UL Standards & Engagement Gas Vents UL 441

Gas Vents UL 441 1.1 These requirements cover Types B and BW gas vents and Types B and BW gas vent roof jacks intended for venting gas appliances equipped with draft hoods to burn only gas. Type B vents are also intended for use with other Category I appliances that specify they are for use with Type B gas vents. 1.2 The gas vents covered by these requirements are intended for installation in accordance with the National Fire Protection Association Standards for Chimneys, Fireplaces, Vents, and Solid-Fuel Burning Appliances, NFPA 211 the National Fuel Gas Code, NFPA 54, the Department of Housing and Urban Development Mobile Home Construction and Safety Standards, Chapter II of 24 CFR, Part 280, the International Mechanical Code, and the Uniform Mechanical Code.