Description
What is the need to check filters in clean rooms?
Checking the integrity of the installed filtration system is carried out during tests of clean rooms in medical institutions, in pharmaceutical production, and in testing biosafety cabinets. It is obligatory to control the integrity of the filters in the aseptic production of medical products.
Obviously, without an efficient filtration system, a clean room cannot fully perform its functions. Most often, the presence of leaks is associated with damage to the filter seal, but there are also damage to the material of the filters themselves, resulting from the transportation or installation of a filtration system.
A timely test can detect and localize a leak, and repair or replace a damaged filter.
How are leakage filters tested
In the presence of multiple mechanical damage HEPA-filter need to replace it is obvious. In all other cases, it is necessary to perform a scan in accordance with the procedure given in GOST R ISO 14644-3-2007 "Cleanrooms and associated controlled environments. Part 3. Test methods", clause B.6.3.
Since HEPA or ULPA class filters with very high filtration efficiency of aerosol particles are used in clean rooms, it is necessary to create a high concentration of aerosol in order to detect leaks in the duct in front of the filter.
The test is carried out in two stages.
At the first stage, using an aerosol generator, an aerosol is fed through special hatches or holes in the ducts, and its concentration is measured before the final filter, after which the filter surface is scanned to determine potential leaks. If the signal value is exceeded, the potential leak is recorded. At the second stage, stationary monitoring of the integrity of the filters is carried out in those places where potential leaks were recorded. In the event that leaks are also detected during stationary monitoring, it is concluded that the filter does not conform.
This technique allows not only to conclude that the HEPA filter complies with the established requirements, but also to localize the leak points and, in some cases, repair the filters.
Filter test results and test report
The result of checking the integrity of the installed filtering system is always a conclusion about its compliance or non-compliance with the requirements for HEPA filters of this class.
In order to certify clean rooms, we recommend that customers keep in stock a sufficient number of filters of the required classes and sizes, so that in case of detection of damaged filters, it was possible to promptly replace the filters and retest. Often, this approach saves time and money, since there is no need for an additional visit to the site for re-testing.
