It is important to understand the differences between filters. There are various ways of measuring the performance of a filter: the ability to trap dust, efficiency and pressure drops are the values taken into account by the main standards to foresee the actual performance of the filters and compare them.
As a matter of fact, there are many variables involved in a comparative study, some are obvious and others aren’t. Most filters actually remain inside a ventilation system for months or for years. However, tests carried out to check a filter take minutes or hours at most.
During the operating life of a filter, environmental conditions such as humidity and temperature may vary endlessly, as the air flow and the particulate load that needs to be filtered vary. Nevertheless, comparative tests are carried out under controlled environmental conditions.
Therefore it is clear that one needs to fully understand how to interpret the results of a test before using these parameters alone to choose a product rather than another one.
Here are the main sector reference norms.