scope:

This Standard describes a calibration and verification method for a light scattering airborne particle counter (hereafter referred to as "particle counter"), which sucks in air and measures the size and number or particle number concentration of particles suspended in the air. The particle counter specified in this Standard performs single particle measurements, and the typical size range of particles measured by it in the method specified in this Standard is between 0.1 μm and 10 μm in particle size.

NOTE 1 Instruments that conform to this Standard are used for the classification of air cleanliness in cleanrooms and associated controlled environments in accordance with JIS B 9920, as well as the measurement of number and size distribution of particles in various environments.

NOTE 2 The particle size measured by the particle counter is not the actual particle size-it is the light scattering equivalent diameter of the calibration particles suspended in air.

The particle size is a diameter of particle and is also called the particle diameter.

NOTE 3 The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

ISO 21501-4: 2007 Determination of particle size distribution-Single particle light interaction methods-Part 4: Light scattering airborne particle counter for clean spaces (MOD)

The symbols which denote the degree of correspondence in the contents in the corresponding International Standard and JIS are IDT (identical), MOD (modified) and NEQ (not equivalent) according to ISO/lEC Guide 21-1.