ISO 21501-4: Light Scattering Airborne Particle Counter for Clean Spaces
ISO 21501-4 covers instrument calibration procedures to ensure air particle counter sampling measurement inaccuracies are reduced. A Counting Efficiency Test is also included as a final confirmation of air particle counting performance.
All GMP cleanroom operators/users must ensure the air particle counters used to classify and monitor their cleanrooms are compliant with ISO 21501-4 requirements.
|ISO 21501-4 Parameters||Target Limit|
|Counting efficiency at first channel||50% ± 20%|
|Counting efficiency at particle size 1.5-2.0 times first channel||100% ± 10%|
|Instrument resolution (at manufacturer specified size)||≤ 15%|
|Zero count test||≤ 1 count in 5 mins|
|Max particle number concentration (specified by manufacturer)||≤ 10%|
|Sampling flow rate (volumetric)||± 5%|
|Sampling time||± 1%|
|Calibration interval||≤ 1 year|