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5
While it is good to make your home energy
efficient, your home needs to breathe. Fresh
air must enter your home. All fuel-burning ap-
pliances need fresh air for proper combustion
and ventilation.
Exhaust fans, fireboxes, clothes dryers and fuel
burning appliances draw air from the house to
operate. You must provide adequate fresh air
for these appliances. This will insure proper
venting of vented fuel-burning appliances.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from
National Fuel
Gas Code ANSI Z223.1/NFPA 54, Section 5.3,
Air for Combustion and Ventilation.
All spaces in homes fall into one of the three
following ventilation classifications:
1. Unusually Tight Construction
2. Unconfined Space
3. Confined Space
The information on pages 4 through 6 will help
you classify your space and provide adequate
ventilation.
Unusually Tight Construction
The air that leaks around doors and windows
may provide enough fresh air for combus-
tion and ventilation. However, in buildings of
unusually tight construction, you must provide
additional fresh air.
Unusually tight construction is defined as
construction where:
a. walls and ceilings exposed to the out
-
side atmosphere have a continuous
water vapor retarder with a rating of
one perm (6x10
-11
kg per pa-sec-m
2
) or
less with openings gasketed or sealed
and
b. weather stripping has been added on
openable windows and doors
and
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.
AIR FOR COMBUSTION
AND VENTILATION
Continued
If your home meets all of the three criteria
above, you must provide additional fresh
air. See
Ventilation Air From Outdoors
,
page 6.
If your home does not meet all of the three
criteria above, proceed to
Determining
Fresh-Air Flow For Firebox 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 m3 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 m3 per kw)
of the aggregate 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 un-
confined space.
* Adjoining rooms are communicating only if
there are doorless passageways or ventilation
grills between them.
DETERMINING FRESH-AIR FLOW
FOR HEATER 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 heater plus any adjoining rooms with
doorless passageways 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 0 ft. (length) x 16 ft.
(width) x 8 ft. (ceiling height) = 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.
. Multiply the space volume by 0 to determine
the maximum Btu/Hr the space can support.
________ (volume of space) x 0 = (Maxi-
mum Btu/Hr the space can support)
Example:
560 cu. ft. (volume of space) x 0
= 51,00 (maximum Btu/Hr the space can
support)
