ISO 21501-4:2007

Determination of particle size distribution — Single particle light interaction methods — Part 4: Light scattering airborne particle counter for clean spaces

Scope

ISO 21501-4:2007 describes a calibration and verification method for a light scattering airborne particle counter (LSAPC), which is used to measure the size and particle number concentration of particles suspended in air. The light scattering method described in ISO 21501-4:2007 is based on single particle measurements. The typical size range of particles measured by this method is between 0,1 �m and 10 �m in particle size.
Instruments that conform to ISO 21501-4:2007 are used for the classification of air cleanliness in cleanrooms and associated controlled environments in accordance with ISO 14644-1, as well as the measurement of number and size distribution of particles in various environments.
The following are within the scope of ISO 21501-4:2007:
size calibration;verification of size setting;counting efficiency;size resolution;false count rate;maximum particle number concentration;sampling flow rate;sampling time;sampling volume;calibration interval;test report.