per hour of the total input rating of all gas utilization equipment in the confined space, but not less than 100 square inches. One open- ing shall be within 12 inches of the top and one within 12 inches of the bottom of the enclosure.
Chimney or Gas Vent
NOTE: Each opening must have a free area of not less than one square inch per 1000 BTU of the total input rating of all equip- ment in the enclosure, but not less than 100 square inches.
Opening
Water
Furnace Heater
Opening
Equipment Located in Confined Spaces; All Air from Inside
Building. See 5.3.3-a.
Chimney or Gas Vent
Ventilation louvers (each end of attic)
NOTE: The inlet and outlet air openings must each have a free area of not less than one square inch per 4000 BTU of the
total input rating of all equipment in the enclosure.
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Equipment Located in Confined Spaces; All Air from Outdoors
Through Ventilated Attic. See
3.When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2,000 BTU per hour of total input rating of all equipment in the enclosure.
(b)All Air from Outdoors: The confined space shall be provided with two permanent openings, one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure. The openings shall communicate directly, or by ducts, with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors.
1.When directly communicating with the outdoors, each opening shall have a minimum free area of 1 square inch per 4,000 BTU per hour of total input rating of all equipment in the enclosure.
Chimney or Gas Vent
Outlet air duct
Water
Heater
NOTE: The air duct openings must have a free area of not less than one square inch per 2000 BTU of the total input rating of all equipment in the enclosure*.
Alternate air inlet
Chimney or Gas Vent
Ventilation louvers (each end of attic)
NOTE: The inlet and outlet air openings must each have a free area of not less than one square inch per 4000 BTU of the
total input rating of all equipment in the enclosure.
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Ventilation louvers for unheated crawl space
Furnace
Inlet air duct
*If the appliance room is located against an outside wall and the air openings communicate directly with the outdoors, each opening shall have a free area of not less than one square inch per 4,000 BTU per hour of the total input rating of all appliances in the enclosure.
Equipment Located in Confined Spaces; All Air from Outdoors.
See
4.When ducts are used, they shall be of the same
NOTE: The single opening must have
a free area of not less than one Chimney or Gas Vent square inch per 3000 BTU of
Equipment Located in Confined Spaces; All Air from Outdoors— Inlet Air from Ventilated Crawl Space and Outlet Air to Ventilated Attic. See
2.When communicating with the outdoors through vertical ducts, each opening shall have a minimum free area of 1 square inch per 4,000 BTU per hour of total input rating of all equipment in the enclosure.
the total input rating of all equip-
ment in the enclosure, but not less than the sum of the areas of all vent connectors in the confined space.
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Furnace |
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Equipment Located in Confined Spaces; All Air from Outdoors -
Single Air Opening. See
10