Loading...
504.9 Commercial clothes dryers.
The installation of dryer exhaust ducts serving commercial clothes dryers shall comply with the appliance manufacturer's instructions and NFPA 54. Exhaust fan motors installed in exhaust systems shall be located outside of the airstream. In multiple installations, the fan shall operate continuously or be interlocked to operate when any individual unit is operating. Ducts shall have a minimum clearance of 6 inches (152.4 mm) to combustible materials. Clothes dryer transition ducts used to connect the appliance to the exhaust duct system shall be limited to single lengths not to exceed 8 feet (2438.4 mm) in length and shall be listed and labeled for the application. Transition ducts shall not be concealed within construction.
504.10 Common multistory exhaust systems for clothes dryers.
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.
505.1 Domestic systems.
Where domestic range hoods or domestic appliances equipped with downdraft exhaust are provided, such hoods and appliances shall discharge to the outdoors through ducts constructed of galvanized steel, stainless steel, aluminum or copper. Such ducts shall have smooth inner walls, shall be air tight, shall be equipped with a backdraft damper and shall be independent of all other exhaust systems. Such exhaust system shall be installed in strict compliance with the manufacturer's instructions as well as the requirements of the listing.
Exceptions:
1. In other than Group I-1 and I-2, where installed in accordance with the manufacturer's instructions and where mechanical or natural ventilation is otherwise provided in accordance with Chapter 4, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.
2. Ducts for domestic kitchen cooking appliances equipped with downdraft exhaust systems shall be permitted to be constructed of Schedule 40 PVC pipe and fittings provided that the installation complies with all of the following:
2.1. The duct shall be installed under a concrete slab poured on grade.
2.2. The underfloor trench in which the duct is installed shall be completely backfilled with sand or gravel.
2.3. The PVC duct shall extend not more than 1 inch (25.4 mm) above the indoor concrete floor surface.
2.4. The PVC duct shall extend not more than 1 inch (25.4 mm) above grade outside of the building.
2.5. The PVC ducts shall be solvent cemented.
505.2 Makeup air required.
Exhaust hood systems where required by Chapter 4 shall be provided with makeup air at a rate in accordance with Table 403.3.1.1. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system.
Loading...