Explosion-Proof Fan Filter Units

The ISO 14644-3 Guidelines for Cleanrooms and Associated Controlled Environments details a list of required and optional tests performed during certification of a cleanroom. Included in the list of optional tests is the installed filter system leakage test, including criteria for aerosol challenge testing, HEPA filter leak scanning, and leak penetration testing. These tests, as evidenced below, may not be required for a given application and should be mutually selected and agreed upon by the customer and supplier prior to order placement.

Table 2 lists other tests appropriate for testing of an installation. These tests can be applied in each of the three designated occupancy states. These tests may not be all-inclusive, nor may all of the tests be required for any given certification project. Tests and test methods should be selected in a manner agreed between the customer and supplier. Selected tests can also be repeated on a regular basis as part of a routine facility monitoring program (see ISO 14644-2). Guidelines for the selection of tests and a checklist of tests are given in Annex A. Test methods are outlined in Annex B.

The test methods described in Annex B are in outline form only. Specific methods should be developed to meet the needs of the particular application.

Most cleanroom applications will necessitate the required tests, based on the ISO 14644-2 and 14644-3 guidelines: an airborne particle count test, an air flow test, and an air pressure difference test. Specific applications, such as class 10 or cleaner aseptic spaces, or industrial regulations, such as USP <797> guidelines for sterile drug compounding, stipulate additional, regularly optional tests, including, but not limited to, filter system leakage measurements.

For the majority of cleanroom applications, Terra offers a standard, roomside-replaceable HEPA-filtered fan unit, designed to meet published specifications and industry standards. For certain applications requiring filter system leakage tests, Terra offers a premium, roomside-replaceable HEPA-filtered fan unit tested and certified in accordance with the ISO 14644-2 and 14644-3 guidelines for leakage rates.

Each customer must specify either the standard filter fan unit or the leak-tested filter fan unit prior to order placement in order to ensure the appropriate units are delivered to meet the unique specifications of each application.