AIR FORCOMBUSTION AND VENTILATION
WARNING:This heatershallnot be installedin a confinedspace or unusually tight construction
unless provisions are provided foradequate combustion and ventilation air.Read the following instructions to
insureproper fresh airfor this and other fuel-burning appliances in your home.
PRODUCING ADEQUATEVENTILATION
The following are excerpts from National FuelGas Code, NFPA54/ ANSI Z 223.1,Section 5.3, Airfor
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 informationon pages 7 through 9 will help youclassify your space and provide adequate ventilation.
Confined and Unconfined Space
The National Fuel Gas Code, ANS Z223.1 definesa confined space as a space whose volume is less
than 50 cubic feet per 1,000 Btu per hour (4.8 m3per kw) of the aggregate input rating ofall appliances
installed in that space and an unconfining space as a space whose volume is not less than 50 cubic feet
per 1,000 Btu per hour (4.8 m3 per kw) ofthe aggregate input rating ofall appliances installed in that
space. Roomscommunicating directly with the space in which the appliances are installed*,through
openings not furnished with doors,are considereda partofthe unconfined space.
This heatershallnot be installed ina confined space or unusually tight construction unless provisions are
provided for adequate combustion and ventilation air.
* Adjoining rooms are communicating only if there are doorlesspassageways or ventilation grills
between them.
Unusually Tight Construction
The air that leaks around doorsand windows may provide enough fresh air for combustion and ventilation.
However, in buildingsof unusually tight construction,you must provide additional fresh air.
Unusuallytightconstruction isdefined asconstruction where:
a) walls and ceilings exposed to the outside atmosphere have a continuous water vaporretarder with a
rating of one perm (6 10-11kg perpa-sec-m2) or less with openings gasketed orsealed and
b) weather stripping has been added on windows that can be opened and doorsand
c) caulking orsealants are applied to areas such as joints around window and door frames, between sole
plates and floors, between wall-ceiling joints, between wall panels, atpenetrations for plumbing,electrical,
and gas lines, and at other openings.
If yourhome meets all of the three criteria above, you mustprovide additional fresh air. See Ventilation Air
From Outdoors(page 9).Ifyour home does not meet all of the three criteria above, proceed to Determining
Fresh-AirFlow For Heater Location (below).
DETERMININGFRESH-AIR FLOW FOR HEATERLOCATION
Determining ifYou Have aConfined or Unconfined Space
Use this worksheet to determine if you have a confined or unconfined space.
Space: Includes the room in which you will install heaterplus any adjoining rooms with doorless
passageways or ventilation grillsbetween the rooms.
1.Determine the volumeofthe space.
Length Width Height=_____________ cu. ft. (volume of space)
Example: Space size 20ft. (length) 16ft. (width) 8ft. (ceiling height)= 2560cu. ft.(volume ofspace)If
additional ventilation to adjoining room is suppliedwith grillsor openings, add the volume of these rooms to
the total volume of the space.
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