Ventilation and Acceptable Indoor Air Quality in Residential Buildings

Abstract

Background:

Since 2007, Section 4.1 (Ventilation Rate) of ASHRAE Standard 62.2 has stated that “each dwelling unit” is to be provided with “outdoor air” at the rate specified.

This rate is understood to be the minimum amount of continuous outdoor air needed to achieve acceptable indoor air quality within a dwelling unit.

Outdoor air has a clear definition in the standard: “air, outdoor: air from outside the building taken into a ventilation system or air from outside the building that enters a space through infiltration or natural ventilation openings.”

Transfer air also has a clear and intentionally separate definition in the standard: “air, transfer: air moved from one occupiable space to another, usually through doorways or grilles.”

Based on the distinctly different definitions and the consistent use of the term “outdoor air” rather than “transfer air” in Section 4.1, the intent of the Standard seems clear that the “outdoor air” must come from outside the building and not from adjacent spaces such as other dwelling units or attached garages