Chimney Safety Institute of America (CSIA) Certification Practice Test

What type of construction characterizes a B vent?

1. Single wall with insulation

2. Double wall and listed for use with draft hoods

3. Flexible and lightweight

4. Wooden framed

The correct answer is: Double wall and listed for use with draft hoods

A B vent, or Type B vent, is specifically designed for venting appliances that are equipped with draft hoods, such as gas furnaces and water heaters. The construction of a B vent features a double wall design, which is crucial for safely venting flue gases. The inner wall is typically made of metal, which allows for the passage of hot gases, while the outer wall serves as an insulating layer, providing protection from heat transfer and minimizing the risk of fire hazards. This double wall construction also promotes the proper drafting of combustion gases, ensuring efficient operation of the appliance it serves. The requirement for B vent to be listed for use with draft hoods highlights the specific safety and operational standards it must meet. Other types of venting systems, like single wall or flexible systems, do not have the same capability to manage the higher temperatures and flue gas byproducts that come from appliances with draft hoods. Therefore, B vents are particularly suited for these applications, making their double wall construction the correct choice.