This part of ISO 14644 defines the purity classification of clean rooms and clean zones and insulated cabinets and rooms according to ISO 14644‑7 on the basis of airborne particulate matter.
For the particle populations, only concentrations between 0.1 µm k 5 µm in the cumulative distribution are taken into account.
The determination of the particulate concentration in the air at the designated sampling points is based on the light scattering method (LSAPC) used for particle counting when the particle size is equal to or greater than the specified values.
This part of ISO 14644 is not applicable to classification according to particle size populations outside the defined range of 0,1 µm… 5 µm. Concentrations of ultrafine particles (particle size less than 0.1 µm) are addressed in their own standard, where classification is based on nanoparticles. The term M can be used to calculate macroparticle populations (particle size greater than 5 µm) (see Appendix C).
This part of ISO 14644 cannot be used to characterize without the physical, chemical, radiological or living nature of the particles.