+86 18186671616
Jason@cleanroomequips.com
When performing cleanliness testing on a Microbiological clean room, the following points should be understood:
Cleanliness level classification:
| Cleanliness level | Maximum allowable number of suspended particles/cubic meter | |||
| Static | Dynamic | |||
| ≥0.5um | ≥5.0um | ≥0.5μm | ≥5.0um | |
| Alevel | 3520 | 20 | 3520 | 20 |
| Blevel | 3520 | 29 | 352000 | 2900 |
| Clevel | 352000 | 2900 | 3520000 | 2900 |
| Dlevel | 3520000 | 29000 | ||
Note:
1. To confirm the level of a Class A clean area, the sampling volume at each sampling point shall not be less than 1m3. The level of airborne particles in a Class A clean area is ISO4.8, with 25.0um suspended particles as the limit standard. The levels of airborne particles in a Class B clean area (static) are iso7 and ISO8 respectively. For a Class D clean area (static), the level of airborne particles is 8. The test method can refer to ISO14644-1.
2. When confirming the level, a portable dust particle counter with a shorter sampling tube should be used to avoid the sedimentation of suspended particles greater than or equal to 5.0um in the long sampling tube of a remote sampling system. In a unidirectional flow system, an isokinetic sampling head should be used.
3. Dynamic testing can be performed during routine operation and culture medium simulation filling to prove that the dynamic cleanliness level has been achieved, but the culture medium simulation filling test requires dynamic testing under the "worst condition".
Dynamic standards for clean area microbial testing:
| Cleanliness level | Planktonic bacteria | Settling bacteria | Surface microorganisms | ||
| cfu/m3 | cfu/4hour | Contact plate (f55mm) cfu/plate | 5-finger gloves cfu/gloves | ||
| Alevel | 1 | 1 | 1 | 1 | |
| Blevel | 10 | 5 | 5 | 5 | |
| Clevel | 100 | 50 | 25 | _ | |
| Dlevel | 200 | 100 | 50 | _ | |
Note: All values in the table are average values; the exposure time of a single sedimentation dish can be less than 4 hours, and multiple sedimentation dishes can be used at the same location for continuous detection and cumulative counts.
