ASHRAE s. Indoor Air Quality Procedure. in Ventilation Design

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1 Elliott Horner, PhD UL Environment M: ASHRAE s Indoor Air Quality Procedure Jim Dennison, CIH, PhD Century Environmental Hygiene jim@centuryenvironmental.com O: in Ventilation Design

2 Acknowledgements ASHRAE SSPC 62.1 ASHRAE TRG4.IAQP

3 ASHRAE American Society of Heating, Refrigerating and Air- Conditioning Engineers Publish Content a wide variety of standards 55-- Thermal Environmental Conditions for Human Occupancy Methods of Testing Performance of Laboratory Fume Hoods Ventilation and Acceptable Indoor Air Quality in Residential Buildings Legionellosis: Risk Management for Building Water Systems Design of High Performance Buildings

4 Standard 62.1 Ventilation for Acceptable Indoor Air Quality Content Design standard Last complete update 2016 Continuous maintenance with triennial updates ANSI Standard

5 Mechanical Code In the U.S., cities and states generally adopt the International Mechanical Code, with local modifications IMC is based mostly on ASHRAE Outdoor Air Required The minimum outdoor airflow rate shall be determined in accordance with Section Exception: Where the registered design professional demonstrates that an engineered ventilation system design will prevent the maximum concentration of contaminants from exceeding that obtainable by the rate of outdoor air ventilation determined in accordance with Section 403.3, the minimum required rate of outdoor air shall be reduced in accordance with such engineered system design. [IMC commentary states An engineered ventilation system is more of a direct method of controlling air quality and would be classified as an Indoor Air Quality Procedure in ASHRAE ASHRAE 62.1, as a whole, is not a referenced standard in the code but, the exception to this section could certainly be viewed as allowing the indoor air quality (IAQ) method of that standard as one of the possible means of complying with the exception.

6 ASHRAE 62.1: Minimum OA requirements Content Compliance methods Ventilation Rate Procedure L/s per person + L/s per area IAQ procedure Dilution needed for acceptable IAQ Natural Ventilation

7 ASHRAE 62.1: Minimum OA requirements Ventilation Rate Procedure L/s per person + L/s per area Count people, Measure the area and Add May waste energy, but defensible

8 ASHRAE 62.1: Minimum OA requirements IAQ procedure Dilution needed for acceptable IAQ Identify Design Compounds, Find Emission Rate, Determine Limit Compute Mass Balance May save energy, but values needed may be absent Add in air cleaner: What is the removal efficiency? (add factor to mass balance) Cleaning conditioned air saves energy Manufacturers want to know the compound(s) for efficiency measurement

9 ASHRAE 62.1: Minimum OA requirements IAQ procedure Dilution needed for acceptable IAQ What is the removal efficiency? (add factor to mass balance) Manufacturers want to know the compound(s) for efficiency measurement Removal efficiency measurement is expensive Chemical classes probably behave similarly within limits (pentane / heptane) Similar compounds: very dangerous (benzene), others not (toluene) Short list (8 10) of representative compounds for efficiency testing is needed

10 LEED Green Building program Content Does not currently permit using IAQP

11 2019 Proposed Revision Design Compounds Content Content

12 Selection of Design Compounds Content Look at prevalence in IA As compared to possible Design Targets (limits to design to) Selected Compounds from different classes

13 Carbon Dioxide Content Controversial Compound Data on direct cognitive effects of CO 2 exists but not confirmed CO 2 is used as a surrogate for bioeffluents from people Several studies reported that perceived acceptable AQ correlated with ~1100 ppm CO 2 or ventilation rates that are in the range giving 1100 ppm

14 Mixtures Must Content have a way to address Consider the VOCs: toluene 300 ug/m3. Add just 3 more VOCs at this level and IAQ is probably unacceptable

15 Mixtures Content Em = C 1 DT 1 + C 2 DT 2 + C i DT i Pre-Defined Mixtures in draft

16 TVOC: backstop or red herring? Criticisms Not health based Was it ever? Misrepresented Different definitions Selected list vs sum? Should be sum! (that is what total means see Webster) Sum of C5-C17 or C6-C16? Does that difference exceed TAB % error? wear on HVAC parts?

17 TVOC: backstop or red herring? Benefits Aggregate limit Overall chemical hygiene more clean vs less clean Precautionary Principal Formaldehyde in 1980 vs today Flame retardants, bisphenol A 2000 new compounds / year into commerce

18 Conclusions IAQP is a logical way to design HVAC if you get the right compounds and limits, and can accurately estimate sources Consensus must be developed over the method, compounds and limits Difficult to select compounds and limits based on current knowledge base, but with enough effort, may be reasonable Involved discussion with groups like AIHA and USGBC needs to occur

19 Bibliography ANSI/ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality. 2016

20 Questions? Jim Dennison Elliott Horner

21 Content Content Content Slides

22 Content Content Content Slides