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119315-01A 7
construction where:
-
2
and
and
If your home meets all of these three
Ventilation Air From
Outdoors
If your home does not meet all of the
Deter-
mining Fresh-Air Flow For Fireplace
Location
The National Fuel Gas Code, ANSI Z223.1/NFPA
54 denes a conned space as a space whose
volume is less than 50 ft
3
per 1,000 Btu/hr (4.8
m
3
/kw) of the aggregate input rating of all appli-
ances installed in that space and an unconned
space as a space whose volume is not less than
50 ft
3
per 1,000 Btu/hr (4.8 m
3
/kw) of the ag-
gregate input rating of all appliances installed in
that space. Rooms communicating directly with
the space in which the appliances are installed*,
through openings not furnished with doors, are
considered a part of the unconned space.
* Adjoining rooms are communicating only if
there are doorless passageways or ventilation grills
between them.
AIR FOR COMBUSTION
AND VENTILATION
Continued
DETERMINING FRESH-AIR FLOW
Use this work sheet to determine if you have a
conned or unconned space.
Includes the room in which you will install
replace plus any adjoining rooms with doorless pas-
sageways or ventilation grills between the rooms.
1. Determine the volume of the space (length x
width x height).
Length x Width x Height =__________cu. ft.
(volume of space)
Example: Space size 16 ft. (length) x 14 ft.
(width) x 8 ft. (ceiling height) = 1792 cu. ft.
(volume of space)
If additional ventilation to adjoining room is
supplied with grills or openings, add the volume
of these rooms to the total volume of the space.
2. Multiply the space volume by 20 to determine
the maximum Btu/Hr the space can support.
__________ (volume of space) x 20 = (Maximum
Btu/Hr the space can support)
Example: 1792 cu. ft. (volume of space) x 20 =
35,840 (maximum Btu/Hr the space can support)
3. Add the Btu/Hr of all fuel burning appliances in
the space.
Vent-free replace __________ Btu/Hr
Gas water heater* __________ Btu/Hr
Gas furnace __________ Btu/Hr
Vented gas heater __________ Btu/Hr
Gas replace logs __________ Btu/Hr
Other gas appliances* + __________ Btu/Hr
Total = __________ Btu/Hr
* Do not include direct-vent gas appliances. Di-
rect-vent draws combustion air from the outdoors
and vents to the outdoors.
Example:
Gas water heater __________ Btu/Hr
Vent-free replace + __________ Btu/Hr
Total = __________ Btu/Hr
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: 35,840 Btu/Hr (maximum the space
can support)
40,000 Btu/Hr (actual amount of
Btu/Hr used)
30,000
10,000
40,000