Saying you need better maintenanceisn’tenough. If you want a program packed with processes that really work for you, you need to choose the right maintenance strategy.
And that starts with knowing your options, what they are, and how they’re different from one another.
Before looking at the what,it’simportant to first figure out the why. Why is there more than one maintenance strategy?
Why are theredifferent typesof maintenance strategies?
One of the answers is that because there aredifferent typesof assets, there are different strategies. Different machines break down fordifferent reasonsand indifferent ways, so you need tailored ways to keep them up and running.
It seems a bit obvious to say not all assets and equipment are the same. Butit’sworth remembering that there are evendifferent kindsof differences.
Any two assets can be different is terms of how they work and how they usually break.So,an AC unit isnot the same asan ice machine. But even two similar assets, for example two AC units, can be different in terms of:
- Age
- Manufacturer
- Repairs and maintenance histories
- Relative criticality
And because of these differences, you couldconceivably havetwo similar units that each need a different maintenance strategy.
That’sone of the answers. Another is thatnew technologiesmake new strategies possible. When new tech gives us a new ability, we canleverageit into a new strategy. For condition-based maintenance and predictive maintenance, for example, sensors mounted on your assets and equipment capture a constant stream of data that you can use to helpdeterminewhen to schedule to next maintenance inspections and tasks.
What are the maintenance strategies?
Generally, thereare six main maintenance strategies:
- Reactive (run-to-failure)
- Predetermined maintenance
- Preventive maintenance
- Corrective maintenance
- Condition-based maintenance
- Predictive maintenance
Let’slook at each in more detail.
Reactive / Run-to-failure maintenance
Yes, this is a real strategy, even thoughit’seasy to confuse it with having no strategy at all.Basically, youwait for things to break before you fix them.
The trick is choosing the right assets for the strategy. You need things that are cheap to carry in inventory, easy to replace, hard to inspect ormaintain, and have a low criticality. Light bulbs are the classic example. Because theydon’trequire a special environment andaren’ttoo big,they’rerelatively cheapto carry in inventory. When they burn out, screwing in a new one takes almost no time at all. Even if you wanted to swap them out just before they died,it’shard to accurately check how much longer any givenfilamentcan last.
And they are notgenerally criticalto your operations.It’shard to imagine a manufacturing facility having to shut down the line because of aburned-outlight bulb.
Run-to-failure also sometimes makes sense when you haveduplicatesofthe same asset, making any given one of them redundant. You can wait for one to break down knowing that when you’re fixing it, you have all the others still running. The maintenance strategy can also make sense for continuous production facilities that use assets that almost never break down. Instead of periodically shutting down the line for proactive maintenance, guaranteeing additional costs, you keep going until something breaks. Because breakdowns are so rare, your total cost of ownership is less.
Advantages of reactive maintenance
One of the overarching goals of maintenance is to get the most value out of your assets and equipment. You want maximum return on your investment, so you need to squeeze outeverydrop of value. With something like light bulbs, the only way to get all the possible value is to keep going until they burn out.
But it’s more than just getting the most value. Youwantto get the most value for the least amount of money. And run-to-failure can save you money because it usually requires a smaller maintenance team. Because you’re not running a schedule of planned maintenance, you only ever need a small number of techs. Another way you save money is on training. While other strategies require special prep and training, even the most stuck-in-their-ways tech can understand reactive maintenance. “If itain’tbroke, don’t fix it” is a clear, simple concept.
Disadvantages of reactive maintenance
Althoughthere’remany assets where reactive maintenance is the best choice, there are even more whereyou’resimply courting disaster. If you use the strategy on the wrong assets and equipment,you’resuddenly dealing with a lot of unscheduleddowntimeand expensive repairs.
Learn more about corrective maintenance.
Preventive maintenance
Here, you use a schedule of inspections and tasks to find and fix small issues before they have a chance to develop into big problems. Preventive maintenance is basically the idea behind the old saying that “An ounce of prevention is worth a pound of cure.”
How do you develop the schedule? It candepend onwhere you are in the asset’s life span and what sorts of problems you’re seeing. When an asset isnew, it makes more sense to schedule everything according to the manufacturer’s recommendations. They’re the ones who designed and built it, so they know the asset best. But as time goes on, your senior techs likely have a better understanding of the asset’s common problems, and so you can adjust the schedule as needed.
