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12�21�2011 08;54 {FAx} P,006�007 <br /> � , , <br /> Dlrecrtons-7he Mlnnesoto Fue/Gas Code method to calcufote to si:e of o required combusilon alr opening, is called the Known Alr <br /> /nf)ltratlon Rate Method. For new constructlon,46 of step 41a requ/red to be f;lled out, <br /> IFGC Appendlx E,Worksheet E•1 <br /> Resldentlal Comhuatlon Alr Calculation Mnthod <br /> for Furnace eoller and or water Heater in the Same S ace <br /> Step 1:ComPlete vented combust3on app�iance Informatlon. <br /> Furnaca/Ba11er: <br /> Oraft Hoad _ Fan Asalsted Direci Vant Input: � Htu/hr <br /> or Power Vent <br /> water Heater: '/ <br /> _araft Hoad �! Fan assisted �oirect vent input: ���� stu/hr <br /> or Power Vent <br /> Step 2:Calculate the vplume of the Combustton Appltance Space ICaSy containing combusNon appltances. <br /> The CA5lncludes all spaces conneeted ta one another by eode compllant openings. CAS volume; �4�a?� k' <br /> � ar i r x�o <br /> Step a:Determine Alr Changes per Hour(ACH)1 <br /> OeEavle ACH values have been incorparated Into 7able E•1 for use with Method a6(KAIA MethodJ. <br /> IF the �ar of Gonstructian or ACH IS npi knpwn use methOd 4a Stdndard Methpd. <br /> Se�p Ai Determfne Requlred Volume for Combuation Alr.{DO NOT COUNT DIREtT VENT APPLIAtVCES) <br /> aa.5tandard Method <br /> Total Btu/hr Input of all comhustlon appllences Input: Btu/hr <br /> Use 5tanderd Mathad column fn Table E-1 to flnd Total RaqulrQd TRV: ft' <br /> Volume(TRV) <br /> If CAS Valume(from Step 2)!a Qr�atar thon TRV then no outdoar opentngs are needed. <br /> If CJ1S Volume(frOm Step 2)l6 le66 thon TRV then go to STEp 5. <br /> 4b.Known A!r Infiltratfon Fate(KAIR)Method(DO NOT COUNT DIRELT VENT APPIIANCES) <br /> TOtel Btu/h�lnput Of all fen•esslsted end power vene appllances (npuC �S�_Btu/hr <br /> Use Fan-Asslsted Appllancea column tn Tahle E-1 t0 ftnd RVFA; s ft' <br /> Required Volume Fan Assisted(RVFA) <br /> Total Btu/hr Input of all Natural drah appllances lnput: 0 Btu/hr <br /> Use Naeural draft appllances cotumn in Table E-1 to find RVNFA; ����/ ft' <br /> Requtred votume Natural draft appliances(RVNDA) � <br /> Tatal Requlred volume(TRv)■RVFA+RVNDA TRV■ s�a� + IU01L�� ■ S�a�S� TRV R' <br /> If CAS Voluma(from Step 2)Ir prrat�r thanTRV then no oucdoor openings are needed. <br /> If CAS Volume from Ste 2 !rliir thon TRV then o to STEP B. <br /> Step 5:Calculete the ratlo of av�llable Interlor vofume to the total requtred volume. <br /> Ratlo;CAS Volume(from Step 2J d!vlded by TRV(fram Step Aa or Step Ab) <br /> Ratfo■ � . <br /> Step 6;Calculate Reductlon Factor(RF). <br /> RF�1 minus Ratlo RF�1- . - :$7 <br /> seep�:Calculate stngle outdoor oqenin8 as 1f a11 combustlon alr Is from outside. <br /> 7otal Btu/hr input of all Combustlon Applianaes ln the same CAS Input� MDO� Btu/hr <br /> (EXCEPT DIRECT VENT) <br /> Combustian Air Opening Aree(CAOA): <br /> Totel Btu/hr dlvlded b 9000 Btu/hr er In� CAOA a 7 C> 3p00 Btu r er�n'� In' <br /> Step 8;Calculats Mlnlmum CAQA. <br /> Minlmum CAOA=CAOA mult! 11ed 6 RF M�ntmum CAOA. x ■ /�j! In' <br /> Step 9:Calculate Cambustlon Alr Opening Diameter�CAOD) <br /> CAOD�1.13 mult/plled by the square root of Mlnimum CAOA CAOD■1.13� Mlntmum CAOA■ ��In.dldmeter <br /> o u one Inch In sl:a IF usin flox duct <br /> f If deslred,ACH can he det2rmined using ASHRAE celculatlon or blowar door test.Follow proaduns In Sectlon <br /> G30a. <br /> Page 5 of 6 <br />