9
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation
grills or duct. You must provide two
permanent openings: one within 12 inches
of the ceiling and one within 12 inches of
the floor. Connect these items directly to the
outdoors or spaces open to the outdoors.
These spaces include attics and crawl
spaces. Follow the National Fuel Gas Code
NFPA 54/ANS Z223.1. Air for Combustion
and Ventilation for required size
of ventilation grills or ducts.
Ventilation Air From Inside Building
This fresh air would come from adjoining
unconfined space. When ventilating to an
adjoining unconfined space, you must
provide two permanent openings: one
within 12 inches of the wall connecting
the two spaces (see options 1 and 2,
Fig. 1). You can also remove door into
adjoining room (see option 3, Fig. 1).
Follow the National Fuel Gas Code
NFPA 54/ANS Z223.1. 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. 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.
Fig. 1 - Ventilation Air from
Inside Building
Fig. 2 - Ventilation Air from
Outdoors
WARNING
: If the area in which the heater may be operated does not meet the required
volume for indoor combustion air, combustion and ventilation air shall be provided by one
of the methods described in the NATIONAL FUEL GAS CODE, ANSI Z223.1/NFPA 54, the
INTERNATIONAL FUEL GAS CODE, or applicable local codes.
Ventilation
Grills
Into Adjoining
Room,
Option 1
Or
Remove
Door
Into
Adjoining
Room,
Option 3
Ventilation Grills
Into adjoining Room,
Option 2
12 in.
12 in.
Outlet
Air
Ventilated
Attic
To Attic
To Crawl
Space
Outlet
Air
Inlet
Air
Inlet Air
Ventilated
Crawl Space
