What type of pipe does a B vent represent?

A B vent represents a double wall pipe system specifically designed for venting gas appliances. It consists of an inner pipe that carries the exhaust gases and an outer pipe that provides insulation and protects the inner pipe from the external environment. The double-wall design allows for safe venting of high-efficiency appliances while minimizing heat loss and protecting against corrosion.

The inner pipe contains the flue gases, while the space between the inner and outer pipes allows for air circulation, which helps prevent overheating. This design is particularly important for gas-burning appliances that produce hot exhaust, ensuring that the temperature of the outer wall remains at a safe level to prevent any fire hazards or damage to nearby structures.

Given this context, the other options either refer to types of pipes that lack the specific design features of a B vent or don’t adequately fulfill the requirements for venting gas appliances. Single wall pipes do not provide the same level of insulation and safety as double wall systems. Flex pipes are typically used in other applications and don’t have the structural integrity needed for venting. Insulated pipes may have insulation but do not necessarily conform to the double-wall design requirements essential for safely venting gas appliances.