What type of vent connector is used when located in an attic serving an appliance?

• A. Type B vent
• B. Type L vent
• C. PVC vent
• D. Single-wall vent

Answer: (A)

Venting through an attic requires a vent that is designed for vertical runs in unconditioned spaces and can safely carry combustion gases to the outdoors. Type B vent is a factory-built double-wall metal vent specifically made for gas-fired appliances and vertical venting through attics and roofs. The outer jacket stays cooler, reducing fire risk to attic materials, while the inner passage provides smooth, reliable exhaust flow for the appliance. This makes it the appropriate choice for an attic installation serving an appliance.

Single-wall vents aren’t ideal in attic spaces because they run hotter and pose a greater fire hazard near combustibles. PVC venting is used for certain high-efficiency appliances but isn’t the standard for typical attic vent connections, and Type L vents are generally associated with different appliance applications and installation rules.