air for combustion
and ventilation
Continued
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an uncon- fined space. You will need no additional fresh air ventilation.
WARNING: If the area in which the heater may be oper- ated is smaller than that defined as an unconfined space or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1/NFPA54 Section 5.3 or applicable local codes.
VENTILATION AIR
Ventilation Air From Inside Building
This fresh air would come from an adjoining un- confined 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 2). You can also remove door into adjoining room (see option 3, Figure 2). Follow the National Fuel Gas Code, ANSI Z223.1/NFPA 54, 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 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. Follow the National Fuel Gas Code, ANSI Z223.1/NFPA 54, 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.
| Outlet | Ventilated |
| Attic | |
| Air | |
|
| |
Outlet |
|
|
Air |
| To Attic |
|
| |
|
| To |
|
| Crawl |
Inlet |
| Space |
|
| |
Air |
|
|
| Inlet Air | Ventilated |
| Crawl Space | |
|
|
Figure 3 - Ventilation Air from Outdoors
Ventilation |
| |
Grills |
| |
Into Adjoining | Or | |
Room, | ||
Remove | ||
Option 1 | ||
Door into | ||
| ||
| Adjoining | |
| Room, | |
| Option | |
| 3 |
12"
Ventilation Grills
Into Adjoining Room,
Option 2
12"
Figure 2 - Ventilation Air from Inside
Building
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