Cleanroom classifications

The ISO 14644-1:1999 – ‘Classification of Air Cleanliness’ is the European standard for cleanroom classification.

The table below shows the class limits for each particle size under the ISO Classification system.

ISO Classification NumberMaximum concentration limits (particles/m³ of air) for particles equal to and larger than the considered sizes shown below.

≥ 0.1µm≥ 0.2µm≥ 0.3µm≥ 0.5µm≥ 1.0µm≥ 5.0µm
ISO Class 1102
ISO Class 210024104
ISO Class 31,000237102358
ISO Class 410,0002,3701,02035283
ISO Class 5100,00023,70010,2003,52083229
ISO Class 61,000,000237,000102,00035,2008,320293
ISO Class 7352,00083,2002,930
ISO Class 83520000832,00029,300
ISO Class 935,200,0008,320,000293,000