It’sworth noting that “scheduling” comes in two forms, based on time or use. For some PMs, you perform them according to calendar dates. So, for example, you have a tech look at the AC units in early spring, checking for any damage that happened over the winter. You might also have seasonal PMs for the roof. But for something like a hydraulic press, you can schedule PMs to trigger based on use. So, after X number of cycles, you have a list of inspections and maintenance for the team.
Advantages of preventive maintenance
One way to understand the benefits of preventive maintenance is to look at all the hassles you avoid.
Because you know what work the maintenance team is going to do on any given day, you have more than enough lead time to ensure they have the right parts and materials. No more scrambling to find the right inventory. No more expensive rush deliveries. Andit’snot just inventory.
Becauseyou’vescheduled the work in advance, you can easily schedule the right people to be there at the right times. No more calling in that one special tech for overtime becausethey’rethe only onewho’sgood at troubleshooting that one tricky asset.
And because you can choose when things get done, you can easily schedule around peak production times. No more idle operators standing around watching the maintenanceteam.That’sa lot of stress you just avoided.
Disadvantages of preventive maintenance
It’s possible to stray over into over-maintenance, where you’re doing more than youneed. Can you have too much of a good thing? In maintenance, you can.
The two big issues are extra waste and added risk. If you’re changing the fan belts on an engine too soon, you’re throwing out perfectly good inventory. And every time youopenthe hood and have a technician pulling things apart and putting them back together, you’re increasing the risk of accidental damage. The tech might strip a bolt or drop a metal tool across the terminals on the battery. Even something as simple as checking the oil could introduce foreign objects into the engine.
Predetermined maintenance
When is ita good ideato have someone else set up your maintenance program? When they know your assets and equipment better than you do, which might be only right after you get them or could also be long into the asset and equipment life cycle.
Predetermined maintenance is when you simply follow the manufacturer’s recommendations for maintenance, including when to do inspections and maintenance.
Advantages of predetermined maintenance
All the work’s been done for you, so all you need to do is follow the schedule and do the work. And the schedule should be good because the manufacturer has based it on both their knowledge of their products and continuing research.
Disadvantages of predetermined maintenance
The program is based on averages, soit’snot always an exact match for your assets.
Stats can be both true and unhelpful. Imagineyou’resitting in a regular restaurant enjoying a nice meal. Bill Gates walks in, and suddenly, every single person in that restaurant is, on average, a multimillionaire.
But do you feel any richer?
Condition based maintenance
Just like the name suggests, condition based maintenance is based on the asset or equipment’s condition. So, instead of setting up a schedule to periodically check on an asset, here you’re constantly monitoring it, looking for any deviations that suggest the start of trouble.
For example, you have an engine you want to maintain. You can set up a schedule where you check the temperature every three hours.Oryou can just attach a sensor that constantly reads the temperature, setting of an alarm when things fall below or jump above set perimeters. The idea is your sensor is set to always be on the lookout for a hint of smoke. As soon as it sees it, the sensor lets you know, and you can make sure those bits of smoke never have a chance to develop into a full-fledge fire.
Temperature is just one of the conditions you canmonitor. Others include:
- Vibration
- Speed
- Power
- Moisture (bothtoo much and too little)
Advantages of condition based maintenance
Condition based maintenance is done while the assets is up and running, saving you on overall downtime. Now, instead of turning the equipment off to inspect it, you can keep it running and let the sensors do the work for you.
You also save on overall maintenance because you don’t have to schedule as manyinspections,and you only perform tasks when you know you need them.
Being able to “see” inside an asset without having to shut it down and then lock it out saves you more than just time and effort. For many assets, it also saves you from the risk of damage to the asset and injury to technicians. Having a sensor on the fan over the welding stations means youhave tosend up a technician to check on it only when you already knowthere’sa problem.
Disadvantages of condition based maintenance
Cost. Both for the required equipment as well as theadditionaltraining you need for your technicians, who now need to know how to set up andcalibratethe sensors. In a way,you’vecreated a new class of equipment for them to worry aboutmaintaining.
That said, if you pick the right assets for the strategy, you can see concrete returns on your investment. But youhave tochoose the right assets and set up the sensors to look for the right things.
Even with the “right” sensors, though, you can still run into trouble if the environment is a harsh enough to eventually break them. And even if they all survive,it’sgenerally hardfor them to detect certain types of failures, including those caused by fatigue or uniform wear.
Learn more about condition-based maintenance.
Predictive maintenance
Basically,it’sthe same as condition-based maintenance except that the data is analyzed to make accurate predictions about future failures.
