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.�, <br /> ' I <br /> prrections-The Minnesota Fuei Gas Code method to ealculate to sire o}a requi�ed combustion air openirrg,is cat/ed the Known Air <br /> lnfiltration Rote Method. For new consbuction,4h of step 4 is required ta be fifted out. <br /> IFGC Appendix E,Wprksheet E-1 <br /> Residential Cambustio�Afr Caiculation Method <br /> {for Furnace,Boiler,andJor Warer Heater in the Same Space} <br /> Step 1:Campiete vented combustion appiiance information. v �� <br /> Furnate/Boiler: <br /> _Draft Hood _ Fan Assisted �Direct Vent Input ��� �-� E3tu/M <br /> o�Power V2nt <br /> Water Heater: �,,r. <br /> _Qraft Hood Fan Assisted �Direct Vent input: �.7�Btu/hr <br /> or Power Vent <br /> Step 2:Calculate the voiume of the Combustio�Apptiance Space(CAS)containing combustion appliances. r"—' <br /> The CAS inc(udes aii spaces connected to one anpther by code compliant openings. �'�7 CAS volume: ..7 �� ft° <br /> lxWxH L I> W H <br /> Step 3:Determine Air Changes per Hour(ACH)1 <br /> Defauit ACN values have been incorpnrated intp Table E-1 for use with Method Ob(KAIR Methodj. <br /> if the year of construction or ACH is not known,use method 4a(Standard Method). <br /> Step 4:Determine Required Volume for Combustion Air,�DQ NOT COUNT DiRECT VENT APFLIANCES� <br /> 4a.Siandard Method <br /> Totai BtuJhr input of aU combustion appliances Input Btu/hr <br /> Use Standard Method cotumn in Tab1e E-1 to find Totat Requi�ed TRV� ft' <br /> Volume(TRV) <br /> if CAS Volume(from Step 2)is g�eater thon TRV then no outdoor openings are needed. <br /> if CAS Yotume{from Step 2)is less ihon TRV then go to STEP 5. <br /> 4b.Known Alr infiltration Rate(KAiR)Method(DO NOT COUNT DIRE[T VENT AFPLfAN�Sj <br /> 7otai Btu/hr input of aA fan-assisted and power veM appiiances fnput C��etu/hr <br /> Use Fan-Assisted Appliances column in Table E i to find RVFA �ft' <br /> Reyu�red vpiume Fan Assisted(RVFA) <br /> Total Btu/hr input of aIi Naturai draft app4ances Input: _�Btu/hr <br /> Use Natura�drah Appiiances calumn in Table E•1 to(ind RVNFA: �ft� <br /> Required Volume Natural draft appliances(RVNDA) <br /> Total Required Vofume{7RV}=RVFA+RVNDR TRV=�+ ��� TRV ft' <br /> if CAS Volume{from Step 2)is greater than 7RV then no outdoor openings are needed. <br /> !f CAS Volume(from Step 2}is tess ihan TRV then o to STEP 5. <br /> Step S:Caicuiate the ratio of available interior volume to the totai required voiume. <br /> Ratio=CAS volume(from Step 2}divided by TRV(from Step 4a or Step 4b) .-^�, r <br /> Ratio= � / ���j'v = i � � <br /> Step 6:Caiculate Heduction faaor(RF). <br /> RF=1 minus Ratio RF=1- � � _ + �`,l <br /> SYep 7:Calculate singie outdoor opening as if ali combustion air is from qutside. <br /> Totai BtuJhr input of aif Combustian Appiiantes in the same CAS input: �`r`�'�,e,,,`_Btu/hr <br /> (EXCEPT DIRECT VENT) <br /> Combustion Air Qpening Area{CAOA�: {'� (/,, f � <br /> Totai Btu/hr divided by 3000 BtuJhr per i�` CAOA= �7U�/3000 Btu/hr per in`'= `w.�r'�7 in` <br /> Step 8;Calculate Minimurn CAQA. �� <br /> M€nimum CAOA=CAOA mu/ti lied by RF Minimum CAOA=�����x '23 y = 4'4 't 1� in' <br /> Step 9:Calculate Combustion Air Opening Diameter(CAOD) .�t. <br /> �, Y ' r— <br /> ; CAQD=i.Y3 mukiptied try the square roat of Minimum CAOA CAOD=1.23 v Min�mum CAOA=�<2� in.diameter („�{ � <br /> o up one inch in size if using flex duCt «J <br /> 1!f desired,ACH tan be determined using ASMRRE calculatian or blower daor test.follow procedures in Section <br /> G3Q4. <br /> 'i <br /> I I <br /> II <br /> I I' Page 5 af 6 <br /> �II i <br />