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Fan AMCA Classification

Fan classification established by AMCA.

AMCA - Air Movement and Control Association International fan-class standards are established to simplify the specification of fans. AMCA fan-class standards are based on fan horsepower required per square foot of outlet area representing the structural requirements imposed on a fan for a given set of operating conditions.

AMCA class limits for a double-width airfoil centrifugal fan:

Fans - AMCA Classification
Fan Class
Lower RangeUpper Range
Static Pressure
(in W.G.)
Outlet Velocity
Static Pressure
(in W.G.)
Outlet Velocity
I 2.5 3200 5.0 2300
II 4.25 4175 8.5 3000
III 6.75 5256 13.5 3780

AMCA Fan Classes I II III - Static Pressure vs. Outlet Vleocity

Example - Classification of Fan

AMCA Fan Classes I II III - Static Pressure vs. Outlet Vleocity - Example

A fan working with static pressure 4.5 in W.G. and outlet velocity 3500 ft/min is within AMCA Fan Class II.  

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