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.. Multiply.the.space.volume.by.0.to.determine.
the.maximum.Btu/Hr.the.space.can.support.
.
. ________ (volume. of. space). x. 0. =..
(Maximum.Btu/Hr.the.space.can.support)
.
Example:
2,560 cu. ft. (volume of space) x
20 = 51,200 (maximum Btu/Hr the space can
support)
3.. Add.the.Btu/Hr.of.all.fuel.burning.appliances.
in.the.space.
Vent-free fireplace
.__________ 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.
.
Example:
.
Gas water heater
.__________ Btu/Hr
Vent-free fireplace + .__________ 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:
51,200 Btu/Hr (maximum the
space.can.support)
79,000 Btu/Hr (actual amount of
Btu/Hr.used)
The space in the 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
,
page.8
.
B.. Vent. room. directly. to. the. outdoors.. See.
Ventilation Air From Outdoors
, page 8
.
C. Install a lower Btu/Hr fireplace, if lower Btu/Hr
size makes room unconfined.
If.the.actual.Btu/Hr.used.is.less.than.the.maxi-
mum Btu/Hr the space can support,
the.space.is.
an unconfined space. You will need no additional
fresh.air.ventilation.
c. caulking or sealants are applied to
areas such as joints around window
and door frames, between sole plates
and floors, between wall-ceiling joints,
between wall panels, at penetrations
for plumbing, electrical and gas lines
and at other openings.
If your home meets all of the three criteria
above, you must provide additional fresh
air. See
Ventilation Air From Outdoors
,
page 8.
If your home does not meet all of the three
criteria above, proceed to
Determining
Fresh-Air Flow For Heater Location
.
Confined Space and Unconfined Space
The.
National Fuel Gas Code, ANSI Z223.1/
NFPA 54
defines a confined space as a space
whose volume is less than 50 cubic feet per
1,000 Btu per hour (4.8 m
3
per kw) of the ag-
gregate.input.rating.of.all.appliances.installed.in.
that space and an unconfined space as a space
whose volume is not less than 50 cubic feet per
1,000 Btu per hour (4.8 m
3
per 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 unconfined space.
* Adjoining rooms are communicating only if
there are doorless passageways or ventilation
grills between them.
DETERMINING FRESH-AIR FLOW
FOR FIREPLACE LOCATION
Determining if you Have a Confined or
Unconfined Space
Use this work sheet to determine if you have
a confined or unconfined space.
Space:
Includes the room in which you will
install fireplace plus any adjoining rooms with
doorless passageways or ventilation grills be-
tween 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 20 ft. (length) x 16 ft.
(width) x 8 ft. (ceiling height) = 2,560 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.
40,000
39,000
79,000
AIR FOR COMBUSTION AND VENTILATION
Continued