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Preventive maintenance is a scheduled and planned approach to maintaining equipment and other assets. Preventive maintenance focuses on performing maintenance operations before malfunctions occur, ideally preventing breakdowns from happening in the first place. It is also known as preventative maintenance or by the acronym PM.
The most efficient way to solve a problem is make sure it never arises at all. This is the key idea behind preventive maintenance.
Simply repairing assets as they malfunction is reactive maintenance. Preventive maintenance relies on taking the assets offline at specified times to replace components that are likely to fail soon. Predictive maintenance has similar aims but leverages technology to maximize component and asset longevity. See “Reactive vs. Preventive vs. Predictive Maintenance” for a complete breakdown of the three maintenance strategies.
Regularly scheduled preventive maintenance typically has a lower overall cost than reactive maintenance, especially once you start to add up all the unproductive labour hours, lost production, and repair bills caused by running equipment into the ground. No matter the strategy used, maintenance will always provide you plenty of challenges when it comes to setting budgets. See our whitepaper “Solving Maintenance Budgeting Challenges” for a detailed breakdown of how you can overcome the most common of these hurdles.
Considering its drawbacks, it’s puzzling that many facilities still follow a reactive maintenance strategy. They may be looking at the short-term benefits of reactive maintenance. It’s a very common mistake to focus on “benefits” and ignore the part where it says “short-term.”
A reactive maintenance strategy means that most of the time you have optimum production and asset uptime. It’s a great method to control costs … right up until the equipment breaks. Production on that machine (and maybe an entire line or facility) grinds to a halt. Days of production may be lost while the maintenance team moves heaven and earth to get the equipment running again. Any challenges they encounter during maintenance will see the downtime increase, sometimes dramatically. This is assuming that the maintenance crew can repair it at all. The nature of the breakdown may mean repair is simply not cost-effective and the equipment will have to be replaced.
A reactive maintenance strategy turns your team into fire fighters, rushing from one disaster to the next. This puts undue stress on the maintenance crew, in addition to the obvious monetary costs. In turn, this will lead to lowered morale and higher staff turnover. This combination of factors is almost guaranteed to negatively impact both profitability and productivity.
Loss of revenue is bad enough, but it can get much, much worse. A look back at a disaster from a century ago can help us to understand just how bad it can get.
The Great Boston Molasses Flood took place on January 15, 1919. At the time, a molasses storage tank owned by Purity Distilling Company stood on Boston’s Commercial Street near Keany Square. The tank was about 15 m tall by 27 m in diameter. On the day of the disaster, it held over 8.7 million gallons of molasses. The tank collapsed around 12:30 pm, sending tons of molasses roaring through the streets of Boston’s North End neighbourhood.
The image of a tidal wave of molasses may seem comical at first, but there was nothing funny about the results. The disaster claimed the lives of over 20 people, including two children. Over 100 others were injured. Property damage was extensive.
The company had been following a reactive maintenance strategy with the tank and frankly had done a poor job even in that regard. Leaks were clumsily patched … sometimes. At one point, executives decided to simply paint the tank brown so the leaks wouldn’t be so obvious.
Modern analyses have pointed to definite evidence that the tank was poorly constructed. The steel used was only half the thickness it should have been, even given the relatively lax standards in force at the time. The rivets used were also flawed, which was were cracks first formed.
It seems likely that preventive maintenance, no matter how rigorous, would not have been able to save that tank. However, the routine inspections that are part of any PM program would have showed the tremendous flaws in its construction and just how dangerous it was.
The biggest problem with reactive maintenance is that it piles up problems for the future, regardless of the benefits you experience in the short term. Preventive maintenance may cost more upfront and require more planning but it’s also much more effective.
Using an asset to its limits has an undeniable appeal. We get maximum utilization from the asset and hence we can achieve maximum production output. However, that’s only effective up until the time the asset fails. The cost of repairing or replacing the asset after failure may be higher than any production received by running it into the ground. For more information on the challenges of relying on reactive maintenance, please see “11 Disadvantages of a Reactive Maintenance Program.”
There are other advantages to be gained from following a preventive maintenance strategy as opposed to a reactive method. Reactive maintenance treats symptoms and may miss the actual cause entirely. For example, say your maintenance crew has repeatedly replaced a particular bearing. It overheats frequently and shuts the line down completely until it’s repaired.
Preventive maintenance, on the other hand, encourages your team to look at the asset as a system, rather than just focusing on whatever symptom is occurring right now. A reactive maintenance team may simply keep replacing that bearing, time after time. A preventive maintenance team, however, will dig into the real causes of the issue and find out what’s causing that bearing to overheat so often in the first place. Preventive maintenance can help you solve the underlying problem, rather than just treating the symptoms.
Preventive maintenance is usually more cost-effective than reactive maintenance, but it may be difficult to convince your colleagues that it’s a good idea to take operational equipment offline even for brief periods. Check out our whitepaper “Why Scheduling is Vital to Your Maintenance Strategy” for a breakdown on why a PM program is more cost effective than running the asset to failure.