cleanroom classifications

About Cleanroom Classifications

Cleanrooms are classified according to the number and size of particles permitted per volume of air (Table 1. ISO 14644-1 Cleanroom Standards). Cleanrooms typically come with a cleanliness level quantified by the number of particles per cubic meter at a predetermined molecule measure. The ambient outdoor air in a typical urban area contains 35,000,000 particles for each cubic meter in the size range 0.5 μm and bigger — equivalent to an ISO 9 certified cleanroom. By comparison, an ISO 1 certified cleanroom permits no particles in the 0.5 μm size range, and just 12 particles of 0.3 μm and/or smaller for each cubic meter. As an example, semiconductor production facilities are often ISO 7 or ISO 5, while ISO 1 facilities are extremely rare.  Cleanrooms may also be characterized by attributes such as chemical concentration along with ISO classification.