Hart & Cooley Type B gas vent pipe and fittings are Underwriters Laboratories-tested and listed to Standard 441 for use with listed gas-fired appliances that have been certified for use with Type B gas vent. B-Vent is intended for neutral or negative draft applications. It is designed for vertical installations (including laterals) but may be used for horizontal applications with a draft-inducing fan located such that all indoor portions of the vent are under negative pressure. The materials in this B-Vent have been selected to provide maximum resistance to corrosion and heat; however, their use with temperatures exceeding 550° F or in highly corrosive atmospheres, such as chlorinated hydrocarbons (i.e., refrigerants, drycleaning fluids, degreasers, paint removers, etc.), may substantially reduce their life expectancy.