Type B vent pipe must be kept at least _____ from combustible materials.

Type B vent pipe is specifically designed for venting appliances that produce exhaust gases, such as gas water heaters and furnaces. The requirement to maintain a minimum distance from combustible materials is crucial for safety reasons. A distance of one inch is specified because it provides adequate separation to prevent heat from the vent pipe from igniting nearby combustible materials. This safety measure is essential in ensuring that the surrounding areas remain protected from excessive heat that can lead to fire hazards.

By adhering to this one-inch clearance, it helps to facilitate proper airflow around the vent pipe, which is important for maintaining efficient operation and reducing the risk of overheating. Compliance with these regulations not only enhances safety but also ensures that the venting system operates within the parameters prescribed by building codes and standards.