607.5.5 Shaft enclosures.
MC § 607.5.5
Ducts and air transfer openings shall not penetrate a shaft serving as an exit enclosure except as permitted by Section 1022.4 of the New York City Building Code. Shaft enclosures that are permitted to be penetrated by ducts and air transfer openings shall be protected with approved fire and smoke dampers installed in accordance with their listing. Exceptions: 1. Fire dampers are not required at penetrations of shafts where any of the following apply: 1.1. In buildings equipped throughout with an automatic sprinkler system in accordance with Chapter 9 of the New York City Building Code, where steel exhaust subducts have a minimum thickness of 0.0187 inch (0.4712 mm) (No. 26 gage) and extend not less than 22 inches (558.8 mm) vertically in exhaust shafts, provided that there is a continuous airflow upward to the outdoors whenever the building is occupied. 1.2. Penetrations are tested in accordance with ASTM E 119 or UL 263 as part of the fire-resistance-rated assembly. 1.3. Ducts are used as part of an engineered smoke control system designed and installed in accordance with Section 909 of the New York City Building Code, and where the fire damper will interfere with the operation of the smoke control system. 1.4. The penetrations are in parking garage exhaust or supply shafts that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction.
2.Smoke dampers are not required in exhaust ducts or shafts where the exhaust fan is maintained in operation whenever the building is occupied, in bathrooms and toilet room exhausts.
3.Smoke dampers are not required at penetrations of exhaust or supply shafts in parking garages that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction.
4.Smoke dampers are not required at penetrations of shafts where ducts are used as part of an engineered mechanical smoke control system designed in accordance with Section 909 of the New York City Building Code and where the smoke damper will interfere with the operation of the smoke control system.
5.Fire dampers and/or smoke dampers are not required at a shaft where the shaft is acting as an extension of the mechanical equipment room that it serves and the shaft and mechanical equipment room maintain fire and smoke separation required by the greater of the two spaces from the occupied portions of the building and meet the requirements of Sections 713.11 and 713.12 of the New York City Building Code.
6.Smoke dampers are not required to be located within a prescribed distance of a fire-rated enclosure within which the air handling equipment is located and where isolation smoke dampers are used in air-handling equipment. See Section 607.2.3 for additional requirements.
7.Smoke dampers are not required in ducts where the air continues to move and the air-handling system installed is arranged to prevent recirculation of exhaust or return air during a fire emergency condition. Such fans shall be provided with standby power in accordance with Chapter 27 of the New York City Building Code.
