Calculate cfm of an exhaust fan

Old 03-11-09, 01:54 AM
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Calculate cfm of an exhaust fan

Hi Everyone,

Am creating a simulator application for HVAC. I also need to calculate the CFM of exhaust fan. Is there any generalized formula to calculate the approximate air flow rate of exhaust fan given motor & fan specifications. If anyone know, please do tell me. It'll be a great help for my application. Thanks in advance...
Old 03-11-09, 05:25 AM
Join Date: Oct 2008
Location: New England
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Hi Vin, there are general approximations, but I know of no list for mfg, or specified motors to relate to exhaust volume. In the energy auditing business we have a special hood to place over the exhaust fan (when it fits) to measure the depressurization. From that we can estimate the cfm rating. How accurate do you need to be?


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