Goodman AKSS9/GKS9 Installation Instructions Manual page 10

(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 out-
doors 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
Water
Heater
Furnace
Alternate
air inlet
Ventilation louvers for
unheated crawl space
Equipment Located in Confined Spaces; All Air from Outdoors—Inlet
Air from Ventilated Crawl Space and Outlet Air to Ventilated Attic.
See 5.3.3-b
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.
Chimney or Gas Vent
Water
Heater
Furnace
Equipment Located in Confined Spaces; All Air from Outdoors
Through Ventilated Attic. See 5.3.3-b.
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.
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.
Outlet Air
Inlet Air
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.
Outlet Air
Inlet air duct
[ends 1 ft (300 mm)
above floor]
Chimney or Gas Vent
Water
Heater
Furnace
*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 cross-sectional
area as the free area of the openings to which they connect. The
minimum dimension of rectangular air ducts shall not be less than
3 inches.
NOTE: The single opening must have
a free area of not less than one
square inch per 3000 BTU of
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.
Equipment Located in Confined Spaces; All Air from Outdoors -
Single Air Opening. See 5.3.3-b.
5. When directly communicating with the outdoors, the single open-
ing shall have a minimum free area of 1 square inch per 3,000
BTU per hour of total input rating of all equipment in the enclo-
sure.
5.3.4 Specially Engineered Installations:
The requirements of 5.3.3 shall not necessarily govern when special engi-
neering, approved by the authority having jurisdiction, provides an ad-
equate supply of air for combustion, ventilation, and dilution of flue gases.
5.3.5 Louvers and Grilles:
In calculating free area in 5.3.3, consideration shall be given to the block-
ing effect of louvers, grilles or screens protecting openings. Screens used
shall not be smaller than 1/4 inch mesh. If the area through a design of
louver or grille is known, it should be used in calculating the size of open-
ing required to provide the free area specified. If the design and free area
is not known, it may be assumed that wood louvers will have 20-25 per-
cent free area and metal louvers and grilles will have 60-75 percent free
area. Louvers and grilles shall be fixed in the open position or interlocked
with the equipment so that they are opened automatically during equip-
ment operation.
10
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*.
Outlet air duct
Inlet air duct
5.3.3-b.
Chimney or Gas Vent
Water
Heater
Furnace
Opening
Alternate
Opening
Location