ISO 14644-1: Classification of air cleanliness
ISO 14644-1 is the most commonly used standard for cleanroom airborne particulate cleanliness. There are nine ISO classifications, based on the number of particles of different sizes allowed per cubic meter of air.ISO Class | Maximum # of particles per m3 | |||||
0.1 microns | 0.2 microns | 0.3 microns | 0.5 microns | 1 micron | 5 microns | |
ISO 1 | 10 | 2 | ||||
ISO 2 | 100 | 24 | 10 | 4 | ||
ISO 3 | 1,000 | 237 | 102 | 35 | 8 | |
ISO 4 | 10,000 | 2,370 | 1,020 | 352 | 83 | |
ISO 5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | 29 |
ISO 6 | 1,000,000 | 237,000 | 102,000 | 35,200 | 8,320 | 293 |
ISO 7 | 352,000 | 83,200 | 2,930 | |||
ISO 8 | 3,520,000 | 832,000 | 29,300 | |||
ISO 9 | 35,200,000 | 8,320,000 | 293,000 |