Reliability Assessment: A Guide to Aligning Expectations, Practices, and Performance. Daniel Daley

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СКАЧАТЬ it and any level of acceptance testing to ensure they receive what they expect.

      •They believe the device can be operated in any manner and the reliability will be the same.

      •They understand little of the relationship between maintenance and reliability.

      •They believe they can change a system in almost any manner and the change will have inconsequential effects on reliability.

      Or, at least, it seems.

      You may be saying to yourself, this author is exaggerating so he can make his case or sell more books. I wish I were. However, I can cite any number of examples of situations where experienced individuals have made choices that indicate they understand little about reliability.

      •A major transportation company purchases equipment with the most meager of specifications — these specifications do not address standards for fasteners, materials, and components.

      •A major durable good manufacturer purchases key components from third world countries without specifications for metallurgical content, heat treating, or quality control.

      •A senior executive of a major oil company views regular inspection and equipment integrity programs as being voluntary and cuts them from annual budgets.

      •Another senior executive at a major chemical company cuts the external paint program at a Gulf Coast plant, then professes not to understand the relationship between painting and external corrosion when there is a leak of toxic materials.

      •Refinery and chemical plant executives chronically profess not to understand the relationship between emergency, short-cut repairs and continually degrading reliability of that equipment.

      •Project managers for new plants, plant modifications, and new durable products chronically are allowed to develop designs without addressing reliability, availability, or maintainability requirements.

      •Shop managers for a major transportation shop, when ound to be cancelling or deferring work, profess not to understand the relationship between predictive or preventative maintenance and the reduction of equipment failures.

      It is indeed unfortunate that people in key positions do the kinds of things described above, but these are all actual examples. I doubt it would sell, but it would be possible to assemble an entire volume of similar examples. If you are an individual who is active in the reliability business, you probably have a myriad of examples of your own. After dealing with such examples for so long, you begin to become cynical and view these paradigms in one of two ways:

      1.The individuals know better, but it is inconvenient for them to admit it. Were they to admit understanding what is proper, they would have to do the right thing. Feigning misunderstanding relieves them of doing the right thing.

      2.It is possible for dumb people to rise to positions of responsibility and authority. Maybe a kinder way to say this is that people in positions of authority are intelligent enough to know how to deal with everything else, but reliability is too complex for them.

      I personally have a difficult time accepting the second explanation. I believe it is the responsibility of reliability professionals to do everything in their power to inform individuals in responsible positions about reliability and how it works so they can no longer hide behind naivety. There should be no reason for naivety.

      In addition to performing the actions needed to address reliability needs, reliability professionals need to find the ways to articulate issues so decision makers understand the impact of their choices. Clearly, there are times that decision makers need to make difficult choices in the face of overwhelming current business needs. On the other hand, they should not make such choices in a vacuum.

      They need to understand both the immediate risks that those choices introduce and the long-term lifecycle costs they will cause.

      Each and every step in the lifecycle of a system has an activity that can result in enhanced reliability or, conversely, an inaction that can result in reduced reliability. I find that there are a great many analogies between the lifecycle of an electrical or mechanical system and the life of a human being. In the same way that poor life style choices can impact the life of a person, poor choices can reduce reliability and shorten the life of a physical system.

      If individuals choose to smoke for a portion of their lives, it is possible to stop smoking and minimize the negative impact. But it is impossible to completely reverse the effects of the poor choice. Similarly, if a choice is made to ignore on-going maintenance (say regular oil changes), it is possible to again begin changing oil. But that will not reverse the wear or other deterioration from the period of inadequate maintenance.

      If expectant mothers choose to smoke and drink and use drugs during the period they are pregnant, it is possible that their unborn children will be affected. The problems inherent at birth will stay with their children their entire lives. Similarly, if a system is designed without adequate attention to reliability, the inherent reliability of the system will suffer. It is possible that configuration will be inadequate or robustness of components will not meet expectations for the entire life of the system.

      Extending the comparison between the human condition and physical systems, we might compare the issue of naivety or naïve expectations.

      If you are an old movie buff and enjoy old detective movies, you seldom see Phillip Marlowe without a cigarette hanging from his lips or Sherlock Holmes without his pipe smoking. In fact, if you go back more than forty years, there is lots of evidence that there was little or no stigma associated with smoking. There were no studies linking smoking to cancer, heart disease, or problems with unborn children. In the last twenty-five years, there has been a tremendous amount of information available for consumers telling them about the ill effects of smoking. A person would have had to live under a rock to avoid being exposed to information about the negative consequences of smoking.

      Because of that, if a person is a heavy smoker and gets cancer or develops heart problems, you can say, “What did you expect? You have been bombarded with information telling you what to expect.” I recall seeing the warning label on a package of local cigarettes during a visit to Ireland. Being very simple and direct, it stated, “Smokers die younger.” That is what they should expect. Anything better is luck.

      Unfortunately, physical systems do not have warning labels saying, “Inadequate maintenance practices lead to early failures.” Maybe they should.

      The inherent reliability of a system is determined during design, procurement, and construction. Many design processes are focused entirely on the functionality and integrity of a system. Meanwhile, the design processes ignore reliability, availability, and maintainability — the three characteristics people typically roll into the commonly accepted concept of reliability.

      For pumping and piping systems, the designers will determine the size of the pipe and the head and capacity of the pump to achieve the desired functionality. They will see that the appropriate pipe schedule or thickness is selected to ensure system integrity. They will even determine that the metallurgy is compatible with the properties of the liquid being handled to avoid corrosion.

      On the other hand, design processes frequently do not analyze the MTBF (Mean Time Between Failures) of pumps in similar services. Therefore, designers often have difficulty determining if a spare pump should be installed or if a more robust pump should be selected — for reasons of reliability. Designers seldom analyze the required maintenance program and inspection СКАЧАТЬ