency, regular HVAC systemmaintenance, the rate of airflow, and goodhousekeeping practices in the occupiedspace. Problems with biological pollutantscan be prevented by minimizing dust anddirt build-up, promptly repairing leaks andwater damage, preventing moistureaccumulation in the components that aresupposed to be dry, and cleaning thecomponents such as the drip pans thatcollect and drain water.

In cases where sheet metal ductworkhas become damaged or water-soaked,building owners will need to undertakeclean-up or repair procedures. Forexample, in cases where the thermal lineror fiberboard has become water-soaked,building managers will need to replace theaffected areas. These procedures shouldbe scheduled and performed in a way thatdoes not expose building occupants to

increased levels of pollutants and shouldbe carried out by experienced workers.Correcting theproblems that allowed theductwork to become contaminated in thefirst place is important. Otherwise, thecorrective action will only be temporary.

The porous surface of fibrous glass ductliner presents more surface area (whichcan trap dirt and subsequently collectwater) than sheet metal ductwork. It istherefore particularly important to payattention to the proper design, installation,filtration, humidity, and maintenance ofducts that contain porous materials. Inaddition, techniques developed forcleaning unlined metal ducts often are notsuitable for use with fibrous glass thermalliner or fiberboard. Such ducts mayrequire a special type of cleaning tomaintain the integrity of the duct (i.e., noheavy brushing tools that might fray theinner lining) while removing dirt anddebris.

More research on both the efficacy andthe potential for unintended exposures tobuilding occupants from various cleaningtechniques is needed before firm guidancecan be provided regarding duct cleaning.

Pay attention to worker safety whenworking with air handling systemsincluding during duct cleaning. Anyworker who may potentially breathe ductcontaminants or biocides should wearsuitable protective breathing apparatus.Workers who are doing the duct cleaningshould be encouraged to also look forother types of problems, such as holes orgaps in the ducts that could allow contami-nants to enter the ventilation airstream.

Building managers can obtain moreinformation on the issue of HVACcontamination and cleaning from theprofessional standards developed by sometrade associations (See Guidelines of CareDeveloped by Professional and TradeAssociations in Section 5 and refer toAppendix G for a list of organizationswith expertise and materials on theseissues.)

132 Appendix B

1. Any duct cleaning should bescheduled during periods whenthe building is unoccupied toprevent exposure to chemicalsand loosened particles.

The air handling unit should not beused during the cleaning or as an airmovement device for the cleaningprocess. The National Air DuctCleaning Association recommendsthat the system should be run toallow at least eight air changes in theoccupied space when duct cleaninghas been completed.

2. Negative air pressure that willdraw pollutants to a vacuumcollection system should bemaintained at all times in theduct cleaning area to preventmigration of dust dirt, andcontaminants into occupiedareas.

Where possible, use vacuumequipment or fans during cleaningand sanitizing to make sure thatcleaning vapors are exhausted to theoutside and do not enter the occu-pied space.

3. If it is determined that theductwork should be cleaned,careful attention must be givento protecting the ductwork.

When gaining access to sheet metalducts for cleaning purposes, it isessential to seal the access holeproperly in order to maintain theintegrity of the HVAC system.Access doors are recommended ifthe system is to be cleaned periodi-cally, and all access holes should beidentified on the building’s mechani-cal plans.

Particular attention is warrantedwhen cutting fibrous glass ducts, andmanufacturers’ recommendedprocedures for sealing should befollowed stringently. Use existingduct system openings wherepossible because it is difficult torepair the damage caused by cuttingnew access entries into theductwork. Large, high volume

vacuum equipment should only beused with extreme care because highnegative pressure together with limitedairflow can collapse ducts.

4. Duct cleaning performed withhigh velocity airflow (i.e., greaterthan 6,000 cfm) should includegentle, well-controlled brushing ofduct surfaces or other methods todislodge dust and other particles.

Duct cleaning that relies only on a highvelocity airflow through the ducts is notlikely to achieve satisfactory resultsbecause the flow rate at the ductsurface remains too low to removemany particles.

5. Only HEPA filtered (high-efficiency particle arrestor) vacu-uming equipment should be used ifthe vacuum collection unit is insidethe occupied space.

Conventional vacuuming equipmentmay discharge extremely fine particu-late matter back into the atmosphere,rather than collecting it. Duct cleaningequipment that draws the dust and dirtinto a collection unit outside thebuilding is also available. Peopleshould not be allowed to remain in theimmediate vicinity of these collectionunits.

6. If biocides are to be used, thenselect only products registered byEPA for such use, use the productsaccording to the manufacturer’sdirections, and pay careful atten-tion to the method of application.

At present, EPA accepts claims andtherefore registers antimicrobials foruse only as sanitizers, not disinfectantsor sterilizers in HVAC systems. (SeeAppendix F for definitions of antimicro-bials.) There is some question aboutwhether there areany application techniques thatwill deposit a sufficient amount of thebiocide to kill bacteria, germs,or other biologicals that may bepresent. Materials such as deodorizersthat temporarily eliminate odors causedby microorganisms provide only a fresh

smell, and are not intended to providereal control of microbiologicalcontaminants.

7. Use of sealants to coverinterior ductwork surfaces is notrecommended.

No application techniques have beendemonstrated to provide a completeor long-term barrier to microbiologicalgrowth, nor have such materials beenevaluated for their potential healtheffects on occupants. In addition,using sealants alters the surfaceburning characteristics of the ductmaterial and may void the fire safetyrating of the ductwork.

8. Careful cleaning and sanitizingof any parts of coils and drip panscan reduce microbiologicalpollutants.

Prior to using sanitizers, deodorizers,or any cleansing agents, carefullyread the directions on the productlabel. Once cleaned, these compo-nents should be thoroughly rinsedand dried to prevent exposure ofbuilding occupants to the cleaningchemicals.

9. Water-damaged or contami-nated porous materials in theductwork or other air handlingsystem components should beremoved and replaced.

Even when such materials arethoroughly dried, there is no way toguarantee that all microbial growthhas been eliminated.

10. After the duct system hasbeen cleaned and restored touse, a preventive maintenanceprogram will prevent the recur-rence of problems.

Such a program should includeparticular attention to the use andmaintenance of adequate filters,control of moisture in the HVACsystem, and periodic inspection andcleaning of HVAC system compo-nents. (See discussion of PreventiveMaintenance on page 36 in Section5.)

PRELIMINARY RECOMMENDATIONS ON DUCT CLEANING


Return air is frequently car-ried through non-ducted ple-nums. It is more difficult tocontrol leakage of pollutantsinto or out of this type of re-turn air system than a ductedsystem.

Terminal Devices

Thermal comfort and effective contami-nant removal demand that air deliveredinto a conditioned space be properlydistributed within that space. Terminaldevices are the supply diffusers, return andexhaust grilles, and associated dampersand controls that are designed to distributeair within a space and collect it from thatspace. The number, design, and location(ceiling, wall, floor) of terminal devicesare very important. They can cause aHVAC system with adequate capacity toproduce unsatisfactory results, such asdrafts, odor transport, stagnant areas, orshort-circuiting.

Occupants who are uncomfortablebecause of distribution deficiencies (drafts,odor transport, stagnant air, or uneventemperatures) often try to compensate byadjusting or blocking the flow of air fromsupply outlets. Adjusting system flowswithout any knowledge of the properdesign frequently disrupts the propersupply of air to adjacent areas. Distribu-tion problems can also be produced if thearrangement of movable partitions,shelving, or other furnishings interfereswith airflow. Such problems often occur ifwalls are moved or added without evaluat-ing the expected impact on airflows.

Return Air Systems

In many modern buildings the above-ceiling space is utilized for the unductedpassage of return air. This type of systemapproach often reduces initial HVACsystem costs, but requires that the designer,maintenance personnel, and contractorsobey strict guidelines related to life andsafety codes (e.g., building codes) thatmust be followed for materials and devicesthat are located in the plenum. In addition,if a ceiling plenum is used for the collec-tion of return air, openings into the ceilingplenum created by the removal of ceilingtiles will disrupt airflow patterns. It is

particularly important to maintain theintegrity of the ceiling and adjacent wallsin areas that are designed to be exhausted,such as supply closets, bathrooms, andchemical storage areas.

After return air enters either a ductedreturn air grille or a ceiling plenum, it isreturned to the air handlers. Some systemsutilize return fans in addition to supplyfans in order to properly control thedistribution of air. When a supply andreturn fan are utilized, especially in a VAVsystem, their operation must be coordi-nated in order to prevent under- or over-pressurization of the occupied space oroverpressurization of the mixing plenum inthe air handler.

Exhausts, Exhaust Fans, andPressure Relief

Most buildings are required by law (e.g.,building or plumbing codes) to provide forexhaust of areas where contaminantsources are strong, such as toilet facilities,janitorial closets, cooking facilities, andparking garages. Other areas whereexhaust is frequently recommended but

134 Appendix B

achieving a neutral or slightly positivepressure.

Self-Contained Units

In some designs, small decentralized unitsare used to provide cooling or heating tointerior or perimeter zones. With theexception of induction units, units of thistype seldom supply outdoor air. They aretypically considered a low priority mainte-nance item. If self-contained units areoverlooked during maintenance, it is notunusual for them to become a significantsource of contaminants, especially for theoccupants located nearby.

Controls

HVAC systems can be controlled manuallyor automatically. Most systems are con-trolled by some combination of manual andautomatic controls. The control system canbe used to switch fans on and off, regulatethe temperature of air within the conditionedspace, or modulate airflow and pressures bycontrolling fan speed and damper settings.Most large buildings use automatic controls,and many have very complex and sophisti-cated systems. Regular maintenance andcalibration are required to keep controls ingood operating order. All programmabletimers and switches should have “batterybackup” to reset the controls in the event of apower failure.

Local controls such as room thermostatsmust be properly located in order tomaintain thermal comfort. Problems canresult from:

■ thermostats located outside of theoccupied space (e.g., in return plenum)

■ poorly designed temperature controlzones (e.g., single zones that combineareas with very different heating orcooling loads)

■ thermostat locations subject to drafts orto radiant heat gain or loss (e.g., exposedto direct sunlight)

may not be legally required include:reprographics areas, graphic arts facilities,beauty salons, smoking lounges, shops,and any area where contaminants areknown to originate.

For successful confinement and exhaustof identifiable sources, the exhausted areamust be maintained at a lower overallpressure than surrounding areas. Any areathat is designed to be exhausted must alsobe isolated (disconnected) from the returnair system so that contaminants are nottransported to another area of the building.

In order to exhaust air from the build-ing, make-up air from outdoors must bebrought into the HVAC system to keep thebuilding from being run under negativepressure. This make-up air is typicallydrawn in at the mixed air plenum asdescribed earlier and distributed within thebuilding. For exhaust systems to functionproperly, the make-up air must have a clearpath to the area that is being exhausted.

It is useful to compare the total cfm ofpowered exhaust to the minimum quantityof mechanically-introduced outdoor air.To prevent operating the building undernegative pressures (and limit the amount ofunconditioned air brought into the buildingby infiltration), the amount of make-up airdrawn in at the air handler should alwaysbe slighter greater than the total amount ofrelief air, exhaust air, and air exfiltratingthrough the building shell. Excess make-up air is generally relieved at an exhaust orrelief outlet in the HVAC system, espe-cially in air economizer systems. Inaddition to reducing the effects of un-wanted infiltration, designing and operat-ing a building at slightly positive or neutralpressures will reduce the rate of entry ofsoil gases when the systems are operating.For a building to actually operate at aslight positive pressure, it must be tightlyconstructed (e.g., specified at less thanone-half air change per hour at 0.25pascals). Otherwise unwanted exfiltrationwill prevent the building from ever


■ thermostat locations affected by heatfrom nearby equipment

To test whether or not a thermostat isfunctioning properly, try setting it to anextreme temperature. This experiment willshow whether or not the system is respond-ing to the signal in the thermostat, andalso provides information about how theHVAC system may perform under extremeconditions.

Boilers

Like any other part of the HVAC system, aboiler must be adequately maintained tooperate properly. However, it is particu-larly important that combustion equipmentoperate properly to avoid hazardousconditions such as explosions or carbonmonoxide leaks, as well as to provide goodenergy efficiency. Codes in most parts ofthe country require boiler operators to beproperly trained and licensed.

Both ASME and ASHRAE have maderecommendations of how much combus-tion air is needed for fuel burning appli-ances.

Elements of boiler operation that areparticularly important to indoor air qualityand thermal comfort include:

■ Operation of the boiler and distributionloops at a high enough temperature tosupply adequate heat in cold weather.

■ Maintenance of gaskets and breeching toprevent carbon monoxide from escapinginto the building.

■ Maintenance of fuel lines to prevent anyleaks that could emit odors into thebuilding.

■ Provision of adequate outdoor air forcombustion.

■ Design of the boiler combustion exhaustto prevent re-entrainment, (especiallyfrom short boiler stacks, or into multi-story buildings that were added after theboiler plant was installed).

Modern office buildings tend to havemuch smaller capacity boilers than olderbuildings because of advances in energyefficiency. In some buildings, the primaryheat source is waste heat recovered fromthe chiller (which operates year-round tocool the core of the building).

Cooling Towers

Maintenance of a cooling tower ensuresproper operation and keeps the coolingtower from becoming a niche for breedingpathogenic bacteria, such as Legionellaorganisms. Cooling tower water qualitymust be properly monitored and chemicaltreatments used as necessary to minimizeconditions that could support the growth ofsignificant amounts of pathogens. Propermaintenance may also entail physicalcleaning (by individuals using properprotection) to prevent sediment accumula-tion and installing drift eliminators.

It is important to determineperiodically whether theHVAC controls are correctlycalibrated. In addition, timeclocks must be checked tosee if they are properly setand running. Power failuresfrequently cause time clocksto be out of adjustment.

136 Appendix B

Application

Food and BeverageService

Offices

Public Spaces

Retail Stores, Sales Floors,Showroom Floors

Sports andAmusement

Theaters

Education

Hotels, Motels,Resorts,Dormitories

Dining roomsCafeteria, fast foodBars, cocktail loungesKitchen (cooking)

Office spaceReception areasConference rooms

Smoking loungeElevators

Basement and streetUpper floorsMalls and arcadesSmoking lounge

Spectator areasGame roomsPlaying floorsBallrooms and discos

LobbiesAuditorium

ClassroomMusic roomsLibrariesAuditoriums

BedroomsLiving roomsLobbiesConference roomsAssembly rooms

Occupancy Cfm/person Cfm/ft2

(people/1000 ft2)

70 20100 20100 3020 15

7 2060 1550 20

70 601.00

30 0.3020 0.2020 0.2070 60

150 1570 2530 20

100 25

150 20150 15

50 1550 1520 15

150 15

30 cfm/room30 cfm/room

30 1550 20

120 15

FIGURE B-2: Selected Ventilation Recommendations

SOURCE: ASHRAE Standard 62-1989, Ventilation for Acceptable Air Quality


used because source strength is usually notknown.

Whichever procedure is utilized in thedesign, the standard states that the designcriteria and assumptions shall be docu-mented and made available to thoseresponsible for the operation and mainte-nance of the system.

Important features of ASHRAE 62-1989 include:

■ a definition of acceptable air quality■ a discussion of ventilation effectiveness■ the recommendation of the use of source

control through isolation and localexhaust of contaminants

■ recommendations for the use of heatrecovery ventilation

■ a guideline for allowable carbon dioxidelevels

■ appendices listing suggested possibleguidelines for common indoor pollutants

Standard 55-1981, “ThermalEnvironmental Conditions forHuman Occupancy”

ASHRAE 55-1981 covers several environ-mental parameters including: temperature,radiation, humidity, and air movement.

