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I <br /> Catie Peck-Long Ext691 ( 10/11 ) 02/24/2015 02:44: 01 PM -0600 <br /> Directions- rhe Minnesota Fuel Gas Code,method to catculate to size of o required combustion air opening,is called the Known Air <br /> Infiltration Rate Method. For new construction,4b of step 4 is required to be filled out. <br /> -iF­cFippe-ndTix—f7,Worksheet E-1 .......... <br /> Residential Combustion Air Calculation Method <br /> (for Furnace,Boiler,and/or Water Heater in-the.same Space) ........... <br /> step i:Compiete vented combustion appliance information. <br /> Furnace/Boiler: <br /> Draft Hood Fan Assisted XDirect Vent Input* <br /> .......Btu/hr <br /> or Power Vent <br /> Water Heater: <br /> Draft Hood Fan Assisted Direct Vent Input: ........Bru/h r <br /> rir Power Vent <br /> ............................-------....... <br /> Step 2:Calculate the volume <br /> of the Combustion Appliance Space(CAS)containing combustion appiltances. <br /> The CAS includes all spaces connected to one another by code compliant openings. CAS volume:, <br /> .............. <br /> L x W x H L. vv FI <br /> p-,3­:­5-et,e-r-m­1`n`e"Air Changes per-Hour(ACf I)1 <br /> Default ACH values have been incorporated Into Table E-1 for use with Method 4b(KAIR Method). <br /> If theyear of construction or ACH is not known,use method 4a(Standard Method). <br /> Step 4:Determine.Required Volume for Combustion Air.(DO NOT COUNT DIRECT VENT APPLIANCES) <br /> 4a.Standard Method <br /> Total Btu/hr input of all combustion appliances input:----Btu/hr <br /> Use Standard Method column in Table.F-1 to find Total Required TRV:--­...--­­.­..­ft' <br /> Volume(TRV) <br /> If CAS Volume(from Step 2)is greater than TRV then no outdoor openings are needed. <br /> If CAS Volume(from Step 2)is less than TRV then go to STEP S. <br /> 4b,Known Air(riflitution Rate(KAIR)Method(DO NOT COUNT DIRECT VENT APPLIANCES) <br /> Total Btu/hr input of all fan-aul3ted and power vent appliances Input:,._ �J.„LO. Btu/hr <br /> cl W <br /> Use Fan-Assisted Appliances column in Table E-1 to find RVFA!. <br /> Required Volume ran Assisted(RVFA) <br /> Total Btu/hrmput of all Natural draft appliances Input; <br /> Use Natural draft Appliances column In Table L"...1 to find RVNFA:­­.­­,!.�............ <br /> Required Voiume Natural draft appliances(RVNDA) <br /> Total Required Volume(TRV)=RVFA+RVNDA TRV- TRV ft' <br /> If CAS Volume(from Step 2)is yrnater than TRV then no outdoor openings are needed. <br /> If CAS Volume{from�L.eL214 0 to STEP'S. <br /> ..Le.5jL!hCTTRV their 0 <br /> Step 5:Calculate the ratio of available interior volume to the total required volume. <br /> Ratio-CAS Volume(from Step 2)divided by TRV(f rorn Step 4a or Step 41b) Ratic, <br /> Step 6:Calculate Reduction Factor(RF). <br /> RF,.,.-I mutts RatioRF--I -ja <br /> ........... .............. <br /> ............. ..........-- <br /> Step 7:Caicu(ate single outdoor opening as if all combustion air Is from ot,itslde.. <br /> Total Btu/hr input of all Combustion Applhances in the same CAS I riput: Bt.ujhr <br /> (EXCEPT DIRECT VENT) <br /> Combustion Air Opening Area(CAOA): <br /> Total Btu/hr dividedby 3000 Btu/hr per in' CAOA- 3000 Dtu/hr per in'= �3 in' <br /> Step Fl:Calculate Minimum CAOA. <br /> MinimumCAOA=CAOAmultipfiedbyRF Mlnlmum(-AOA= x in, <br /> Step 9:Calculate Combustion Air Opening Diameter(CAOD) <br /> CAoo=:1..13 mrarlpfledby thE squane root ofMinirnurn CAOA CAOD 1.13 V M!n 1 rn j in CAOA L,..S-"-­ ,�4,�,,_�­i,in.d la mete r <br /> po up one inch in site if us!rff-f Lexs!�E:L­­­­ ............... ..................................... <br /> .1.if desired,ACK can be determined using ASH RAE calculation or blower door test Follow procedures in.Section <br /> G3Q4. <br /> Pap 5 of 6 <br /> ............. <br />