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NYC Building Code

§ 909.20.4.2 — § 909.20.4.2

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What is NYC BC § 909.20.4.2?

Quick Answer

This section establishes ventilation requirements for vestibules, mandating a minimum of one air change per minute and an exhaust rate of at least 150 percent of the supply air. It specifies the construction and location of ducts for supply and exhaust air. Applies to building owners responsible for compliance with ventilation standards.

General informational summary. Not legal advice for your situation. Consult an attorney before acting on any specific matter.

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909.20.4.2 Vestibule ventilation.

BC § 909.20.4.2

The vestibule shall be supplied with not less than one air change per minute and the exhaust shall not be less than 150 percent of supply. Supply air shall enter and exhaust air shall discharge from the vestibule through separate, tightly constructed ducts used only for that purpose. Supply air shall enter the vestibule within 6 inches (152.4 mm) of the floor level. The top of the exhaust register shall be located at the top of the smoke trap but not more than 6 inches (152.4 mm) down from the top of the trap, and shall be entirely within the smoke trap area. Doors in the open position shall not obstruct duct openings. Duct openings with controlling dampers are permitted where necessary to meet the design requirements, but dampers are not otherwise required.

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