The standard specifies thermal environ-mental conditions for the comfort ofhealthy people in normal indoor environ-ments for winter and summer conditions.It also attempts to introduce limits on thetemperature variations within a space. Inaddition to specifications for temperatureand humidity, guidelines are given for airmovement, temperature cycling, tempera-ture drift, vertical temperature difference,radiant asymmetry, and floor temperatures.Adjustment factors are described forvarious activity levels of the occupants,and different clothing levels.

Important features of this standardinclude:■ a definition of acceptable thermal

comfort

Water Chillers

Water chillers are frequently found in largebuilding air conditioning systems becauseof the superior performance they offer. Awater chiller must be maintained in properworking condition to perform its functionof removing the heat from the building.Chilled water supply temperatures shouldoperate in the range of 45°F or colder inorder to provide proper moisture removalduring humid weather. Piping should beinsulated to prevent condensation.

Other than thermal comfort, IAQconcerns associated with water chillersinvolve potential release of the workingfluids from the chiller system. The rupturedisk (safety release) of the system shouldbe piped to the outdoors, and refrigerantleaks should be located and repaired.Waste oils and spent refrigerant should bedisposed of properly.

ASHRAE STANDARDS ANDGUIDELINES

Standard 62-1989, “Ventilation forAcceptable Air Quality”

ASHRAE 62-1989 is intended to assistprofessionals in the proper design ofventilation systems for buildings. Thestandard presents two procedures forventilation design, a “Ventilation Rate”procedure and an “Air Quality” procedure.

With the Ventilation Rate procedure,acceptable air quality is achieved byspecifying a given quantity and quality ofoutdoor air based upon occupant densityand space usage. Examples of the tableslisting the prescriptive amounts of outdoorair for the Ventilation Rate procedure arepresented at the end of this section.

The Air Quality procedure is a perfor-mance specification that allows acceptableair quality to be achieved within a space bycontrolling for known and specifiablecontaminants. This procedure is seldom

138 Appendix B

test and the atmospheric dust spot test.The atmospheric dust spot test is the testused to determine the “efficiency “ of anair cleaner. The values obtained withthese two tests are not comparable. Forexample, a filter with a weight arrestanceof 90% may have an efficiency by theatmospheric dust spot test below 40%.

The weight arrestance test is generallyused to evaluate low efficiency filtersdesigned to remove the largest andheaviest particles; these filters are com-monly used in residential furnaces and/orair-conditioning systems or as upstreamfilters for other air cleaning devices. Forthe test, a standard synthetic dust is fedinto the air cleaner and the proportion (byweight) of the dust trapped on the filter isdetermined. Because the particles in thestandard dust are relatively large, theweight arrestance test is of limited value inassessing the removal of smaller, respi-rable-size particles from indoor air.

The atmospheric dust spot test isusually used to rate medium efficiency aircleaners. The removal rate is based on thecleaner’s ability to reduce soiling of aclean paper target, an ability dependent onthe cleaner removing very fine particlesfrom the air. However, it should be notedthat this test addresses the overall effi-ciency of removal of a complex mixture ofdust, and that removal efficiencies fordifferent size particles may vary widely.Recent studies by EPA, comparingASHRAE ratings to filter efficiencies forparticles by size, have shown that efficien-cies for particles in the size range of 0.1 to1 microgram are much lower than theASHRAE rating.

Important features of this ASHRAEstandard include:

■ definitions of arrestance and efficiency■ establishment of a uniform comparative

testing procedure for evaluating theperformance of air cleaning devices usedin ventilation systems

■ a discussion of the additionalenvironmental parameters that mustbe considered

■ recommendations for summer and wintercomfort zones for both temperature andrelative humidity

■ a guideline for making adjustment foractivity levels

■ guidelines for making measurementsIt should be noted that space tempera-

tures above 76°F but within the summercomfort envelope have nevertheless beenassociated with IAQ complaints in offices.

Note: As of summer 1991, a revisedStandard 55 was nearly ready.

Standard 52-76, “Method of TestingAir-Cleaning Devices Used inGeneral Ventilation for RemovingParticulate Matter”

This standard is intended to assist profes-sionals in the evaluation of air cleaningsystems for particle removal. Two testmethods are described: the weightarrestance test and the atmospheric dustspot test. The standard discusses differ-ences in results from the weight arrestance

This air washer is used toremove particles and water-soluble gaseouscontaminants and may alsocontrol temperature andhumidity in the airstream.Such systems are subjectto severe bacterialcontamination.


■ establishment of a uniform reportingmethod for performance

■ methods for evaluating resistance toairflow and dust-holding capacity

No comparable guidelines or standardsare currently available for use in assessingthe ability of air cleaners to remove gas-eous pollutants or radon and its progeny.

Guideline 1-1989, “Guideline for theCommissioning of HVAC Systems”

This guideline is intended to assist profes-sionals by providing procedures and meth-ods for documenting and verifying theperformance of HVAC systems so thatthey operate in conformity with the designintent. The guideline presents a format fordocumenting the occupancy requirements,design assumptions, and the design intentfor the HVAC system. It provides a for-

mat for testing the system for acceptanceby the owner. In addition, the guidelineaddresses adjustments of the system tomeet actual occupancy needs within thecapacity of the system when changes inbuilding use are made andrecommissioning is warranted.

Important features of this guidelineinclude:

■ definition of the commissioning process■ discussion of the process involved in a

proper commissioning procedure■ sample specification and forms for log-

ging information■ recommendation for the implementation

of corrective measures as warranted■ guideline for operator training■ guidelines for periodic maintenance and

recommissioning as needed

Moisture, Mold and Mildew 141

Appendix C:Moisture, Mold and Mildew

Molds and mildew are fungi that growon the surfaces of objects, within pores,and in deteriorated materials. They cancause discoloration and odor problems,deteriorate building materials, and lead toallergic reactions in susceptible individu-als, as well as other health problems.

The following conditions are necessaryfor mold growth to occur on surfaces:

■ temperature range above 40°F and below100°F

■ mold spores■ nutrient base (most surfaces contain

nutrients)■ moisture

Human comfort constraints limit the useof temperature control. Spores are almostalways present in outdoor and indoor air,and almost all commonly used construc-tion materials and furnishings can providenutrients to support mold growth. Dirt onsurfaces provides additional nutrients.Cleaning and disinfecting with non-polluting cleaners and antimicrobial agentsprovides protection against mold growth.Other sections of this document havediscussed the importance of buildingmaintenance and proper sanitation inpreventing IAQ problems. However, it isvirtually impossible to eliminate allnutrients. Moisture control is thus animportant strategy for reducing moldgrowth.

Mold growth does not require thepresence of standing water; it can occurwhen high relative humidity or thehygroscopic properties (the tendency toabsorb and retain moisture) of buildingsurfaces allow sufficient moisture toaccumulate. Relative humidity and the

factors that govern it are often misunder-stood. This appendix is intended to givebuilding managers an understanding of thefactors that govern relative humidity, andto describe common moisture problemsand their solutions.

BACKGROUND ON RELATIVEHUMIDITY, VAPOR PRESSURE,AND CONDENSATION

Water enters buildings both as a liquid andas a gas (water vapor). Water, in its liquidform, is introduced intentionally inbathrooms, kitchens, and laundries andaccidentally by way of leaks and spills.Some of that water evaporates and joinsthe water vapor that is exhaled by buildingoccupants as they breathe or that isintroduced by humidifiers. Water vaporalso moves in and out of the building aspart of the air that is mechanically intro-duced or that infiltrates and exfiltratesthrough openings in the building shell. A

There were complaints of vis-ible water damage and mustyodors in this senior citizenhousing complex. Investiga-tors confirmed that the prob-lem was rain entry by usingan array of hoses to spray thewalls withwater, while operating thebuilding under negative pres-sure. The test showed thatrain was entering at the jointsof the exteriorcladding, rather than atcracks around windows.

142 Appendix C

lesser amount of water vapor diffuses intoand out of the building through thebuilding materials themselves. Figure C-1illustrates locations of moisture entry.

The ability of air to hold water vapordecreases as the air temperature is lowered.If a unit of air contains half of the watervapor it can hold, it is said to be at 50%relative humidity (RH). As the air cools,the relative humidity increases. If the aircontains all of the water vapor it can hold,it is at 100% RH, and the water vaporcondenses, changing from a gas to a liquid.It is possible to reach 100% RH without

FIGURE C-1: Moisture Gain in a Building

changing the amount of water vapor in theair (its “vapor pressure” or “absolutehumidity”); All that is required is for the airtemperature to drop to the “dew point.”

Relative humidity and temperatureoften vary within a room, while theabsolute humidity in the room air canusually be assumed to be uniform. There-fore, if one side of the room is warm andthe other side cool, the cool side of theroom has a higher RH than the warm side.

The highest RH in a room is alwaysnext to the coldest surface. This is referredas the “first condensing surface,” as it will

Courtesy of Dean WallaceShakun, Clayton StateCollege, Morrow, GA


be the location where condensation firstoccurs, if the relative humidity at thesurface reaches 100%. It is important tounderstand this when trying to understandwhy mold is growing on one patch of wallor only along the wall-ceiling joint. It islikely that the surface of the wall is coolerthan the room air because there is a void inthe insulation or because wind is blowingthrough cracks in the exterior of thebuilding.

FIGURE C-2: Relationship of Temperature, Relative Humidity, and Moisture in the Air

A relative humidity reading taken in a room will only give an accurateindication of the actual amount of moisture present if a temperaturereading is taken at the same time. The chart below shows that air at70°F and 40% RH contains approximately 0.006 pounds ofmoisture per pound of dry air (as indicated by the bold line), whileair that is at 50°F and 40% RH contains approximately 0.003pounds of moisture per pound of dry air (as indicated by the dashedline). Although both are at 40% RH, the 70°F air contains roughlytwice as much moisture as the 50°F air.

SOURCE: Adapted from Psychometric Chart from ASHRAE Fundamentals, 1981

TAKING STEPS TO REDUCEMOISTURE

Mold and mildew growth can be reducedwhere relative humidities near surfaces canbe maintained below the dew point. Thiscan be accomplished by reducing themoisture content (vapor pressure) of theair, increasing air movement at the surface,or increasing the air temperature (either thegeneral space temperature or the tempera-ture at building surfaces).

144 Appendix C

Either surface temperature or vaporpressure can be the dominant factor incausing a mold problem. A surfacetemperature-related mold problem may notrespond very well to increasing ventilation,whereas a vapor pressure-related moldproblem may not respond well to increas-ing temperatures. Understanding whichfactor dominates will help in selecting aneffective control strategy.

Consider an old, leaky, poorly insulatedbuilding. It is in a heating climate andshows evidence of mold and mildew.Since the building is leaky, its high naturalair exchange rate dilutes interior airbornemoisture levels, maintaining a low absolutehumidity during the heating season.Providing mechanical ventilation in thisbuilding in an attempt to control interiormold and mildew probably will not beeffective in this case. Increasing surfacetemperatures by insulating the exteriorwalls, and thereby reducing relativehumidities next to the wall surfaces, wouldbe a better strategy to control mold andmildew.

Reduction of surface temperature-dominated mold and mildew is bestaccomplished by increasing the surfacetemperature through either or both of thefollowing approaches:

■ Increase the temperature of the air nearroom surfaces either by raising thethermostat setting or by improving aircirculation so that supply air is moreeffective at heating the room surface.

■ Decrease the heat loss from roomsurfaces either by adding insulation or byclosing cracks in the exterior wall toprevent wind-washing (air that enters awall at one exterior location and exitsanother exterior location withoutpenetrating into the building).

Vapor pressure-dominated mold andmildew can be reduced by one or more ofthe following strategies:

Above: In this building, mold and mildewspots appeared on drywalljoints on the interior walls. When the wallwas cut open, mold growth was visible inthe wall cavity and the structural steelshowed corrosion. The problem wascaused by construction moisture trappedbetween the interior finish and the exteriorsheathing. The solution was to modify theexterior wall so that moisture could vent tothe outdoors. Below: This is visualevidence of air movement through thebuilding shell. The water vapor in thewarm, humid indoor air has condensed andfrozen on the exterior wall.


■ source control (e.g., direct venting ofmoisture-generating activities such asshowers) to the exterior

■ dilution of moisture-laden indoor airwith outdoor air that is at a lowerabsolute humidity

■ dehumidification

Note that dilution is only useful as acontrol strategy during heating periods,when cold outdoor air tends to contain lessmoisture. During cooling periods, outdoorair often contains as much moisture asindoor air.

IDENTIFYING AND CORRECTINGCOMMON PROBLEMS FROM MOLDAND MILDEW

Exterior Corners

Exterior corners are common locations formold and mildew growth in heatingclimates, and in poorly insulated buildingsin cooling climates. They tend to be closerto the outdoor temperature than other partsof the building surface for one or more ofthe following reasons:

■ poor air circulation (interior)■ wind-washing (exterior)■ low insulation levels■ greater surface area of heat loss

Sometimes mold and mildew growthcan be reduced by removing obstructionsto airflow (e.g., rearranging furniture).Buildings with forced air heating systemsand/or room ceiling fans tend to havefewer mold and mildew problems thanbuildings with less air movement, otherfactors being equal.

“Set Back” Thermostats

Set back thermostats are commonly used toreduce energy consumption during theheating season. Mold and mildew growthcan occur when building temperatures arelowered during unoccupied periods.(Maintaining a room at too low a tempera-ture can have the same effect as a set backthermostat.) Mold and mildew can often

HOW TO IDENTIFY THE CAUSE OF A MOLD AND MILDEWPROBLEM

Mold and mildew are commonly found on the exterior wall surfaces ofcorner rooms in heating climate locations. An exposed corner room islikely to be significantly colder than adjoining rooms, so that it has a higherrelative humidity (RH) than other rooms at the same water vapor pressure.If mold and mildew growth are found in a corner room, then relativehumidities next to the room surfaces are above 70%. However, is the RHabove 70% at the surfaces because the room is too cold or because thereis too much moisture present (high water vapor pressure)?

The amount of moisture in the room can be estimated by measuringboth temperature and RH at the same location and at the same time.Suppose there are two cases. In the first case, assume that the RH is30% and the temperature is 70°F in the middle of the room. The low RHat that temperature indicates that the water vapor pressure (or absolutehumidity) is low. The high surface RH is probably due to room surfacesthat are "too cold." Temperature is the dominating factor, and controlstrategies should involve increasing the temperature at cold room sur-faces.

In the second case, assume that the RH is 50% and the temperature is70°F in the middle of the room. The higher RH at that temperatureindicates that the water vapor pressure is high and there is a relativelylarge amount of moisture in the air. The high surface RH is probably dueto air that is "too moist." Humidity is the dominating factor, and controlstrategies should involve decreasing the moisture content of the indoorair.

be controlled in heating climate locationsby increasing interior temperatures duringheating periods. Unfortunately, this alsoincreases energy consumption and reducesrelative humidity in the breathing zone,which can create discomfort.

Air Conditioned Spaces

The problems of mold and mildew can beas extensive in cooling climates as inheating climates. The same principlesapply: either surfaces are too cold,moisture levels are too high, or both.

A common example of mold growth incooling climates can be found in roomswhere conditioned “cold” air blows againstthe interior surface of an exterior wall.This condition, which may be due to poorduct design, diffuser location, or diffuserperformance, creates a cold spot at theinterior finish surfaces. A mold problemcan occur within the wall cavity as outdoorair comes in contact with the cavity side ofthe cooled interior surface. It is a particu-lar problem in rooms decorated with low

146 Appendix C

temperatures. The advent of higherperformance glazing systems has led to agreater incidence of moisture problems inheating climate building enclosures,because the buildings can now be operatedat higher interior vapor pressures (moisturelevels) without visible surface condensa-tion on windows. In older buildingenclosures with less advanced glazingsystems, visible condensation on thewindows often alerted occupants to theneed for ventilation to flush out interiormoisture (so they opened the windows).

