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AMCA Standard 260 (published in 2013) is the laboratory method of testing induced flow fans. This test standard defines the appropriate fashion in which any manufacturer can test induced flow fans within an accredited test facility.
Induced flow fans are somewhat of an anomaly in the fan business because at a given speed, power, and air density, they accelerate X amount of volume at the inlet of the fan but discharge something greater than X, at a higher velocity.The purpose of using this type of fan is to increase the airstream, mass flow and velocity (which is momentum), thereby generating a very tall, stable, and predictable plume column of air to exhaust effluent from a space.
With this method of testing, the fan is essentially tested two times in two different fashions in the AMCA accredited facility. The first test defines the performance of the fan on the inlet side. Next, the fan is turned over on its side and repositioned on the testing chamber. It's started again and the fan performance on the discharge side is tested.
From these two tests, the manufacturer of the induced flow/high plume fans will develop performance ratings, which are typically published in the public domain. Engineers typically receive these ratings in the form of a printed catalog or electronic fan selection package.
When the manufacturer produces a fan performance catalog, they have the option to submit the laboratory test results and catalog performance to AMCA for third party verification/validation, which demonstrates that the catalog performance data is an accurate reflection of the laboratory performance test data. Then, AMCA can license the manufacturer to certify the ratings so that the AMCA Certified rating seal can be applied to the product.
Why is the AMCA Seal Important?
The bottom line is, these fans are used in life saving applications. The performance of both the inlet side and discharge side of the fan have life safety impacts. On the inlet side, the fan needs to perform as the manufacturer claims so that the system will develop the necessary flows and pressures to maintain a safe environment within the facility.
On the discharge side of the fan, the product needs to perform accurately as the manufacturer has claimed because the effluent that is expelled must be jettisoned far enough from the building to keep it away from workers on the roof and/or reentrainment into air conditioning units on the building or the neighboring buildings.
The interesting aspect is that during commissioning, the test and air balance contractors stop doing their testing of the system at about the inlet side of the fans on the roof. In other words, nobody ever tests what happens on the discharge side of these fans. This becomes particularly interesting if additional monies have been spent for wind dispersion analysis on the building.
The performance on the discharge side of the fan, including the related safety and accuracy of wind dispersion analysis rests solely on the manufacturer's claim. Therefore, AMCA Certified induced flow fan performance gives credibility to the engineers' design. All M.K Plastics Axijet® Induced Flow Fans are licensed to bear the AMCA Certified rating seal for induced flow fan air and sound performance. To learn more about the AMCA Certified ventilation systems best suited for your application, contact us today.