453.4.7.4 Laboratory Suite Exhaust Air

Exhaust air from laboratory suites shall not be recirculated.

Laboratory suite exhaust air shall be independently ducted to a point outside the building or a roof top structure.

Exceptions:

1. Exhaust ducts serving a single laboratory suite.
2. Exhaust ducts serving separate laboratory suites on the same story may be connected to a common duct within a fire rated vertical shaft when the sub-duct extends vertically upward at least 22 inches.
3. Exhaust ducts serving separate laboratory suites on the basement through the 4^th story may be connected to a common duct within a fire rated vertical shaft when the sub-duct extends vertically upward at least 22 inches.
4. Exhaust ducts serving separate laboratory suites on the 5^th story and above may be connected to a common duct that does not exceed 100 vertical feet within a fire rated vertical shaft when the subducts extends vertically upward at least 22 inches. Ducts serving the 5^th story and above shall be separate from the duct serving the 4^th story and below, but may be within the same fire rated shaft^.

Laboratory suite exhaust ducts shall not penetrate the 2-hour fire barrier required by Section 453.4.3.

Exception: Where the exhaust duct is enclosed in a 2-hour shaft in accordance with Section 708.