Concealed Condensation

The use of thermal insulation in wallcavities increases interior surface tempera-tures in heating climates, reducing thelikelihood of interior surface mold, mildewand condensation. However, the use ofthermal insulation also reduces the heatloss from the conditioned space into thewall cavities, decreasing the temperature inthe wall cavities and therefore increasingthe likelihood of concealed condensation.The first condensing surface in a wallcavity in a heating climate is typically theinner surface of the exterior sheathing, the“back side” of plywood or fiberboard. Asthe insulation value is increased in the wallcavities, so does the potential for hiddencondensation.

Concealed condensation can be con-trolled by either or both of the followingstrategies:

■ Reducing the entry of moisture into thewall cavities (e.g., by controllinginfiltration and/or exfiltration of mois-ture-laden air)

■ Elevating the temperature of the firstcondensing surface. In heating climatelocations, this change can be made byinstalling exterior insulation (assumingthat no significant wind-washing isoccurring). In cooling climate locations,this change an be made by installinginsulating sheathing to the interior of thewall framing and between the wallframing and the interior gypsum board.

maintenance interior finishes (e.g.,impermeable wall coverings such as vinylwallpaper) which can trap moisturebetween the interior finish and the gypsumboard. Mold growth can be rampant whenthese interior finishes are coupled withcold spots and exterior moisture.

Possible solutions for this probleminclude:

■ preventing hot, humid exterior air fromcontacting the cold interior finish (i.e.,controlling the vapor pressure at thesurface)

■ eliminating the cold spots (i.e., elevatingthe temperature of the surface) byrelocating ducts and diffusers

■ ensuring that vapor barriers, facingsealants, and insulation are properlyspecified, installed, and maintained

■ increasing the room temperature to avoidovercooling

In this case, increasing temperaturedecreases energy consumption, though itcould cause comfort problems.

Thermal Bridges

Localized cooling of surfaces commonlyoccurs as a result of “thermal bridges,”elements of the building structure that arehighly conductive of heat (e.g., steel studsin exterior frame walls, uninsulatedwindow lintels, and the edges of concretefloor slabs). Dust particles sometimesmark the locations of thermal bridges,because dust tends to adhere to cold spots.

The use of insulating sheathingssignificantly reduces the impact of thermalbridges in building envelopes.

Windows

In winter, windows are typically thecoldest surfaces in a room. The interiorsurface of a window is often the firstcondensing surface in a room.

Condensation on window surfaces hashistorically been controlled by using stormwindows or “insulated glass” (e.g., double-glazed windows or selective surface gas-filled windows) to raise interior surface

Asbestos 147

Appendix D: Asbestos

"Asbestos” describes six naturallyoccurring fibrous minerals found in certaintypes of rock formations. When minedand processed, asbestos is typically sepa-rated into very thin fibers that are normallyinvisible to the naked eye. They mayremain in the air for many hours if re-leased from asbestos-containing material(ACM) and may be inhaled during thistime. Three specific diseases — asbestosis(a fibrous scarring of the lungs), lungcancer, and mesothelioma (a cancer of thelining of the chest or abdominal cavity) —have been linked to asbestos exposure. Itmay be 20 years or more after exposurebefore symptoms of these diseases appear;however, high levels of exposure can re-sult in respiratory diseases in a shorterperiod of time.

Most of the health problems resultingfrom asbestos exposure have been experi-enced by workers whose jobs exposedthem to asbestos in the air over a pro-longed period without the worker protec-tion that is now required. Asbestos fiberscan be found nearly everywhere in ourenvironment (usually at very low levels).While the risk to occupants is likely to besmall, health concerns remain, particularlyfor the custodial and maintenance workersin a building. Their jobs are likely to bringthem into proximity to ACM and maysometimes require them to disturb theACM in the performance of maintenanceactivities.

EPA estimates that “friable” (easilycrumbled) ACM can be found in an esti-mated 700,000 public and commercialbuildings. About 500,000 of those build-ings are believed to contain at least somedamaged asbestos. Significantly damagedACM is found primarily in building areas

not generally accessible to the public, suchas boiler and mechanical rooms, whereasbestos exposures generally would belimited to service and maintenance work-ers. However, if friable ACM is present inair plenums, it can be distributed through-out the building, thereby possibly exposingbuilding occupants.

When is asbestos a problem? Intact andundisturbed asbestos materials do notpose a health risk. The mere presence ofasbestos in a building does not mean thatthe health of building occupants is endan-gered. ACM which is in good condition,and is not damaged or disturbed, is notlikely to release asbestos fibers into the air.When ACM is properly managed, releaseof asbestos fibers into the air is reduced,and the risk of asbestos-related disease isthereby correspondingly reduced.

There are a number of guidelines andregulations that govern asbestos exposure.Occupational standards for preventingasbestos-related diseases are recommendedby NIOSH and promulgated by OSHA.NIOSH guidance contain RecommendedExposure Limits (RELs) and OSHAstandards set Permissible Exposure Limits(PELs). The standards also contain manyother measures, such as surveillance,medical screening, analytical methods, andmethods of control. OSHA regulationsand the EPA Worker Protection Rule alsoprovide guidance on day-to-day activitiesthat may bring workers in contact withACM. EPA National Emission Standardsfor Hazardous Air Pollutants (NESHAP)define acceptable practices for renovationand demolition activities that involve as-bestos-containing materials. In addition,many States have set exposure standardsand other regulations concerning asbestos.

148 Appendix D

EPA and NIOSH recommend a practicalapproach that protects public health byemphasizing that ACM in buildings shouldbe identified and appropriately managed,and that those workers who might disturbit should be properly trained and protected.

EPA AND NIOSHPOSITIONS ON ASBESTOS

In an effort to calm unwarranted fears thata number of people seem to have about themere presence of asbestos in their build-ings and to discourage the decisions bysome building owners to remove all ACMregardless of its condition, the EPA Ad-ministrator issued an Advisory to the Pub-lic on Asbestos in Buildings in 1991. Thisadvisory summarized EPA’s policies forasbestos control in the presentation of thefollowing “five facts”:

■ Although asbestos is hazardous, the riskof asbestos-related disease depends uponexposure to airborne asbestos fibers.

■ Based upon available data, the averageairborne asbestos levels in buildingsseem to be very low. Accordingly, thehealth risk to most building occupantsalso appears to be very low.

■ Removal is often not a building owner’s

best course of action to reduce asbestosexposure. In fact, an improper removalcan create a dangerous situation wherenone previously existed.

■ EPA only requires asbestos removal inorder to prevent significant public expo-sure to airborne asbestos fibers duringbuilding demolition or renovationactivities.

■ EPA does recommend a pro-active, in-place management program wheneverasbestos-containing material isdiscovered.

NIOSH’s position on asbestos exposurehas been expressed in NIOSH policy state-ments and internal reports and at OSHApublic hearings:

■ NIOSH recommends the goal of elimi-nating asbestos exposure in the work-place. Where exposures cannot be elimi-nated, exposures should be limited to thelowest concentration possible.

■ NIOSH contends that there is no safeairborne fiber concentration for asbestos.NIOSH therefore believes that any de-tectable concentration of asbestos in theworkplace warrants further evaluationand, if necessary, the implementation ofmeasures to reduce exposures.

■ NIOSH contends that there is no scien-tific basis to support differentiatinghealth risks between types of asbestosfibers for regulatory purposes.

Copies of the EPA and NIOSH policystatements and public advisories are avail-able, respectively, from those agencies.See the last section in this appendix andthe Resources section for information onhow to obtain them.

OSHA requires that signs beposted around areas wherework is being done thatinvolves damaged asbestos-containing materials. Thesesigns must communicatespecific types of information.

Asbestos 149

After the material is identified, the build-ing management and staff can then insti-tute controls to ensure that the day-to-daymanagement of the building is carried outin a manner that prevents or minimizes therelease of asbestos fibers into the air.These controls will ensure that when as-bestos fibers are released, either acciden-tally or intentionally, proper managementand clean-up procedures are implemented.

Another concern of EPA, NIOSH, andother Federal, State, and local agencies thatare concerned with asbestos and publichealth is to ensure proper worker trainingand protection. In the course of their dailyactivities, maintenance and service work-ers in buildings may disturb materials andthereby elevate asbestos fiber levels andasbestos exposure, especially for them-selves, if they are not properly trained andprotected. For these persons, risk may besignificantly higher than for other buildingoccupants. Proper worker training andprotection, as part of an active in-placemanagement program, can reduce anyunnecessary asbestos exposure for theseworkers and others. AHERA requires thistraining for school employees whose jobactivities may result in asbestos distur-bances.

In addition to the steps outlined above,an in-place management program willusually include notification to workers andoccupants of the existence of asbestos intheir building, periodic surveillance of thematerial, and proper recordkeeping. EPArequires all of these activities for schoolsand strongly recommends that other build-ing owners also establish comprehensiveasbestos management programs. Withoutsuch programs, asbestos materials could bedamaged or could deteriorate, which mightresult in elevated levels of airborne asbes-tos fibers. While the management costs ofall the above activities will depend uponthe amount, condition, and location of thematerials, such a program need not beexpensive.

PROGRAMS FOR MANAGING AS-BESTOS IN-PLACE

In some cases, an asbestos operations andmaintenance program is more appropriatethan other asbestos control strategies, in-cluding removal. Proper asbestos manage-ment is neither to rip it all out in a panic norto ignore the problem under the false pre-sumption that asbestos is “risk free.”Health concerns remain, particularly forcustodial and maintenance workers.

In-place management does not mean “donothing.” It means having a program toensure that the day-to-day management ofthe building is carried out in a manner thatminimizes release of asbestos fibers into theair, and that ensures that when asbestosfibers are released, either accidentally orintentionally, proper control and clean-upprocedures are implemented. Such a pro-gram may be all that is necessary to controlthe release of asbestos fibers until the as-bestos-containing material in a building isscheduled to be disturbed by renovation ordemolition activities.

The first responsibility of a buildingowner or manager is to identify asbestos-containing materials, through a building-wide inventory or on a case-by-case basis,before suspect materials are disturbed byrenovations or other actions. The AsbestosHazard Emergency Response Act(AHERA) program requires that in schoolsan inventory of asbestos materials be doneby properly accredited individuals. Startingin late 1991 or 1992, there will also be arequirement that if an inventory of asbestosmaterials is done in public and commercialbuildings, the inventory must be done byproperly accredited individuals. In publicand commercial buildings facing majorrenovations or demolition, inspections forthe presence of ACM are required, accord-ing to the 1990 revision of the EPA Asbes-tos NESHAP. A carefully designed airmonitoring program can be used as an ad-junct to visual and physical evaluations ofthe asbestos-containing materials.

150 Appendix D

WHERE TO GO FOR ADDITIONALINFORMATION

For guidance on asbestos, building ownersand managers are urged to become familiarwith two EPA documents: ManagingAsbestos in Place (published in 1990 andalso known as the “Green Book”) andGuidance for Controlling Asbestos-Con-taining Materials in Buildings (publishedin 1985 and also known as the “PurpleBook”).

To obtain copies of the guidance publi-cations and other materials mentionedabove, or to get additional information ontechnical issues, call or write:

Environmental Assistance DivisionOffice of Toxic SubstancesU.S. EPA (TS-799)401 M Street SWWashington, DC 20460Telephone (TSCA Information Hotline):202-554-1404

National Institute for OccupationalSafety and HealthTechnical Information Branch4676 Columbia ParkwayCincinnati, OH 45226Telephone: 1-800-35-NIOSH or1-800-356-4674

Contact State air pollution control or healthagencies for information on pertinent Stateactivities and regulations. To find an as-bestos contact in State agencies, consultthe EPA Directory of State Indoor AirContacts. For a more complete listing ofpublications concerning asbestos, refer toAppendix G.

Radon 151

Radon is a radioactive gas produced bythe decay of radium. It occurs naturally inalmost all soil and rock. Radon migratesthrough the soil and groundwater and canenter buildings through cracks or otheropenings in their foundations. Radon’sdecay products can cause lung cancer, andradon is second only to smoking as a causeof lung cancer in America.

Based on early data, the EPA concen-trated its radon reduction efforts on one-and two- family homes. Citing resultsfrom a radon survey conducted jointlywith 25 States, the EPA and the SurgeonGeneral’s office issued a National HealthAdvisory that called for testing mosthomes for the presence of radon. Ex-tensive research and case studies in thefield have demonstrated practical remed-iation methods that typically reduce theindoor radon concentrations below 4 pCi/L,the current EPA action level for all occu-pied buildings.

Now that EPA technical guidance isbeing successfully used to reduce humanhealth risk in homes, the EPA is emphasiz-ing the development of radon measure-ment, mitigation, and prevention tech-niques for schools and large buildings.Preliminary data from a nationwide surveyof Federal buildings indicates that radonwill probably not be as widespread a prob-lem in large buildings as it is in homes.One of the major factors for this differenceis that multi-story buildings have propor-tionally less space in direct contact withthe earth when compared to homes.

Some of the control technologies utilizedfor homes are being studied for their ap-propriateness to other building types, in-

cluding schools and large buildings. Inaddition, new methods and technologies arebeing developed to ensure a practical andcost-effective reduction of radon in thesebuildings. As a result, published docu-ments on guidance and protocols for mea-surement and remediation of radon in largebuildings are not currently available.

This publication provides an overview ofradon issues, and should be used only asbackground information. For more infor-mation, refer to other sources of informa-tion that are specific to radon in indoor air.

BUILDING MEASUREMENT,DIAGNOSIS, AND REMEDIATION

Protocols specific to the measurement ofradon and radon progeny in large buildingsare tentatively scheduled to be published byEPA in early 1992. These large buildingmeasurement protocols can assist skilledbuilding owner or facility personnel inmaking initial screening tests for thepresence of radon. A new protocol specificto large buildings is necessary due to themajor differences in building dynamics,HVAC systems, and occupancy patternsbetween large buildings and homes, andhow these impact radon.

As part of its effort to develop wide-spread State and private sector capabilities,the EPA established a voluntary proficiencyprogram (Radon Measurement ProficiencyProgram) for radon laboratories and com-mercial measurement firms. A State Profi-ciency Report (EPA 520/1-91-014), whichgives information on specific radon mea-surement firms in your area, can be ob-tained from your State radon office or fromyour EPA Regional Office.

Appendix E: Radon

152 Appendix E

Three elements must be present forradon to be a problem: a radon source, apathway that allows radon to enter thebuilding, and a driving force that causesthe radon to flow through the pathway andinto the building. Preventing radon fromentering the building is always desirablecompared with mitigation after radon hasentered. The reduction of pathways anddriving forces are therefore usually thefocus of attention during diagnostic andremediation efforts.

Due to the diversity and complexity oflarge buildings, and because the researchand development of appropriate radonremediation technologies for these struc-tures are in the early phases, generalizedbuilding diagnostic and remediation meth-odologies are not yet available. For assis-tance, please contact the appropriate orga-nizations on the following list or a profes-sional engineering firm or mitigation com-pany with experience in this matter.

WHERE TO GO FOR ADDITIONAL INFORMATION

Western Regional RadonTraining CenterGuggenheim HallColorado State UniversityFort Collins, CO 805231-800-462-7459/303-491-7742

Southern Regional RadonTraining CenterAuburn UniversityHousing Research CenterHarbert Engineering CenterAuburn University, AL 36849-5337205-844-6261

EPA Regional OfficesIf you want additional information fromEPA regarding radon, start with the EPARegional Offices. Telephone numbersfor radon information contacts are givenin the list of EPA Regional Offices inAppendix G of this publication.

