Type B Vent pipe consists of which of the following?

Type B Vent pipe is specifically designed for gas appliances and consists of a distinct construction that includes an inner and outer pipe. The inner pipe is typically made of aluminum or a similar material that can withstand high temperatures and corrosive gases produced by combustion. The outer pipe serves a protective purpose, encasing the inner pipe and providing insulation. This design fosters the safe venting of exhaust gases while preventing fires and allowing for proper airflow.

The correct answer highlights the essential components of a Type B Vent pipe system, which are designed to ensure efficient exhaust of combustion products from appliances like furnaces and water heaters. This construction prevents issues related to corrosion and ensures the venting system can function effectively under varying conditions. The other options do not accurately represent the structural integrity and material composition necessary for Type B Vent pipes, focusing on limitations such as the absence of one of the components or the use of incorrect materials like plastic.