NOTE 1 Various methods for defining its size may be used and are dependant upon the measurement technique.
NOTE 2 For the manual method the apparent maximum linear dimension of a particle in the plane of observation as observed with instruments such as optical, electron, or atomic force microscopes is the particle size.
NOTE 3 For the automatic method, the equivalent diameter of a particle detected by automatic instrumentation is the particle size.
NOTE 4 The equivalent diameter is the diameter of a reference sphere having known properties and producing the same response in the sensing instrument as the particle being measured.
NOTE 5 A fibre is considered a particle, see clause 3.2.6