Air For Combustion And Ventilation - Desa LMFP33PR Owner's Operation And Installation Manual

AIR FOR COMBUSTION AND
VENTILATION
Continued
PROVIDING ADEQUATE VENTILATION
The following are excerpts from National Fuel Gas Code, ANSI
Z223.1/NFPA 54, 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 4 through 6 will help you classify your
space and provide adequate ventilation.
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 additional fresh air.
Unusually tight construction is defined as construction
where:
a. walls and ceilings exposed to the outside atmosphere
have a continuous water vapor retarder with a rating
of one perm (6 x 10
openings gasketed or sealed and
b. weather stripping has been added on openable win-
dows 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-ceiling joints, between
wall panels, at penetrations for plumbing, electrical,
and gas lines, and at other openings.
If your home meets all of the three criteria above,
you must provide additional fresh air. See Ventilation
Air From Outdoors , page 6 .
If your home does not meet all of the three criteria above,
proceed to Determining Fresh-Air Flow For Heater Loca-
tion, column 2.
Confined and Unconfined Space
The National Fuel Gas Code, ANSI Z223.1/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 m
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
3
hour (4.8 m 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.
For more information, visit www.desatech.com
For more information, visit www.desatech.com
111604-01B
-11 kg per pa-sec-m 2 ) or less with
3
per kw) of the aggregate input rating

AIR FOR COMBUSTION AND VENTILATION

Providing Adequate Ventilation
Determining Fresh-Air Flow for Heater Location
DETERMINING FRESH-AIR FLOW FOR
HEATER LOCATION
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 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. Multiply the space volume by 20 to determine the maximum Btu/Hr
the space can support.
__________ (volume of space) x 20 = (Maximum Btu/Hr the space
can support)
Example: 2,560 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.
Vent-free heater
Gas water heater*
Gas furnace
Vented gas heater
Gas fireplace logs
Other gas appliances* + _____________ Btu/Hr
Total
* Do not include direct-vent gas appliances. Direct-vent draws com-
bustion air from the outdoors and vents to the outdoors.
Example:
Gas water heater
Vent-free heater
Total
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)
73,000 Btu/Hr (actual amount of Btu/Hr used)
_____________ Btu/Hr
_____________ Btu/Hr
_____________ Btu/Hr
_____________ Btu/Hr
_____________ Btu/Hr
= _____________ Btu/Hr
40,000
_____________ Btu/Hr
33,000
+ _____________ Btu/Hr
73,000
= _____________ Btu/Hr
5 5