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Book Review

Reliability-Centered Maintenance
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Reliability-Centered Maintenance

By: Anthony M. Smith

Hardcover
Published by: McGraw Hill
Publication Date: September 1992
ISBN: 007059046X

Our Review

There are currently at least two books that have been published with this title, the other is John Moubray's book which is reviewed here. Comparisons can sometimes be odious, but this isn't going to stop me making them anyway! While Smith's book covers the same topic, the differences between his book and Moubray's are quite interesting.

Smith's book starts by discussing some of the opportunities and challenges relating to Preventive Maintenance, and the points that he raises will strike a chord with many. It serves as worthwhile motivation to learn more about how RCM can assist in addressing these points.

He then moves on to establishing a definition for Preventive Maintenance, and describing the elements that go to make up a successful Preventive Maintenance program. I have a minor problem with semantics here, as he defines Preventive Maintenance as "the performance of inspection and/or servicing tasks that have been preplanned (i.e. scheduled) for accomplishment at specific points in time to retain the functional capabilities of operating equipment or systems." Some have a narrower definition for Preventive Maintenance, that includes only fixed interval overhauls or repairs, but not inspections, but this isn't where my concern lies. My concern lies with the fact that he then describes "Run-to-Failure" as a category of Preventive Maintenance. it clearly isn't, given his previous definition of Preventive Maintenance.

One of the more useful parts of this section of the book, however, is his debunking of some of the myths of PM development, including such myths as "All failures can be prevented", "Our PM program is based on experience", and "The OEM knows best". In addition, his outline of the supporting technologies that are important in developing the ideal PM program is a useful contribution to the subject.

The book goes on to outline some basic reliability and probability theory, and to describe the Failure Modes and Effects Analysis process (FMEA), before presenting the successful track record of RCM in the Aviation and other industries, and debunking another myth - namely that all failures follow the "bath-tub" curve.

Then follows a fairly detailed description of the RCM process itself, starting with the initial system selection process, and system description, and finishing with the task selection process. Here the differences between Smith and Moubray are quite marked. Smith does a more comprehensive job than Moubray in describing the steps involved in selecting the appropriate systems for analysis using RCM - he even admits that analysing some systems using RCM cannot be justified (Smith's background is in turbines, in both aviation and power generation applications, and he suggests that, as a rule of thumb, a typical Thermal Power Station may only want to analyse 35-50% of the systems in the station). He does an excellent job of detailing all of the documentation and technical information that (ideally) would be required to complete an RCM analysis - and also discusses why much of this information may not actually be available, or if available, may not be accurate.

When it comes to PM task selection, Smith uses a different decision making model to Moubray (Moubray uses his decision model - RCM 2). Overall it would appear that Smith's model is somewhat more cumbersome, and is certainly more documentation-intensive. In addition, Smith, unlike Moubray, doesn't give much guidance as to how to decide whether specific tasks are "Applicable" and "Effective". He gives no guidelines regarding how to determine the most effective task frequency, although he implies (but doesn't explicitly state) that the frequency of Condition-Directed tasks is linked to the failure rate of the component - no discussion of the "PF Interval" here. (You may like to click here for documentation of a discussion on this subject that recently took place in the plantmaint Maintenance Discussion List).

The next section of the book deals with the steps involved in optimising the "ideal" maintenance schedules that are the output of the RCM process, and the issues involved in implementing those decisions. In this area, Smith's book is more comprehensive than Moubray's.

Finally, Smith runs through some examples of RCM Implementation - one rather simple example is based on the swimming pool at his home. The others outline the results of implementations at several Power Generation facilities in the US (both Thermal and Nuclear).

So, if you are looking to obtain a book on RCM, which should you buy? My preference, if you are going to only buy one book, is Moubray's - I believe it does a better job of describing the core RCM process, and includes several tips and guidelines in this area that are not included in Smith's book. However, Smith's book expands on areas that are only briefly covered in Moubray's book, in areas such as selecting the systems to be analysed using RCM, obtaining the technical information desired for RCM Analysis, and post-RCM task optimisation. As such, you may wish to consider buying this book as well.


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