Vestibule Pressurization Calculator

Calculate vestibule or lobby pressurization requirements for smoke-proof enclosures per IBC/NFPA 92

Input Parameters

Results

--
Required Supply Air
CFM
--
Door Leakage Flow
CFM
--
Air Changes per Hour
ACH
--
Min Fan Size
CFM
Note: IBC Section 909.20 requires vestibule pressurization for smoke-proof enclosures. The vestibule must maintain positive pressure relative to the fire floor. Design for worst case: one door open while maintaining pressure through all other leakage paths.

Reference

Vestibule Pressurization per IBC/NFPA 92: Door Leakage = 2610 x A_leak x sqrt(dP) Open Door Flow = Door Area x 200 ft/min Total CFM = Open Door Flow + Remaining Leakage ACH = (CFM x 60) / Volume Fan Size = Total CFM x 1.2 (safety)