Stairwell Pressurization Calculator

Calculate stairwell pressurization airflow for smoke control per IBC 909.20 and NFPA 92

Input Parameters

Results

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Required Pressure Differential
in w.g.
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Total Leakage Airflow
cfm
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Open Door Airflow
cfm
--
Total Supply Airflow Required
cfm
Note: Stairwell pressurization per IBC 909.20 and NFPA 92. System must maintain minimum pressure with doors closed and design velocity with doors open. Compensating supply fans or barometric relief required for varying door configurations. Testing per IBC 909.18.

Reference

IBC 909.20.5.1: Min 0.05 in w.g. (sprinklered), 0.10 in w.g. (non-sprinklered) Max 0.35 in w.g. (door opening force < 30 lbf) IBC 909.20.5.2 / NFPA 92: 200 fpm min velocity through open doors Leakage: Q = 300 x A_gap x sqrt(deltaP) Door gap area: ~0.4 sq ft (weather-stripped) Stack effect adds ~0.004 in w.g./ft height