To accurately determine the performance of a circulation fan is no easy task.
For most circulation fans it is possible to determine the characteristic curves flow/pressure similarly to what is done with the exhaust fans; anyway, this operation doesn’t provide accurate information about the performance in real working conditions.
This happens because the real difference in pressure that a circulation fan develops is not zero – as one may expect- but it depends on the amount of air movement. For this reason, it is very hard to estimate the real curve point in which the circulation fan is working at.
The circulation fans test method – called AMCA 230- is different than the one used for exhaust fans (AMCA 210, ISO 5801) mainly because during the test it is installed in an open environment without any separation between intake and exhaust and it operates in a real working condition.
A further advantage is that it is possible to test also fans without any internal ring which couldn’t be tested using ISO5801.
Test method AMCA 230 is based on the fact that a working circulation fan gives to air some thrust which produces air movement and distributes it in the whole environment.
By measuring the reaction force on the fan it is possible to estimate with good approximation the amount of air movement and consequently the various parameters of efficiency and performances.
However, it should be emphasized that in order to compare performance data you need to pay attention to which test version was considered, in fact, there are many different versions of AMCA230, due to the continuous development and improvement of legislation.
For example, version AMCA 230-99 estimates an airflow 1.41higher than the one calculated in the last release now in force. This is the reason why in many brochures it is possible to find impressive air flow rates in compliance with an old test method.
An efficient method to compare tests of air circulation fans with the same size, carried out according to different standards, is to refer to the trust instead of airflow. Although the thrust value is normalized according to the environmental test parameters, its value generally differs for less than a few decimals.
Following a transparency philosophy with its customers, Pericoli Group decided to show in its brochure both the test methods AMCA230-99 and AMCA230-12 in order to explain how the performance data may change using a method rather than another one.