9
(b) Equipment shall be installed in a location in which the
facilities for ventilation permit satisfactory combustion of
gas, proper venting and the maintenance of ambient
temperature at safe limits under normal conditions of use.
Equipment shall be located so as not to interfere with
proper circulation of air. When normal infiltration does not
provide the necessary air, outside air shall be introduced.
(c) In addition to air needed for combustion, process air shall
be provided as required for: cooling of equipment or
material, controlling dew point, heating, drying, oxidation or
dilution, safety exhaust, odor control, and air for
compressors.
(d) In addition to air needed for combustion, air shall be
supplied for ventilation, including all air required for comfort
and proper working conditions for personnel.
(e) While all forms of building construction cannot be covered
in detail, air for combustion, ventilation and dilution of flue
gases for gas utilization equipment vented by natural draft
normally may be obtained by application of one of the
methods covered in 5.3.3 and 5.3.4.
(f) Air requirements for the operation of exhaust fans, kitchen
ventilation systems, clothes dryers, and fireplaces shall be
considered in determining the adequacy of a space to
provide combustion air requirements.
5.3.2 Equipment Located in Unconfined Spaces:
In unconfined spaces (see definition below) in buildings,
infiltration may be adequate to provide air for combustion
ventilation and dilution of flue gases. However, in buildings
of tight construction (for example, weather stripping, heavily
insulated, caulked, vapor barrier, etc.), additional air may
need to be provided using the methods described in 5.3.3-
b or 5.3.4.
Space, Unconfined.
For purposes of this Code, a space whose volume is not
less than 50 cubic feet per 1,000 BTU per hour of the
aggregate input rating of all appliances installed in that
space. Rooms communicating directly with the space in
which the appliances are installed through openings not
furnished with doors, are considered a part of the
unconfined space.
5.3.3 Equipment Located in Confined Spaces:
(a)
All Air from Inside the Building:
The confined space shall
be provided with two permanent openings communicating
directly with an additional room(s) of sufficient volume so
that the combined volume of all spaces meets the criteria
for an unconfined space. The total input of all gas utilization
equipment installed in the combined space shall be
considered in making this determination. Each opening
shall have a minimum free area of 1 square inch per 1,000
BTU per hour of the total input rating of all gas utilization
equipment in the confined space, but not less than 100
square inches. One opening shall be within 12 inches of
the top and one within 12 inches of the bottom of the
enclosure.
Furnace
Water
Heater
Opening
Chimney or Gas Vent
Opening
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.
Equipment Located in Confined Spaces;
All Air from Inside Building. See 5.3.3-a.
(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.
Furnace
Water
Heater
Outlet Air
Chimney or Gas Vent
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.
Inlet Air
Ventilation louvers for
unheated crawl space
Alternate
air inlet
Ventilation louvers
(each end of attic)
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.
