What is double walled pipe commonly known as?

Double-walled pipe is commonly known as B vent. This type of venting is specifically designed for gas appliances that produce flue gases that need to be safely expelled from the living space. The double-wall construction consists of an inner pipe that carries the flue gases and an outer pipe that provides insulation. This design helps to prevent heat loss and minimizes the risk of flammable materials igniting due to the heat generated by the exhaust gases.

B vent systems are typically used for appliances that operate with natural gas and require an efficient way to vent exhaust safely. The design allows for the safe movement of flue gases while ensuring that the exterior of the vent does not reach temperatures that could be hazardous to surrounding materials. This double-walled configuration adheres to safety standards and is widely accepted in gas venting applications.

In contrast, the other types of venting—such as A vent, C vent, and D vent—serve different purposes or are designed for specific types of appliances or applications, making them distinct from B vent systems.