Gas fireplaces (not wood burning) may choose to not install a glass door if they meet the following requirements. However, no credit may be awarded for EQ c 2.2 Enhanced Combustion Venting Measures in Homes v2008:
1) There must be exterior air ducted to the fireplace (per IRC SECTION R1006 EXTERIOR AIR SUPPLY, details provided below). Note that we will not follow the provision in the IRC exempting exterior air supply if ‘the room is mechanically ventilated and controlled so that the indoor pressure is neutral or positive’.
AND
2) The flue must be mechanically powered, OR the space around the fireplace must pass the BPI or RESNET back draft potential test.
SECTION R1006 EXTERIOR AIR SUPPLY
R1006.1 Exterior air.
Factory-built or masonry fireplaces covered in this chapter shall be equipped with an exterior air supply to assure proper fuel combustion unless the room is mechanically ventilated and controlled so that the indoor pressure is neutral or positive.
R1006.1.1 Factory-built fireplaces.
Exterior combustion air ducts for factory-built fireplaces shall be a listed component of the fireplace and shall be installed according to the fireplace manufacturer’s instructions.
R1006.1.2 Masonry fireplaces.
Listed combustion air ducts for masonry fireplaces shall be installed according to the terms of their listing and the manufacturer’s instructions.
R1006.2 Exterior air intake.
The exterior air intake shall be capable of supplying all combustion air from the exterior of the dwelling or from spaces within the dwelling ventilated with outside air such as nonmechanically ventilated crawl or attic spaces. The exterior air intake shall not be located within the garage or basement of the dwelling nor shall the air intake be located at an elevation higher than the firebox. The exterior air intake shall be covered with a corrosion-resistant screen of 1/4-inch (6 mm) mesh.
R1006.3 Clearance.
Unlisted combustion air ducts shall be installed with a minimum 1-inch (25 mm) clearance to combustibles for all parts of the duct within 5 feet (1524 mm) of the duct outlet.
R1006.4 Passageway.
The combustion air passageway shall be a minimum of 6 square inches (3870 mm2) and not more than 55 square inches (0.035 m2), except that combustion air
R1006.5 Outlet.
Locating the exterior air outlet in the back or sides of the firebox chamber or within 24 inches (610 mm) of the firebox opening on or near the floor is permitted. The outlet shall be closable and designed to prevent burning material from dropping into concealed combustible spaces.