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.
With the RAS 3000 C , up to six OPCs can be calibrated simultaneously. The protection degree can be determined as well.
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.