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Extracted Content
(This appendix is not part of this standard. It is merely informative and does not contain require- ments necessary for conformance to the standard. It has not been processed according to the ANSI requirements for a standard and may contain material that has not been subject to public review or a consensus process. Unresolved objectors on informative material are not offered the right to appeal at ASHRAE or ANSI.)
INFORMATIVE APPENDIX N INDOOR AIR QUALITY PROCEDURE
N1. SUMMARY OF SELECTED AIR QUALITY GUIDELINES
If the IAQP is used, acceptable indoor concentration limits are needed for design compounds (DCs) and particles. When using this procedure, these concentration limits need to be referenced from a cognizant authority as defined in the standard. At present, no single organization develops acceptable concentrations limits for all substances in indoor air, nor are limits available for all potential DCs or particles.
Cognizant authorities, such as the United States Environmental Protection Agency (U.S. EPA), California EPA, and the Committee for Health Related Evaluation of Building Products (AgBB) publish concentration limits for compounds, many of which may be present in the indoor environment. Compounds included in the IAQP design need to be included if data were judged sufficient to indicate a compound was likely to be found in buildings at concentrations that were a substantial fraction of the proposed design target. The goal is not to include every possible compound that may appear in indoor air but rather sufficient numbers of diverse compounds, such that control of the compounds is anticipated to result in air quality that meets the standard’s definition of “acceptable.”
A summary of considerations is presented below:
a. Is a compound expected to be present in indoor air with reasonable frequency at concentrations relevant
to (but not necessarily above) the design target? Specifically, the design outdoor airflow rate ( Voz ) and design features will be controlled by the compounds with the highest emission rates and lowest targets (taking mixtures into account); thus, compounds with low concentrations and high targets will have little or no impact on the calculated Voz . b. Is there a design target that has been proposed by a cognizant authority? c. Does it seem reasonable to expect that product emissions rates may be available for the proposed com pound? d. It there an established sampling and analytical method for the proposed compound?
Occupational exposure limits (e.g., permissible exposure limits and threshold limit values) are not appropriate as DTs, as they are not established for acceptable IAQ or for typical commercial buildings. In general, they were developed for industrial applications evaluating effects of substances on healthy adult male workers.
N2. GUIDELINE FOR EMISSION RATES
Several published peer-reviewed papers provide a reference for design teams to use to compile reasonable DC emission rates. A nonexhaustive list of peer-reviewed papers is shown in Section N4. In addition, multiple established certification programs include empirical measures of emission rates for construction materials as well as finishes, furniture, and equipment intended for indoor use. These include third-party programs as well as industry trade association programs and programs in support of government regulations (e.g., the AgBB evaluation scheme used in Germany and parts of Europe, Blue Angel, BIFMA, Green Label, France A+, CDPH Standard Method for testing and evaluation of VOC emissions [CDPH Section 01350], Greenguard, SCS Indoor Advantage Gold, and Floorscore). Engineers may use the emission rates for the specific materials that a designer is including or considering for use. The IAQP (Section 6.3) requires that emission rates must consider DCs emitted by occupants and their activities, by materials, and by specific sources within the occupied spaces and introduced into the building with outdoor air.
N3. SUBJECTIVE EVALUATION
Section 7.3.2 requires that an occupant survey be conducted. Many subjective evaluation approaches have been used with varying degrees of success. The following is an example of an evaluation approach that focuses on adapted occupants:
a. After the building is completed and substantially occupied, provide all occupants with an electronic or
written survey of questions, including, “Do you perceive the air quality in your environment to be acceptable or unacceptable?”
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