Which statement describes the IAQ Procedure as per ASHRAE 62.1-2022?

• A. It is identical to the Ventilation Rate Procedure.
• B. It is a performance-based method that must control specific design compounds and PM2.5 while ensuring 80% occupant satisfaction.
• C. It prescribes only one path for all buildings.
• D. It is optional and rarely used.

Answer: (B)

The IAQ Procedure in ASHRAE 62.1-2022 is a performance-based compliance path, not a fixed ventilation-rate rule. It lets the design team show that indoor air quality meets targets by modeling pollutant concentrations rather than just meeting a prescribed outdoor air quantity. Specifically, it requires controlling designated indoor contaminants (a defined set of design pollutants) and PM2.5 to target levels using a mass-balance approach that accounts for emissions, filtration, and ventilation. In addition, it includes an occupant-acceptance requirement, typically aiming for about 80% of occupants to be satisfied with IAQ. Because of these features, this procedure is an optional alternative path that can be used when a project seeks to demonstrate IAQ performance through pollutant concentrations and occupant satisfaction, rather than strictly through ventilation rates.