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. <br /> . y <br /> Diied`ons-The Minnesota Fue!Gos Code method to colculate to size of a requlred combustion air openfng,Fs ca/led the Known Alr <br /> Irt�'iliraiion Rate Method. For new construd/on,4b of step 41s requJrsed to 6e})lled oat. <br /> I WC ApperMix E,WorksheK E-1 <br /> ,�lesidendai CombusUon Air Gicubdon Method <br /> (tor fumaee,Boiler,and/or Water Heater In the S�me 5 ace) � � <br /> Sqp 1:Complete wented combustion�pplla InformaUon. � <br /> Pumaa/Boiler. /�) �� <br /> ,_Dr�ft Hood _Fan Assisted ect Vent Input: � �V Btu/hr '� '� ���`� <br /> or Power Vent <br /> W�ter He�ter. ��r�� <br /> _Droft Hood F�n Aaslsted _Dircct Vent Input BW/� <br /> �°i <br /> Or Pow�r Vent <br /> St�p 2•Glculate e voiume of the Combustion Appliance Space(CAS)containi combusUon appliances. � ' <br /> The US indudes�II spaces conneated to on��nother by code eompliant openin`s.' Q me: h� <br /> _ _...____.�---._ __. _ _.__..._- ------ - ---- __ ____--- __ __ _ _ � __ ___--- -- --_____._.._ <br /> Step l:Gt�rmine Air than�es per Hour(ACH►1 <br /> flehuh ACH wlues h�ve been hxorponted into T�ble E-1 for use with Method 46(KAIR Method). <br /> If the ar of tonstrucdo�or ACH is not known,use method 4a Sqndard Method. <br /> Step k Oet�rmine Requtred Volume for Combustfon Air.(DO NOT COUNT DIRECT VENT APPUANCES) <br /> 4a.Sandart!Melhod <br /> Total Bw/hr Input of�li combustion�ppliantes Input Btu/hr <br /> Use Standard MeLhod column in Tabie E-1 to flnd Total Requirod TRV: h' <br /> Volume(TR1� <br /> If CAS Voluma(from Step 2)h ynalar�an TRV then no outdoor openings�ro needed. <br /> N GAS Volume(from Step 2)@ kss than TRV then`o to STEP 5. <br /> 4b.Known Air Inflhradon Rate(KAIR)Method(DO NOT COUNT DIRE[T VENT APPUAI��r <br /> Totai BtuJhr input of�II hn-assiated and pow�r vent appliances Input: ��9� � • <br /> Uu Fsn-�lssistad Appliances column in T�bie E-1 to flnd RVFA: Z ft' <br /> Required Voiume Fan Assisted(RYFA) <br /> Tohl Btu/h�input af�II NsWrai desh appli�nces Input: � gq�/hr <br /> Use Natunl draft AppNances column in Tab�e E-1 w Nnd RVNFA:�{�' <br /> Requirad Volume Natunl drsR appilances(RVNDA) � <br /> Total Required Volume(TR1/)■RVfA+RYNDA TRV:� z. + ����i � J�j/� <br /> � TRV ft� <br /> If G15 Volume(from Step 2)!s qrrata tl�on TRV then no outdoor openU�s are needed. <br /> If CAS Voluma irom Ste 2)is les�ehan TRV then "o to STEP S. <br /> Stap S:Glculate the ntio of av�ilable Uterior volume to the toqi requind volume. <br /> RaUo=6AS Volume{from Step��divided by TRV{from Step 4a or Step 4b) L+ � /� �/�� <br /> Raao= 7 � � � <br /> St�p 6:Glculate Reductlon factor(RF). <br /> Rf s 1 mltqis Ra�o RF■1. i �� s � f/ � <br /> Sttp 7:Glculste si��le outdoor openin;as ff all combustion air is irom outside. �J <br /> Tot�l Btu/hr input of�il Combustlon Appliances In the same CAS InpuC l��g�/hr <br /> �EXCEPT DIRER VEi� <br /> Combusdon Ak Openin�Are�(GOA): <br /> Topl 8tu/hr dlvfOtd 3000 BtuJhr per ina CAOA= �'3000 Btu/hr per int■ !� �in� <br /> Sap i:Gkulate Minimum GOA. <br /> Mir►imum UOA■GOA mu b RF Minimum CAOA. � x S : �/?ji in� <br /> Step!:Glculate Combustion Air Opening�ismeter(CA00) <br /> G00 s 1.13 muldppee by tht squort root of Minimum GIOA CAOD■1.13 J Minimum CAOA■/ • In.diameter <br /> up one inch in sizc if usf flez duct <br /> 1 If desrced,ACH an 6e determined usinQ ASHRAE eakulaaon or blower door test.Fallow procndures in SecUon <br /> G304. <br /> G:�Forms\VentMakupCombAirCaIs041511.docx Page 5 of 6 <br />