Assessments - 2, GPA: 4 ( )

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• Cleaning solvents (such as perchloroethylene). • Printing inks, paint removers, varnishes, etc. • Hydrochloric acid. • Sulfuric Acid. • Solvent cements and glues. • Antistatic fabric softeners for clothes dryers. • Masonry acid washing materials. Outdoor Combustion Air Method A space having less than 50 cubic feet per 1,000 BTUH input rating for all gas appliances installed in the space requires outdoor air for combustion and ventilation. Air Openings and Connecting Ducts 1. Total input rating for all gas appliances in the space MUST be considered when determining free area of openings. 2. Connect ducts or openings directly to the outdoors. 3. When screens are used to cover openings, the openings MUST be no smaller than 1/4" mesh. 4. The minimum dimension of air ducts MUST NOT be less than 3 '_ . When sizing a grille, louver or screen use the free area of opening. If free area is NOT stamped or marked on grill or louver, assume a 20% free area for wood and 60% for metal. Screens shall have a mesh size not smaller than 1/4". Requirements 1. Provide the space with sufficient air for proper combustion and ventilation of flue gases using horizontal or vertical ducts or openings. Figure 8 illustrates how to provide combustion and ventilation air when two permanent openings, one inlet and one outlet, are used. a. One opening MUST commence within 12" of the floor and the second opening MUST commence within 12" of the ceiling. b. Size openings and ducts per Table 1. c. Horizontal duct openings require 1 square inch of free 2 area per 2,000 BTUH (1,100 mm /kW) of combined input for all gas appliances in the space (see Table 1). d. Vertical duct openings or openings directly communicating with the outdoors require 1 square inch of free area 2 per 4,000 BTUH (550 mm /kW) for combined input of all gas appliances in the space (see Table 1). When one permanent outdoor opening is used, the opening requires: a. 1 sq. in of free area per 3,000 BTUH (700 mm2/kW) for combined input of all gas appliances in the space (see Table 1) and b. not less than the sum of the areas of all vent connectors in the _space. G3 Outside Air (This is ONLY a guide. SubJect to codes of country having jurisdiction.) ThisinstallationNOTapprovedinCanada Vent GasVent G Vent_j_.Gable , GableV_/) ba_ventilated Attic'_ (1) I Top Above Insulation_ I 1 €_:;;_l TM I/ SoffitVen, Soffit Vent I_ utletAir (1) Outlet/1_ II _. Air(1) Inlet F...... NG_ Air (1) _,, _ r-_ Inlet --Air (2) Inlet Air (1) ........ Air (2) May be in andCombination Shown Inlet Air OpeningMust beWithin12"(300mm)of floor OutletAir OpeningMustbeWithin12"(300mm)ofceiling MinimumOne Inletand OneOutlet AirSupply is Required (1) 1 SquareInch (6cm2) per4000 BTUH (2) 1 Square Inch(6cm2) per2000 BTUH The opening shall commence within 12" of the top of the enclo-b. Outdoor openings located as required in the Outdoor Combustion air Method above and sure. Appliances shall have clearances of at least 1" from the sides and back and 6" from the front. The opening shall directly commu-c. Outdoor openings sized as follows. nicate with the outdoors or shall communicate through a vertical or 1) Calculate the Ratio of all Indoor Space volume divid horizontal duct to the outdoors or spaces (crawl or attic) that freely ed by required volume for Indoor Combustion Air Meth communicate with the outdoors. od. Outdoor openings sized as follows. 2) Outdoor opening size reduction Factor is I minus the 4. Combination of Indoor and Outdoor Air shall have: Ratio in 1) above. 3) Minimum size of Outdoor openings shall be the size a. Indoor openings that comply with the Indoor Combus-required in Outdoor Combustion Air Method above tion Air Method below and multiplied by reduction Factor. FreeArea BTUH MinimumFree Area Required for EachOpeningor DucttoOutdoors Input Two HorizontalDucts SingleOpening TwoVerticalDuctsor Openings RoundDuct Rating (sq.inJ2,000 BTUH) (sq. in./3,000BTUH) (sq.inJ4,000 BTUH) (sq. in./4,000 BTUH) 50,000 25 sq, in. 16.7sq. in. 12,5sq. in. 4" 75,000 37,5 sq. in. 25 sq, in, 18.75sq. in. 5" 100,000 50 sq. in. 33.3 sq. in. 25 sq. in, 6" 125,000 62,50 sq. in. 41,7 sq. in. 31.25sq, in. 7" 150,000 75 sq, in. 50 sq, in, 37,5 sq. in. 7" EXAMPLE: Determining Free Area Furnace Water Heater Total Input 100,000 + 30,000 (130,000 + 4,000) 32.5 Sq. In. Vertical Furnace Water Heater Total Input 100,000 + 30,000 (130,000 + 2,000) 65 Sq. In. Horizontal Indoor Combustion Air Standard and Known-Air-Infiltration Rate Methods CARBON MONOXIDE POISONING HAZARD. © NFPA & AGA Failure to supply adequate combustion air could Indoor air is permitted for combustion and ventilation, if the result in death or personal injury. Standard or Known-air-lnfiltration Rate Method is used, Most homes will require additional air from outdoors for combustion and ventilation. A space with at least 50 cubic feet per 1,OOOBTUH input rating or homes with tight construction may need outdoor air to supplement air infiltration for proper combustio...

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