EPA Radon DivisionIf information is unavailable from theabove sources, please contact the EPARadon Division at:

Radon Division (ANR-464)U.S. EPA401 M Street, SWWashington, DC 20460202-260-9605

State Radon OfficesThere are several ways to get the name of acontact person in your State radon office orinformation about that office. You can callthe radon contact in the EPA RegionalOffice for your state or you can order theDirectory of State Indoor Air Contactsfrom the EPA Public Information Center.(See list of IAQ and radon contacts and listof EPA publications in Appendix G.)

Regional Radon Training CentersAs part of its effort to develop State andprivate sector capabilities for radon reduc-tion, the EPA has coordinated the forma-tion of four Regional Radon TrainingCenters (RRTCs). The RRTCs provide arange of radon training and proficiencyexamination courses to the public for a fee.

Eastern Regional RadonTraining CenterRutgers, The State UniversityLivingston Campus, Building 4087New Brunswick, NJ 08903-0231908-932-2582

Mid-West UniversitiesRadon ConsortiumUniversity of Minnesota1985 Buford Avenue (240)St. Paul, MN 55108-6136612-624-8747

Glossary and Acronyms 153

ACGIH — American Conference ofGovernmental Industrial Hygienists.

ASHRAE — American Society ofHeating, Refrigerating, and Air-Condition-ing Engineers.

ASTM — American Society for Testingand Materials.

Air Cleaning — An IAQ control strategyto remove various airborne particulatesand/or gases from the air. The three typesof air cleaning most commonly used areparticulate filtration, electrostatic precipita-tion, and gas sorption.

Air Exchange Rate — Used in two ways:1) the number of times that the outdoor airreplaces the volume of air in a building perunit time, typically expressed as airchanges per hour; 2) the number of timesthat the ventilation system replaces the airwithin a room or area within the building.

Antimicrobial — Agent that kills micro-bial growth. See “disinfectant,” “sani-tizer”, and “sterilizer.”

BRI — See “Building-Related Illness.”

Biological Contaminants — Agentsderived from or that are living organisms(e.g., viruses, bacteria, fungi, and mammaland bird antigens) that can be inhaled andcan cause many types of health effectsincluding allergic reactions, respiratorydisorders, hypersensitivity diseases, andinfectious diseases. Also referred to as“microbiologicals” or “microbials.”

Breathing Zone — Area of a room inwhich occupants breathe as they stand, sit,or lie down.

Building Envelope — Elements of thebuilding, including all external building

Appendix F: Glossary and Acronyms

materials, windows, and walls, that enclosethe internal space.

Building-Related Illness — Diagnosableillness whose symptoms can be identifiedand whose cause can be directly attributedto airborne building pollutants (e.g.,Legionnaire’s disease, hypersensitivitypneumonitis).

CFM — Cubic feet per minute.

CO — Carbon monoxide.

CO2 — Carbon dioxide.

Ceiling Plenum — Space below theflooring and above the suspended ceilingthat accommodates the mechanical andelectrical equipment and that is used aspart of the air distribution system. Thespace is kept under negative pressure.

Commissioning — Start-up of a buildingthat includes testing and adjusting HVAC,electrical, plumbing, and other systems toassure proper functioning and adherence todesign criteria. Commissioning alsoincludes the instruction of buildingrepresentatives in the use of the buildingsystems.

Conditioned Air — Air that has beenheated, cooled, humidified, or dehumidi-fied to maintain an interior space withinthe “comfort zone.” (Sometimes referred toas “tempered” air.)

Constant Air Volume Systems — Airhandling system that provides a constantair flow while varying the temperature tomeet heating and cooling needs.

Dampers — Controls that vary airflowthrough an air outlet, inlet, or duct. Adamper position may be immovable,manually adjustable, or part of an auto-mated control system.

154 Appendix F

Diffusers and Grilles — Components ofthe ventilation system that distribute anddiffuse air to promote air circulation in theoccupied space. Diffusers supply air andgrilles return air.

Disinfectants — One of three groups ofantimicrobials registered by EPA forpublic health uses. EPA considers anantimicrobial to be a disinfectant when itdestroys or irreversibly inactivatesinfectious or other undesirable organisms,but not necessarily their spores. EPAregisters three types of disinfectantproducts based upon submitted efficacydata: limited, general or broad spectrum,and hospital disinfectant.

EPA — United States EnvironmentalProtection Agency.

ETS — Environmental tobacco smoke.

Environmental Agents — Conditionsother than indoor air contaminants thatcause stress, comfort, and/or healthproblems (e.g., humidity extremes, drafts,lack of air circulation, noise, and over-crowding).

Ergonomics — Applied science thatinvestigates the impact of people’sphysical environment on their health andcomfort (e.g., determining the proper chairheight for computer operators).

Exhaust Ventilation — Mechanicalremoval of air from a portion of a building(e.g., piece of equipment, room, or generalarea).

Gas Sorption — Devices used to reducelevels of airborne gaseous compounds bypassing the air through materials thatextract the gases. The performance ofsolid sorbents is dependent on the airflowrate, concentration of the pollutants,presence of other gases or vapors, andother factors.

HEPA — High efficiency particulatearrestance (filters).

HVAC — Heating, ventilation, and air-conditioning system.

Hypersensitivity Diseases — Diseasescharacterized by allergic responses toanimal antigens. The hypersensitivitydiseases most clearly associated withindoor air quality are asthma, rhinitis, andhypersensitivity pneumonitis. Hypersensi-tivity pneumonitis is a rare but seriousdisease that involves progressive lungdamage as long as there is exposure to thecausative agent.

IAQ — Indoor air quality.

IPM — Integrated pest management.

Indicator Compounds — Chemicalcompounds, such as carbon dioxide, whosepresence at certain concentrations may beused to estimate certain building condi-tions (e.g., airflow, presence of sources).

MCS — See “Multiple Chemical Sensitiv-ity.”

MSDS — Material Safety Data Sheet.

Make-up Air — Air brought into abuilding from the outdoors through theventilation system that has not beenpreviously circulated through the system.

Microbiologicals — See “BiologicalContaminants.”

Multiple Chemical Sensitivity — A termused by some people to refer to a conditionin which a person is considered to besensitive to a number of chemicals at verylow concentrations. There are a number ofviews about the existence, potential causes,and possible remedial actions regardingthis phenomenon.

NIOSH — National Institute for Occupa-tional Safety and Health.

NTIS — National Technical InformationService.

Negative Pressure — Condition thatexists when less air is supplied to a spacethan is exhausted from the space, so the airpressure within that space is less than thatin surrounding areas.

OSHA — Occupational Safety and HealthAdministration.

Glossary and Acronyms 155

PELs — Permissible Exposure Limits(standards set by OSHA).

PM — Preventive Maintenance.

Plenum — Air compartment connected toa duct or ducts.

Positive Pressure — Condition that existswhen more air is supplied to a space thanis exhausted, so the air pressure within thatspace is greater than that in surroundingareas.

Psychosocial Factors — Psychological,organizational, and personal stressors thatcould produce symptoms similar to poorindoor air quality.

RELs — Recommended Exposure Limits(recommendations made by NIOSH).

Radiant Heat Transfer — Radiant heattransfer occurs when there is a large differ-ence between the temperatures of twosurfaces that are exposed to each other, butare not touching.

Re-entrainment —Situation that occurswhen the air being exhausted from a build-ing is immediately brought back into thesystem through the air intake and otheropenings in the building envelope.

SBS — See “Sick Building Syndrome.”

Sanitizer — One of three groups of anti-microbials registered by EPA for publichealth uses. EPA considers an antimicro-bial to be a sanitizer when it reduces butdoes not necessarily eliminate all the mi-croorganisms on a treated surface. To be aregistered sanitizer, the test results for aproduct must show a reduction of at least99.9% in the number of each test microor-ganism over the parallel control.

Short-circuiting — Situation that occurswhen the supply air flows to exhaust regis-ters before entering the breathing zone. Toavoid short-circuiting, the supply air mustbe delivered at a temperature and velocitythat results in mixing throughout the space.

Sick Building Syndrome — Term some-times used to describe situations in which

building occupants experience acute healthand/or comfort effects that appear to belinked to time spent in a particular build-ing, but where no specific illness or causecan be identified. The complaints may belocalized in a particular room or zone, ormay be spread throughout the building.

Soil Gases — Gases that enter a buildingfrom the surrounding ground (e.g., radon,volatile organics, pesticides).

Stack Effect —Pressure-driven airflowproduced by convection as heated air rises,creating a positive pressure area at the topof a building and a negative pressure areaat the bottom of a building. The stackeffect can overpower the mechanical sys-tem and disrupt ventilation and circulationin a building.

Static Pressure — Condition that existswhen an equal amount of air is supplied toand exhausted from a space. At staticpressure, equilibrium has been reached.

Sterilizer — One of three groups of anti-microbials registered by EPA for publichealth uses. EPA considers an antimicro-bial to be a sterilizer when it destroys oreliminates all forms of bacteria, fungi,viruses, and their spores. Because sporesare considered the most difficult form of amicroorganism to destroy, EPA considersthe term sporicide to be synonymous with“sterilizer.”

TLVs — Threshold Limit Values (guide-lines recommended by ACGIH).

TVOCs — Total volatile organic com-pounds.

Tracer Gases — Compounds, such asulfur hexafluoride, which are used toidentify suspected pollutant pathways andto quantify ventilation rates. Tracer gasesmay be detected qualitatively by their odoror quantitatively by air monitoring equip-ment.

VAV — Variable air volume system.

VOCs — See “Volatile Organic Com-pounds.”

156 Appendix F

Variable Air Volume System — Airhandling system that conditions the air to aconstant temperature and varies the outsideairflow to ensure thermal comfort.

Ventilation Air — Defined as the total air,which is a combination of the air broughtinto the system from the outdoors and theair that is being recirculated within thebuilding. Sometimes, however, used inreference only to the air brought into thesystem from the outdoors.

Volatile Organic Compounds (VOCs) —Compounds that evaporate from the manyhousekeeping, maintenance, and building

products made with organic chemicals.These compounds are released fromproducts that are being used and that are instorage. In sufficient quantities, VOCs cancause eye, nose, and throat irritations,headaches, dizziness, visual disorders,memory impairment; some are known tocause cancer in animals; some are sus-pected of causing, or are known to cause,cancer in humans. At present, not much isknown about what health effects occur atthe levels of VOCs typically found inpublic and commercial buildings.

WHO — World Health Organization.

Resources 157

FEDERAL AGENCIES WITH MAJORINDOOR AIR RESPONSIBILITY FORPUBLIC AND COMMERCIALBUILDINGS

U.S. EnvironmentalProtection AgencyConducts a non-regulatory indoor airquality program that emphasizes research,information dissemination, technicalguidance, and training. Issues regulationsand carries out other activities that affectindoor air quality under the laws forpesticides, toxic substances, and drinkingwater.

Public Information Center(PM-211B)401 M Street, SWWashington, DC 20460202-382-2080Distributes indoor air qualitypublications.

National Pesticides TelecommunicationsNetwork National toll-free number:1-800-858-PESTIn Texas: 806-743-3091Provides information on pesticides.

TSCA Hotline Service202-554-1404Provides information on asbestos andother toxic substances.

Appendix G: Resources

Occupational Safety and HealthAdministrationPromulgates safety and health standards,facilitates training and consultation, andenforces regulations to ensure thatworkers are provided with safe andhealthful working conditions. (For furtherinformation contact OSHA RegionalOffices.)

National Institute forOccupational Safety and HealthConducts research, recommends standardsto the U.S. Department of Labor, andconducts training on various issuesincluding indoor air quality to promotesafe and healthful workplaces. Undertakesinvestigations at request of employees,employers, other federal agencies, andstate and local agencies to identify andmitigate workplace problems.

Requests for Field InvestigationsNIOSHHazard Evaluations and TechnicalAssistance Branch (R-9)4676 Columbia ParkwayCincinnati, OH 45226513-841-4382

Requests for Information:1-800-35-NIOSHor 1-800-356-4674

158 Appendix G

EPA Regional Offices

Address inquiries to the contacts in theEPA Regional Offices at the followingaddresses:

(CT,ME,MA,NH,RI,VT)EPA Region 1John F. Kennedy Federal BuildingBoston, MA 02203617-565-3232 (indoor air)617-565-4502 (radon)617-565-3744 (asbestos)617-565-3265 (NESHAP)

(NJ,NY,PR,VI)EPA Region 226 Federal PlazaNew York, NY 10278212-264-4410 (indoor air)212-264-4410 (radon)212-264-6671 (asbestos)212-264-6770 (NESHAP)

(DE,DC,MD,PA,VA,WV)EPA Region 3841 Chestnut BuildingPhiladelphia, PA 19107215-597-8322 (indoor air)215-597-4084 (radon)215-597-3160 (asbestos)215-597-1970 (NESHAP)

(AL,FL,GA,KY,MS,NC,SC,TN)EPA Region 4345 Courtland Street, NEAtlanta, GA 30365404-347-2864 (indoor air)404-347-3907 (radon)404-347-5014 (asbestos)404-347-5014 (NESHAP)

(IL,IN,MI,MN,OH,WI)EPA Region 5230 South Dearborn StreetChicago, IL 60604Region 5 Environmental Hotline:1-800-572-2515 (IL)1-800-621-8431 (IN, MI, MN, OH, WI)312-886-7930 (outside Region 5)

(AR,LA,NM,OK,TX)EPA Region 61445 Ross AvenueDallas, TX 75202-2733214-655-7223 (indoor air)214-655-7223 (radon)214-655-7223 (asbestos)214-655-7223 (NESHAP)

(IA,KS,MO,NE)EPA Region 7726 Minnesota AvenueKansas City, KS 66101913-551-7020 (indoor air)913-551-7020 (radon)913-551-7020 (asbestos)913-551-7020 (NESHAP)

(CO,MT,ND,SD,UT,WY)EPA Region 8999 18th Street Suite 500Denver, CO 80202-2405303-293-1440 (indoor air)303-293-0988 (radon)303-293-1442 (asbestos)303-294-7611 (NESHAP)

(AZ,CA,HI,NV,AS,GU)EPA Region 975 Hawthorne Street, A-1-1San Francisco, CA 94105415-744-1133 (indoor air)415-744-1045 (radon)415-744-1136 (asbestos)415-744-1135 (NESHAP)

(AK,ID,OR,WA)EPA Region 101200 Sixth AvenueSeattle, WA 98101206-553-2589 (indoor air)206-553-7299 (radon)206-553-4762 (asbestos)206-553-1757 (NESHAP)

Resources 159

OSHA Regional Offices

(CT,ME,MA,NH,RI,VT)OSHA Region 1133 Portland Street, 1st FloorBoston, MA 02114617-565-7164

(NJ,NY,PR,VI)OSHA Region 2210 Varick Street, Room 670New York, NY 10014212-337-2376

(DE,DC,MD,PA,VA,WV)OSHA Region 3Gateway Building, Suite 21003535 Market StreetPhiladelphia, PA 19104215-596-1201

(AL,FL,GA,KY,MS,NC,SC,TN)OSHA Region 41375 Peachtree Street, NE, Suite 587Atlanta, GA 30367404-347-3573

(IL,IN,MI,MN,OH,WI)OSHA Region 5230 South Dearborn Street, Room 3244Chicago, IL 60604312-353-2220

(AR,LA,NM,OK,TX)OSHA Region 6525 Griffin Street, Room 602Dallas, TX 75202214-767-4731

(IA,KS,MO,NE)OSHA Region 7911 Walnut Street, Room 406Kansas City, MO 64106816-426-5861

(CO,MT,ND,SD,UT,WY)OSHA Region 8Federal Building, Room 15761961 Stout StreetDenver, CO 80294303-844-3061

(AZ,CA,HI,NV,AS,GU)OSHA Region 971 Stevenson Street, 4th FloorSan Francisco, CA 94105415-744-6570

(AK,ID,OR,WA)OSHA Region 101111 Third Avenue, Suite 715Seattle, WA 98101-3212206-442-5930

160 Appendix G

OTHER FEDERAL AGENCIES WITHINDOOR AIR RESPONSIBILITIES

Bonneville Power AdministrationP.O. Box 3621-RMRDPortland, OR 97208503-230-5475Provides radon-resistant constructiontechniques, source control, and removaltechnology for indoor air pollutants.

