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y+..e'�' <br /> Directions-The Minnesota Fuel Gas Code method to calcutate to size of a required combust�orr air opening,is ca0ed the Known Air <br /> 1n�iJtrotion Rate Method. For new constructfon,4b of step�i is required to 6e filted nut• c <br /> 1FGC Appendix E,Worksheet E-1,1346.5412 <br /> Residentiai Combusdon A��Ca�a+kation Methad <br /> (for Fumace,Boiter,and/or Water Heater in the Same S ace) <br /> Step i:Compfeoe vente�l combustion appliance information. <br /> Pumace/8oiler. �8C� L1CJC:.Y_Btu/hr C!� Y �./f' �1 t�','e��� <br /> Draft Hood _„Fan Assisted ��rect Vent �nP"r-� <br /> or Power Vent <br /> Water Heater: � (�`Y�('J Btu/hr <br /> DraftHood �FanAssisted _D3rectVertt �nP"t' <br /> � or Power Vent }janCes. f�/i/�� <br /> Step 2:Calculate the votume of the Com4ustion Appliance Space(CAS�containing COmbUstiOn 8pp �vUium2: %�� � <br /> 7he CAS inctudes all spaces mnnected to one another by code compliant openings- <br /> LXWxH � `N H I� <br /> Step 3:Determine Air Changes per Hour(ACH)1 <br /> Default ACH vatues fiave been incorporated�Mo Tabte E-1 for use witfi Method Ab(KA1R Method). <br /> kf the year of wnmuc[ion or ACH is not known,use method 4a(Srandard Method}. <br /> c <br /> Step 4:Determine Required Volurne for Combusti0n Air.(DO NOT COUNT��RE�T��T'v'PuaNCFS <br /> 4a.Standard Method ��p�}._____,._Btu/hr <br /> 'rota�etu/hr input of ail combustion appliances .��_ �a <br /> Use Standard Method column in Table E-1 to find TOtd�Requked <br /> Volume(TRV} <br /> If CAS Vofume(from Step Z�►s 9re�er tt'Q"TRv then no outdoor openings are needed_ <br /> If CAS Volume(from Step 2)fs tess thcn TRv then go to SrEP s• <br /> 4b.Known air tnfiltration Rate(KAIR)Method E�N�T COUIVT OIRECf VENl'RnP�C� �ES�� B�/hr <br /> wer vent app�lante5 <br /> Tota�Btu/hr input of ali fao-assistgd a^d P° <br /> i7 <br /> Use Fan-Assisted Apptiances Column in TabVe E-1 io find <br /> RVFA: �'�� - <br /> Required Volume Fan Assts[ed(RVFA} ,g` <br /> Uanws ��p�='v��t�lhr <br /> Tota!etu/hr input of a!1 Naturai draft app <br /> Use Naturat draft Appiianc.es column in Fable E-1 to find <br /> RVNFR:�� <br /> Required Volume Natural draR app��ances(RVNdA) <br /> � Q (�`ls�C'i' -rrtv t� <br /> Total Reqnired Volume[Cft1�_ <br /> RVFA t RVNDA TRv-------------+ <br /> If CAS vo�ume(fro�n step a}�s greater d+Q^TRV then no outdoo�openings are needed. <br /> If CAS Volume from Step Z)�S�ess ihan?RV then go to StEP 5. <br /> Step 5:Caltutate the fdt�0 Of availabte inter�or voiurte to the total required volume. L/G�� J �� , �� <br /> Ratio=�volume�from Step 2j dtvfded bY TRV(from Step 4a or Step 4bl Ratio= <br /> Step 6:Calculate Reductlon Factor(RP). + �� <br /> RF=1- • 1 = <br /> RF=1 mtaru Ratio <br /> Step 7:Ca�cu�ate single outdoor opening as iF ail combustion air is from outside• ln�� �,ry��-��.., g��hr <br /> Tota!fitu/hr input Of ait CombuSt�on�°�PPUances in the same t'AS <br /> � <br /> (EXCEPT D6RECF VENT) <br /> GQRib45GOT1 A�t OQOning Area(CE.oa). �(��3�p Btu/hr er in2= d�''�'` � ��2 <br /> Total Btu/hr dfWdeA b 3000 Beu�hr per in2 ��Q- <br /> S�p g:CatcuVate Minimum CAOA. / � <br /> �G � % r�`� _ (vr ��Z <br /> Minimum CA�A=��A�"utdplied 6y RE Minimum CAOA=�� ��� <br /> Step 9:Caiculate Combustion Air Opening Diameter(caoo) a� �S3 � �/, <br /> CAOD=1.13 multTplied by the square root of Minimurn cJ�oA cAo�=1.13 J Minirrtum C/+OA= <br /> in.diameter �� <br /> go up one�nch i�size if using flex dutt <br /> 1 ff desired,ACH can be deteRnined using ASMRAE ca�u'�aUon or blower doortest_Follow procedures in Section G304. <br /> Page 5 of 6 <br /> h\Buitding�5afetyl'ol�des►nfqrmation\Curtent\2016\VentMakupCombAlrta�s20i6.doac <br />