ISO 14644-1 Cleanroom Standards
Class maximum particles/m3 FED STD 209E
equivalent
=0.1 µm >=0.2 µm >=0.3 µm >=0.5 µm >=1 µm >=5 µm
ISO 1 10 2
ISO 2 100 24 10 4
ISO 3 1,000 237 102 35 8 Class 1
ISO 4 10,000 2,370 1,020 352 83 Class 10
ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100
ISO 6 1,000,000 237,000 102,000 35,200 8,320 293 Class 1,000
ISO 7 352,000 83,200 2,930 Class 10,000
ISO 8 3,520,000 832,000 29,300 Class 100,000
ISO 9 35,200,000 8,320,000 293,000 Room Air
BS 5295 Cleanroom Standards
maximum particles/m3
Class >=0.5 µm >=1 µm >=5 µm >=10 µm >=25 µm
Class 1 3,000 0 0 0
Class 2 300,000 2,000 30
Class 3 1,000,000 20,000 4,000 300
Class 4 20,000 40,000 4,000