By Tony Pavell, Plant Manager, Fresenius Kabi
Airflow visualization testing, conducted as part of a routine review program, can help assure that aseptic filling areas remain under a state of proper control.
In fact, ISO standards recommend frequent airflow measurements. ISO standard 14644-2 requires “specifications for testing and monitoring to prove continued compliance with ISO 14644-1,” i.e., periodic measurements of airflow (1). The recommended tests to prove continued compliance include particle concentration testing, air volume or velocity and air differential pressure. Other recommendations suggest a maximum time interval of 24 months (1–3). This time interval may be extended based on the installation of instrumentation for continuous monitoring or other environmental control schemes based on a risk-based approach and area-specific data.
One process for conducting periodic airflow visualization testing is the tracer injection method, commonly referred to as the “smoke study.” An aseptic facility used this method for a routine airflow visualization program to provide assurance of unidirectional airflow in a critical part of the filling area.