Elliott Horner, PhD “ASHRAE’s Jim Dennison, CIH, PhD ...

2019 IAQA Annual Meeting

Elliott Horner, PhD

UL Environment

[email protected]

M: 678-249-8856

Jim Dennison, CIH, PhD

Century Environmental Hygiene

[email protected]

O: 970-266-8000

“ASHRAE’s

Indoor Air Quality Procedure

in Ventilation Design”


Acknowledgements

• ASHRAE SSPC 62.1

• ASHRAE TRG4.IAQP


ASHRAE

• Content

• American Society of Heating, Refrigerating and Air-

Conditioning Engineers

• Publish a wide variety of standards

• 55-- Thermal Environmental Conditions for Human

Occupancy

• 110-- Methods of Testing Performance of Laboratory

Fume Hoods

• 62.2 -- Ventilation and Acceptable Indoor Air Quality in

Residential Buildings

• 188-- Legionellosis: Risk Management for Building Water

Systems

• 189.1-- Design of High Performance Buildings


Standard 62.1

Ventilation for Acceptable Indoor

Air Quality• Content

• Design standard

• Last complete update 2016

• Continuous maintenance with triennial updates

• ANSI Standard


Mechanical Code

• In the U.S., cities and states generally adopt

the International Mechanical Code, with

local modifications

• IMC is based mostly on ASHRAE 62.1

403.2 Outdoor Air Required The minimum outdoor airflow rate shall be determined in accordance with Section 403.3. 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 62.1. 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.”

https://up.codes/viewer/colorado/imc-2015/chapter/4/ventilation#403.3

https://up.codes/viewer/colorado/imc-2015/chapter/4/ventilation#403.3


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


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


ASHRAE 62.1:


• IAQ procedure


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


ASHRAE 62.1:


• IAQ procedure


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


LEED Green Building program

• Content• Does not currently permit using IAQP


2019 Proposed Revision

“Design Compounds”

• Content• Content


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


Carbon Dioxide

• Content• Controversial Compound

• Data on “direct cognitive effects of CO2” exists

but not confirmed

• CO2 is used as a surrogate for bioeffluents from

people

• Several studies reported that

perceived acceptable AQ correlated with ~1100

ppm CO2 or ventilation rates that are in the

range giving 1100 ppm


Mixtures

• ContentMust 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


Mixtures

• Content

𝐸𝑚 =𝐶1𝐷𝑇1

+𝐶2𝐷𝑇2

+⋯𝐶𝑖𝐷𝑇𝑖

• Pre-Defined Mixtures in draft


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?


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

https://www.pbs.org/newshour/science/it-could-take-centuries-for-epa-to-test-all-the-unregulated-chemicals-under-a-new-landmark-bill

https://www.pbs.org/newshour/science/it-could-take-centuries-for-epa-to-test-all-the-unregulated-chemicals-under-a-new-landmark-bill


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


Bibliography

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


Questions?

Jim [email protected]

Elliott [email protected]

mailto:[email protected]

mailto:[email protected]


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