Clean Room Particle Technology

for the applications: acceptance measurement, leakage test, protection degree determination, etc.

The most important requirement for reliable particletechnological function tests, acceptance measurements, leakage test, protection degree determination, etc. is, that the used particletechnological components such as optical clean room counters, aerosol generators, dilution systems and aerosol distributors are clearly characterized and function stably over the entire measurement time.

The relevant device parameters (see Tab. 1) must be known and verifiable. Table 1 indicates typical values of the necessary device parameters of the aerosoltechnological components.

AGF/UGF : Aerosol generators for clean room applications

VKL / DC 10000: Dilution systems for clean room applications

RAS 3000 + ACA 1000 ensure a reliable and reproducible determination of the degree of protection according to guideline SWKI 99-3 and DIN 1946-4

Tab. 1: Typical device parameters

Note: 1 m³ = 10⁶cm³ = 35.3 ft³ , V_F = dilution factor

For the applications mentioned, the following standards have to be considered:

EN 779 / ASHRAE 52.2: Ambient air filters
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
ISO 14644-3: Cleanrooms and associated controlled environments
VDI 3491: Generation of test aerosols
VDI 3491 p. 15: Dilution of test aerosols
ISO 21501-1: Light-scattering aerosol spectrometers (OAS)
ISO 21501-4: Light-scattering airborne particle counter for clean spacer (OPC)
VDI 3867: Particle measurement in the atmosphere and characterization of test aerosols

Unfortunately, new standards do not always guarantee that the measurement results being obtained with them are more safe and more reliable. So, for example, the number concentration measured with two OPCs being identical in construction may differ about 50%, as the tolerance in the ISO 21501-4 is indicated with ± 5% for the volume flow and for the lower detection limit with ± 20%.

The aerosol generators described in the following are characterized by a dosing constancy of
± 4% and a ± 2% constancy of the dilution factor over the measuring time of 1 hour.

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Clean Room Particle Technology

for the applications: acceptance measurement, leakage test, protection degree determination, etc.