8
099403
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
VENTILATION AIR
(Continued)
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. 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.
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 Outdoors
Outlet
Air
Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air
Ventilated
Crawl Space
To
Crawl
Space
To Attic
