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Last Updated March 2010 |
Availability and Costs
For many maintenance professionals there are two burning issues which are always at the forefront of their minds:
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Equipment availability: whenever your equipment is unavailable it is not running so it is not playing its part in earning revenue and, even worse, is probably causing increased costs until it is repaired and back into service. In some industries the loss of availability also means penalty charges. In short, plant availability can mean the difference between making a loss or a profit or even whether or not the business continues or closes. The pressure to keep equipment available often leads to short-
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Costs: not only are you having to keep the equipment permanently available, you have to do it on an ever-
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cut costs but this makes it even harder to achieve your availability targets and the situation goes from bad to worse!
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So what is the answer? How can you break into this vicious circle and regain control of your costs whilst maintaining availability?
Improve Reliability
Well, the answer is to improve the reliability of your equipment.
More reliable equipment breaks down less often, so you spend less time fixing it, so it spends more time doing what it was purchased for; in other words, it is more available.
Because it fails less often, you do fewer repairs so you use fewer spare parts, which in turn reduces costs.
Because you spend less time fixing fewer failures you pay for less labour. No more weekend overtime trying to keep that backlog of maintenance out of sight (and praying that you’ve done enough to keep the equipment safe).
How to Improve Reliability
So, if you accept that improving the reliability of your equipment will lead to better availability and reduced costs, your next question, naturally, is how to go about doing it.
The actions that you can take to improve reliability fall into two major groups:
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Making failures less likely to happen in the first place (e.g. By maintaining the equipment properly or fitting more reliable equipment)
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Making changes such that the overall system continues to function satisfactorily even when a failure occurs (e.g. By fitting standby equipment).
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The most common approach to improving reliability focuses on modifying the equipment in some way and is based on the underlying assumption that there must be something wrong with it or its original design. The in-built or inherent reliability of the equipment is established by its design whereas the operational reliability (which is what is seen and measured in practice) depends on how well the equipment is maintained. Simply improving the inherent reliability does not always ensure that the operational reliability improves (unless the plant is modified so that the overall system continues to function satisfactorily when a failure occurs - eg by fitting standby equipment).
Modifying the equipment in some way can be very expensive and often disruptive; in a lot of cases they can take a very long time to implement (especially if there is a large group of similar assets, such as a fleet of trains for example).
Whilst engineers often favour the approach of 'modifying the equipment', there are other approaches that can improve operational reliability so that it approaches the in-built or inherent reliability. The advantage of these techniques is that they avoid a modification-based time-consuming and expensive reliability improvement program and are simply aimed at sticking with the equipment as it is today and getting it to perform better (ie fail less often)
By far the best such technique is Reliability Centred Maintenance (RCM). RCM is a derivative of an approach that is used by the civil
aviation industry (very successfully!) to ensure that aircraft achieve their inherent reliability and safety. The key to improving operational reliability so that it approaches the in-built or inherent reliability is to maintain it correctly. RCM focuses on improving operational reliability by determining an appropriate set of scheduled maintenance tasks. Only if maintenance cannot satisfactorily manage a failure or achieve the desired system requirements will a modification be considered.
The key to its success is that RCM is applied by your own staff, extracting and utilising their experience and detailed knowledge of your equipment to derive maintenance that will ensure (as far as possible) that the equipment continues to meet its system requirements..
If you apply RCM correctly, your equipment will become as reliable as it possibly can be without any modification which in turn means that availability improves. Furthermore, the RCM approach ensures that you only spend money on maintenance tasks that are actually worth doing which in turn means that money spent on maintenance is being spent where it will do the most good.
To learn more about RCM and how it can improve your equipment reliability, please visit our RCM pages.
