All New Editions of Five IEST Cleanroom Filtration Recommended Practices

Be Sure To Use the Latest HEPA and ULPA Filter Testing Practices

ARLINGTON HEIGHTS, IL (April 18, 2016) – IEST, the world leader in cleanroom standards development, announces the release of its updated filter testing Recommended Practices (RPs) series. These new editions reflect current technologies and approaches for evaluating filters and devices for controlled environments and are available now from These RPs contain the definitive test methods for complying with the latest ISO 14644 standards and may be used as a basis for agreement in the specification and procurement of HEPA and ULPA filters.

Among the highlights of the new editions: (1) IEST-RP-CC021.4: Testing HEPA and ULPA Filter Media now includes photometric methodologies in addition to particle count procedures for testing physical and filtration properties of HEPA and ULPA filtration media, and (2) For ease of use, IEST-RP-CC034.4: HEPA and ULPA Filter Leak Tests has separated the procedures for production and in-situ testing into individual sections. The RP provides methods for leak-testing filters in the factory, at the job site, and after installation in cleanrooms and clean-air devices.

Also newly revised are: (1) IEST-RP-CC001.6: HEPA and ULPA Filters, which describes 11 levels of filter performance and five grades of construction for filters suitable for use in clean air devices and cleanrooms that fall within the scope of ISO 14644 and in systems requiring filter efficiency of 99.97% or higher for submicrometer (µm) particles, (2) IEST-RP-CC007.3: Testing ULPA Filters, which provides guidelines and test criteria for determining the efficiency of ULPA and super ULPA filters in the factory using particle counters, and (3) IEST-RP-CC002.4: Unidirectional-Flow, Clean-Air Devices, which outlines procedures for evaluating performance for classification of air cleanliness in accordance with ISO 14644-1.

These five RPs are available individually or at a savings by purchasing the Filtration Handbook. All of the filtration RPs are also included in IEST’s Contamination Control Handbook, a comprehensive volume containing 32 documents on a range of topics.

IEST Recommended Practices for cleanrooms and controlled environments are available through IEST at

Contact IEST Technical Program Manager Jennifer Sklena ( if you are interested in more information on participating in the development of IEST Recommended Practices.


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