Los Angeles County Municipal Code § 910.3 Smoke and heat vent design and installation
Los Angeles County Municipal Code · 2026-09 edition · updated 2026-10-04 · Los Angeles County
Cite as: Los Angeles County Municipal Code § 910.3 · Text as of 2026-10-04
The design and installation of smoke and heat vents shall be as specified in Sections 910.3.1 through 910.3.5.
910.3.2 - Smoke and heat vent locations.¶
Smoke and heat vents shall be located 20 feet (6096 mm) or more from adjacent lot lines and fire walls and 10 feet (3048 mm) or more from fire barriers. Vents shall be uniformly located within the roof in the areas of the building where the vents are required to be installed by Section 910.2, with consideration given to roof pitch, sprinkler location, draft curtains, and structural members.
910.3.4 - Vent operation.¶
Smoke and heat vents shall be designed to operate automatically, but also have the capability of being opened by an approved exterior manual operation. Automatic operation of smoke and heat vents shall conform to the provisions of Sections 910.3.4.1 through 910.3.4.3.
910.3.4.1 - Gravity-operated drop-out vents.¶
Thermoplastic drop-out vents, designed to shrink and drop out of the vent opening when exposed to fire, shall fully open within 5 minutes after the vent cavity is exposed to an air temperature of 500°F (260°C).
910.3.4.2 - Sprinklered buildings.¶
Where installed in buildings provided with an approved automatic sprinkler system, smoke and heat vents shall be designed in accordance with Sections 910.3.2.2.1 through 910.3.2.2.2.
910.3.4.2.1 - Control mode sprinkler system.¶
Smoke and heat vents installed in areas of buildings with a control mode sprinkler system shall have operating elements with a higher temperature classification than the automatic fire sprinklers in accordance with NFPA 13.
910.3.4.2.2 - Early suppression fast-response (ESFR) sprinkler system.¶
Smoke and heat vents installed in areas of buildings with early suppression fast-response (ESFR) sprinklers shall be equipped with a standard-response operating mechanism having a minimum temperature rating of the greater of either 360ºF (182ºC), or 100ºF (56ºC) above the operating temperature of the sprinklers.
910.3.4.3 - Nonsprinklered buildings.¶
Where installed in buildings not provided with an approved automatic sprinkler system, smoke and heat vents shall operate by actuation of a heat-responsive device rated at between 100°F (38°C) and 220°F (104°C) above ambient.
Exception: Gravity-operated drop-out vents complying with Section 910.3.2.1.
910.3.5 - Vent dimensions.¶
The effective venting area of an individual vent shall not be less than 16 square feet (1.5 m 2 ) with no dimension less than 4 feet (1219 mm), excluding ribs or gutters having a total width not exceeding 6 inches (152.4 mm).
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