8
AIR FOR COMBUSTION AND VENTILATION
Today’s homes are built more energy efficient than ever. New materials, increased insulation, and new construction methods
help reduce heat loss in homes. Home owners weather strip and caulk around windows and doors to keep the cold air out
and the warm air in. During heating months, home owners want their homes as airtight as possible.
While it is good to make your home energy
efficient, your home needs to breathe. Fresh air must enter
your home. All fuel-burning appliances need fresh air for
proper combustion and ventilation.
Exhaust fans, fireboxes, clothes dryers, and fuel burning
appliances draw air form the house to operate. You must
provide adequate fresh air for these appliances. This will
insure proper venting of vented fuel-burning appliances.
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 9 through 11
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
building of usually 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 10-11 per pasec-m2) or less with openings gasketed or sealed and
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-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 11
.
Confined and Unconfined Space
The National Fuel Gas Code
(ANSIZ223.1, 1992 Section 5.3)
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.
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 AIR FLOW FOR FIREBOX LOCATION
Determining if You Have a Confined or Unconfined Space
Use the work sheet on the next page to determine if you have a confined or unconfined space.
Space:
Includes the room in which you will install firebox plus any adjoining rooms with doorless
passageways or ventilation grills between the rooms.
WARNING
This firebox shall not be installed in a confined space
unless provisions are provided for adequate combustion
and ventilation air. Read the following instructions to
insure proper fresh air for this and other fuel-burning
appliances in your home.
Содержание FVF300
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