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49D0090
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Ventilated
Crawl Space
Inlet Air
Outlet
Air
Outlet
Air
Outlet
Air
Ventilated
Attic
To Attic
To
Crawl
Space
FRESH AIR FOR COMBUSTION AND VENTILATION
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 6)
. You can also remove door
into adjoining room (see option 3, Figure 6).
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.
VENTILATION AIR FROM OUTDOORS
Provide extra fresh air by using ventilation
grills or ducts. You must provide two perma-
nent 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. F
ollow 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.
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 6 - Ventilation Air from Inside Building
Figure 7 - Ventilation Air from Outdoors
Rework worksheet, adding
the space of the adjoining
unconfined space. The
combined spaces must
have enough fresh air to
supply all appliances in
both spaces.
W
ARNING
Option 1:
Ventilation
Grills into
Adjoining
Room
Option 2:
Ventilation Grills into
Adjoining Rooms
Option
3:
Remove
Door into
Adjoining
Room
Summary of Contents for BTU/Hr
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