Wash. Admin. Code § 51-51-1503
M1503.2.1 Open-top broiler exhaust. Domestic open-top broiler units shall be provided with a metal exhaust hood, having a minimum thickness of 0.0157 inch (0.3950 mm) (No. 28 gage). Such hoods shall be installed with a clearance of not less than 1/4 inch (6.4 mm) between the hood and the underside of combustible material or cabinets. A clearance of not less than 24 inches (610 mm) shall be maintained between the cooking surface and the combustible material or cabinets. The hood width shall not be less than the width of the broiler unit and shall extend over the entire unit.
EXCEPTIONS: | 1. Broiler units that incorporate an integral exhaust system, and that are listed and labeled for use without an exhaust hood, shall not be required to have an exhaust hood. 2. Broiler units permanently installed outside the building envelope and having the cooking surface at least 5 feet below a 1-hour fire resistance rated ceiling shall not be required to have an exhaust hood. |
M1503.3 Exhaust discharge. Domestic cooking exhaust equipment shall discharge to the outdoors through a duct. The duct shall have a smooth interior surface, shall be airtight, shall be equipped with a back-draft damper and shall be independent of all other exhaust systems. Ducts serving domestic cooking exhaust equipment shall not terminate in an attic or crawl space or areas inside the building.
EXCEPTION: | Where installed in accordance with the manufacturer's instructions, and where continuous local exhaust is provided in an enclosed kitchen in accordance with Table M1505.4.4.1, listed and labeled ductless range hoods shall not be required to discharge to the outdoors. |
M1503.5 Kitchen exhaust rates. Where domestic kitchen cooking appliances are provided with exhaust equipment, the fans shall be sized in accordance with Section M1505.4.4.1.
Wash. Admin. Code § 51-51-1503