Small Changes, System-Wide Impact

A closer look at elastomer changeout times provides one example of using industry knowledge to improve operations and cost.
Apr 01, 2012
Volume 25, Issue 4

Simon Chalk
The butterfly effect is a much cited phenomena where a small change in a system can have a significant effect on the overall state of the system. In a similar way, relatively inexpensive elastomers can contribute disproportionately to the cost of running a biopharmaceutical manufacturing operation.

Elastomers and plastics play a vital role in the operation of a bioprocessing plant, forming gaskets, "o"-rings, and diaphragms deep within the structure of the processing equipment. Their function is to prevent leaks and to separate fluids that should never come into contact. These rubber-like materials are useful because they are flexible, elastic, and can ensure tight seals between hard metal surfaces.

Over time, and with the harsh temperature, chemical, and pressure cycles that they are subjected to, these materials can become brittle and deformed, and can fail. They need to be exchanged well before there is a risk of failure, the consequence of which could be a contaminated product or a dangerous breach of a system. Many biopharmaceutical plants have a large installed base of valves for example, maybe 5000 or more. Each one needs to be maintained correctly to avoid problems.

Although the cost of failure is high, the cost of exchange is also high. It is estimated that up to 50% of maintenance activity is consumed by soft parts changeout. Add this to the plant downtime and there is a clear target for cost-saving scrutiny. So, what scope is there for improvement? Can current practice be challenged?

The currently accepted and common approach for elastomer changeout is temporal based (i.e., there is a fixed frequency—perhaps annually or biannually—for scheduled maintenance to replace the component).

Although this approach is acceptable, it does not take into account the conditions that the elastomer has been subjected to. In cases where the component has been lightly used, it may be exchanged even though continued use would be perfectly acceptable. At the opposite end of the spectrum, severe use could risk failure of the elastomer before its fixed time period had been reached.

Several engineering leaders in biopharmaceutical operations are questioning this methodology. They are being driven by the unrelenting quest for operational excellence and more effective ways of working. As well as cost savings, there is the realization that their talented engineers could be better deployed working on high value-adding technical projects rather than routine maintenance.

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