Laserfiche WebLink
I If <br />free Appendix 9, Worksheat B -x <br />Residential Combustion Air Calculation Method <br />mace, Boiler, and/or Water Heater in the same <br />p 1, Complete vented combustion appliance Information, <br />Furnace/Boiler; <br />Draft Hood Fan Assisted <br />(Notfan assisted) & Power Vent <br />Water Heater: <br />___ .PraftHood -an Assisted <br />(Not fan assisted) & Power Vent <br />:2; Galculate.tile volume of the Combustion Appliance Space <br />The CAS includes all spaces connected to one another <br />by code compliant openings, <br />,c, DlrectVent Input; <br />,r* <br />Y� Btu/hr <br />Direct Vent Input, <br />containing Combustion dppliancds, <br />CAS volume: -lb <br />),U; Determine Air Changes per Hours (ACH).x <br />Default AC.H values have been In Into fable E-1 for use with Method 46 (KAiR Method), lithe <br />year of construction orACH is not know, use method 4a (standard Method). <br />4: Determine. Volume for Combustion Air,, <br />4a. Standard Method <br />Totnl Btu/hr input of all.combustion appllances <br />,(DO NOT COUNT DIRECT VENT APPLIANCES) <br />Use Standard Method column In Table E.l to find Total Required Volume (TRV) <br />IF GAS Volume (from Step 2) Isgreater than TRV then na Outdoor openings are needed, <br />If CAS VolUmo,(froln Step 2) is lens than TRV then go to sTEP S, <br />4b, Known Air infiltration Rate (KAIR) Method <br />Total Btu/hr input ofall fan -assisted and power Vent appliances <br />(DO N.0TQOUNTpIRECTVENTAPPLIANCES) <br />Use Fan -Assisted Appliances column In Table E-1 to find <br />Required Volume I=an Assisted (RVFA) <br />Total Btu/hrinput,ofall non -fan -assisted appliances <br />Use Non -Fan -Assisted Appllances column In Table Ii -I to find <br />Required Volume Non -Pan -Assisted (RVNFA) <br />Total Required Volume (TRV) = RVFA •1• RVNFA <br />if CAS Volume (from Step Z) Is greater than TRV then no outdooropenings are needed, <br />If CAS Volume (from Step 2) is loss than TRV then go to STEP S. <br />Input: <br />TRV: <br />9 <br />RV a 1• fts <br />ip 5: Calculate the ratio of available Interlarualume to the fatal required volume, <br />Ratio = CAS Volume (from Step 2) divided by TRV (from Step 4a or Step 4b) Ratio � � � 1 Z�✓�C , `� �� <br />p fi: Calculate Reduction Factor (RF), <br />RF -:1. minus Ratio RF M I - � o'/ 5` <br />p 7: Calculate single outdoor opening as if all combustion air is from outside. <br />Total Btu/hr Input of all Combustion Appliances In the same CAS (EXCEPT DIR,CCTVENT)input; � 5;_c UP u/hr <br />Combustion Air OpeningArea (CAQA): <br />Total Btu/hr divided by 3000 Btu/hr per M2 CAQA-75ecqVca h n n Bth <br />18. Calculate Minimum CAQA, <br />Minimum CAQA CAQA multiplied by RF <br />9: <br />Ali, opening Diameter <br />CAOD t:;x.18 multiplied by the square rook of Minimum CAQA <br />ACH rant be determined using ASHRAE calculation or <br />M / , per in2._ Inz <br />Minimum CAQA ,_ _ x 7- fnz <br />CACTI) =1,13 Minimum CAQA [ in <br />test, Follow procedures in Section Q304, <br />`� <br />