SuperiorFireplaces.us.com
126871-01B
7
AIR FOR COMBUSTION AND VENTILATION
Today’s homes are built more energy effi cient
than ever. New materials, increased insulation
and new construction methods help reduce
heat loss in homes. Homeowners apply
weather strip and caulk around windows and
doors to keep the cold air out and the warm air
in. During heating months, homeowners want
their homes as airtight as possible.
While it is good to make your home energy
effi cient, 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, some fi replaces, clothes dryers
and some fuel-burning appliances draw air
from the house to operate. You must provide
adequate fresh air for these appliances. This
will ensure proper venting of vented fuel-
burning appliances.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from
National
Fuel Gas Code ANS Z223.1/NFPA 54,Air for
Combustion and Ventilation
.
All spaces in homes fall into one of the three
following ventilation classifi cations:
1. Unusually Tight Construction
2. Unconfi ned Space
3. Confi ned Space
The information on
Pages 7 Through 9
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 combustion
and ventilation. However, in buildings of un-
usually tight construction, you must provide
additional fresh air.
Unusually tight construction is
defi ned 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 (6 x 10
-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 fl oors, 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 9
.
If your home does not meet all of the three
criteria above, proceed to
Determining
Fresh-Air Flow for Firebox Location
,
Page 8
.
Confi ned and Unconfi ned Space
The National Fuel Gas Code, ANSI Z223.1/
NFPA54
allows two methods for determining
whether the space in which the heater is being
installed is confi ned or unconfi ned space. The
standard method
defi nes a confi ned space as
a space whose volume is less than 50 cubic
feet per 1,000 Btu/hr (4.8 m
3
per kw) of the ag-
gregate input rating of all appliances installed
in that space and an unconfi ned space as
a space whose volume is not less than 50
cubic feet per 1,000 Btu/hr (4.8 m
3
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-
confi ned space.
This appliance shall not be installed in a
confi ned space or unusually tight construction
unless provisions are provided for adequate
combustion and ventilation air.
Where the air infi ltration rate of a structure is
known, the Known Air Infi ltration Rate Method
may be used. Follow The National Fuel Gas
Code, ANSI Z223.1/NFPA 54 to use this
method to determine if the space is confi ned
or unconfi ned.
* Adjoining rooms are communicating only if
there are doorless passageways or ventilation
grills between them.
WARNING: This appliance shall
not be installed in a room or space
unless the required volume of indoor
combustion air is provided by the
method described in the National
Fuel Gas Code, ANSI Z223.1/NFPA 54,
the International Fuel Gas Code, or
applicable local codes. Read the fol-
lowing instructions to ensure proper
fresh air for this and other fuel-burning
appliances in your home.
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