COVERAGE:

Vented Gas Fireplace Heater.  A vented appliance which simulates a solid fuel
fireplace and furnishes warm air, with or without duct connections, to the space in which
it is installed.  A Vented Gas Fireplace Heater may be controlled by an automatic
thermostat.  The circulation of heated room air may be by gravity or mechanical
means.  A Vented Gas Fireplace Heater may be freestanding, recessed, zero clearance
or an insert,  and is further defined as:

• Direct Vent Gas Fireplace Heater. A system consisting of :

1. combustion air connections between the appliance and the vent-air intake terminal;
2. flue gas connections between the appliance and the vent-air intake terminal; and
3. a vent-air intake terminal for installation outdoors. 

• Air for combustion is obtained from the outdoor atmosphere and all flue gases are
  discharged to the outdoor atmosphere.   These components shall be supplied by the
  manufacturer.

• Gas Fireplace Heater Insert.  A vented appliance designed to be fully or partially
  installed in a solid fuel burning fireplace.
• Gravity Vented Gas Fireplace Heater.  Constructed so all air for combustion is
  obtained from the room in which the appliance is installed, and all flue gases are
  discharged to the outdoor atmosphere.  The discharge of the flue gases is by gravity.
• Power Vented Gas Fireplace Heater.  Equipped with a mechanical means to either draw
  or force products of combustion through the combustion chamber and/or heat exchanger to
  the outdoor atmosphere.

REQUIREMENTS:

Input ratings are shown in Btu per hour.

In the United States, input ratings are for elevations up to 2,000 feet.  For
elevations above 2,000 feet, burner inputs should be reduced 4 percent for each 1,000 feet
above sea level.

For additional information, reference should be made to the current edition of the
National Fuel Gas Code, ANSI Z223.1/NFPA 54.

/mac