Measurement and evaluation of clean rooms.
We conduct our measurement using the equipment that follows:
Particulate matter measurement
A PC running LMS Express software controls SOLAIR 3100 particle counter via RS 232 bus, which controls the Mini-Manifold using RS 485 bus. The measured particles sizes depend on the number of particle channels of the apparatus, i.e. the LightHouse SOLAIR 3100+ can measure particle sizes 0.3, 0.5, 1.0, 3.0, 5.0 a 10.0 μm.
For temperature measurement, type T thermocouples (TT-T-24-SLE) by OMEGA are employed. Having been welded, the thermocouples are calibrated using OMEGA CL1000 calibrator at temperatures 30 and 100 °C, while field calibration makes use of OMEGA CLD-II calibrator. The precision achievable after calibration is 0.1 °C among individual thermocouples and the maximum measurement error of the absolute temperature is 0.5 °C within the range of 20 and 250 °C.
Pressure differences are measured with the use of Dwyer Magnesense pressure gauges. Their measurement ranges reach up to 25 Pa, 50 Pa, and 100 Pa. They provide analog output signal ranging between 0 and 10 V. The gauges are interconnected to an OMEGA made transducer/converter; the measured values are saved into files that can be merged with the particle counter data files as well as measured temperatures.
Indoor Flow System IFS-100 is a piece of equipment produced by Dantec Dynamics that makes use of three anemometers which cover air speeds ranging from 0.05 to 1 m/s and one which measuring range of is from 0.2 to 30 m/s (labelled T28 in the report). The system enables measurement of the air speed, air temperature and turbulence intensity. Its maximum measuring frequency of the measured air speed is 10 Hz (excluding turbulence intensity evaluation and raw data regime). The system consists of an analog-to-digital converter which transfers the measured data into the computer via the PCMCIA card.
The data acquisition makes use of QMG 55/56 system equipped with 24 bit converters of 30 measuring channels each.
The resulting reports comply with the ISO 14644 Standard and Federal Standard 209D Class Limits.
Tested set-up schematics
1) Testing clean box
2) Dilution unit 1 : 10, Topas Dilution DIL 554
3) Aerosol generator Topas ATM 226
4) Particles counter Solair 3100
5) Mini-Manifold switch
6) Vacuum pump
7) PC with the control and measuring software Solar LMS Express
8) Isokinetic probe measuring the air cleanness prior to clean box entry
9) Isokinetic probes sampling the clean box air
Measurement graphic outputs
Laboratory equipment - hardware: Set of apparatuses by LightHouse for measurement and generation of particles sizing from 0.3 μm
Laboratory equipment - software: Software for assessment of clean rooms according to ISO standards, measuring software LabVIEW, and MatLab
Services offered: clean room measurement, mathematical simulations
Keywords: clean rooms, aerosol, deposition
Ing. Josef ŠTĚTINA, Ph.D.
Tel/Fax: +420 541 143 269
Mobil: +420 603 731349