Hart & Cooley’s Type B Gas Vent system is a UL-listed double-wall, air-insulated venting solution engineered for Category I gas appliances. The 4-inch variant is commonly used for smaller gas furnaces, water heaters, or other gas appliances with modest flue requirements. The system incorporates locking joints to prevent separation under vibration, with a galvanized outer shell and corrosion-resistant aluminum inner liner. It is designed for draft (negative pressure) applications and tolerates flue gas temperatures no more than about 400 °F above ambient.

Hart & Cooley

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The product line includes straight pipe segments, elbows, tees, adapters, storm collars, and caps to allow full venting runs. Installation is simplified by curled ends, locking bands, and modular fittings to maintain alignment and structural integrity