Standard 52.2-2007, the most recent edition of this standard, incorporates Addendum a into the standard’s previous edition, Standard 52.2-1999. Addendum a changed the procedure for evaluating the results of the reference filter test in order to make the reference filter test more practical and to allow a wider selection of filters to fulfill the test requirements.

Standard 52.2 was developed so that both users and specifiers can compare products, predict a uniform level of known performance under operating conditions with reasonable certainty, and determine appropriate air-cleaner efficiencies for specific situations.

Historically, standards for testing air cleaners have been developed in response to the needs of the times. Protection of machinery and coils came first, then reduction of soiling. Now concerns about indoor air quality and respirable particles, protection of products during manufacturing, and protection of HVAC equipment have prompted development of this test standard based on particle size. 44pp.