Cleanroom suitability
Cleanroom suitability describes the suitability of a system, equipment, material etc. for use in rooms, the air purity and other parameters of which are assessed on the basis of technical rules according to DIN EN ISO 14644-1 (see clean room ).
The cleanroom suitability is a sub-area of the cleanliness suitability and essentially describes the particle emission behavior of a system or an operating medium (test item).
The aim of the cleanroom suitability tests is to determine the suitability of systems and equipment for use in cleanrooms. The investigation must be carried out using measurement technology, since the particle emission behavior cannot be sufficiently determined by visual inspection or the like. Obviously relevant defects in systems and operating resources, such as rust , porous or completely unsuitable materials ( wood, etc.), do not require a metrological examination, as these are to be regarded as unsuitable.
The metrological determination of the cleanroom suitability of a system or equipment takes place in a clean room in order to be able to clearly assign the particle emission of a test object to it. The test clean room must be at least one clean room class better than the intended suitability of the test item, since otherwise the measurable particles cannot be assigned to the test item. The exception here is the proof of suitability for class 1 according to DIN EN ISO 14644-1: This can be done in class 1, as no higher-quality clean room class is defined. The design of the test clean room must be low in turbulence (often referred to as “laminar” in this context) so that both high air cleanliness classes can be detected and the particle sources can be spatially assigned. So-called optical particle counters are used as measuring devices, so that particulate contaminations can be clearly determined in terms of their geometric size, number, distribution and temporal progression as well as spatially.
Execution:
- Infiltration of the test item into the test clean room
- Cleaning of the test item (avoidance of carried over contamination)
- Construction of the system in the clean room
- Definition of the test parameters
- Run-in phase ( warm-up ) over 24 hours (avoidance of initial symptoms)
- Coarse and fine localization of the particle sources
- Classification measurements
- Statistical evaluation of the results
- Classification of the results for suitability in discrete air purity classes (DIN EN ISO 14644-1)
Depending on the size and complexity of the test item, there is a number of representative measuring points for the classification measurement. The worst measurement point is the measure of the suitability of the entire test item. This " worst case " analysis leads to the minimization of contamination risks in the production itself.
The cleanroom suitability of materials describes their particle emission behavior. However, the particle emission of materials can only be determined under load, which is why model tests of material pairings have proven to be useful, which lead to reproducible and comparable results. The determination of the particle emission behavior must be carried out under the same conditions as for systems and equipment; optical particle counters are also used as measurement technology.
Clean room suitability tests in clean room ISO class 1 (Fraunhofer IPA)
Measuring probe
Heavy duty clean room
See also
Web links
- Database of cleanroom-compatible equipment
- Database of materials suitable for clean rooms
- Definition of clean room classes