Our 4" CPVC duct is lightweight and easy to install. It meets ULC S102.2 and has max flame spread rating of 5 or less and max smoke generation of 25 or less. Handles temperatures up to 200 degrees F. Call today for a quote on the amount you need. Size: 4", Material: CPVC, O.D.: 4.500", Wall: .173", Std Length: 10 or 20 ft. Standards: ASTM D1784