Cleanroom Criteria
Cleanrooms are classified as Class 1, Class 10, ------ Class 100,000 according to FED STD 209E. A Class 1 cleanroom, for example, is defined by the number of allowable particles per cubic foot of air, in this case, no more than 35 particles of 0.1 µm diameter. A new ISO standard will likely replace the current US FED STD 209E. Table A & B outline the number of particles allowed of each size in a cleanroom. Table C gives a relative sense of the two standard's classes.
| Particle Size 1 |
| Class |
0.1 µm |
0.2 µm |
0.3 µm |
0.5 µm |
1 µm |
5 µm |
| 1 |
35 |
7 |
3 |
1 |
|
|
| 10 |
350 |
75 |
30 |
10 |
1 |
|
| 100 |
|
750 |
300 |
100 |
10 |
1 |
| 1,000 |
|
|
|
1,000 |
100 |
10 |
| 10,000 |
|
|
|
10,000 |
1,000 |
100 |
| 100,000 |
|
|
|
100,000 |
10,000 |
1,000 |
Notes: 1 Number of particles per cubic foot (ft 3 )
| Particle Size 1 |
| Class |
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 |
|
| 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 |
Notes: 1 Number of particles per cubic meter (m 3 )
| ISO 14644-1 |
FED STD 209E |
| ISO 3 |
1 |
| ISO 4 |
10 |
| ISO 5 |
100 |
| ISO 6 |
1,000 |
| ISO 7 |
10,000 |
| ISO 8 |
100,000 |
