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.