ISO 14644-1:1999, Cleanrooms and associated controlled environments -- Part 1: Classification of air cleanliness

This part of ISO 14644 covers the classification of air cleanliness in cleanrooms and associated controlled environments exclusively in terms of concentration of airborne particles. Onlyparticlepopulationshavingcumulativedistributionsbased on threshold (lower limit) sizes ranging from 0,1 ?m to 5 ?m are considered for classification purposes.This part of ISO 14644 does not provide for classification of particle populations that are outside of the specified particle size range, 0,1 ?m to 5 ?m. Concentrations of ultrafine particles (particles smaller than 0,1 ?m) and macroparticles (particles larger than 5 ?m) may be used to quantify these populations in terms of U descriptors and M descriptors, respectively.This part of ISO 14644 cannot be used to characterize the physical, chemical, radiological, or viable nature of airborne particles.