This Recommended Practice (RP), IEST-RP-CC034.5, covers definitions, equipment, and procedures for leak-testing high-efficiency particulate air (HEPA) filters and ultralow-penetration air (ULPA) filters in the factory as they are produced, at the job site before they are installed, and after they are installed in cleanrooms and in unidirectional-flow, clean-air devices. When used in conjunction with other RPs, including IEST-RP-CC001, IEST-RP-CC002, IEST-RP-CC006, IEST-RP-CC007, IEST-RP-CC021, and IEST-RP-CC028, this RP may be used to define the basis of an agreement between customer and supplier in the specification and procurement of HEPA and ULPA filters, and in the testing of unidirectional-flow, clean-air devices and cleanrooms.

This RP also includes procedures for measuring the uniformity of the aerosol challenge approaching the filter under test.

For your convenience, changes to this RP from the previous edition are listed:

New content: Best practices for sample tube length

Expanded content:

·         Total leakage test

·         Spatial uniformity acceptance

·         Circular vs rectangular probe heads (circular not allowed)

·         Considerations in sample port location

First printing, July 2022 (Supersedes previous versions, including IEST-RP-CC034.4, IEST-RP-CC034.3, IEST-RP-CC034.2, IEST-RP-CC034.1)

HEPA and ULPA Filter Leak Tests was prepared by Working Group 034 of the IEST Contamination Control Division (WG-CC034).