ASHRAE Further Improves the IAQP with Addendum n

The Indoor Air Quality Procedure (IAQP) within ASHRAE Standard 62.1, Ventilation and Acceptable Indoor Air Quality requires the use of a mass balance calculation to determine the volume of outside air required, in conjunction with source control and removal measures, to provide indoor air quality (IAQ) that is “acceptable to human occupants and minimizes adverse health effects.”[1]

There are many benefits to using the IAQP rather than the alternative Ventilation Rate Procedure (VRP) to meet IAQ requirements using a hybrid ventilation and air cleaning approach. These benefits include smaller and less expensive HVAC systems, lower energy use and carbon emissions from less conditioning of outside air, lower operating expenses from less energy use and lower peak demand, and increased resilience to polluted outside air.

Despite these many benefits, a challenge with the IAQP has been lax efficiency testing requirements for air cleaning technologies used with the IAQP. Any mass balance calculation that includes filtration or air cleaning requires a particle filtration efficiency and gaseous removal efficiency, but Standard 62.1 did not define acceptable testing standards to measure particle filtration and gaseous removal efficiency resulting in a wide range of testing approaches, some of which have undermined the rigor and credibility of the IAQP.

ASHRAE has now addressed this weakness with Addendum n to Standard 62.1-2022, which builds on other important updates to Standard 62.1 included in Addendum aa published in 2022.

Together, Addendum n and Addendum aa make the IAQP the new “gold standard” for designing highly efficient and cost-effective hybrid ventilation and air cleaning systems to support building decarbonization and electrification goals and lower HVAC costs.

The ASHRAE Position Document on Filtration and Air Cleaning states that “All filtration and air cleaning technologies should be accompanied by data documenting their performance regarding removal of contaminants; these data should be based on established industry test standards.” Building on this guidance, Standard 62.1, through Addendum n, now specifies requirements for “test apparatus properties and validation tests” that must be used to determine cleaning efficiencies when applying the IAQP.

According to Addendum n, gas-phase air cleaners shall report an efficiency test for all compounds included in the design in accordance with ASHRAE Standard 145.2[2], ISO 10121-2, or testing to another national consensus standard approved by the authority having jurisdiction.

Addendum n also allows for “custom efficiency tests” to demonstrate removal efficiency for all compounds included in the design. These custom tests must be performed by a third party, must comply with a series of standards specified in the addendum, and must be documented and approved by the authority having jurisdiction.  All test results, along with relevant equipment settings, also need to be provided upon request.

Prior to Addendum n, mass balance calculations could be based on any type of testing, including “custom efficiency tests” conducted by manufacturers that do not conform to national standards. Additionlly, air cleaning devices that have not been tested for all contaminants defined in Standard 62.1 (see table 6-5 in 62.1-2022) could simply use an efficiency of zero for the untested contaminants. For some contaminants, using zero does not change the final results for outdoor air requirements since some contaminants remain below the Standard 62.1 defined “design limits” with minimal outdoor air. This is okay for “subtractive” air cleaning technologies like sorbent filters that do not produce any byproducts, but this can be problematic when using “additive” air cleaning technologies such as electronic air cleaners that add reactive constitutents to the space to clean the air.

enVerid applauds ASHRAE for publishing Addendum n to clarify the efficiency testing requirements for gas-phase filters used to comply with the IAQP. This latest update to Standard 62.1 further strengthens the IAQP, which provides a cost effective pathway to design high IAQ, low energy, climate resilient buildings for the future.

enVerid’s Sorbent Ventilation Technology^® has been independently tested by third-party labs for all the Standard 62.1 contaminants (also referred to as Design Compounds) according to ASHRAE Standard 145.2. Click here to learn more about how Sorbent Ventilation Technology works. 

[1] ASHRAE Standard 62.1 specifies minimum ventilation rates and other measures intended to provide IAQ that is acceptable to human occupants and minimizes adverse health effects.

[2] Addendum n also states that if Standard 145.2 does not apply to a specific technology one can also test using the methods in Section 6.1.2, 10.4, and 10.5 and report results as required in Section 11 of Standard 145.2.