Product specifications

8
AIR FOR COMBUSTION AND VENTILATION
WARNING: If the area in which the heater may be operated does not meet the required volume for indoor combustion air,
combustion and ventilation air shall be provided by one of the methods described in the National Fuel Gas Code,
ANSI Z223.1/NFPA 54, the International Fuel Gas Code, or applicable local codes.
PRODUCING ADEQUATE VENTILATION
All spaces in homes fall into one of the three following ventilation classications:
1. Unusually Tight Construction
2. Unconned Space
3. Conned Space
The information on pages 8 through 10 will help you classify your space and provide adequate ventilation.
Conned and Unconned Space
A conned space is a space whose volume is less than 50 cu. ft. per 1,000 BTU/hr (4.8 m^3 per kw) of the aggregate input rating
of all appliances installed in that space and an unconning space as a space whose volume is not less than 50 cu. ft. per 1,000
BTU/hr (4.8 m^3 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 unconned space.This heater shall not be installed in a conned space or
unusually tight construction unless provisions are provided for adequate combustion and ventilation air.
* Adjoining rooms are connecting only if there are doorless 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 dened as construction where:
a) walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating of one perm
(6x10
-11
kg per pa-sec-m
2
) or less with openings gasketed or sealed and
b) weather stripping has been added on windows that can be opened and on doors and
c) caulking or sealants are applied to areas such as joints around window and door frames, between sole plates and oors,
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
10). If your home does not meet all of the three criteria above, proceed to “Determining Fresh-Air Flow For Heater Location”.