Maximum concentration limits (particles/m3of air) for particles equal to and
larger than the considered sizes shown below (concentration limits are
calculated in accordance with equation (1).
0.1mm
0.2mm
0.3mm
0.5mm
1mm
5mm
ISO Class 1
10
2
ISO Class 2
100
24
10
4
ISO Class 3
1 000
237
102
35
8
ISO Class 4
10 000
2 370
1 020
352
83
ISO Class 5
100 000
23 700
10 200
3 520
832
29
ISO Class 6
1 000 000
237 000
102 000
35 200
8 320
293
ISO Class 7
352 000
83 200
2 930
ISO Class 8
3 520 000
832 000
29 300
ISO Class 9
35 200 000
8 320 000
293 000
NOTE Uncertainties related to the measurement process requires that
concentration data with no more then three significant figures be used in
determining the classification level.