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Catie Peck-Long Ext691 (7/10) O1/30/2015 09:03: 32 AM -0600 <br /> Direciions-The Minnesota fuel Gas Code method to calculate io sire of a requlred combustlon air opening,is ca//ed the Known Alr <br /> Infilfrotion Rate Method. For new consfructian,4b of step 41s rrqulred to be filkd aut.� <br /> ? �F a�"`,�" �•:?'w.. �.e�f;,,a ,Y.=,;r� ���' <br /> IfGCAppendix E,Worksheet f-1 <br /> Residential Combustio�Atr Gkuutlon Method <br /> (fo�furnace,BoAer,and/or Woter Heater in tAe Same 5 ace) <br /> Step 1:Complete vented combusHon appliance information. <br /> Fumsu/Boiier. � �IF� <br /> Draft Hood �Fan Asslsted �OMect Vent Input; ���C1 6tu/hr - <br /> or PoWer Vent <br /> Wattr Heater: <br /> Dnft Hood �� Fan Assisted _,Direct Vent I�put: a� �,�+� Btu/hr <br /> v►Power Vent <br /> Sc�p 2:Calculate the volume of the Combustion Appiiance Space(CA51 containing combustlon appliances. ,,., <br /> 7he CAS includes aN spaces connected to one another by code compllant openings, CA5 volume; � � � � ft' <br /> Step 3:Determine Air Changes per Hour(ACH)1 <br /> Defauh ACH values have been incorporated int�Table E-1 for use with Method 4b(KAfR Method). <br /> Hthe ar of cnnstructbn orACH is not known,use method 4a(Standard Method). <br /> Step 4:Determine Required Volume for Combustion Air.(00 NGT COUNT DIRECT VENTAPPtIANCES} <br /> 4a.Standard Method <br /> TotalBtu/hrinputofalicombustlonappliances lnput: Btu/hr <br /> Use Standard Method wlumn!n 7able E-1 to find Total Requlred TRV: ft' <br /> Volume(TRV) <br /> If CAS Volume(from Step 2j b pnater thon TRV then no outdoor openings are needed. <br /> If CAS Volume(trom Step 2)!s Aea thon TRV then go to STEP S. <br /> 4b.Known Air InfiRration Rate(KAIR)Merhod(00 NOT CO UNT DIRECT VENT APPUANCES) <br /> Total Btu/hr inpu#of all fan-asadsted sad power vent appliances Input: ���.�*=�x.�Btu/hr <br /> Use Fan-Assisted Appliances calumn in Table E-1 to find RVFA: �,r` i .S '� ft' <br /> Required Volume Fan Assisted(RVFA) <br /> Total Btu/hr input of all Matura!dnR appliances Input: �J Btu/hr, <br /> Use NaturaJ draftAppliances cotumn in Table E-1 to find RVMFA: r�✓�^^'�'�<"�- R' <br /> Requfred Volume Natural dnft appliances(RVNOA) , <br /> Tota!Required Volume(TRV)=RV�A+RVNdA TRV= r ,:��+.a' + "'•�""`""� _ � �� �' ' <br /> � TRV ft <br /> if CAS Volume(from Step 2)h grcotei than TRV then no outdoor openings are needed, <br /> If CAS Volume(from 5tep 2)is hss thon 7RV then go to STEV 5. <br /> Step 5:Calcutate the ratio of available Interior volume to the total required volume. <br /> Ratio=CAS Vo(ume(from Step 2}divfded by TRV(trom Siep 4a or Step 4b) y� <br /> Ratio= ��(p '� � 't ^� ..� - ,,.�U <br /> , .� <br /> Scep 6:Caltulate Reductiort factor(Rf). <br /> RF=iminusRatlo RF=1- . tA � , ? t <br /> Step 7;Calculate single outdoor opening as if all tombusUon afr is from outside. ,,, <br /> Total Btu/hr input ofaU Combustion Apptiances in the same CAS Input: ..> �.+�.,,,�d`^'�+� Btu/hr <br /> (EXCEPT DfRECT VEN'� <br /> Combustion Air Openine Area(CAOA); <br /> 7otal etu/hr dlvldad 3000 Btu/hr per Inz CAOA= ° �+W:s;� /3600 Btu/hr r(n'� � .+����,yr in2 <br /> Step B:Calculate Minimum CAOA. <br /> Minimum CAOA=CAOA m�lttplled b Rf Minimum CAOA= � �� W x ��E �� = � d �� �.�T in� <br /> Sup 9:Calwlate Combustion A'u Opening Diameter{CAOD� <br /> CAOD=1.23 muMipfkd0ythesquore root oJMinimum CAOA CApD=1.13� Minlmum CAOA= ��7�_in.diameter <br /> go up one inch in size if using�lex duct <br /> 1 If desired,ACH can be determined using ASHRAE calculation or blower door test Follow procedures in Sedion <br /> G3U4. <br /> Page 5 of 6 <br />