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126885-01B
6
AIR FOR COMBUSTION AND VENTILATION
WARNING: This fireplace shall not be installed in
a confined space or unusually tight construction un-
less provisions are provided for adequate combustion
and ventilation air. Read the following instructions to
insure proper fresh air for this and other fuel-burning
appliances in your home.
Today’s homes are built more energy efficient than ever. New materi-
als, increased insulation and new construction methods help reduce
heat loss in homes. Home owners weather strip and caulk around
windows and doors to keep the cold air out and the warm air in.
During heating months, home owners want their homes as airtight
as possible.
While it is good to make your home energy efficient, your home needs
to breathe. Fresh air must enter your home. All fuel-burning appliances
need fresh air for proper combustion and ventilation.
Exhaust fans, fireplaces, 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 6 through 8 will help you classify your space
and provide adequate ventilation.
The air that leaks around doors and windows may provide enough fresh
air for combustion 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 outside 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 floors, between
wall-ceiling joints, between wall panels, at penetrations for plumb-
ing, electrical and gas lines and at other openings.
If your home meets all of these three criteria, 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 Fireplace Location.
Confined and Unconfined Space
The National Fuel Gas Code, ANSI Z223.1/NFPA 54 defines a con-
fined 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 appliances
installed in that space and an unconfined 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
aggregate input rating of all appliances installed in that space.
Rooms communicating directly with the space in which the appli-
ances 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 uncon-
fined space.
Space:
Includes the room in which you will install fireplace 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 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 fireplace ________Btu/Hr
Gas water heater* ________Btu/Hr
Gas furnace
________Btu/Hr
Vented gas heater ________Btu/Hr
Gas fireplace logs ________Btu/Hr
Other gas appl _____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 30,000 Btu/Hr
Vent-free fireplace + 10,000 Btu/Hr
Total
= 40,000 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)
