OWNER’S MANUAL
FRESH AIR FOR COMBUSTION AND VENTILATION
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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 x width x height).
Length x Width x Height =
__________ cu. ft. (volume of space)
Example: Space size 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) = 2560 cu. ft. (volume of space)
If additional ventilation to adjoining room is supplied with grills or open- ings, 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 sup- port)
3.Add the Btu/Hr of all fuel burning ap- pliances in the space.
Gas fireplace logs ________ Btu/Hr
Other gas appliances* + | ___ Btu/Hr | ||
Total | = | ___ Btu/Hr | |
Example: |
|
|
|
Gas water heater | 40,000 | Btu/Hr | |
+ 20,000 | Btu/Hr | ||
Total | = 60,000 Btu/Hr | ||
*Do not include
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)
Example: 51,200 Btu/Hr (maximum the space can support)60,000 Btu/Hr (actual amount of Btu/Hr used)
The space in the above example is a con- fined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support. You must provide additional fresh air. Your options are as follows:
A.Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoining room or add ventila- tion grills between rooms. See Ventila- tion Air From Inside Building, page 6.
B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 6.
C.Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no additional fresh air ventilation.
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