AMCA 250

What Are the Key Metrics of a Jet Fan?
The key metrics of a jet fan include thrust, airow,
throw, and induction. Thrust measurements and
airow calculations, obtained from AMCA 250 testing,
are the foundation of other key metrics designers
seek when implementing a jet fan system. These
other key metrics, such as throw and induction,
are the result of Computational Fluid Dynamics
(CFD) simulation. With accurate and certied AMCA
250 data, designers can trust CFD results to make
condent choices and accurately predict jet fan
performance for the end application.
Why Is Measuring Thrust Recommended
Instead of Measuring Airow?
Thrust represents the rate of change in momentum,
and is a primary measurement of a jet fan. Jet
fans are designed to be unducted, high-thrust
products, meaning an ANSI/AMCA Standard 210/
ASHRAE Standard 51 airow test chamber can not
replicate the end application of a jet fan accurately.
In addition, measuring airow cannot provide
the information needed to predict the induction
produced by thrust.
AMCA 250 offers methods to measure airow
separately from the thrust measurement; however,
these methods have the potential to alter fan
operation, and varying results should be expected.
3
Which AMCA Standards Provide the Most
Accurate Methods to Simulate Jet Fan
Performance?
The AMCA standards that best replicate the end
application and eventual consumer experience
are AMCA 250 and ANSI/AMCA Standard 300,
Reverberant Room Method for Sound Testing of Fans.
AMCA 250 provides testing methods to measure
the thrust of a jet fan in a large test setup that is
representative of a parking garage. ANSI/AMCA
Standard 300 provides the methods to measure
sound levels at the inlet, sound levels at the outlet,
or the total sound power of the jet fan. For the best
representation of a jet fan, testing the total sound
power of a jet fan in a large test setup is most
representative of a parking garage.
Manufacturers could still test jet fans to ANSI/AMCA
Standard 210; however, AMCA will no longer certify a
jet fan to ANSI/AMCA Standard 210/ASHRAE Standard
51 because the test method does not represent
the end application, and ultimately, the methods
provided within the standard alter the operation of a
jet fan. AMCA 250 is specically designed to test the
performance of jet fans, meaning that the prescribed
testing methods best represent an open parking
garage in a lab environment.
So, What Do We Do With the Certied Data?
The certied data from AMCA allows jet fan
manufacturers to assist designers in the development
of their project.
A CFD analysis, using certied AMCA 250 data, will
show the certied data in action, ensuring that the
nal ventilation system, optimized with jet fans will
completely and effectively ventilate the space as
intended.
With CFD simulation driven by certied data,
designers have a valuable tool to assist them in the
development of their project.
The Final Verdict
To conclude, AMCA has stated AMCA 250 must be used
when certifying jet fan data. No other AMCA standard
can provide accurate methods to measure the thrust
and airow of a jet fan. The corresponding certied
performance data, through a 3rd party body like AMCA,
ensures accurate and reputable data that represents
real world applications. Since the initial data is backed
by AMCA certication, designers can trust that the
proposed ventilation system, optimized by jet fans,
will ensure effective dilution and extraction of harmful
gasses. Manufacturers that certify their jet fans to
AMCA 250 equip designers with accurate information
to condently complete projects with safe and proper
ventilation.
6 systemair