Consumer Product Safety Commission5401 Westbard AvenueBethesda, MD 202071-800-638-CPSCReviews complaints regarding the safety ofconsumer products and takes action toensure product safety.

General Services Administration18th and F Streets, NWWashington, DC 20405202-501-1464Writes indoor air quality policy for Fed-eral buildings. Provides proactive indoorair quality building assessments. Assessescomplaints and provides remedial action.

U.S. Department of EnergyOffice of Conservation and RenewableEnergy1000 Independence Avenue, SW, CE-43Washington, DC 20585202-586-9455Quantifies the relationship among reducedinfiltration, adequate ventilation, and ac-ceptable indoor air quality.

U.S. Department of Health and HumanServicesOffice on Smoking and HealthNational Center for Chronic DiseasePrevention and Health PromotionCenters for Disease Control1600 Clifton Road, NEMail Stop K50Atlanta, GA 30333404-488-5705Disseminates information about the healtheffects of passive smoking and strategiesfor eliminating exposure to environmentaltobacco smoke.

Tennessee Valley AuthorityOccupational Hygiene Department328 Multipurpose BuildingMuscle Shoals, AL 35660205-386-2314Provides building surveys and assessmentsassociated with employee indoor airquality complaints.

STATE AND LOCAL AGENCIES

Your questions and concerns about indoorair problems can frequently be answeredmost readily by the government agenciesin your State or locality. Responsibilitiesfor indoor air quality issues are usuallydivided among many different agencies.You will often find that calling or writingthe agencies responsible for health or airquality control is the best way to startgetting information from your State orlocal government. The EPA and PublicHealth Foundation publication, Directoryof State Indoor Air Contacts, lists Stateagency contacts. (See publications list forinformation on ordering this publication.)

Resources 161

PRIVATE SECTOR CONTACTS

The private sector organizations that haveinformation for the public on indoor airquality issues in commercial and publicbuildings include the following:

Building Management Associations

Association of Physical Plant Adminis-trators of Universities and Colleges1446 Duke StreetAlexandria, VA 22314-3492703-684-1446

Building Owners and ManagersAssociation International1201 New York Ave., NW, Suite 300Washington, DC 20005202-408-2684

Institute of Real Estate Management430 North Michigan AvenueChicago, IL 60611312-661-1930

International Council of ShoppingCenters1199 North Fairfax Street, Suite 204Alexandria, VA 22314703-549-7404

International Facilities ManagementAssociationSummit Tower, Suite 171011 Greenway PlazaHouston, TX 77046713-623-4362

National Apartment Association1111 14th Street, NW, Suite 900Washington, DC 20005202-842-4050

National Association of Industrial andOffice Parks1215 Jefferson Davis Highway, Suite 100Arlington, VA 22202703-979-3400

Professional and Standard Setting

Organizations

Air and Waste Management AssociationP.O. Box 2861Pittsburgh, PA 15230412-232-3444

Air-Conditioning and RefrigerationInstitute1501 Wilson Blvd., Suite 600Arlington, VA 22209703-524-8800

American Conference of GovernmentalIndustrial Hygienists6500 Glenway Avenue, Building D-7Cincinnati, OH 45211513-661-7881

American Industrial HygieneAssociationP.O. Box 8390345 White Pond DriveAkron, OH 44320216-873-2442

American Society for Testing andMaterials1916 Race StreetPhiladelphia, PA 19103215-299-5571

American Society of Heating,Refrigerating, and Air-ConditioningEngineers1791 Tullie Circle, NEAtlanta, GA 30329404-636-8400

National Conference of States onBuilding Codes and Standards, Inc.505 Huntmar Park Drive, Suite 210Herndon, VA 22070703-437-0100

Product Manufacturers

162 Appendix G

Adhesive and Sealant Council1627 K Street, NW, Suite 1000Washington, DC 20006-1707202-452-1500

Asbestos Information Association1745 Jefferson Davis Highway, Room 509Arlington, VA 22202703-979-1150

Business Council on Indoor Air Quality1225 19th Street, Suite 300Washington, DC 20036(202) 775-5887

Carpet and Rug Institute310 Holiday AvenueDalton, GA 30720404-278-3176

Chemical Specialties ManufacturersAssociation1913 I Street, NWWashington, DC 20006202-872-8110

Electric Power Research InstituteP.O. Box 10412Palo Alto, CA 94303415-855-2902

Formaldehyde Institute, Inc.1330 Connecticut Avenue, NWWashington, DC 20036202-822-6757

Foundation of Wall and CeilingIndustries1600 Cameron StreetAlexandria, VA 22314-2705703-548-0374

Gas Research Institute8600 West Bryn Mawr AvenueChicago, IL 60631312-399-8304

National Paint and Coatings Association1500 Rhode Island Avenue, NWWashington, DC 20005202-462-6272

Thermal Insulation ManufacturersAssociation Technical Services

Air Handling Committee1420 King StreetAlexandria, VA 22314(703) 684-0474

Building Service Associations

Air-Conditioning and RefrigerationInstitute1501 Wilson Boulevard, 6th floorArlington, VA 22209703-524-8800

Air-Conditioning Contractors ofAmerica1513 16th Street, NWWashington DC 20036202-483-9370

American Consulting Engineers Council1015 15th Street, NW, Suite 802Washington, DC 20005202-347-7474

Associated Air Balance Council1518 K Street, NWWashington, DC 20005202-737-0202

Association of Energy Engineers4025 Pleasantdale Rd., Suite 420Atlanta, GA 30340404-447-5083

Association of Specialists in Cleaningand Restoration International10830 Annapolis Junction Road, Suite 312Annapolis Junction, MD 20701301-604-4411

National Air Duct Cleaners Association1518 K Street, NW, Suite 503Washington, DC 20005202-737-2926

National Association of Power Engineers3436 Haines Way, Suite 101Falls Church, VA 22041703-845-7055

National Energy Management Institute601 North Fairfax Street, Suite 160

Resources 163

Alexandria, VA 22314703-739-7100

National Environmental BalancingBureau1385 Piccard DriveRockville, MD 20850301-977-3698

National Pest Control Association8100 Oak StreetDunn Loring, VA 22027703-573-8330

Sheet Metal and Air ConditioningContractors National Association4201 LaFayette Center DriveChantilly, VA 22021703-803-2980

Unions

AFL-CIODepartment of Occupational SafetyandHealth815 16th Street, NWWashington, DC 20006202-637-5000

American Federation of GovernmentEmployees80 F Street, NWWashington, DC 20001202-737-8700

American Federation of State, County,and Municipal Employees1625 L Street, NWWashington, DC 20036(202) 429-1215

American Federation of Teachers555 New Jersey Avenue, NWWashington, DC 20001202-879-4400

Communication Workers of America501 3rd Street, NWWashington, DC 20001202-434-1160

International Union of Operating

Engineers1125 17th Street, NWWashington, DC 20036202-429-9100

Service Employees International Union1313 L Street, NWWashington, DC 20005

Environmental/Health/Consumer Organizations

American Academy of Allergy andImmunology611 East Wells StreetMilwaukee, WI 53202414-272-6071

American Lung Associationor your local lung association1740 BroadwayNew York, NY 10019

Consumer Federation of America1424 16th Street, NW, Suite 604Washington, DC 20036

National Center for EnvironmentalHealth Strategies1100 Rural AvenueVoorhees, NJ 08043609-429-5358

National Environmental HealthAssociation720 South Colorado Blvd.South Tower, Suite 970Denver, CO 80222303-756-9090

National Foundation for the ChemicallyHypersensitiveP.O. Box 9Wrightsville Beach, NC 28480517-697-3989

Occupational Health Foundation1126 16th Street, NWWashington, DC 20036202-842-7840

PUBLICATIONS

164 Appendix G

Items marked * are available from EPAPublic Information Center (PM-211B),401 M Street, SW, Washington, DC20460. 202-382-2080.

Items marked ** are available from TSCAAssistance Hotline (TS-799), 401 MStreet, SW, Washington, DC 20460.(202)554-1404.

Items marked*** are available fromNIOSH Publications Dissemination,4676 Columbia Parkway, Cincinnati, OH45202. 513-533-8287.

General Information

Cone, James E. and Michael J. Hodgson,MD, MPH. Problem Buildings: Build-ing-Associated Illness and the SickBuilding Syndrome. 1989. From theseries “Occupational Medicine: State ofthe Art Reviews.” Hanley & Belfus, Inc.,210 South 13th Street, Philadelphia, PA19107.

Godish, Thad. Indoor Air PollutionControl. 1989. Lewis Publishers, 121South Main Street, Chelsea, MI 48118.

Rajhans, G.S., Report of the Inter-ministerial Committee on Indoor AirQuality, 1988. Contact: G. Rajhans,Health and Safety Support ServicesBranch, Ministry of Labour, 400 Univer-sity Avenue, 7th Floor, Toronto, Ontario,Canada M7A 1T7.

Sheet Metal and Air ConditioningContractor’s National Association, Inc.(SMACNA). Indoor Air Quality. 1988.8224 Old Courthouse Road, Vienna,Virginia 22180.

U.S. Environmental Protection Agency.and the Public Health Foundation. Direc-tory of State Indoor Air Contacts. Up-dated, 1991. *

U.S. Environmental Protection Agency.

Designing for Good Indoor Air Quality:An Introduction for Design Professionals.(In progress).

U.S. Environmental Protection Agency.Project Summaries: Indoor AirQuality in Public Buildings. 1988.Contains findings of research on IAQ in 10new public and commercial buildings andon building material emissions.*

U.S. Environmental Protection Agencyand the U.S. Consumer Product SafetyCommission. The Inside Story: A Guideto Indoor Air Quality. 1988. Addressesresidential indoor air quality primarily, butcontains a section on offices. *

U.S. Environmental Protection Agency.Sick Building Syndrome. Indoor AirQuality Fact Sheet #4. Revised, 1991.*

U.S. Environmental Protection Agency.Ventilation and Air Quality in Offices.Indoor Air Quality Fact Sheet #3.Revised, 1990.*

World Health Organization. Air QualityGuidelines for Eiurope. 1987. WHORegional Publications, European Series No.23. Available from WHO PublicationsCenter USA, 49 Sheridan Avenue, Albany,NY 12210.

Asbestos

Keyes, Dale L. and Jean Chesson. A Guideto Monitoring Airborne Asbestos inBuildings. 1989. Environmental Sciences,Inc., 105 E. Speedway Blvd., Tucson,Arizona 85705.

U.S. Department of Health and HumanServices, Public Health Service, U.S.Centers for Disease Control, NationalInstitute of Occupational Safety andHealth. Testimony of NIOSH on theOccupational Safety and HealthAdministration’s Proposed Rule onOccupational Exposure to Asbestos,Tremolite, Anthophyllite, and Actinolite.June 1984, May 1990, and January 1991.NIOSH Docket Office, C-34, 4676 Colum-

Resources 165

U.S. Environmental Protection Agency.National Emission Standards for Hazard-ous Air Pollutants. 40 Code of FederalRegulation 61. April 1984. **

U.S. Environmental Protection Agency.Transmission Electron MicroscopyAsbestos Laboratories: Quality AssuranceGuidelines. 1989. EPA 560/5-90-002.**

U.S. Department of Labor. OSHA Regula-tions. 29 Code of Federal Regulation1910.1001. General Industry AsbestosStandard . 29 Code of Federal Regulation1926.58. Construction Industry AsbestosStandard. June 1986; Amended September1988. DOL-OSHA Docket, 200 Constitu-tion Avenue, NW, Room N 2625,Washington, DC 20210

U.S. Department of Labor. OSHA Regula-tions. 29 Code of Federal Regulation1910.134 Respiratory Protection Stan-dard. June 1974. DOL-OSHA Docket,200 Constitution Avenue, NW, RoomN 2625, Washington, DC 20210

Biologicals

American Council of Governmental Indus-trial Hygienists. Guidelines for the Assess-ment of Bioaerosols in the Indoor Envir-onment. 1989. 6500 Glenway Avenue,Building D-7, Cincinnati, OH 45211.

Morey, P., J. Feeley, and J. Otten.Biological Contaminants in IndoorEnvironments. 1990. American Societyfor Testing and Materials Publications,1916 Race Street, Philadelphia, PA 19103.

Building Management, Investigation,and Remediation

Bazerghi, Hani and Catherine Arnoult.Practical Manual for Good Indoor AirQuality. 1989. Quebec Association forEnergy Management. 1259 Berri Street,Suite 510, Montreal, Quebec, Canada, H2L4C7.

Hansen, Shirley J., Managing Indoor AirQuality. 1991. Fairmont Press, 700 Indian

bia Parkway, Cincinnati, OH 45226.

U.S. Environmental Protection Agency. AGuide to Respiratory Protection for theAsbestos Abatement Industry. 1986. EPA560/OTS 86-001. **

U.S. Environmental Protection Agency.Abatement of Asbestos-Containing PipeInsulation. 1986. Technical Bulletin No.1986-2. **

U.S. Environmental Protection Agency.Asbestos Abatement Projects: WorkerProtection. Final Rule 40 CFR. 763.February 1987. **

U.S. Environmental Protection Agency.Asbestos Ban and Phaseout Rule. 40CFR 763.160 to 763.179. Federal Regis-ter, July 12, 1989. **

U.S. Environmental Protection Agency.Asbestos in Buildings: Guidance forService and Maintenance Personnel (inEnglish and Spanish). 1985. EPA 560/5-85-018. (“Custodial Pamphlet”). **

U.S. Environmental Protection Agency.Asbestos in Buildings: Simplified Sam-pling Scheme for Surfacing Materials.1985. 560/5-85-030A. (“Pink Book”). **

U.S. Environmental Protection Agency.Guidance for Controlling Asbestos-Containing Materials in Buildings. 1985.EPA 560/5-85-024. (“Purple Book”). **

U.S. Environmental Protection Agency.Guidelines for Conducting the AHERATEM Clearance Test to DetermineCompletion of an Asbestos AbatementProject, EPA 560/5-89-001. **

U.S. Environmental Protection Agency.Managing Asbestos In Place: A BuildingOwner’s Guide to Operations andMaintenance Programs for Asbestos-Containing Materials, 1990. (“GreenBook”).**

U.S. Environmental Protection Agency.Measuring Airborne Asbestos FollowingAn Abatement Action. 1985. EPA 600/4-85-049. (“Silver Book”). **

166 Appendix G

Trail, Lilburn, GA 30247.

U.S. Department of Health and HumanServices. Public Health Service. Centersfor Disease Control. National Institute forOccupational Safety and Health. IndoorAir Quality: Selected References.1989.***

U.S. Department of Health and HumanServices. Public Health Service. Centersfor Disease Control. National Institute forOccupational Safety and Health. Guid-ance for Indoor Air Quality Investiga-tions. 1987.***

Weekes, Donald M. and Richard B.Gammage. The Practitioner’s Approachto Indoor Air Quality Investigations.Proceedings of the Indoor Air QualityInternational Symposium. 1989. AmericanIndustrial Hygiene Association, P.O. Box8390, Akron Ohio 44320.

Environmental Tobacco Smoke

National Research Council. Environmen-tal Tobacco Smoke: Measuring Expo-sures and Assessing Health Effects. 1986.National Academy Press. 2001 WisconsinAvenue, NW, Washington, DC 20418.

