MBE / HUB-Certified Texas MEP
ASHRAE 62.1 Outdoor Air Calculator
Quick lookup for required outdoor air ventilation rate per ASHRAE Standard 62.1 Table 6.1 (Ventilation Rate Procedure). Pick occupancy type, area, and people count — we return the design OA in CFM. Most TX cities require 62.1 compliance for permit.
Picks the ASHRAE 62.1 Table 6.1 row for your occupancy.
Conditioned floor area for this space.
Peak design occupancy. Leave 0 to use the ASHRAE default people/1000-sf for that type.
Required outdoor air
110CFM
Basis: Office (5 cfm/person + 0.06 cfm/sf): 10 people × 5 + 1,000 sf × 0.06 = 50 + 60 = 110 CFM at zone level (Vbz). Effectiveness Ez=1.0 typical.
62.1 default
If your AHJ adopts ASHRAE 62.1 by reference (most TX cities do), this is the minimum design OA. Local amendments may raise the rate; we apply the higher of 62.1 vs local requirement.
Need this calc on your permit set?
Pyra Engineering produces sealed ventilation calcs and stamps the OA design for permit. Quote in 1 business day.
Important. This tool returns Vbz (zone-level breathing-zone OA). Final design OA at the AHU includes zone-air-distribution effectiveness (Ez), system ventilation efficiency (Ev), and recirculation factors per ASHRAE 62.1 §6.2.5. Permit submittal requires a full ventilation calc by a licensed engineer.