Mechanical Technology February 2015

⎪ Proactive maintenance, lubrication and contamination management ⎪

In this new regular maintenance column, Mario Kuisis of Martec (left), the reliability enhancement specialist, introduces the essential approaches to maintenance and points out that each of them has its place in extending life and maximising productivity. The challenge for the responsible maintenance manager, he suggests, is to decide which strategy to adopt for a particular asset in order to balance the benefits of asset reliability with the cost of asset maintenance. Proactive maintenance – panacea

Mario on maintenance

M aintenance is perhaps not the most glamorous field of engineering, but it is a fundamentally important one. Depending on where you live and work, the result of maintenance – or the lack of it – is seen and felt by every one of us. So it matters. The subject of maintenance is a com- plex one. In fact far more complex than anyone not directly involved will give credit for. Recognition of the complexity and indeed, importance of maintenance in asset management are found in the PAS 55 standard and more recently in the publication of ISO 55000. This holds true for profit oriented businesses and public service organisations alike. It is also interwoven with related matters including plant efficiency, overall-equip- ment-effectiveness, cost-of-ownership, lifecycle-cost, plant-life-extension, etc. Of one thing there can be no doubt, getting it wrong can make the difference between a profitable business or admired public service and a failing organisation. A small indication of the complexity can be seen in the wide variety of terms commonly encountered for describing various maintenance strategies: reactive, preventative, condition-based, run-to- failure, predictive, reliability-centred, corrective, proactive, evidence-based, and so on. And underestimating mainte- nance can be very costly. Simply put, it is relevant to everyone who owns or is re- sponsible for a physical asset of any kind. Are these terms simply marketing hype, or are they linked to meaningful and substantive variations in mainte- nance strategy? Are they consequential? If they are meaningful, what do they mean? Many textbooks have been written on these subjects over a long period of time by very bright, knowledgeable and experienced people. We will certainly not fool ourselves into thinking that we can properly do justice to them here. However, there is merit in gaining a

basic understanding so as to see how different maintenance strategies and techniques can make a difference. With ageing infrastructure all around, along with economic realities that seldom permit wholescale asset replacement, it is becoming more and more important to get maintenance right. There was a time when an asset was created or acquired in order to deliver a function and, for all practical purposes, its only role was to ensure continu- ity in providing that function. Now, it is usually equally, or sometimes even more important, to consider safety and the environment, that is, not only are the maintenance processes important, but also their impact. This, along with the multi-disciplinary nature of today’s plant and equipment, are the main reasons why maintenance has become so complex. Since most of the terms used to describe maintenance strategies mean different things to different people, we should begin by defining what we mean. Here, we take the bigger picture view. When reduced to the basics and using common language meanings, there are

at least five possible approaches to main- tenance. We will consider them below in the order of their general evolution in industry: Passive maintenance means do noth- ing intentionally. Only think about what to do when an asset fails. As- sess the situation when it happens, then act according to the prevailing circumstances. Risk is completely unmanaged. Reactive maintenance means plan- ning for failure. Not to cause failure, but pre-planning for the eventuality, i.e. what will be done when it oc- curs? No particular steps are taken to prevent failure. The time and con- sequential damages associated with the failure are unknown. While the consequences of a failure may be mitigated to some extent, risk remains substantially unmanaged. Preventative maintenance ostensibly seeks to prevent failure, but is a mis- nomer. Maintenance is routinely per- formed on a time or operations basis with the aim of preventing failures, however failure remains inevitable. Done well, mean time before failure

Martec specialises in reliability enhancement using modern technologies such as the SDT ultrasound detectors for preventative maintenance.

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Mechanical Technology — February 2015