U.S. Department of Health and HumanServices. Public Health Service. Officeon Smoking and Helath. The HealthConsequences of Involuntary Smoking,A Report of the Surgeon General. 1986.1600 Clifton Road, NE (Mail Stop K50)Atlanta, GA 30333.

U.S. Department of Health and HumanServices, Public Health Service. Centersfor Disease Control, National Institute forOccupational Safety and Health. CurrentIntelligence Bulletin 54: EnvironmentalTobacco Smoke in the Workplace—Lung Cancer and Other Health Effects.DHHS (NIOSH) Publication No. 91-108.1991.***

U.S. Department of Health and HumanServices, National Cancer Institute.

Office of Cancer Communications. Aseries of one-page information sheets onall aspects of smoking in the workplace.For copies, call 1-800-4-CANCER.

U.S. Environmental Protection Agency.Environmental Tobacco Smoke. IndoorAir Quality Fact Sheet #5. 1989.*

U.S. Environmental Protection Agency.Environmental Tobacco Smoke: A Guideto the Development of Effective SmokingPolicies. (In progress.) *

U.S. Environmental Protection Agency.Health Effects of Passive Smoking:Assessment of Lung Cancer in Adults andRespiratory Disorders in Children. (Inprogress.) *

PCBs

U.S. Department of Health And HumanServices. Public Health Service. Centersfor Disease Control.. National Institute ofOccupational Safety and Health. CurrentIntelligence Bulletin 45: PolychlorinatedBiphenyls—Potential Health Hazardsfrom Electrical Equipment Fires orFailures . DHHS (NIOSH) PublicationNo. 86-111. 1977. Available from theNational Technical Information Service,5285 Port Royal Road, Springfield, VA22161.

U.S. Department of Health and HumanServices. Public Health Service. Centersfor Disease Control. National Institute forOccupational Safety and Health. ARecommended Standard for OccupationalExposure to Polychlorinated BiphenylsDHHS (NIOSH) Publication No. 77-225.1977. Available from the NationalTechnical Information Service, 5285 PortRoyal Road, Springfield, VA 22161.

U.S. Environmental Protection Agency.Transformers and the Risk of Fire: AGuide for Building Owners. 1986. OPA/86-001. **

Radon

U.S. Environmental Protection Agency.

Resources 167

State Proficiency Report. 1991. EPA520/1-94-014. Available from Stateradon offices. List of laboratories thathave demonstrated com- petence in radonmeasurement analysis.

Standards and Guidelines

American Conference of GovernmentIndustrial Hygienists. Threshold LimitValues and Biological Exposure Indices.1990-1991. 6500 Glenway Avenue,Building D-7, Cincinnati, OH 45211.

U.S. Department of Health and HumanServices. Public Health Service. Centersfor Disease Control. National Institute forOccupational Safety and Health . NIOSHRecommendations for OccupationalSafety and Health. Compendium ofPolicy Documents and Statements.DHHS (NIOSH) Publications 91-109.1991.***

U.S. Department of Labor. OSHARrgulations. 29 CFR Part 1910.1000.OSHA Standards for Air Contaminants.Available from the U.S. GovernmentPrinting Office, Washington, DC 20402.202-783-3238. Additional healthstandards for some specific air contami-nants are also available in Subpart Z.

Ventilation/Thermal Comfort

Brief descriptions of the ASHRAEstandards listed below are included inAppendix B. ASHRAE materials areavailable from their Publication SalesDepartment, 1791 Tullie Circle, NE,Atlanta, GA 30329. 404-636-8400.

ASHRAE Guideline 1-1989. Guidelinefor the Commissioning of HVACSystems. 1989.ASHRAE Journal. October 1989 issue.Several articles describing ASHRAEStandard 62-1989.

ASHRAE Standard 52-76. Method ofTesting Air-Cleaning Devices Used inGeneral Ventilation for Removing

Particulate Matter. 1976.

ASHRAE Standard 55-1981. ThermalEnvironmental Conditions for HumanOccupancy. 1981.

ASHRAE Standard 62-1989. Ventila-tion for Acceptable Indoor Air Quality.1989.

National Conference of States on BuildingCodes and Standards, Inc. The VentilationDirectory. 505 Huntmar Park Drive, Suite210, Herndon, VA 22070. 703-481-2020.Summarizes natural, mechanical, andexhaust ventilation requirements of themodel codes, ASHRAE standards, andunique State codes.

TRAINING

American Industrial Hygiene Associa-tion (AIHA). P.O. Box 8390, 345 WhitePond Drive, Akron, OH 44320. 216-873-2442. Sponsors indoor air quality coursesin conjunction with meetings for AIHAmembers only.

American Society of Heating, Refriger-ating, and Air-Conditioning Engineers(ASHRAE). 1791 Tullie Circle NE,Atlanta, GA 30329. 404-636-8400.Sponsors professional developmentseminars on indoor air quality.

NIOSH Division of Training andManpower Development and NIOSH-funded Educational Resource Centers.4676 Columbia Parkway, Cincinnati, OH45226. 513-8221. Provide training tooccupational safety and health profession-als and paraprofessionals.

OSHA Training Institute. 155 TimesDrive, Des Plaines, Il 60018. 708-297-4913. Provides courses to assist healthand safety professionals in evaluatingindoor air quality.

Indoor Air Quality Forms 169

This section of the document is a collec-tion of the forms that appear or are men-tioned in the text. Consider making copiesof the forms, blocking out the page infor-mation at the bottom of the copies, and thenreproducing these copies for use in yourbuilding. Some or all of them may requireadaptation to meet your specific needs.Blank formatted sheets are included forpreparing your own HVAC Checklist andPollutant and Source Inventory.

The forms appear in the followingsequence:

Management Checklist: (4 pages): forkeeping track of the elements of the IAQprofile and IAQ management plan.

Pollutant Pathway Record For IAQProfiles: for identifying areas in whichnegative or positive pressures should bemaintained.

Zone/Room Record: for recording infor-mation on a room-by-room basis on thetopics of room use, ventilation, and occu-pant population.

Ventilation Worksheet: to be used in con-junction with the Zone/Room Record whencalculating quantities of outdoor air that arebeing supplied to individual zones or rooms.

IAQ Complaint Form: to be filled out bythe complainant or by a staff person whoreceives information from the complainant.

Incident Log: for keeping track of eachIAQ complaint or problem and how it ishandled.

Occupant Interview (2 pages): for record-ing the observations of building occupantsin relation to their symptoms and condi-tions in the building .

Occupant Diary: for recording incidentsof symptoms and associated observationsas they occur.

Log of Activities and System Operation:for recording activities and equipmentoperating schedules as they occur.

HVAC Checklist - Short Form (4 pages):to be used as a short form for investigatingan IAQ problem, or for periodic inspec-tions of the HVAC system. Duplicatepages 2 through 4 for each large air han-dling unit.

HVAC Checklist - Long Form (14 pages,followed by one blank formatted sheet):to be used for detailed inspections of theHVAC system or as a long form for inves-tigating an IAQ problem. Duplicate pages1 through 11 for each large air handlingunit.

Pollutant Pathway Form ForInvestigations: to be used in conjunctionwith a floor plan of the building.

Pollutant and Source Inventory (6 pages,followed by one blank formatted sheet):to be used as a general checklist of poten-tial indoor and outdoor pollutant sources.

Chemical Inventory: for recordinginformation about chemicals stored orused within the building.

Hypothesis Form: to be used forsummarizing what has been learned duringthe building investigation, a tool to helpthe investigator collect his or her thoughts.

Indoor Air Quality Forms

. .

BLANK FORMS


IAQ Management Checklist

Building Name:

Address:

Completed by (name/title):

Use this checklist to make sure that you have included all necessary elements in your IAQ profile andIAQ management plan. Sections 4 and 5 discuss the development of the IAQ profile and IAQ management plan.

Date begun Locationor completed Responsible person ("NA" if the item is not

Item (as applicable) (name, telephone) applicable to this building)

Page 1 of 4

IAQ PROFILE

Collect and Review ExistingRecords

HVAC design data, operatinginstructions and manuals

HVAC maintenance and calibrationrecords, testing and balancing reports

Inventory of locations where occu-pancy, equipment, or building use haschanged

Inventory of complaint locations

Conduct a WalkthroughInspection of the Building

List of responsible staff and/or contrac-tors, evidence oftraining,and job descriptions

Identification of area wherepositive or negative pressureshould be maintained

Record of locations that needmonitoring or correction

Collect Detailed Information

Inventory of HVAC system components needing repair, adjustment,or replacement

Record of control settings and operatingschedules

Date:

172 Indoor Air Quality Forms

IAQ Management Checklist Page 2 of 4



Plan showing airflow directions orpressure differentials in significantareas

Inventory of significant polluntantsources and their locations

MSDSs for supplies andhazardous substances that arestored or used in the building

Zone/Room Record

IAQ MANAGEMENT PLAN

Select IAQ Manager

Review IAQ Profile

Assign Staff Responsibilities/Train Staff

Facilities Operation and Maintenance

■ confirm that equipment operatingschedules are appropriate

■ confirm appropriate pressure relation-ships between buildingusage areas

■ compare ventilation quantities todesign, codes, and ASHRAE 62-1989

■ schedule equipment inspectionsper preventive maintenance or recom-mended maintenance schedule

■ modify and use HVAC Checklist(s);update as equipment is added, re-moved, or replaced

■ schedule maintenance activities toavoid creating IAQ problems


■ review MSDSs for supplies; requestadditional information as needed

■ consider using alarms or other devicesto signal need for HVAC maintenance(e.g., clogged filters)

Housekeeping

■ evaluate cleaning schedules andprocedures; modify if necessary

■ review MSDSs for products in use; buydifferent products if necessary

■ confirm proper use and storage ofmaterials

■ review trash disposal procedures;modify if necessary

Shipping and Receiving

■ review loading dock procedures(Note: If air intake is located nearby,take precautions to prevent intake ofexhaust fumes.)

■ check pressure relationships aroundloading dock

Pest Control

■ consider adopting IPM methods

■ obtain and review MSDSs; reviewhandling and storage

■ review pest control schedules andprocedures

■ review ventilation used duringpesticide application





Occupant Relations

■ establish health and safety committeeor joint tenant/management IAQ task force

■ review procedures for respondingto complaints; modify if necessary

■ review lease provisions; modifyif necessary

Renovation, Redecorating,Remodeling

■ discuss IAQ concerns with architects, engineers, contractors,and other professionals

■ obtain MSDSs; use materialsand procedures that minimizeIAQ problems

■ schedule work to minimizeIAQ problems

■ arrange ventilation to isolatework areas

■ use installation proceduresthat minimize emissions fromnew furnishings

Smoking

■ eliminate smoking in the building

■ if smoking areas are designated,provide adequate ventilation andmaintain under negative pressure

■ work with occupants to developappropriate non-smoking policies,including implementationof smoking cessation programs




Pollutant Pathway Record ForIAQ Profiles

This form should be used in combination with a floor plan such as a fire evacuation plan.

Building Name: ____________________________________________________ File Number: _______________________

Address: ____________________________________________________________________________________________

Completed by:_____________________________________ Title: ______________________ Date: _______________

Sections 2, 4 and 6 discuss pollutant pathways and driving forces.

Building areas that contain contaminant sources (e.g., bathrooms, food preparation areas, smoking lounges, print rooms, andart rooms) should be maintained under negative pressure relative to surrounding areas. Building areas that need to beprotected from the infiltration of contaminants (e.g., hallways in multi-family dwellings, computer rooms, and lobbies) should bemaintained under positive pressure relative to the outdoors and relative to surrounding areas.

List the building areas in which pressure relationships should be controlled. As you inspect the building, put a Y or N in the“Needs Attention” column to show whether the desired air pressure relationship is present. Mark the floor plan with arrows,plus signs (+) and minus signs (-) to show the airflow patterns you observe, using chemical smoke or a micromanometer.

Building areas that appear isolated from each other may be connected by airflow passages such as air distribution zones,utility tunnels or chases, party walls, spaces above suspended ceilings (whether or not those spaces are serving as airplenums), elevator shafts, and crawlspaces. If you are aware of pathways connecting the room to identified pollutant sources(e.g., items of equipment, chemical storage areas, bathrooms), it may be helpful to record them in the “Comments” column, onthe floor plan, or both.

Intended Pressure NeedsBuilding Area Use Positive Negative Attention? Comments(zone, room) (+) (-) (Y/N)


Zone/Room Record

Building Name: __________________________________________________ File Number: ______________________________ Date: ______________________

Address: _______________________________________________________ Completed by: _____________________________ Title: ______________________

This form is to be used differently depending on whether the goal is to prevent or to diagnose IAQ problems. During the development of a profile, this form should be usedto record more general information about the entire building; during an investigation, the form should be used to record more detailed information about the complaint areaand areas surrounding the complaint area or connected to it by pathways.

Use the last three columns when underventilation is suspected. Use the Ventilation Worksheet and Appendix A to estimate outdoor air quantitiesCompare results to the design specifications, applicable building codes, or ventilation guidelines such as ASHRAE 62-1989. (See Appendix A for some outdoor airquantities required by ASHRAE 62-1989.) Note: For VAV systems, minimum outdoor air under reduced flow conditions must be considered.

* Sources might include air handling unit (e.g., AHU-4), operable windows, transfer from corridors.** Underline the information in this column if corrent use or number of occupants is different from design specifications.*** Mark the information with a P if it comes from the mechanical plans or an M if it comes from actual measurements, such asrecent test and balance reports.**** ASHRAE 62-1989 gives ventilation guidance per 150 sq. ft.



MechanicalExhaust?


Comments Peak Number ofOccupants or

Sq. Ft. Floor Area**

Total AirSupplied

(in cfm)***

Outdoor Air Suppliedper Person or

per 150 Sq. Ft. Area(in cfm)****




Address: ____________________________________________________________________________________________

Completed by (name):_____________________________________________________ Date: _______________________

This worksheet is designed for use with the Zone/Room Record. Appendix A provides guidance on methods of estimatingthe amount of ventilation (outdoor) air being introduced by a particular air handling unit. Appendix B discusses theventilation recommendations of ASHRAE Standard 62-1989, which was developed for the purpose of preventing indoorair quality problems. Formulas are given below for calculating outdoor air quantities using thermal or CO2 information.

The equation for calculating outdoor air quantities using thermal measurements is:

Outdoor air (in percent) = T return air - T mixed air

T return air - T outdoor air

Where: T = temperature in degrees Fahrenheit

The equation for calculating outdoor quantities using carbon dioxide measurements is:

Outdoor air (in percent) = Cs - Cr

C0 - Cr

Where: Cs= ppm of carbon dioxide in the supply air (if measured in a room), orCs= ppm of carbon dioxide in the mixed air (if measured at an air handler)Cr= ppm of carbon dioxide in the return airCo= ppm of carbon dioxide in the outdoor air

Using the table below to estimate the ventilation rate in any room or zone. Note: ASHRAE 62-1989 generally states ventilation(outdoor air) requirements on an occupancy basis; for a few types of spaces, however, requirements are given on a floor areabasis. Therefore, this table provides a process of calculating ventilation (outdoor air) on either an occupancy or floor areabasis.

Ventilation Worksheet

x 100

x 100

Zone/Room Percent ofOutdoor Air

Total AirSupplied toZone/Room

(cfm)

Peak Occupancy(number of people)

orFloor Area

(square feet)

E = (Ax100) x DOutdoor Air

Supplied Per Person(or per square foot area)

EDCBA

D= BC

Total AirSupplied Per Person

(or per square foot area)

Indoor Air Quality Complaint Form


OFFICE USE ONLY

File Number: Received By: Date Received:

This form can be filled out by the building occupant or by a member of the building staff.

