Worth knowing from the area of cleanroom qualification
The knowledge area cleanroom qualification answers questions about the cleanroom classes and the tests within the scope of a cleanroom qualification. You will also receive an overview of the new features of DIN EN ISO 14644-3:2020-08.
Here you will find answers to the following questions:
- Which cleanroom classes are there?
- Which tests/measurements are carried out during a cleanroom qualification?
- What innovations does DIN EN ISO 14644-3:2020-08 bring with it with regard to the performance of leak tests on HEPA filters?
- What influence do the changes to DIN EN ISO 14644-1 have on the qualification of cleanrooms?
Which cleanroom classes are there?
In DIN EN ISO 14644-1, the various cleanroom classes (ISO 1-9) are classified on the basis of the maximum permissible particle concentration (in particles per cubic metre of air). In the EU GMP guidelines, the cleanroom classes are assigned the letters A to D, with an additional distinction being made between dormante state and manufacturing.
Classification limits in Annex 1:
Which tests/measurements are carried out during a cleanroom qualification?
The following measurements are typically performed during a cleanroom qualification:
- Climate measurements
- Pressure measurements
- Flow measurements
- Particle measurements
- Microbiological monitoring
What innovations does DIN EN ISO 14644-3:2020-08 bring with it regarding the performance of leak tests on HEPA filters?
Performing the filter leak test has not become any easier. There is additional formalism (e.g., derivation of Dp) and continued heavy fare in leakage definition via Na. The conformity statement for filters H13/H14 has become more stringent by a factor of 5. This has an impact on the feasibility (more re-measurements) and especially on the aerosol load of the HEPA filters. The concentrations increase several times compared to the previous version. The acceptance criterion of an in-situ test was formulated more strictly than the local transmittance in EN 1822-1. Further aggravation comes from the unnecessary definition of Na/Np. By choosing such a small value for counting events, there will be many counting events.
What influence do the changes to DIN EN ISO 14644-1 have on the qualification of cleanrooms?
Despite some changes in DIN EN ISO 14644-1, the essence of the standard has remained the same. Basically, the new determination of the measuring points will lead to an increased effort in the qualification of clean rooms. The omission of the 5-µm particles leads to a regulatory grey area, but this can be closed by the M descriptor. Otherwise, the changes do not have a major impact on the operator of high-purity cleanrooms.