Effective equipment maintenance through condition monitoring

Oct. 24, 2006
Reliability programs usually fail because of poor implementation, says Daryl Mather in his latest column. Be diligent and implement reliability initiatives and you can realize your goal of establishing a useful reliability program.

Click here to download the spreadsheet scheduling tool for this column.

As a seasoned professional you have probably had your fair share of experience with selecting and implementing reliability analysis programs for your company. Every time it starts off great, the pilot program runs well, and the forecast benefits seem out of this world.

Why wouldn’t your company take this forward? It seems the obvious thing to do.

Then after a while the benefits don’t materialize, the boss is keen to know where the ROI is for the pilot program, and you are facing an increasingly difficult time in getting any further improvement programs approved. Sound familiar?

In my experience many reliability programs fail because of poor implementation. What we sometimes neglect to consider is that implementation of reliability initiatives, particularly those aimed at optimizing or improving the maintenance regimes, doesn’t stop at the production of maintenance regimes; we need to turn these into reality and monitor their execution before we can truly say we have implemented a reliability program.

In my book, The Maintenance Scorecard, I detail why it is so important that maintenance schedules be executed according to the frequencies they have been assigned.

Maintenance scheduling is often linked to improvements in workforce efficiency, in fact I have come to the belief that if your company is looking to get sustainable improvements in operating efficiency, then short term capacity scheduling is one of the must have capabilities within the team. However, there is another side to the benefits of maintenance scheduling, that of minimizing the risk of an unacceptable failure.

When we establish reliability regimes, for example on an electrical power transformer with a tap changer device, each of the tasks and the frequencies have been chosen for a good reason. First, they represent the best value for money. Second, they reduce the likelihood of unacceptable failure to a level that we can tolerate. Third, they are driven by the characteristics of the failure mechanisms they are managing.

With a power transformer there are a range of tasks that should be done regularly. A good example of this is oil analysis. This can tell us a range of things regarding the state of the transformer in general, as well as the state of the oil itself. Testing the oil for impurities, and break-over voltage in particular, tells us a lot about the rate of degradation of the insulation materials on the coil and the rate of breakdown of the oil over time.

Using the basic method for establishing condition monitoring inspection intervals, the oil is tested at a frequency which we are sure will allow us to capture the initial warning signs of failure and to allow us time to act when we do find something. So, what happens if we execute the task late? We risk not catching the warning signs in time, so there is the risk of an unpredicted and unexpected failure on a large scale. Also, we risk not having enough time to do anything about it even if we did capture the warning signs in time.

Everywhere you look in your plant there are similar examples of this. Other condition monitoring examples could include not testing the motor bearing for vibration in time or not testing H.V. joints for excess heat with thermo-graphic test equipment. In both cases we are reducing the time we have to act on information, and we are increasing the likelihood that there will be an unpredicted failure event.

Even preventive maintenance regimes, as opposed to predictive and other maintenance types, there are examples of slipping maintenance with a direct effect on the likelihood of failure. For example, failure to grease a bearing in time increases the exposure to the risk of damage to the bearing due to breakdown of the lubrication film, a failure to check and adjust belt drives on time also exposes the plant and equipment to an increased likelihood of an unplanned failure event.

All of these lead to a greater level of risk that we are going to experience an equipment failure that we would prefer not to have, one that could cost us a lot of cash, or worse if there are safety and environmental concerns.

But it doesn’t end there. As all of you will know, good maintenance resource management relies on the principles of capacity scheduling. That is, scheduling the maintenance workforce to the realistic limits of its available working hours. This means not only the routine maintenance tasks, but also the corrective and lower priority reactive works.

Corrective and reactive work (yes, I differentiate between the two) are allowed to enter the maintenance backlog on the condition that they are not going to have an imminent adverse effect. It would be great if we all had the workforce hours, spare parts availability, and unlimited downtime allowance to fix everything when it is first noticed. But we don’t, and we never will have. So realistically the maintenance backlog will always exist.

Prioritizing work in progress something your workforce will do anyway as part of the way they manage physical assets, often without even realizing it. The priority program will be related to time in some fashion, therefore is imperative that your maintenance schedule always includes the highest priority corrective tasks first.

For example, a noisy pump is okay at the beginning, maybe even a week later it will still be okay. But what about three weeks later, when the noise has become a lot louder? Now it is one of the things that keep you awake at night now, you realize that if this task is not done soon, then your plant is at risk of an unplanned, and unwanted, failure event.

Understanding how to carry out capacity scheduling is a skill that most planners require and is relatively easy to master. What is difficult is having the ability to convey exactly why this is required, and to have the level of discipline within the workforce to execute it continually.

There are several results that I have seen when capacity scheduling is applied. First there is a change in reliability, worker efficiency and the bottom line of maintenance. This is even more apparent when the maintenance regimes have been optimized. Second, and more noticeably, there is a stark awakening about how much (or how little) time there is in each day that is available for tool time. This doesn’t even take into account the impact of work delays, stock-outs and other issues. So even before the first nut is tightened we become immediately aware of the potential for getting even greater efficiencies’ from the maintenance workforce.

There are some links on this column to a spreadsheet scheduling tool for your use. It is nothing technical and is merely a good way of getting your company started with capacity scheduling if you have not already taken these steps.

Daryl Mather has assisted companies to increase the profitability of their physical asset base in over 23 countries including the USA, Europe, Asia and Latin America. He is the author of “The Maintenance Scorecard” and regularly publishes the Modern Asset Management blog. He currently works with Knowledge Based Management based in London and can be reached on [email protected].

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