6 Pack DuraVent-3PPS-36BC 3" x 36" PolyPro Black UV Resistant Single Wall Straight Pipe w/ Locking Clamp Use to vent condensing appliances. 2"/60mm of overlap at the joint. Listed to ULC S636. Made of UV resistant polypropylene. Includes 1 Locking Clamp PolyPro. is engineered for use with category II and IV condensing gas/oil appliances and heating equipment, including tankless water heaters, high efficiency water heaters, condensing boilers and warm air furnaces. Application PolyPro is a polypropylene vent pipe for use with ANSI Category II and IV gas-burning appliances, including high efficiency water heaters, condensing boilers and warm air furnaces. PolyPro is listed by Intertek to the ULC SC636 standard in Canada as a Class IIA, IIB and IIC vent system suitable for exhaust temperatures up to 230F / 110C, and a maximum positive pressure of 15 in-w.c. Materials and Construction Rigid pipe constructed of 2.2mm (minimum) thick polypropylene. Flex is double-wall polypropylene. EPDM or optional Viton Gaskets. Clearances 0" clearance to combustible for exhaust temperatures up to 194F / 90C, and 0" clearance for vertical installations up to exhaust temperatures of 230F / 110C and 1/4" / 6mm clearance to combustibles for horizontal installations at exhaust temperatures up to 230F / 110C. PolyPro concentric vent system components, including concentric Horizontal Termination and Vertical Termination, are listed at 0" clearance to combustibles for exhaust temperatures up to 230F / 110C.