AIR FOR COMBUSTION AND VENTILATION
Continued
c.caulking or sealants are applied to areas such as joints around window and door frames, between sole plates and floors, between
If your home meets all of the three criteria above, 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
Confined and Unconfined Space
The National Fuel Gas Code, ANSI Z223.1.3/ NFPA 54 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 appliances 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 unconfined space.
*Adjoining rooms are communicating only if there are doorless passageways or ventilation grills between them.
DETERMINING
Determining if You Have a Confined or Unconfined Space
Use this work sheet to determine if you have a confined or unconfined 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 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.
2.Multiply the space volume by 20 to determine the maximum Btu/Hr the space can support.
_ ________ (volume of space) x 20 = (Maxi- mum Btu/Hr the space can support)
Example: 2560 cu. ft. (volume of space) x 20
= 51,200 (maximum Btu/Hr the space can support)
3.Add the Btu/Hr of all fuel burning appliances in the space.
___________ Btu/Hr | |
Gas water heater* | ___________ Btu/Hr |
Gas furnace | ___________ Btu/Hr |
Vented gas heater | ___________ Btu/Hr |
Gas fireplace logs | ___________ Btu/Hr |
Other gas appliances* +__________ Btu/Hr
Total | =__________ Btu/Hr |
*Do not include
Gas water heater |
| 30,000 | Btu/Hr |
+ | 26,000 | Btu/Hr | |
Total | = | 56,000 | 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)
Example: 51,200 Btu/Hr (maximum the space can support)
56,000 Btu/Hr (actual amount of Btu/Hr used)
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 sup- port. 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 ventilation grills between rooms.
See Ventilation Air From Inside Building, page 8.
B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 8.
C.Install a lower Btu/Hr fireplace, 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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