AMCA 250

Q=V
2
× A
2
=340.3√
Tm
× A
2
IP
P
a
A
2
Legend (SI) [IP]:
Q = Volume Airow (m
3
/s) [cfm]
V
2
= Fan vibration velocity, reverse direction (m/s) [ft/min]
A
2
= Fan outlet area (m
2
) [ft
2
]
T
m
= Measured thrust (N) [lbf]
P
a
= Inlet ambient air density taken as equal to the air
density in the test enclosure (kg/m
3
) [lbm/ft
3
]
There are four key performance metrics regarding the overall performance of
a jet fan. They are: Thrust, Airow, Throw, Induction Factor
Thrust, a primary measurement of a jet fan,
is the force exerted by the fan. Thrust is
dependent on the outlet air velocity, shape, and
direction. Thrust is obtained from laboratory
testing in accordance with AMCA Standard 250.
Airow rate is the exact amount of air that moves
through the fan housing. Airow is calculated from
equations provided in AMCA Standard 250.
Jet Fan Key Performance Metrics
Thrust
Commonly expressed as Newtons (N) or pound-force (lbf)
Airow
Commonly expressed as Cubic Feet per Minute (CFM)
ANSI/AMCA Standard 250, Fig. 4B, p. 25
1
Q=V
2
× A
2
=√
Tm
× A
2
SI
P
a
A
2