A. Gas Floor Furnace: A completely self-contained-unit furnace, excluding those having additional or separate returns, suspended from the floor of the space being heated, taking air for combustion from outside this space, and with means for observing flames and lighting the appliance from the space being heated.

B. Vent Collar A means provided to connect the vent pipe to the furnace.

C. Draft Hood: A device placed in and made a part of the flue pipe from an appliance, or in the appliance itself, which is designed to (1) insure the ready escape of the products of combustion in the vent of no draft, back draft, or stoppage beyond the draft hood; (2) prevent a back draft from entering the appliance, and (3) neutralize the effect of stack action of the chimney flue upon the operation of the appliance.

D. Chimney: A vertical structure constructed of masonry, either lined or unlined, for the purpose of carrying away products of combustion from an appliance burning gas as fuel.

E. Vertical Vent: A pipe designed to carry the products of combustion and which rises in a vertical direction from an appliance or horizontal vent connection.

F. Horizontal-vent connection: A pipe designed to carry the products of combustion and which runs in a generally horizontal direction from the vent collar of gas furnace to the vertical vent, flue, or chimney.

G. Crossover or offset: Any deviation from the vertical rise of the vertical vent, necessitating one or more fittings.

H. One-hundred-percent-automatic safety pilot: A device for shutting off, automatically, the gas supply to the main burner and pilot in the event of a pilot or gas failure, and also for preventing the gas from being turned into the main burner unless the pilot is ignited. (Required for liquefied petroleum gases.)

I. Gas-pressure regulator: A device for controlling and maintaining a uniform pressure on a gas supply.