The use of plastic venting systems on gas fired water heaters, furnaces and boilers has undergone a significant change. NFPA 54-18 (National Fire Protection Association), National Fuel Gas Code and IFGC-18 (International Fuel Gas Code) now recognizes the UL 1738 venting standard as an option for venting Categories II and IV gas fired appliances.
The change to these model codes empowers relevant authorities to allow the use of a vent material specified by the appliance manufacturers to be certified to the UL 1738 venting standard.