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:
- Test all filters which show signs of damage
- 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
