5 Militia DriveLexington, MA 02421Phone: (781) 860-9177Fax: (781) 860-9178E-mail: [email protected]: www.neep.orgCommercial Building Indoor Air QualityAn Introduction to the ProblemNovember 1999Prepared By:Hal LevinlBuilding Ecology Research Group2548 Empire GradesSanta Cruz, CA 95060-9748Phone: 831-425-3946Fax: 831-426-6522E-mail: [email protected] Energy Efficiency Partnerships, Inc. Page 1AbstractThis paper provides a background on the issue of indoor air quality. It includes a discussion ofthe financial, technical, legal, insurance and health-related aspects of unacceptable indoor airquality (IAQ). It discusses the roles of ventilation system performance, pollutant sources andhuman responses in determining acceptable indoor air quality as they relate to comfort, health andchronic illness. Finally, it discusses some issues confronting those who seek to formulate andimplement policies to improve IAQ.• IntroductionMore than 3.3 billion square feet of new commercial buildings were constructed from 1988 to1998. A 170% increase in commercial building stock is anticipated by the year 2030. That stockis expected to have a lifetime of 50 to 100 years. All these buildings must provide an acceptableindoor environment to support the productivity and well-being of the work force.Building codes play a role in supporting the welfare of the community. They protect life, healthand safety, and also protect the investments made by bankers, insurance companies, businessesand individuals. Finally, building codes promote economic development by protecting the valueof the built environment. Building codes are one tool that policy makers can use to address thefinancial, legal, insurance and health-related aspects of unacceptable indoor air quality.The process of designing, constructing, starting up, controlling and maintaining building systemsis very complex. If done properly, the final product operates efficiently at reasonable cost,delivering comfort, safety and a healthy environment. If any part of this process breaks down, theproduct fails to deliver the benefits. The health-related and lost worker productivity costs fromoffice environments amount to tens of billions of dollars per year for U.S. businesses (Levin,1994). (See Appendix C with calculations of costs for office workers.) Additional energy costsof $22 to $45 billion (Davis, 1999) are incurred annually to operate buildings, due to these brokensystems. One key to managing the complex process of designing and efficiently operatingbuildings in the future lies in the ability to manage information, deliver it to the proper audienceand use it effectively for building design and operation. Building codes and other buildingregulations can play a constructive role in this process and effectively promote buildingventilation performance that will efficiently and economically achieve good indoor air quality.• BackgroundThe American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE)defines acceptable indoor air quality as “air in which there are no known contaminants atharmful concentrations as determined by cognizant authorities and with which a substantialmajority (80% or more) of the people exposed do not express dissatisfaction.” (ASHRAEStandard 62-1999)The notion that a substantial majority of the occupants do not express dissatisfaction comesdirectly from a tradition of thermal comfort research and ASHRAE’s thermal comfort Standard55. Ordinarily, some fraction of building occupants (or laboratory study subjects) would like theair warmer or colder. Studies show that it is virtually impossible to have less than about 7%(deDear and Brager, 1998) of the occupants express dissatisfaction with the thermal environment,and in most cases it is more than 12% (op cit). As a practical goal, then, a maximum number ofoccupants expressing dissatisfaction with the thermal environment is set at 20%, or stated in theNortheast Energy Efficiency Partnerships, Inc. Page 2positive form, no less than 80% of the occupants should be satisfied with the thermalenvironment. The optimum thermal environment is considered to be one in which half of theoccupants request a warmer environment and half request a cooler environment. Historically,heating, ventilating, and air-conditioning systems were designed for thermal environmentalcontrol. Air quality was usually incidental, but if not, it was addressed simply by injecting someamount of outdoor air into the ventilation supply. The goal was to do this at the least first costand the least operating cost. The amount of outdoor air required was always determined on thebasis of odor studies or control of carbon dioxide (CO2) concentrations. The earliest standardsspecified that CO2 concentrations should not exceed certain minimum levels. Since those earlystandards, a rather wide range of ventilation standards has been adopted (see Appendix B).Ultimately, the amount of outdoor air required depends on numerous factors including the qualityof the outdoor air, the type and strength of sources of contaminants inside the building, theoccupant activities and the susceptibility of the occupant population.The indoor air quality problems that draw our attention today began emerging in Europe andNorth America soon after the energy crisis precipitated by the Arab oil embargo of 1973.Recognition of these problems led to understanding that ventilation systems must addresspollution loads as well as thermal loads. Gradually, more and more practitioners have agreed onthe need for outdoor air to dilute indoor air contaminants and the need for both control ofpollution sources and removal of point source pollution by direct exhaust to the outdoors.• Impacts of Unacceptable Indoor Air QualityGood or acceptable IAQ depends strongly on who must accept it. There are significantdifferences among the needs and perspectives of building owners, building occupants and publichealth organizations. Some of these are shown in Table 1.Table 1 - Three Perspectives on Acceptable IAQBuilding OwnersNo complaints, no tenant requirements forventilation, no tenant polluting activitiesUS Environmental Protection (EPA) / PublicHealth PerspectiveMinimizes exposure to toxics, irritants; noadverse health effects, no comfort complaints Building OccupantsClean, dry, well ventilated; thermallycomfortable, no unfamiliar or objectionableodors.Unacceptable IAQ has been found to affect occupant health,
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