AIR FOR COMBUSTION AND VENTILATION
WARNING: This heater shall not be installed in a confined space or unusually tight con- struction unless provisions are provided for adequate combus- tion and ventilation air. Read the following instructions to insure proper fresh air for this and other
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National Fuel Gas Code, NFPA 54/ANSI Z223. 1, 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 5 through 6 will help you classify your space and provide adequate ventilation.
Confined and Unconfined Space The National Fuel Gas Code, ANSI 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 aggregate 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 ap- pliances 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.
This heater shall not be installed in a confined space or unusually tight con- struction unless provisions are pro- vided for adequate combustion and ventilation air.
*Adjoining rooms are communicat- ing only if there are doorless passage- ways or ventilation grills between them.
Unusually Tight Construction
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 addi- tional fresh air.
Unusually tight construction is defined as construction where:
a)Walls and ceilings exposed to the outside atmosphere have a continu- ous water vapor retarder with a rat- ing of one perm
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 ceil- ing joints, between wall panels, at penetrations for plumbing, electrical, and gas lines, and at other openings.
If your home meets all of the three cri- teria above, you must provide additional fresh air. See Ventilation Air From Outdoors.
If your home does not meet all of the three criteria above, proceed to Deter- mining
DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Confined or Unconfined Space
Use this worksheet 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×width×height).
Length×Width×Height= |
| cu.ft. (volume of space) | |
|
|
|
|
Example: Space size |
| 20ft. (length)×16ft.(width)×8ft. (ceiling height)=2560cu. 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.Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support. (volume of space)÷50 cu. ft.=(Maximum Btu/Hr the space can support)
Example: 2560 cu. ft. (volume of space)÷50 cu.ft.=51.2 or 51,200(maximum Btu/Hr the space can support)
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