|Plant Maintenance Resource Center
M-News Edition 7
Edition 7, April 2000
Welcome to the seventh edition of M-News, a free newsletter on topics of interest to Maintenance professionals, brought to you by the Plant Maintenance Resource Center.
We aim to bring you the latest news and views on what is happening in the world of Maintenance. If you wish to receive notification of future copies of this newsletter by email, please register here. If you have any feedback on the newsletter, or have something to contribute, please send me an e-mail.
In this edition...
This month's feature article is kindly provided by R.T.Co. RFT is an electromagnetic method used to examine tubes such as those commonly found in boilers and heat exchangers. Use of RFT has been expanding during the last decade, helping to improve efficiency in heavy industries such as power, petrochemical, and oil and gas. In this competitive climate, companies seeking RFT services face an increasingly difficult task finding and evaluating vendors. There is a potential for confusion due to the lack of codes of practice. A new ASTM standard practice for RFT is due out soon. This article outlines some of the key features of this standard, and who to contact for further information.
The full article can be read at
The 2000 Maintenance Salary survey has been concluded, and the data analysed. You can read a full analysis at www.plant-maintenance.com/articles/salarysurvey00.shtml
The current Plant Maintenance Resource Center survey is on the subject of Maintenance and the Internet. Completing the survey will tell us what YOU use the internet for, and allow us to tailor our web site to best meet your needs. The survey closes on May 15, 2000, so if you haven't completed the survey yet, please do so. Survey responses are entirely confidential, and the results will be published on-line. Please tell all your friends and colleagues - the more responses we get, the higher the quality of the results. You can register your vote, or view the results to date at http://www.plant-maintenance.com/survey.shtml
The Plant Maintenance Resource Center website now has links to over 700 maintenance-related articles published on the web. While the articles are categorised by topic, with such a large collection, finding that definitive article on the finer points of precision maintenance in sewerage plants has still been difficult - until now. We are proud to introduce a new feature to our website - an on-line search facility that allows you to search the body text of most articles in the collection for the exact terms you are looking for. (Unfortunately you cannot search .pdf files, or those articles where the article owner has prevented the article from being indexed) You can access this new facility, as well as the lists of articles at http://www.plant-maintenance.com/maintenance_articles.shtml.
If you know of any web-published articles that aren't listed here, but should be, please let me know, and I'll make sure they are added.
In addition, the site search facility has been improved to make it significantly faster. You can access this here.
This is the second book that we have reviewed in the field of Reliability Centered Maintenance. The first book that we reviewed was John Moubray's book with the same title. This review can be read in Issue 2. 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.
Both Moubray's and Smith's books may be purchased from amazon.com through the Plant Maintenance Resource Center. For more details, or to order Smith's book, visit http://www.plant-maintenance.com/books/007059046X.shtml. For more details, or to order Moubray's book, visit http://www.plant-maintenance.com/books/0831130784.shtml.
In some foreign country a priest, a lawyer and an engineer are about to be guillotined. The priest puts his head on the block, they pull the rope and nothing happens. He declares that he's been saved by divine intervention and he's let go. The lawyer is put on the block, and again the rope doesn't release the blade, he claims he can't be executed twice for the same crime he is set free too. Then they grab the engineer and shove his head into the guillotine. He looks up at the release mechanism and says, "Wait a minute, I see a kink in the chain ..."
I hope you have enjoyed this newsletter. All feedback, comments and contributions to future editions are very welcome (as are enquiries about sponsorship of this newsletter).
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