8
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 ensure proper
fresh air for this and other fuel-burning
appliances in your home.
Providing Adequate Ventilation
This heater shall not be installed in a room or
space unless the required volume of indoor
combustion air is provided by the method
described in the NATIONAL FUEL GAS CODE,
ANSI Z223.1/NFPA 54, the INTERNATIONAL
FUEL GAS CODE, or applicable local codes.
The following are excerpts from National Fuel
Gas Code, ANSI Z223.1/ NFPA 54. 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 the following pages will help
you classify your space and provide adequate
ventilation.
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 cu. ft. per
1,000 BTU/hr (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/hr (4.8 m3 per kw) of the aggregate
input rating of all appliances installed in that
space. Rooms connecting directly with the space
in which the appliances are installed, through
openings not furnished with doors, are
considered a part of the unconfined space.
This heater shall not be installed in a confined
space or unusually tight construction unless
provisions are provided for adequate combustion
and ventilation air. Adjoining rooms are
connecting only if there are odorless
passageways or ventilation grills between them.
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 (6×10-11kg
per pa-sec-m2) or less with openings gasket or
sealed and
b) Weather stripping has been added on
openable windows and on 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”. If your home
does not meet all of the three criteria above,
proceed to “Determining Fresh-Air Flow for
Heater Location”.
