Inner Diameter 5 . Fuel Type Gas, Liquid Propane. Height 36 . Double Wall Construction. UL Listed. This Aluminum 36 Inch Length Round Rigid Pipe with 5 Inch Inner Diameter from the Round Gas Vent series is a Type B gas component and consists of the duralock system for a tight seal. Use for venting listed natural gas or liquid propane Category I, draft hood appliances, or appliances that have been specifically tested and listed to use Type B Gas Vent. The appliances listed typically use Type B Gas Vent systems, but not always Furnaces, Water Heaters, Boilers, Room Heaters, Decorative Gas Appliances, and Unit Heaters. To calculate installed length, subtract 1 1/2 from each connection of vent. A 1 clearance air space to combustible materials must be maintained. To calculate OD add 5?8 . DuraVent Type B Gas Vent is designed to meet the rugged demands of the job site. The inner wall is recessed to eliminate damage in handling. DuraVent's innovative system for a lock-tight connection for Type B Gas Vent called DuraLock. See the alignment indicators meet; feel the ends grasp together; hear the snap as the connection firmly locks into place. Type B gas vents are not suitable for use with wood-burning or coal applications, industrial ovens, exhaust ranges and hoods, grease or pollution ducting, or as free-standing exhaust vents for high temperature applications. Type B Gas Vent has been engineered to heat up rapidly. It remains hot during the operation of the appliance with minimal condensation in the appliance and vent system. Pipe lengths are available in multiple lengths, 6 to 60 inches, with a full complement of adjustable and rigid fittings.