Sterile block classification qualified

The distinction between at-rest and in-operation classification is the one that matters. An empty room with the air running will meet almost any particle limit; the same room with operators working, equipment moving and an aseptic process under way is the condition the product actually experiences. Qualification therefore measures both, and the in-operation state governs.

“An empty cleanroom passes almost anything. The number that counts is the one taken while people are working in it.”

Testing covers particle counts against ISO 14644-1 with the sampling locations and volumes the standard specifies, filter integrity at installation, pressure differentials across the cascade, recovery after challenge and airflow visualisation at the critical zone. Microbiological qualification follows, establishing baseline viable counts for the areas.

Classification limits under EU GMP Annex 1 Table 1 govern this qualification exercise; the separate limits used for routine monitoring are set out in Table 5 and are not interchangeable with them.