EU Air Classifications
| ISO Class Designation | EU Grade | Maximum Permitted Number of Particles per Cubic Meter Equal to or Greater Than the Tabulated Size | Recommended Limits for Microbial Contamination during Operationa—Air Sample (cfu/m3) | |||
|---|---|---|---|---|---|---|
| At Rest | In Operation | |||||
| ≥0.5 μm particles/m3 | ≥5.0 μm particles/m3 | ≥0.5 μm particles/m3 | ≥5.0 μm particles/m3 | |||
| 4.8b | A | 3520 | 20 | 3520 | 20 | <1 |
| 5 at rest 7 in operation | B | 3520 | 29 | 352,000 | 2900 | 10 |
| 7 at rest 8 in operation | C | 352,000 | 2900 | 3,520,000 | 29,000 | 100 |
| 8 at rest | D | 3,520,000 | 29,000 | Not defined | Not defined | 200 |