Installation manual

6
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.
Ventilation Air From Inside Building
This fresh air would come from an adjoin-
ing 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 2). You can also
remove door into adjoining room (see option
3, Figure 2). 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.
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an
unconfined space. You will need no additional fresh air ventilation.
Example:
Gas water heater 40,000 Btu/Hr
Vent free heater + 18,000 Btu/Hr
Total = 58,000 Btu/Hr
3. Add the Btu/Hr of all fuel burning appliances in the space.
Vent-free heater Btu/Hr
Gas water heater* Btu/Hr
Gas furnace Btu/Hr
Vented gas heater Btu/Hr
Gas Fireplace logs Btu/Hr
Other gas appliances* + Btu/Hr
Total = Btu/Hr
*Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and
vents to the outdoors.
4. Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.
Btu/Hr (maximum the space can support)
Btu/Hr (actual amount of Btu/Hr used)
Example : 51,200 Btu/Hr(maximum the space can support)
58,000 Btu/Hr(actual amount of Btu/Hr used)
The space in the above example is a confined space because the actual Btu/Hr used is more than the
maximum Btu/Hr the space can support.
You must provide additional fresh air. Your options are as follows:
A. Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined
space, remove door to adjoining room or add ventilation grills between rooms. See Ventilation Air From
inside Building
B. Vent room directly to the outdoors. See Ventilation Air From Outdoors
C. Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.
Figure 2 -Ventilation Air from Inside Building
Figure 3 -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. Follow the National Fuel Gas
Code NFPA 54/ANSI Z223.1, Section 5.3. Air
for Combustion and Ventilation for re-
quired 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.
WARNING: If the area in which the heater may be operated 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/NFPA 54, Air for Combustion and Ventilation, or
applicable local codes.