Stairwell Pressurization Calculator

Calculate stairwell pressurization fan sizing per NFPA 92 for smoke-proof enclosures

Input Parameters

Results

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Required Airflow
CFM
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Flow Through Open Doors
CFM
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Total Leakage Flow
CFM
--
Min Fan Static Pressure
in. w.g.
Note: NFPA 92 requires minimum 0.05 in. w.g. across closed doors and minimum 200 ft/min through open doors. Stack effect can significantly increase pressure requirements in tall buildings. Consider wind effects on exterior walls.

Reference

NFPA 92 Stairwell Pressurization: Door Flow = Num Open Doors x Door Area x 200 ft/min Leakage = 2610 x A_leak x sqrt(dP) per floor Total CFM = Door Flow + Leakage + Envelope Leakage Fan SP = dP + Duct Loss + Stack Effect