In 1968, a Standards Project Committee completed work on a test standard for air cleaning devices. The new standard, ASHRAE Standard 52-68 entitled Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter was first published in 1969. The test procedures described in this standard were based on principles employed for many years in determining comparative performance of air cleaning equipment. These basic principles and general procedures had been used for years by the National Bureau of Standards and the Air Filter Institute and were familiar and understood by the users, specifiers and manufacturers of air cleaning devices. The new standard attempted to eliminate confusion created by the multiplicity of test procedures in use at the time and generated a considerable amount of interest. A second reprinting with corrections was made in 1972.

A follow-up committee was formed in 1972 for the purpose of organizing a test program through which those laboratories who had built test stands, and had begun using 52-68 could correlate their results. The objective of the committee was to correct any errors or omissions in the standard to yield reproducible results in the various participating facilities. A final report of this committee was issued August 27, 1974, however, some problems developed in implementing the recommendations of the committee and some additional work was required to resolve these problem areas. Today, this basic test work is complete and the resulting revisions to the standard have been adopted by ASHRAE and are embodied in the current issue of the Standard 52-76. This paper details the tests of the standard.