Cleanroom Applications

Clean Room Particle Technology

There are a range of particle technology based applications in the cleanroom:

  • Acceptance Measurements
  • Leakage Tests
  • Protection Degree determinations

Validation of the performance of cleanroom associated particle control technology requires that the components used in the evaluations, such as optical cleanroom particle counters, aerosol generators, dilution systems and aerosol distributors are clearly characterized and are stable in operation over the entire measurement time.

Palas GmbH aerosol generators offered for use in cleanroom technology assessments are characterised by a dosing constancy of ± 4%, with the diluters offering a ± 2% constancy of the dilution factor over a measuring time of 1 hour, so offering accuracy and consistency in the generated test aerosols.

The following products have been used successfully for the above mentioned applications for more than 20 years worldwide:

There are two main standards relating directly to particle technologies used for cleanrooms in Europe, (also referenced by USA regulatory agencies):

ISO 21501 Series - The purpose of ISO 21501-4:2007 is stated in the introduction:

“Monitoring particle contamination levels is required in various fields, e.g. in the electronic industry, in the pharmaceutical industry, in the manufacturing of precision machines and in medical operations. Particle counters are useful instruments for monitoring particle contamination in air. The purpose of this part of ISO 21501 is to provide a calibration procedure and verification method for particle counters, so as to minimize the inaccuracy in the measurement result by a counter, as well as the differences in the results measured by different instruments”.

It is worth noting that while these new standards, replacing ISO 13323:2000, make efforts to improve the technology and reliability of assessment, their application can not always guarantee that the measurement results being obtained with them are truly repeatable. For example, the number concentration measured with two identical OPCs can show a 50% difference and yet both values be valid according to the ISO 21501-4:2007 standard. This is because the allowable tolerance is ± 5% for the volume flow combined with ± 20% for the lower detection limit. Work on standards continues to drive product development, with technical review typically at 5 year intervals.

ISO 14644 Series - A standards series in 8 parts, with a 9th in draft, defining classifications for clean room environments and how to test and validate performance of components.

Other standards applying to cleanroom technology which may be of interest include:

  • EN 779 / ASHRAE 52.2
    • Ambient air filter
  • EN 1822
    • HEPA / ULPA filters
  • DIN 1946-4
    • Ambient air technology
  • SWKI 99-3
    • Heating and ambient air technological systems in hospitals
  • VDI 2083-3
    • Measurement technology in the clean room technology
  • VDI 3491
    • Generation of test aerosols
  • VDI 3491 p. 15
    • Dilution of test aerosols
  • VDI 3867
    • Particle measurement in the atmosphere and characterization of test aerosols

Please contact us for more detailed information.