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Resumen del manual
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, 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 6 through 8 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 outside atmosphere have a continuous water vapor retarder with a rating of one perm (6x10-11 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 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, page 8. 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 National Fuel Gas Code, ANSI Z223.1/NFPA 54 defines a confined space as a space whose volume is 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 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 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 fireplace plus any adjoining rooms with doorless passageways or ventilation grills between the rooms. 1. Determine the volume of the space (length x width x height). Length x Width x Height =__________cu. ft. (volume of space) Example: Space size 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) = 2,560 cu. ft. (volume of space) If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of the space. 2. Multiply the space volume by 20 to determine the maximum Btu/Hr the space can support. _________(volume of space) x 20 = (Maximum Btu/Hr the space can support) Example: 2,560 cu. ft. (volume of space) x 20 = 51,200 (maximum Btu/Hr the space can support) 3. Add the Btu/Hr of all fuel burning appliances in the space. Vent-free fireplace ___________Btu/Hr Gas water heater* ___________Btu/Hr Gas furnace ___________Btu/Hr Vented gas heater ___________Btu/Hr Gas fireplace logs ___________Btu/Hr Other gas appliances* +__________Btu/Hr Total =__________Btu/Hr * Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors. Example: Gas water heater ___________Btu/Hr Vent-free fireplace +__________Btu/Hr Total =__________Btu/Hr 4. Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used. ________Btu/Hr (maximum the space can support) ________Btu/Hr (actual amount used) Example: 51,200 Btu/Hr (maximum the space can support) 79,000 Btu/Hr (actual amount of Btu/Hr used) The space in the example is a confined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support. You must provide additional fresh air. Your options are as follows: A. Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adj...