www.desatech.com 5113681-01A
AIR FOR COMBUSTION
AND VENTILATION
WARNING: This heater shall
not be installed in a confined space
or unusually tight construction
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.
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, fireplaces, clothes dryers, and fuel
burning appliances draw air from 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, 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 5 through 7 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 out-
side atmosphere have a continuous
water vapor retarder with a rating of
one perm (6 x 10
-11
kg per pa-sec-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 ar-
eas 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 these three criteria, you must provide additional fresh air.
See
Ventilation Air From Outdoors
, page 7.
If your home does not meet all of the three
criteria above, proceed to
Determining
Fresh-Air Flow For Heater Location
.
Confined and Unconfined Space
The National Fuel Gas Code, ANSI Z223.1/NFPA
54 defines a confined space as a space whose vol-
ume 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 m
3
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 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.