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VENT-FREE NATURAL GAS HEATER
AIR FOR COMBUSTION AND VENTILATION
WARNING: This heater shall not be installed in a confined space or unusually tight construction unless provisions are provided for adequate combustion and ven- tilation air. Read the following in- structions to insure proper fresh air for this and other
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. 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
Exhaust fans, fireplaces, clothes dryers, and fuel burning appliances draw air from the house to operate. You must provide ad- equate 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. NFPA 54/ANS Z223.1, Sec- tion 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 5 and 6 will help you classify your space and provide ad- equate ventilation.
Unusually Tight Construction
The air that leaks around doors and win- dows 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 de- fined as construction where:
a.walls and ceilings exposed to the outside atmosphere have a con- tinuous water vapor retarder with a rating of one perm (6 x
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, be- tween sole plates and floors, be- tween
If your home meets all of the three criteria above, you must provide ad- ditional fresh air. See Ventilation Air From Outdoors, page 6.
If your home does not meet all of the three criteria above, proceed to De- termining
Confined and Unconfined Space
The National Fuel Gas Code ANS Z223.1 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 aggre- gate 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 con- sidered a part of the unconfined space.
This heater shall not be installed in a con- fined space or unusually tight construction unless provisions are provided for adequate combustion and ventilation air.
*Adjoining rooms are communicating only if there are doorless passageways or ventila- tion grills between them.
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