BENCH SCAN FILTER LEAK TESTS FOR CLEAN ROOMS

The purpose of this test is to determine the integrity of each filter shipment by spot testing random statistical samples prior to filter installation.
INSTRUMENTATION AND EQUIPMENT

  • An aerosol photometer, aerosol generator and scanning probe.

or

  • A particle counter, microsphere generator and scanning probe.
  • A test bench with a fan capable of delivering the specified airflow volume of the installed filters. The fan shall be capable of supplying the air in a uniform manner upstream of the face of filters. The bench filter seal must prevent excessive aerosol from escaping into the environment

TEST PROCEDURE

  • Test every filter, or if owner approved, develop a statistical sample based on the following:
  1. Test all filters which show signs of damage
  2. Test every fifth filter and upon failure, test additional untested filters.
  • Provide flow test bench, aerosol photometer and oil generator (either Laskin nozzle or thermal) or
  • optical laser particle counter, and microsphere generator and a particle controlled environment.
  • Introduce aerosol oil challenge or microsphere challenge upstream of the filter. A minimum challenge shall be 10μg/l of oil or at least 210,000,000 particles per cubic meter (6,000,000 particles per cubic foot).
  • Measure the upstream challenge of each filter.
  • Scan the entire downstream filter face area in overlapping strokes, moving at the calculated scan rate spaced a distance of 25 mm (1 inch) from the filter face.
  • Repairs, leaks and retesting of filters shall be performed in accordance with the requirements.

FIND MORE AT…
Reference links
http://www.isu.edu.tw/upload/81201/45/news/postfile_23270.ppt
https://www.cleanroomtechnology.com/technical/article_page/Integrity_testing_of_HEPA_filters/51404

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