Laserfiche WebLink
Table 501.4.2 <br /> Makeup Air Opening Sizing Table for New and Existing Dwelling Units <br /> ONE MULTIPLE APPLIANCES <br /> ONE OR MULTIPLE POWER ATMOSPHERICALLY THATARE <br /> VENT OR DIRECT VENT ONE OR MULTIPLE FAN- VENTED GAS OR OIL ATMOSPHERICALLY PASSIVE MAKEUP <br /> APPLIANCES OR NO ASSISTED APPLIANCES APPLIANCE OR ONE VENTED GAS OR OIL AIR OPENING <br /> COMBUSTION AND POWER VENT OR SOLID FUEL APPLIANCES OR SOLID DUCT <br /> TYPE OF OPENING APPLIANCESA DIRECT VENT APPLIANCESs APPLIANCEc FUELAPPLIANCESo DIAMETEftF,e <br /> OR SYSTEM dm (dm) (dm) Win (inches) <br /> Passive opening 1-36 1-22 1-15 1-9 3 <br /> Passive opening 37-66 23-41 16-28 10-17 4 <br /> Passive opening 67-109 42-66 29-46 18-28 5 <br /> Passive opening 110-163 67-100 47 29-42 6 <br /> Passive opening 164-232 101-143 0-99 43-61 7 <br /> Passive opening 233-317 144-195 1 - 62-83 8 <br /> Passive opening <br /> with motorized <br /> damper 318-419 196-258 136-179 84-110 9 <br /> Passive opening <br /> with motorized <br /> damper 420-539 259-332 180-230 111-142 10 <br /> Passive opening <br /> with motorized <br /> damper 540-679 333-419 231-290 143-179 11 <br /> Powered makeup <br /> aint >679 >419 >290 >179 NoYapplicable <br /> A.Use this column If there are other than fan-assisted or atmospherically vented gas or oil appliances or ffthere are no combustion appliances. <br /> B.Use this column 9 there is one fan-assisted appliance per venting system.Other than atmospherically vented appliances may also be included. <br /> C,Use this column If there Is one atmospherically vented(therthan fan-ass)sted)gas or oil appliance per venting system or one solid fuel appliance. <br /> D.Use this column If there are multiple atmospherically vented gas or oil appliances using a common vent or ffthere are atmospherically vented <br /> gas or oil appliances and solid fuel appliances. <br /> E.An equivalent length of 100 feet of round smooth metal duct is assumed.Subtract 40 feet for the exterior hood and ten feet for each 90-degree <br /> elbow to determine the remaining length of straight dud allowable. <br /> F.If flexible duct is used,Increase the duct diameter by one inch.Flexible duct shall be stretched with minimal sags. <br /> G.Barometric dampers are prohibited in passive makeup air openings when any atmospherically vented appliance Is installed. <br /> H.Powered makeup air shall be electrically interlocked with the largest exhaust system. <br />