What Is a Type-B Vent?

Type-B vents come in many different shapes and sizes, including oval and round. It is a double-wall metal construction that is designed for insulation and safety. The inner pipe is made of reflecting aluminum and heats up quickly. It holds the warm flue gases. The outer pipe stays cooler because of the air space between it and the inner pipe, and it is made of corrosion-resistant galvanized steel.