For example: with condition-based, you have an engine that usually runs at temperature X. As soon as it goes above X plus Y, you know it needs maintenance.There’sa constant stream of data coming from the sensor, but the software only really cares ifit’swithin the preset ranges.
But with predictive maintenance, the engine never has a chance to get to X plus Y because now that constant stream of data is being looked at closely by the software. In fact, it’s not simply looking, it’s analyzing it, pushing it through complex algorithms, hunting for clues. So, your engine might be well within the parameters for temperature, but the software still triggers maintenance after “decoding” the data and finding hints that something bad is going to happen.
Advantages of predictive maintenance
It’snice to live inside a sci-fi movie where computers can tell you the future. You get all the benefits of condition based but you see them even faster.
Disadvantages of predictive maintenance
Cost. Now you have all the same costs of condition-based maintenance plus the added expensive of even more sophisticated software requiring even more specialized training for your staff.
And you have all the other drawbacks, too, including worrying about keeping your sensors properly calibrated and up and running.
Which maintenance strategy is right for me?
It’sa trick question. Youdon’thave to choose the onethat’sbest for you. Instead, choose the right strategy for each asset. For some, run-to-failure. For others, preventive. The question should be “What’s the right combination of maintenance strategies for my facility, assets, and equipment?”
Instead of thinking about strategies in isolation, you might be able to better understand them by seeing howthey’redifferent from one another.
Reactive maintenance vs preventive maintenance
It’snot that one is better than the other. Instead,it’sthat some assets match better with one than the other.
For reactive maintenance, an asset or piece of equipment needs to check some of these boxes:
- Impractical or impossible tomaintain
- Cheap to buy and carry ininventory
- Easy toreplace
- Low relative criticality
For assets that don’t fit any of these descriptions, it likely makes more sense to use preventive maintenance.
Preventive maintenance vs predetermined maintenance
Both strategies use a schedule of inspections and tasks to find and fix small issues before they become big, costly problems. The only real difference between the two iswho’swriting out the schedule, you and your department or the manufacturer and their team of experts.
Just like with a lot of the other strategies, youdon’thave to make a hard choice between strictly one or the other. When an asset is newer, you can use predetermined maintenance. Later, whenyou’vebuilt up a history of maintenance and repairs, you can start to fine-tune the schedule to better meet your specific situation.
Condition based maintenance vs predictive maintenance
How do you know which one to use? Both haveadditionalcosts connected to equipment and training, but predictive isgenerally goingto be the more expensive of the two. The way to choose between the two is to carefully the value of your asset, both its cost and how much it would cost you in time, money, and frustration if it unexpectedly failed.
Imagine you’ve decided tobuildyourself a garage but you’re not sure how much to invest. Your first step should be to look at your car, using its relative value to help you decide on the structure that’s going to protect it. Simple, reliable four-door sedan perfect for runs to the grocery store? You need a simple, reliable garage. Fancy imported vintage sports car? It’s better to build something with all the possible garage bells and whistles, including a built-in lift and security system.
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Next step
In the end, no matter which combination of maintenance strategies you choose, a modern CMMS solution makes it a lot easier to get your program off the ground and heading in the right direction. From there, it’s a lot easier to stay on course when you have software that keeps your data safe, secure, searchable and your workflows streamlined.
Hippo has many ways to help you, no matter how far along you are in the process. We cananswer your questions about maintenance strategies (and everything else related to maintenance), help you book a live software demo, or even set you up witha free trial.
Maintenance Types Summary
Choosing the right maintenance strategy starts with understanding your options, their benefits, and drawbacks. Run-to-failure tends to get a bad name, but for a specific class of assets and equipment,it’sthe best choice. Use it when things are hard or impossible tomaintain, cheap to carry in inventory, easy to replace, or non-essential to your operations. Preventive maintenance helps you find problems early by scheduling inspections and tasks. It also saves you money and frustration because you can plan everything in advance. For predetermined maintenance, everything isbasically thesame as with preventive, exceptyou’refollowing a schedule set up by the manufacturer, not your department. Condition based and predictive by rely on sensors and special software to collect and look at data from sensors installed directly on or near your assets. For condition based, the software is looking for readings outside preset parameters. For predictive, the software analyzes the data to predict future failures long before they start to develop. In the end, there is no one-size-fits-all, all-time perfect strategy. You need to choose the combination that works best for your assets,fine-tuningyour approach as your assets age and your department collects data.
