Section 6.2.2/Ventilation Rate Table
ASHRAE 62.1 Table 6.2.2.1 provides the breathing zone outdoor air rates (Rp and Ra) for each occupancy category.
Table 6.2.2.1 lists the people outdoor air rate (Rp) and area outdoor air rate (Ra) for over 60 occupancy categories. Office space requires 5 cfm per person plus 0.06 cfm per square foot. Conference rooms require 5 cfm per person plus 0.06 cfm per square foot (same rates but higher density). Classrooms require 10 cfm per person plus 0.12 cfm per square foot. The table also provides default occupant densities for calculating zone population when actual counts are not available.
Why this section exists
Different occupancy types have different ventilation needs based on the type and intensity of contaminant generation. A restaurant kitchen generates more contaminants per square foot than an office. A gym generates more bioeffluents per person than a library. The table provides scientifically derived ventilation rates for each occupancy type to achieve acceptable indoor air quality as defined by ASHRAE.
What plan reviewers look for
Plan reviewers verify that the occupancy category selected from Table 6.2.2.1 matches the actual use of each space. They check that the Rp and Ra values in the ventilation calculation correspond to the table. They also check the default occupant density when the actual zone population is not known, ensuring it is not lower than the table default.
Common violations
Related ASHRAE 62.1 requirements
Section 6.2.1 covers the breathing zone outdoor air rate equation. Table 6.2.2.2 provides zone air distribution effectiveness values.Section 6.3.1 covers the system ventilation efficiency calculation.Section 6.2.4 covers exhaust requirements by space type.