Flow loss due to friction in galvanized steel duct
Flow loss due to friction in galvanized steel duct
(OP)
I am trying to figure out what the loss of flow due to friction in an 8" square duct versus a 9" round duct would be. This is an exhaust duct 80' in height. How do I relate pressure drop in in wg to cfm and velocity? Or, how do I relate cfm and velocity to pressure? Any help would be greatly appreciated.





RE: Flow loss due to friction in galvanized steel duct
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RE: Flow loss due to friction in galvanized steel duct
RE: Flow loss due to friction in galvanized steel duct
Assuming 300 CFM, an 8" x 8" duct gives you 0.1" W.C. loss per 100 ft of duct, and the 9" round gives you 0.09" W.C. loss per 100 ft. They are hence insignificantly close but the 9" round is slightly better. BTW, the velocity is approx 700 fpm at this assumed CFM. If you have another airflow rate or velocity in mind, let us know and we/I can re-chug the numbers accordingly.
RE: Flow loss due to friction in galvanized steel duct
RE: Flow loss due to friction in galvanized steel duct
RE: Flow loss due to friction in galvanized steel duct