Pharmaceutical Filtration

Integrity Testing of Sterilising–Grade Filters

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A two-valve solution offers even greater security and reliability. One external valve is installed as a vent valve while a second valve is integrated between the test line and the filter cartridge housing and functions like an isolating valve, which opens only during pressurisation and is closed during both the test and the vent phases.

As the test line is closed off by the isolating valve during the test phase, an external pressure sensor is required in this equipment configuration in order to detect a pressure drop. In either case using automatically takes care of controlling the valves so that the operator does not have to intervene any further.


What Can You Do About Any Contamination of the Integrity Tester?

When integrity test units are operated over the years, even external valves cannot completely prevent particles or similar contaminants from becoming deposited inside the tester. Advanced integrity testers feature specific cleaning functions to enable such contaminants to be completely removed from their interior surfaces or their internal pneumatic components. In this case, the use of compressed air for reliable removal of particles is certainly limited.

Adhesive Contaminants Withstand Cleaning With Pressurised Air

Any contaminants that adhere to the interior surfaces cannot be reliably eliminated alone by pumping in compressed air. However, it is possible to clean the internal lines of the integrity tester using liquids too. Depending on the particular integrity tester model, even aggressive cleaning agents (e.g., up to 1M NaOH) can be used that are then removed by flushing them out with pure water.

After subsequent drying using compressed air, the integrity tester is then ready to operate immediately for regular testing. This option allowing intensive cleaning makes integrity testing more reliable and eliminates the need for expensive servicing. Such preventive cleaning markedly increases the hygiene and microbiological safety during integrity testing.