UL 1978

These requirements cover grease ducts, and grease duct assemblies that are intended to be installed with less than or greater than 18 inch (457 mm) clearance as specified in the Standard for Removal of Smoke and Grease-Laden Vapors from Commercial Cooking Equipment, NFPA 96 or the individual Listing intended for installations where the duct passes through partitions or walls of combustible material or where the duct is located in proximity to combustible building construction.

These requirements also cover fittings, access doors, and the like intended for use with grease ducts installed in accordance with NFPA 96.

A product that contains features, characteristics, components, materials, or systems new or different from those in use when the Standard was developed, and that involves a risk of fire, electric shock, or injury to persons, shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to mai ntain the level of safety for the user of the product as originally anticipated by the intent of this Standard.