a gas fireplace that draws air from inside the home through ports in the firebox itself. (also called Natural vent).

One pipe system, uses room air for combustion and exhausts to the outside. For gas appliances only.

a gas-burning appliance that takes in combustion air from the home and vents products of combustion outside the home. B-Vent is also commonly known as Natural Vent.

Factory built, double-wall metal pipe for venting gas appliances with draft hoods and other appliances listed for use with Type B Gas Vent. It consists of an aluminum inner wall and a galvanized or galvalum outer wall with a dead air space between the walls. ( Losing favor to Direct Vent units.)

A venting system for gas stoves or other gas appliances using approved piping through the roof or into a chimney.