B-Vent, also known as Type B vent or natural draft vent, is commonly used for venting gas appliances that are designed to use indoor air for combustion. These appliances typically have a draft hood to facilitate the flow of air and exhaust gases.

Type B-vents are double-walled metal chimneys/flues and can be used only with listed, draft-hood equipped gas appliances. Type B gas vents such as the Ameri-Vent™ are permitted for venting gas-fired appliances and have their own set of combustible clearance and installation specifications.

Type B Gas Vent is designed for negative pressure applications and flue gas temperatures not exceeding 400°F above ambient for Category I appliances. Durability is the result of high-quality materials and workmanship, with galvanized outer pipe and aluminum inner pipe providing protection against corrosion and external damage.

Type B-vents are double-walled metal chimneys/flues and can be used only with listed, draft-hood equipped gas appliances. A Type B vent is intended for relatively low-heat applications. B-vents are not permitted for use with incinerators and are not intended for use with appliances burning anything other than LP or natural gas.

A b vent is one of the more affordable gas fireplace vents to have installed, which is why many people are initially attracted to the idea of it. When a b vent is installed, the vent pipe must end above the roof. This is because any appliance that uses a b vent only has one exhaust pipe for air to travel through.