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Ventilation Calculator

ASHRAE 62.1 · Outdoor Air Requirements · Commercial Spaces

When to use: Use to determine the minimum outdoor air (OA) requirements for commercial and institutional spaces per ASHRAE Standard 62.1. The ventilation rate consists of a people component (occupant-based, CFM/person) and an area component (CFM/ft²). Required for mechanical permit submittals, Title 24 compliance, and LEED credit documentation. Residential applications use ASHRAE 62.2.

Space Parameters
Peak occupancy
people
ft²
Required Outdoor Air
148
CFM
Breakdown
People Component (Rp)100 CFM
Area Component (Ra)48 CFM
Breathing Zone Flow (Vbz)148 CFM
Zone OA Flow (Voz)148 CFM
CFM per Person7.4 CFM/person
CFM per ft²0.185 CFM/ft²
Est. Air Changes/hr1.23 ACH
References
ASHRAE 62.1 – Ventilation for acceptable IAQ
Table 6-1 – Minimum ventilation rates
Voz = Vbz / Ez (zone distribution)
Ez = 1.0 for ceiling supply / ceiling return