Providing Adequate Ventilation

UNVENTED NATURAL GAS LOG HEATER

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 ven- tilation air. Read the following in- structions to insure proper fresh air for this and other fuel-burning appliances in your home.

Today’s homes are built more energy effi- cient 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 com- bustion and ventilation.

Exhaust fans, fireplaces, clothes dryers, and fuel burning appliances draw air from the house to operate. You must provide ad- equate fresh air for these appliances. This will insure proper venting of vented fuel- burning appliances.

The following are excerpts from National Fuel Gas Code. NFPA 54/ANS Z223.1, Sec- tion 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 4 through 6 will help you classify your space and provide adequate ventilation.

Unusually Tight Construction

The air that leaks around doors and win- dows 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- fined as construction where:

a.walls and ceilings exposed to the outside atmosphere have a con- tinuous water vapor retarder with a rating of one perm (6 x 10-11kg per pa-sec-m2) or less with open- ings 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, be- tween sole plates and floors, be- tween wall-ceiling joints, be- tween wall panels, at penetra- tions for plumbing, electrical, and gas lines, and at other openings.

If your home meets all of the three criteria above, you must provide ad- ditional fresh air. See Ventilation Air From Outdoors, page 6.

If your home does not meet all of the three criteria above, proceed to De- termining Fresh-Air Flow For Heater Location, page 5.

Confined Space and Unconfined Space

The National Fuel Gas Code (ANS Z2123.1, 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 and an unconfined space as a space whose volume is not 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 in- stalled*, through openings not furnished with doors, are considered a part of the unconfined space.

This heater shall not be installed in a con- fined space or unusually tight construction unless provisions are provided for adequate combustion and ventilation air.

*Adjoining rooms are communicating only if there are doorless passageways or ventila- tion grills between them.

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