Combustion Air Calculator

Sheet1.Calculating Room SizeTotal cu. ft. In roomLengthWidthHeightREAD ALL INSTRUCTIONS254088000Insert Numbers Then Hit "Enter" KeyEnter Btu'sTotal cu. ft. neededAdditional cu. ft. needed140,0007000-1000COMBUSTION AIR FROM INSIDE OF BUILDINGCalculation of square inches of Grill Size 1 square inch for every 2000 BTU'sUsing Metal GrillUsing Wooden GrillSquare Inches Needed186.6666666667Square Inches Needed560Size of Metal Grill needed13.6626010213BY13.6626010213Size of Wooden Grill Needed23.6643191324BY23.664319132412" x 12" minimum size grill20" x 20 " minimum size grillObtaining Outside Combustion AirBTU'SSize of Vertical Round Pipe Size without Grill (one 12" of top & one 12" of bottom)Hole Only ----- Sq. Inches of Hole Needed in ceiling and floor or wall Without a Grill 12" of top and one 12" of bottom- Air Openings shall not be less than 3 inchesWhen Using Metal Grill- Size Needed - (one 12" of top & one 12" of bottom)140,000Sq. Inches Needed35Hole SizeSq. Inches Needed35Grill SizeSq. Inches Needed46.6666666667see chart below5.9160797831BY5.91607978316.8313005106BY6.8313005106Obtaining Combustion Air From Outside the BuildingOne Permanent Opening InstallationSquare Inches of Horizontal Ducts1 square inch per 3000 BTU's (1" clearance on Sides & Back & 6" on Front of appliances)1 square inch per 2000 BTU's Ducts to be Installed Top & Bottom with Metal GrillSq. Inches Needed62.2222222222Sq. Inches Needed93.3333333333Opening Size7.8881BY7.8881063775Duct Size9.6609178308BY9.6609178308Round Pipe Chart without a grill.Total Square Inches RequiredRound Pipe SizeTotal Square Inches RequiredRound Pipe Size0thru73"132.8thru153.914"7.1thru12.54"154thru176.715"12.6thru19.65"176.8thru20116"19.7thru28.26"201.1thru226.917"28.3thru38.57"227thru254.418"38.6thru50.38"254.5thru283.519"50.4thru63.69"283.6thru314.120"63.7thru78.510"314.2thru346.321"78.6thru9511"346.4thru380.122"95.1thru11312"380.2thru415.423"113.1thru132.713"415..5thru452.324".