Misconceptions of Maintenance and Reliability: A Biopharmaceutical Industry Survival Guide

The authors provide common misconceptions and key concepts behind reliability engineering.
Jun 01, 2013
Volume 26, Issue 6

Maintenance excellence and reliability have become prominent within the corporate agenda. This is particularly true of the biopharmaceutical industry where such concepts are becoming more widely adopted in attempts to reduce risk and reduce costs. Many techniques, however, are still in their infancy, and while leaders are pressing for wider adoption, organizations are often slow to adopt these techniques because many of the new concepts are counter-cultural.

This article focuses on common misconceptions that can be encountered by those spear-heading the change and introduces some of the key concepts behind reliability engineering. This article also summarizes a detailed white paper created by the authors (1).


Failure is an unfortunate fact of life. Systems have a natural tendency to break and wear out, and the components of any asset are subject to the effects of wear and tear. Eventually, components fail. It is a common misconception that simply because preventive maintenance is employed, the risk of failure can be eliminated. While preventive maintenance can reduce the risk of failure, so long as the failure mode exists, the risk of failure remains.

The reality of failure (2)
Reliability is about managing the probability of failure over time. Contrary to popular belief, only a small percentage of equipment ages or wears out at the end of its expected life (see Sidebar). In practice, most failures occur in early life—infant mortality—or completely randomly at any point in its life (2).

By understanding the failure mode, appropriate maintenance strategies can be established to help detect, prevent, or mitigate failure and improve the reliability of a component. Nevertheless, 100% reliability can never be guaranteed in reality so long as the failure mode still exists.


Historically, the biopharmaceutical industry has adopted mainly time-based maintenance but, in fact, other more effective strategies can often be used. Increasingly, the industry is adopting predictive and condition-based techniques to anticipate failure ahead of time. These techniques enable repairs to be planned and scheduled in a controlled manner, well before failure. Preventive maintenance can be divided into three categories:

  • Time-based or age-related. This type of preventive maintenance applies where the failure rate increases over time. This pattern applies only to a small percentage of failures in the real world. Clearly, it does not make sense for this to be a primary approach to preventive maintenance.
  • Run-based or usage-related. This type of preventive maintenance is a development of time-based approach and applies where the failure rate increases with usage, for example a valve diaphragm deteriorating through thermal cycles.
  • Predictive or conditioned-based. This type of preventive maintenance applies to situations in which failure rates appear randomly, where neither time nor usage provides good early failure indicators. This is the most common pattern of failure and, to be truly effective, preventive maintenance programs should reflect this fact.

In the biopharmaceutical industry, vibration monitoring of bearings, motors, and gearboxes in plant and equipment is increasingly common practice, where an increase in detected vibration can be used to indicate failure. Such systems provide a step increase in reliability compared to invasive time-based replacement. Similarly, thermography can be used to monitor the condition of electrical controls to signal early onset of failure. On the manufacturing floor, visual inspections carried out by operators provide early signals as part of a structured total productive maintenance system.

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