Occupant Name: _____________________________________________________________ Date: ___________________________

Department/Location in Building: _______________________________________________ Phone: _________________________

Completed by: ____________________________________ Title: _________________________ Phone: _____________________

This form should be used if your complaint may be related to indoor air quality. Indoor air quality problems include concernswith temperature control, ventilation, and air pollutants. Your observations can help to resolve the problem as quickly aspossible. Please use the space below to describe the nature of the complaint and any potential causes.

We may need to contact you to discuss your complaint. What is the best time to reach you? ____________________________

So that we can respond promptly, please return this form to: ________________________________________________________IAQ Manager or Contact Person

Room, Building, Mail Code

Incident Log

Building Name: _____________________________________________________________________ Dates (from): _________________ (to): _________________

Address: _______________________________________________________ Completed by (name):____________________________________________________

FileNumber

ProblemLocation

Outcome/Comments (use more than one line if needed)Log Entry By

(initials)


Date

Occupant Interview Page 1 of 2



Address: ____________________________________________________________________________________________

Occupant Name: ______________________________________ Work Location: __________________________________

Completed by:_____________________________________ Title: ________________________ Date:_______________

Sections 4 discusses collecting and interpreting information from occupants.

SYMPTOM PATTERNSWhat kind of symptoms or discomfort are you experiencing?

Are you aware of other people with similar symptoms or concerns? Yes ___________ No ___________

If so, what are their names and locations? __________________________________________________________________

Do you have any health conditions that may make you particularly susceptible to environmental problems?

❑ contact lenses ❑ chronic cardiovascular disease ❑ undergoing chemotherapy or radiation therapy

❑ allergies ❑ chronic respiratory disease ❑ immune system suppressed by disease orother causes

❑ chronic neurological problems

TIMING PATTERNSWhen did your symptoms start?

When are they generally worst?

Do they go away? If so, when?

Have you noticed any other events (such as weather events, temperature or humidity changes, or activities in the building) thattend to occur around the same time as your symptoms?

SPATIAL PATTERNSWhere are you when you experience symptoms or discomfort?

Where do you spend most of your time in the building?

ADDITIONAL INFORMATIONDo you have any observations about building conditions that might need attention or might help explain your symptoms (e.g.,temperature, humidity, drafts, stagnant air, odors)?

Have you sought medical attention for your symptoms?

Do you have any other comments?


Occupant Interview Page 2 of 2


On the form below, please record each occasion when you experience a symptom of ill-health or discomfort that you thinkmay be linked to an environmental condition in this 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 theypersist). Any other observations that you think may help in identifying the cause of the problem should be notedin the "Comments" column. Feel free to attach additional pages or use more than one line for each event if you need moreroom to record your observations.

Section 6 discusses collecting and interpreting occupant information.

Occupant Name:__________________________ Title: __________________________ Phone: ____________________

Location: ___________________________________________________ File Number: ____________________________

Occupant Diary

CommentsTime/Date Location Symptom Severity/Duration


Building Name: _______________________ Address: __________________________ File Number:________________

Completed by:_________________________________ Title: _________________________ Phone: ________________

On the form below, please record your observations of the HVAC system operation, maintenance activities, and any otherinformation that you think might be helpful in identifying the cause of IAQ complaints in this building. Pleasereport any other observations (e.g., weather, other associated events) think may be important as well.

Feel free to attach additional pages or use more than one line for each event.

Equipment and activities of particular interest:

Air Handler(s): _______________________________________________________________________________________

Exhaust Fan(s): ______________________________________________________________________________________

Other Equipment or Activities: __________________________________________________________________________

Log of Activities and System Operations

Observations/CommentsDate/Time Day of Week Equipment Item/Activity

Building Name: ____________________________________________ Address: __________________________________________

Completed by: ___________________________________________ Date: ______________ File Number: ___________________

HVAC Checklist - Short Form


Sections 2, 4 and 6 and Appendix B discuss the relationships between the HVAC system and indoor air quality.

Page 1 of 4

MECHANICAL ROOM

■ Clean and dry? Stored refuse or chemicals?

■ Describe items in need of attention

MAJOR MECHANICAL EQUIPMENT

■ Preventive maintenance (PM) plan in use?

Control System

■ Type

■ System operation

■ Date of last calibration

Boilers

■ Rated Btu input Condition

■ Combustion air: is there at least one square inch free area per 2,000 Btu input?

■ Fuel or combustion odors

Cooling Tower

■ Clean? no leaks or overflow? Slime or algae growth?

■ Eliminator performance

■ Biocide treatment working? (list type of biocide)

■ Spill containment plan implemented? Dirt separator working?

Chillers

■ Refrigerant leaks?

■ Evidence of condensation problems?

■ Waste oil and refrigerant properly stored and disposed of?





Page 2 of 4

AIR HANDLING UNIT

■ Unit identification Area served

Outdoor Air Intake, Mixing Plenum, and Damper

■ Outdoor air intake location

■ Nearby contaminant sources? (describe)

■ Bird screen in place and unobstructed?

■ Design total cfm outdoor air (O.A.) cfm date last tested and balanced

■ Minimum % O.A. (damper setting) Minimum cfm O.A. =

■ Current O.A. damper setting (date, time, and HVAC operating mode)

■ Damper control sequence (describe)

■ Condition of dampers and controls (note date)

Fans

■ Control sequence

■ Condition (note date)

■ Indicated temperatures supply air mixed air return air outdoor air

■ Actual temperatures supply air mixed air return air outdoor air

Coils

■ Heating fluid discharge temperature ∆T cooling fluid discharge temperature ∆T

■ Controls (describe)

■ Condition (note date)

Humidifier

■ Type if biocide is used, note type

■ Condition (no overflow, drains trapped, all nozzles working?)

■ No slime, visible growth, or mineral deposits?

(total cfm x minimum % O.A.)

100





DISTRIBUTION SYSTEM

Supply Air Return Air Power Exhaust

Zone/ System ducted/ cfm* ducted/ cfm* cfm* control servesRoom Type unducted unducted (e.g. toilet)

Condition of distribution system and terminal equipment (note locations of problems)

■ Adequate access for maintenance?

■ Ducts and coils clean and obstructed?

■ Air paths unobstructed? supply return transfer exhaust make-up

■ Note locations of blocked air paths, diffusers, or grilles

■ Any unintentional openings into plenums?

■ Controls operating properly?

■ Air volume correct?

■ Drain pans clean? Any visible growth or odors?

Filters

Location Type/Rating Size Date Last Changed Condition (give date)

Page 3 of 4





OCCUPIED SPACE

Thermostat types

Zone/ Thermostat What Does Setpoints Measured Day/Room Location Thermostat Temperature Time

Control? Summer Winter(e.g., radiator,

AHU-3)

Humidistats/Dehumidistats type

Zone/ Humidistat/ What Does It Setpoints Measured Day/Room Dehumidistat Control? (%RH) Temperature Time

Location

■ Potential problems (note location)

■ Thermal comfort or air circulation (drafts, obstructed airflow, stagnant air, overcrowding, poorthermostat location)

■ Malfunctioning equipment

■ Major sources of odors or contaminants (e.g., poor sanitation, incompatible uses of space)

Page 4 of 4


Building: _________________________________________________________ File Number: ________________________________

Completed by: __________________________________ Title: _____________________________ Date Checked: _____________

HVAC Checklist - Long Form

Appendix B discusses HVAC system components in relation to indoor air quality.

Page 1 of 14

NeedsAttention

NotApplicableOKComponent Comments

Outside Air Intake

Location

Open during occupied hours?

Unobstructed?

Standing water, bird droppingsin vicinity?

Odors from outdoors?(describe)

Carryover of exhaust heat?

Cooling tower within 25 feet?

Exhaust outlet within 25 feet?

Trash compactor within 25 feet?

Near parking facility, busy road,loading dock?

Bird Screen

Unobstructed?

General condition?

Size of mesh? (1⁄2" minimum)

Outside Air Dampers

Operation acceptable?

Seal when closed?




HVAC Checklist - Long Form Page 2 of 14

NeedsAttention



Actuators operational?

Outdoor Air (O.A.) Quantity(Check against applicable codesand ASHRAE 62-1989.)

Minimum % O.A. __________________

Measured % O.A. _________________Note day, time, HVAC operating modeunder "Comments"

Maximum % O.A. _________________

Is minimum O.A. a separate damper?

For VAV systems: is O.A. increased astotal system air-flow is reduced?

Mixing Plenum

Clean?

Floor drain trapped?

Airtightness

■ of outside air dampers

■ of return air dampers

■ of exhaust air dampers

All damper motors connected?

All damper motors operational?

Air mixers or opposed blades?





NeedsAttention


Mixed air temperature control setting OF

Freeze stat setting OF

Is mixing plenum under negativepressure? Note: If it is underpositive pressure, outdoor airmay not be entering.

Filters

Type

Complete coverage?(i.e., no bypassing)

Correct pressure drop? (Compare tomanufacturer's recommendations.)

Contaminants visible?

Odor noticeable?

Spray Humidifiers orAir Washers

Humidifier type

All nozzles working?

Complete coil coverage?

Pans clean, no overflow?

Drains trapped?

Biocide treatment working?Note: Is MSDS on file?

Spill contaminant system in place?





NeedsAttention



Face and Bypass Dampers

Damper operation correct?

Damper motors operational?

Cooling Coil

Inspection access?

Clean?

Supply water temp. OF

Water carryover?

Any indication of condensationproblems?

Condensate Drip Pans

Accessible to inspect and clean?

Clean, no residue?

No standing water, no leaks?

Noticeable odor?

Visible growth (e.g., slime)?

Drains and traps clear, working?

Trapped to air gap?

Water overflow?





NeedsAttention


Mist Eliminators

Clean, straight, no carryover?

Supply Fan Chambers

Clean?

No trash or storage?

Floor drain traps are wet or sealed?

No air leaks?

Doors close tightly?

Supply Fans

Location

Fan blades clean?

Belt guards installed?

Proper belt tension?

Excess vibration?

Corrosion problems?

Controls operational, calibrated?





NeedsAttention



Control sequence conformsto design/specifications?(describe changes)

No pneumatic leaks?

Heating Coil

Inspection access?

Clean?

Contol sequence conforms to design/specifications?(describe changes)

Supply water temp. OF

Discharge thermostat?(air temp. setting OF)

Reheat Coils

Clean?

Obstructed?

Operational?

Steam Humidifier

Humidifier type

Treated boiler water

Standing water?





NeedsAttention


Visible growth?

Mineral deposits?

Control setpoint OF

High limit setpoint OF

Duct liner within 12 feet? (If so,check for dirt, mold growth.)

Supply Ductwork

Clean?

Sealed, no leaks, tight connections?

Fire dampers open?

Access doors closed?

Lined ducts?

Flex duct connected, no tears?

Light troffer supply?

Balanced within 3-5 years?

Balanced after recent renovations?

Short circuiting or other air distribution problems? Notelocation(s)

Pressurized CeilingSupply Plenum

No unintentional openings?

All ceiling tiles in place?





NeedsAttention



Barrier paper correctly placed andin good condition?

Proper layout for air distribution?

Supply diffusers open?

Supply diffusers balanced?

Noticeable flow of air?

Short circuiting or other airdistribution problems? Notelocation(s) in"Comments"

Terminal Equipment (supply)

Housing interiors clean and unob-structed?

Controls working?

Delivering rated volume?


Filters in place?

Condensate pans clean, drainfreely?

VAV Box

Minimum stops %

Minimum outside air %(from page 2 of this form)

Minimum airflow cfm

Minimum outside air cfm





NeedsAttention


Supply setpoint OF (summer)

OF (winter)

Thermostats

Type

Properly located?

Working?

Setpoints OF (summer)

OF (winter)

Space temperature OF

Humidity Sensor

Humidistat setpoints % RH

Dehumudistat setpoints % RH

Actual RH %

Room Partitions

Gap allowing airflow at top?

Gap allowing airflow at bottom?

Supply, return each room?





NeedsAttention


Page 10 of 14

Stairwells

Doors close and latch?

No openings allowinguncontrolled airflow?

Clean, dry?

No noticeable odors?

Return Air Plenum

Tiles in place?

No unintentional openings?

Return grilles?

Balancing capability?

Noticeable flow of air?

Transfer grilles?

Fire dampers open?

Ducted Returns


Unobstructed grilles?

Unobstructed return air path?

Return Fan Chambers

Clean and no trash or storage?

No standing water?

Floor drain traps are wet or sealed?






NeedsAttention


Page 11 of 14

No air leaks?

Doors close tightly, kept closed?

Return Fans

Location

Fan blades clean?

Belt guards installed?

Proper belt tension?

Excess vibration?

Corrosion problems?

Controls working, calibrated?

Controls sequence conforms todesign/specifications?(describe changes)

Exhaust Fans

Central?

Distributed (locations)

Operational?

Controls operational?

Toilet exhaust only?

Gravity relief?





NeedsAttention


Page 12 of 14

Total powered exhaust cfm

Make-up air sufficient?

Toilet Exhausts

Fans working occupied hours?

Registers open, clear?

Make-up air path adequate?

Volume according to code?

Floor drain traps wet or sealable?

Bathrooms run slightly negative rela-tive to building?

Smoking Lounge Exhaust

Room runs negative relative tobuilding?

Print Room Exhaust

Room runs negative relativeto building?

Garage Ventilation

Operates according to codes?

Fans, controls, dampers all operate?






NeedsAttention


Page 13 of 14

Garage slightly negative relativeto building?

Doors to building close tightly?

Vestibule entrance to buildingfrom garage?

Mechanical Rooms

General condition?

Controls operational?

Pneumatic controls:

■ compressor operational?

■ air dryer operational?

Electric contols?

EMS (Energy Management System) orDDC (Direct Digital Control):

■ operator on site?

■ controlled off-site?

■ are fans cycled "off" whilebuilding is occupied?

■ is chiller reset to shed load?

Preventive Maintenance

Spare parts inventoried?

Spare air filters?

Control drawing posted?





NeedsAttention


Page 14 of 14

PM (Preventive Maintenance) schedule available?

PM followed?

Boilers

Flues, breeching tight?

Purge cycle working?

Door gaskets tight?

Fuel system tight, no leaks?

Combustion air: at least 1 squareinch free area per 2000 Btu input?

Cooling Tower

Sump clean?

No leaks, no overflow?

Eliminators working, no carryover?

No slime or algae?

Biocide treatment working?

Dirt separator working?

Chillers

No refrigerant leaks?

Purge cycle normal?

Waste oil, refrigerant properlydisposed of and spare refrigerantproperly stored?

Condensation problems?






NeedsAttention


Page ___ of ___

Building Name: _____________________________________________ File Number : ___________________________

Address: _____________________________________________ Completed by: ________________________________

Pollutant Pathway Form For Investigations

Pressure Relative toComplaint Area

Rooms or ZonesConnected to theComplaint Area

By PathwaysComments (e.g., potential pollutant sources)Use

This form should be used in combination with a floor plan such as a fire evacuation plan.

Building areas that appear isolated from each other may be connected by airflow passages such as air distribution zones,utility tunnels or chases, party walls, spaces above suspended ceilings (whether or not those spaces are serving as air ple-nums), elevator shafts, and crawl spaces.

Describe the complaint area in the space below and mark it on your floor plan. Then list rooms or zones connected to thecomplaint area by airflow pathways. Use the form to record the direction of air flow between the complaint area and theconnected rooms/zones, including the date and time. (Airflow patterns generally change overtime). Mark the floor plan witharrows or plus (+) and minus (-) signs to map out the airflow patterns you observe, using chemical smoke or amicromanometer. The "comments" column can be used to note pollutant sources that merit further attention.

Rooms or zones included in the complaint area: ____________________________________________________________

______________________________________________________________________________________________________________________________________

Sections 2, 4 and 6 discuss pollutant pathways and driving forces.

