SubscribeUnderstanding the Proposed Changes and Particle Monitoring from FMS.
There is a revised classification table which allows a particle limit at ≥5.0µm of 20/m³ for both Grade A and B at rest and Grade A in operation to be considered.
Does this mean a limit of 20/m³ ≥5.0µm will be universally used? False counts on modern particle counters at 5 µm are normally real counts; they are not valid in terms of the process because they are caused by contaminated sample tubing/ particle counter sensor assemblies.
5µm particles fall out of the airflow in the sample tube and become reintroduced at a later time. If the new cleanroom classification table is adopted, the particle limits that companies use will depend on how the Annex is interpreted by the inspection authorities.
Companies may be able to demonstrate using historical particle count data to help them assess which limit should be adopted. One possible rationale could be: Regular 5µm counts, during the filling run for example, would suggest process related problems. Occasional 5µm counts at random intervals may be related to false counts due to an unknown source, therefore a 20/m³ ≥5.0µm limit could be considered.
The draft Annex says "...consecutive or regular counting of low levels is an indicator of a possible contamination event and should be investigated". Emphasis on a monitoring system as a diagnostic tool (early indication of a failure) is mentioned.
The proposed Annex 1 corrections do make a clear point of mentioning that it is not necessary for an automated particle monitoring system to take the same sample volumes as that taken for formal classification of cleanrooms.
Proposed EU GMP ANNEX 1 Classification Table. | ||||
| At Rest | In Operation | ||
Grade | 0.5mM | 5mM | 0.5mM | 5mM |
A | 3,500 | 1* | 3,500 | 1* |
B | 3,500 | 1* | 350,000 | 2,000 |
C | 350,000 | 2,000 | 3,500,000 | 20,000 |
D | 3,500,000 | 20,000 | Not defined | Not defined |
*The maximum permitted number of particles at ≥5.0µm is established at 1/m³ but for reasons related to false counts associated with electronic noise, stray light, etc. a limit of 20/m³ could be considered.