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AIR FOR
COMBUSTION
AND
VENTILATION
Continued
WARNING ICON
G 001
WARNING
If the area in which the heater may be operated is smaller than that defined as an
unconfined space, provide adequate combustion and ventilation air by one of the
methods described in the
National Fuel Gas Code, ANSI Z223.1, 1992, Section 5.3.
VENTILATION AIR
Ventilation Air From Inside Building
This fresh air would come from an adjoining unconfined space. When ventilating to an adjoining
unconfined space, you must provide two permanent openings: one within 12" of the ceiling and
one within 12" of the floor on the wall connecting the two spaces (see options 1 and 2, Figure 3).
You can also remove door into adjoining room (see option 3, Figure 3). Follow the National Fuel
Gas Code NFPA 54/ANSI Z223.1, Section 5.3, Air for Combustion and Ventilation for required
size of ventilation grills or ducts.
WARNING ICON
G 001
WARNING
Rework worksheet, adding the space of the adjoining unconfined space. The com-
bined spaces must have enough fresh air to supply all appliances in both spaces.
Figure 4 - Ventilation Air from Outdoors
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation grills or ducts. You must provide two permanent
openings: one within 12" of the ceiling and one within 12" of the floor. Connect these items
directly to the outdoors or spaces open to the outdoors. These spaces include attics and crawl
spaces.
IMPORTANT:
Do not provide openings for inlet or outlet air into attic if attic has a thermostat-
controlled power vent. Heated air entering the attic will activate the power vent.
Figure 3 - Ventilation Air from Inside Building
Outlet
Air
Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air
Ventilated
Crawl Space
To
Crawl
Space
To Attic
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Or
Remove
Door into
Adjoining
Room,
Option
3
Ventilation Grills
Into Adjoining Room,
Option 2
Ventilation
Grills
Into Adjoining
Room,
Option 1
12"
12"