+/- date/time

Building Name: ___________________________________________ Address: ____________________________________

Completed by: ____________________________________ Date: _______________ File Number: ___________________


Pollutant and Source Inventory

Using the list of potential source categories below, record any indications of contamination or suspected pollutants that mayrequire 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 time of peak activity or contaminant production, includingcorrelations with weather (e.g., wind direction).

Page 1 of 6

Source Category CheckedNeeds

Attention Location Comments

Sections 2, 4 and 6 discuss pollutant sources. Appendix A provides guidance on common measurements.

SOURCES OUTSIDE BUILDING


Pollen, dust

Industrial contaminants

General vehicular contaminants

Emissions from Nearby Sources

Vehicle exhaust (parking areas,loading docks, roads)

Dumpsters

Re-entrained exhaust

Debris near outside air intake

Soil Gas

Radon

Leaking underground tanks

Sewage smells

Pesticides






Page 2 of 6



Moisture or Standing Water

Rooftop

Crawlspace

EQUIPMENT

HVAC System Equipment

Combustion gases

Dust, dirt, or microbial growthin ducts

Microbial growth in drip pans,chillers, humidifiers

Leaks of treated boiler water

Non HVAC System Equipment

Office equipment

Supplies for equipment

Labratory equipment






Page 3 of 6



HUMAN ACTIVITIES

Personal Activities

Smoking

Cosmetics (odors)

Housekeeping Activities

Cleaning materials

Cleaning procedures (e.g., dustfrom sweeping, vacuuming)

Stored supplies

Stored refuse

Maintenance Activities

Use of materials with volatilecompunds (e.g., paint, caulk,adhesives)

Stored supplies with volatilecompounds

Use of pesticides






Page 4 of 6



BUILDING COMPONENTS/FURNISHINGS

Locations Associated with Dust or Fibers

Dust-catching area(e.g., open shelving)

Deteriorated furnishings

Asbestos-containing materials

Unsanitary Conditions/Water Damage

Microbial growth in or on soiledor water-damaged furnishings






Page 5 of 6



Chemicals Released From Building Components or Furnishings

Volatile compounds

OTHER SOURCES

Accidental Events

Spills (e.g., water, chemicals,beverages)

Water leaks or flooding

Fire damage






Page 6 of 6



Special Use/Mixed Use Areas

Smoking lounges

Food preparation areas

Underground or attachedparking garages

Laboratories

Print shops, art rooms

Exercise rooms

Beauty salons

Redecorating/Repair/Remodeling

Emissions from new furnishings

Dust, fibers from demolition

Odors, volatile compounds






Page___of ___

Sections 2, 4 and 6 discuss pollutant sources. Appendix A provides guidance on common measurements.

Source Category Checked Location CommentsNeeds

Attention


Building Name: ___________________________________________________ File Number: ________________________________

Address: ______________________________________________________________________________________________________

Completed by: __________________________________________________ Phone: ______________________________________

Chemical Inventory

The inventory should include chemicals stored or used in the building for cleaning, maintenance, operations, and pestcontrol. If you have an MSDS (Material Safety Data Sheet) for the chemical, put a check mark in the right-hand column.If not, ask the chemical supplier to provide the MSDS, if one is available.

Sections 2 and 6 discuss pollutant sources. Section 4 discusses MSDSs.

MSDS on file?Date Chemical/Brand Name Use Storage Location(s)


Building Name: ____________________________________________________ File Number: _______________________________

Address: ______________________________________________________________________________________________________

Completed by: ________________________________________________________________________________________________

Complaint Area (may be revised as the investigation progresses):

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Complaints (e.g., summarize patterns of timing, location, number of people affected):

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

HVAC: Does the ventilation system appear to provide adequate outdoor air, efficiently distributed to meet occupant needsin the complaint 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 oroperating schedule?

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Pathways: What pathways and driving forces connect the complaint area to locations of potential sources?

__________________________________________________________________________________________________________________

Are the flows opposite to those intended in the design? ___________________________________________________________

Sources: What potential sources have been identified in the complaint area or in locations associated with the complaintarea (connected by pathways)?

__________________________________________________________________________________________________________________

Is the pattern of complaints consistent with any of these sources? __________________________________________________

Hypothesis Form Page 1 of 2


Hypothesis Form Page 2 of 2

Hypothesis: Using the information you have gathered, what is your best explanation for the problem?

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Hypothesis testing: How can this hypothesis be tested?__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

If measurements have been taken, are the measurement results consistent with this hypothesis?

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Results of Hypothesis Testing:

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Additional Information Needed:

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

Index 225

Air distribution, see also HVAC system, Ventilation 7-8,24-27,35,38,57-71,82-84,88,92-93, 111-115, 121-135, 146,177, 193, 201-206

Air handling units, see also HVAC system 124-130, 177, 192, 199Air pressure, see HVAC system, Pressure relationships, and VentilationAirflow, see also Pressure relationships and Ventilation 24, 26, 64, 71, 99, 104, 114, 121-122, 125Asbestos 63, 147-150, 164-165ASHRAE, see also Standards, guidelines, and advisories 121, 167

Guideline 1-1989 139Standard 52-1976 126, 138Standard 55-1981 57, 66, 129, 137Standard 62-1989 8, 14, 28, 34-35, 41, 60, 64-66, 82-87, 115, 126, 136-137

Bioaerosols, see Biological contaminantsBiocides 5, 73, 91, 94-95, 132Biological contaminants 5, 24, 35-36, 40, 48, 56, 63, 76, 82, 86, 91-95, 102-105, 117-118, 125, 127, 129, 131-132, 135,

138, 141-146, 165measuring 105, 117

Boilers, see also HVAC system 87-88, 113, 124, 135Building-related illness (BRI) 11, 86, 101, 105

Carbon dioxide (CO2) 36, 49, 57-58, 60-61, 74-76, 87, 110-115

Carbon monoxide (CO) 10, 37, 56, 58, 75-77, 100, 113, 118, 135Chemical Inventory 23, 26, 72-73, 169, 221Chemical smoke 22, 60-61, 68, 75, 77, 110-112Chillers, see also HVAC system 124, 135, 137Cleaning materials 32, 36, 73, 97Combustion gases 29, 56, 75, 86, 89, 100, 113Complaint area 49, 53-54, 65, 68-69, 76Complaints 10-11, 27, 32, 46, 103

Indoor Air Quality Complaint Form 15, 32, 169, 181responding to 14-17

Control systems, see also HVAC system 8, 19-21, 23, 26, 31, 34-36, 47, 57, 60, 64-65, 76, 82, 92,122-126, 128-130, 134-135, 145

Cooling coils, see also HVAC system 35, 67, 97, 123-124, 126, 128Cooling towers, see also HVAC system 24, 28, 35, 89, 101, 135

Dampers, see also HVAC system 24, 60, 65, 87, 125, 130, 133fire dampers 25, 130mixing boxes (mixed air plenums) 124-126outdoor air dampers 59-60, 125

Diffusers, see also HVAC system 58-61, 67, 82-83, 87-88, 113-114, 133

Index

226 Index

Ductwork, see also HVAC system 36, 61, 73, 91, 102, 127, 131-132cleaning 36, 61, 73, 91, 102, 127, 131-132leakage 67, 87, 130plenum 24-25, 61, 67, 87, 92, 123, 125, 130, 131, 133return 65, 87, 99, 130, 133supply 61, 65, 99-100, 114, 123

Dust 23, 25, 32, 67, 72-73, 118, 126, 131, 138

Elevators 68- 69, 93Environmental stressors Il, 55-56, 77-78, 85Environmental tobacco smoke (ETS) 6, 9-10, 24-25, 32, 35, 40-41, 66, 73, 81-82, 90, 116, 118, 166EPA, see Standards, guidelines, and advisoriesErgonomic stressors 55-56, 78, 85Exhaust air, see HVAC system and Ventilation 8-9, 58, 65, 82, 89, 114, 124, 133, 154Exhaust fumes 53, 72, 100

Fans, see also HVAC system 22, 48, 87, 89, 124, 130, 133, 145Filters, see also HVAC system 2, 36, 48, 60-61, 84, 91-92, 123, 126-128, 130, 138Firecodes 27, 58, 83Formaldehyde 56, 82, 85, 116-117Furnishings 34, 40, 72-73, 78, 86, 93, 96, 99, 102, 122, 133, 145

Health and safety 52, 56, 63, 76, 101, 105, 117, 147committee 16-17, 40, 76considerations for investigators 52, 56, 63, 76, 101, 105

Humidification, see also HVAC system 35, 56, 60, 90, 101, 129, 141Humidity, see Moisture 24, 49, 56, 67, 60, 82, 89, 94, 110-111, 123, 125, 129HVAC Checklist - Long Form 26, 58, 61, 169, 175, 195-209HVAC Checklist - Short Form 26, 58, 61-62, 169, 191-194HVAC system 5, 6-9, 57-59, 62, 79, 86, 89, 111, 121, 123, 154

components 57, 64, 83, 87, 94, 123-137design types 7-8, 57-59, 61- 62, 64- 65, 121-123maintenance 22-23, 62, 67, 91, 122operation 6, 25, 52, 55-59, 62, 89, 122, 189zones 47, 58, 76, 82, 112, 121-122, 169

Hypothesisdeveloping and testing hypotheses 46, 57, 67, 71, 74-75, 78-79, 223Hypothesis Form 57, 67, 71, 74, 78-79, 169, 223-224

IAQ Incident Log 16, 49, 169, 183IAQ Management Checklist 42, 169, 171-174IAQ management plan flowchart 32IAQ manager 32-33IAQ profile flowchart 20IAQ task force 13, 17,40Indoor Air Quality Complaint Form 15, 169, 181Infiltration, see Airflow and Pressure relationshipsIntegrated Pest Management (IPM), see Pest control

Index 227

Intermittent problems 10, 55, 59, 72, 74, 77Interview, see Occupant InterviewInvestigation

collecting additional information 20, 25-29, 49-74flowchart 45forming hypotheses, see Hypothesis, developing and testingoutside assistance 20, 40, 45, 47, 63, 105-108, 117reviewing existing records 20-22, 50, 58sampling 74-77, 109-119walkthrough 45, 47-49

Legionnaire’s disease 11, 56, 101Lighting 11, 24-25, 55, 77-78, 85-86Loading docks 23, 25, 37, 89, 100Local exhaust, see also HVAC system and Pressure relationships 9, 22, 40, 65, 82-83, 90, 92, 94, 97, 99-100, 102, 137Log of Activities and System Operations 52, 53, 58, 77, 139, 169, 189

Maintenance 24, 31, 34, 36, 67, 97preventive 23, 36records 22-23schedule 23, 34-35, 139

Manometer 36, 58, 68-69, 110Material Safety Data Sheets (MSDS) 20, 28, 32, 35, 38-40, 73Measurement

comparing to standards and guidelines 75- 76, 87devices 48, 58, 75, 109-119developing measurement strategy 48, 74-77

Microbiological contaminants, see Biological contaminantsMildew, see Biological contaminantsMitigation

evaluating approaches 102-103judging success 75, 103-104managing projects 103persistent problems 104using air cleaning 81, 84-85, 89, 92using exposure control 81, 85, 93, 96-99using source control 81-82, 89-101using ventilation 41, 81-84, 87-100

Mixing boxes, see also HVAC system 61, 124-126Moisture 23-24, 95, 128, 131, 141-146

humidity 24, 60, 120, 122, 137-138, 141-146waterdamage 24, 73, 94, 128, 131-132, 141-142

Mold, see Biological contaminantsMultiple chemical sensitivity (MCS) 12

NIOSH, see also Standards, guidelines, and advisories 41, 63, 75, 81,84, 111, 116, 119, 147-149, 154, 157,164-165, 167

Noise 11, 55, 77-78, 85-86, 127

228 Index

Occupants 5, 10-11complaints 10, 46, 48, 50, 72, 131density 24, 66, 73, 78, 87, 122, 136Occupant Diary 52, 77, 169, 187Occupant Interview 50-52, 169, 185occupant relations (IAQ management plan) 40

Odors 8, 24-25, 49, 65Outdoor air intake 5, 10, 25, 56, 58, 65, 89, 99-100, 121, 124-125Outdoor sources of contaminants 5, 25, 56- 57, 72-74, 86, 89, 102, 113, 127

Peppermint oil 69Pest control 23, 32, 37-38, 43, 73, 84, 89

Integrated Pest Management (1PM) 38pesticides 23, 32, 37-38, 76, 85, 96, 116

Pollutant pathways and driving forces 5, 9-10, 50, 54, 69-70, 79, 82, 84, 89, 97, 100, 115, 152Pollutant and Source Inventory 25-26, 28, 72-74, 169, 213Pollutant Pathway Form for Investigations 67, 69, 169, 211Pollutant Pathway Record IAQ Profile 26-27, 33, 169, 175Pressure relationships, see also Airflow and HVAC system 8-9, 27, 35, 37, 45, 66-68, 71, 82-83, 89, 93, 98, 100-111, 127,

133-134, 144negative/positive 8, 26-27, 37, 70, 82-83, 89, 98, 100, 110-111, 127, 132, 141, 154-155

Preventive Maintenance, see also Maintenance 36, 132Psychrometer 111, 143Psychosocial stressors 11, 55- 56, 77-78Purchasing 32, 35, 37, 41, 81

Radon 5, 89, 151-152, 167Recirculation, see VentilationRedecorating/Renovation/Remodeling 21, 32, 34, 40, 55, 66, 73, 86, 99Return air, see HVAC system and VentilationRoofing 23, 85, 89, 99

Sampling and analysis, see MeasurementSick building syndrome (SBS) 11, 155Smoking, see Environmental tobacco smokeSources, see also Pollutant and Source Inventory and specific sources (by name) 5, 6, 8-9, 26, 28, 35, 48, 72-74, 76,

81-82, 90Special use areas 25, 65, 73, 86, 90, 93, 96, 98, 133-134Standards, guidelines, and advisories, see also ASHRAE, NIOSH 43, 75-76, 167Storage practices 23, 25, 37, 73, 97Supply air, see HVAC system and VentilationSurface contamination, see also Biological contaminants 6, 37, 76, 86, 91, 94

Terminal devices, see HVAC systemTesting and balancing 21, 43, 48, 58, 87, 92, 94, 98-99, 103, 123Thermal comfort 7, 24, 56-57, 87, 89, 110-111, 121,133-134,137,167Thermal mass balance 114-115Thermostats, see also HVAC system 24, 59-60, 64-65, 67, 111, 122, 134-135, 145

Index 229

Toolsfor IAQ investigations 45, 48-50, 58, 68, 72, 77, 109-119for IAQ profiles 20, 22

Total volatile organic compounds (TVOCs) 115-116Tracergas 58, 69, 77, 112-113, 126Trainingm 31, 33, 41, 117, 139, 167Trash disposal 23, 37, 89

Unit ventilators, see HVAC systemUnsanitary conditions 24-25, 38, 65, 67, 72, 94, 117

Ventilation, see also Airflow, ASHRAE 62-1989, HVAC system, Pressure relationships 7, 8-10, 24, 65, 83-84, 110, 113,122, 126, 130-131, 133, 136, 139, 144, 167air distribution 61, 69, 86-87, 95, 104outdoor air 24, 65, 82-83, 86-87, 91-92, 96, 99-100, 102, 113-115, 121, 122-125, 135, 145measuring 87-88recirculation 82, 92total air 65, 82-83, 95, 99, 104, 113-114underventilation 24, 56-57, 60, 66-67, 82-83, 87-88, 112-113

Ventilation Worksheet 169, 179Vibration 11, 77-78, 85-86Volatile organic compounds (VOCs) 6, 82, 96, 99, 102, 115-116

Walkthroughprofile 20-25investigation 45, 47-49

Water chillers, see also HVAC system 137Water, see Moisture

Zone/Room Record 28-29, 61- 62, 169, 177

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