What is the primary purpose of a Type B-W gas vent?

A Type B-W gas vent is specifically designed for the purpose of venting listed wall furnaces. These types of vents are used in conjunction with gas appliances that are installed in exterior walls and require a venting system to safely remove combustion gases outside. This ensures that the appliances operate efficiently and safely, preventing the buildup of harmful gases inside the premises.

The design and functionality of a Type B-W vent are crucial for maintaining safe operation of gas-fired appliances, particularly those that vent through walls. Their construction allows for the appropriate flow of exhaust while minimizing the risks associated with improper ventilation. By directing the gases outside, these vents help ensure optimal performance of the attached appliances.

Options like venting excess fuel, reducing combustion emissions, or stabilizing pressure levels do not directly pertain to the explicit function of a Type B-W vent. Instead, the primary focus remains on facilitating the proper venting of wall-mounted appliances, thereby highlighting choice B as the most accurate description of the vent's purpose.