504.10 Common multistory exhaust systems for clothes dryers.
MC § 504.10
Where a common multistory duct system is designed and installed to convey exhaust from multiple clothes dryers, the construction of the system shall be in accordance with all of the following: 1. The shaft in which the duct is installed shall be constructed and fire-resistance rated as required by the New York City Building Code.
2.Dampers and subducts shall be prohibited in the exhaust duct.
3.Rigid metal ductwork shall be installed within the shaft to convey the exhaust. The ductwork shall be constructed of sheet steel having a minimum thickness of 0.0187 inch (0.4712 mm) (No. 26 gage) and in accordance with SMACNA/ANSI Duct Construction Standards. The common ductwork ducts shall not be connected or installed with sheet metal screws or other fasteners that will obstruct the exhaust flow.
4.Exhaust ducts 20 square inches (129 cm 2 ) or less connected into a common multistory exhaust system shall not require fire dampers when the exhaust fan runs continuously. Exhaust ducts greater than 20 square inches (129 cm 2 ) shall not be connected into a common multistory exhaust system.
5.The exhaust fan motor design shall be in accordance with Section 503.2.
6.The exhaust fan motor shall be located outside of the airstream.
7.The exhaust fan shall run continuously, and shall be connected to a standby power source, where a building standby power source is required per the New York City Building Code.
8.Exhaust fan operation shall be monitored in an approved location and shall initiate an audible or visual signal when the fan is not in operation.
9.Makeup air shall be provided for the exhaust system.
10.A cleanout opening shall be located at the base of the shaft, at all offsets and at all changes of direction to provide access to the duct to allow for cleaning and inspection. The finished opening shall be not less than 12 inches by 12 inches (304.8 mm by 304.8 mm).
11.Screens shall not be installed at the termination.
12.The common multistory duct system shall serve only clothes dryers and shall be independent of other exhaust systems. (Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023) Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.
