lS,OOO To30,000BTu,..
VENT-FREE PROPANE/LP HEATER
AIR FOR
COMBUSTION AND
VENTILATION
Continued
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.
I.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 openings, add the volume of these rooms to the total volume of |
the space. |
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|
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
Example: 2560 cu. ft. (volume of space) + 50 cu. ft. =51.2 or 51,200 (maximum Btu/Hr the space can support)
3.Add the Btu/Hr of all fuel burning appliances in the space.
heater |
| B |
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| |
Gas water | heater* |
| Btu/Hr | Example: |
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|
|
Gas furnace |
| Btu/Hr | Gas water heater |
| 30,000 | Btu/Hr | |
Vented gas heater |
| Btu/Hr | + | 30,000 | Btu/Hr | ||
Gas fireplace logs |
| Btu/Hr | Total | = | 60,000 | Btu/Hr | |
Other gas appliances* | + | Btu/Hr |
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|
|
| |
Total |
| = | Btu/Hr |
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|
|
*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
Example: 51,200 Btu/Hr (maximum the space can support) 60,000
The space in the above example is a confined 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 worksheat, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoin- ing room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 7.
B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 7.
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.
or If the bulldlng Is of unusually tight constructlon, provide adequate combustion and ventllatlon alr by one of I
_WARNING: If the area In which the heater may be operated Is smaller than that defined as an unconfined space the methods descrlbed In the National Fuel Gas Code, ANSI 7.223.1, 1992, Section 5.3 or appllcable local codes.
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