The short answer is no, it's not always bad. In fact, there are many situations where letting things fail is the best possible maintenance strategy.
But before you can know where to use run to failure (RTF), you have to first know exactly what it is and why it's not the maintenance boogeyman it's often made out to be.
Let's start with some basic definitions.
What is the run to failure (RTF) maintenance strategy?
Just like the name suggests, run to failure is when you let an asset or piece of equipment run until it fails. But to be a bit more precise, it's generally when you let a part run until it fails.
Before the failure point, you don't really do anything. There's no maintenance inspections or tasks connected to that part. You're not actively monitoring it. After the failure, you swap out the broken part for a new one. Instead of repairing it, you are just replacing it.
What are examples of run to failure?
Before looking at where, it's worth remembering that what's true about run to failure is true about all other maintenance strategies: you need to carefully match them to your assets and equipment. Maintenance is not one size fits all. What works for one asset might not work for another.
But it's even more specific than that. Think about what's likely one of your most valuable assets, your car. It's only one asset, but you use a combination of different strategies to keep it on the road. You schedule oil changes based on some combination of time and mileage. But the windshield washer fluid only gets topped up when the reservoir is empty. For the engine, the built-in sensors are constantly checking the temperature, alerting you as soon as it rises above a set parameter.
When it's like a light bulb
So, where does run to failure make the most sense? The classic example is light bulbs. If something is basically like a light bulb, you can use run to failure.
So, what are the defining characteristics of a light bulb? One, it's very likely non-critical to your operations. If one burns out, it's not going to stop your entire production line. It's also likely non-critical in terms of safety. They don't explode when they fail; no one gets hurt when they burn out. Two, it's not hard and it doesn't cost a lot of money to keep spares in inventory. You don't have to worry about them going stale or getting stolen. Three, you can assume there's always someone on the maintenance team who knows how to swap in a fresh one.
And four, there is no practical way to maintain it. You can't use a special light bulb monitor to check how much longer the filament should last. When the light bulb gets close to the end of its life cycle, there's no practical, cost-effective way to open it up and install and new filament. Without wasting a ton of time and money, you can't check it and you can't fix it.
So, if you have a part that's a close cousin to light bulbs, you can likely use run to failure.
When it costs the same anyway
But it doesn't always have to be like a light bulb. In some cases, where you have a good sense of what it costs to maintain vs. what it costs to repair, you might decide it's cheaper to just wait until it breaks before you fix it.
Remember, even scheduled downtime can cost you lost production time. The advantage with scheduling the downtime is that it costs you as little as possible, because you can plan out what work the team needs to do and make sure you have all the parts and materials they need on hand. It costs you less, but it still costs you.
Imagine you have Asset A on the production line. Every hour that asset is offline costs you X. With a preventive maintenance program, you're locked into Y number of hours of offline time thanks to inspections and tasks. By multiplying X by Y and adding in labor, parts, and materials, you can quickly calculate the total cost of maintenance. With most assets, it's less than the cost of not having a PM program.
It's the same with your car. Changing the oil takes time and money. But it's less than the cost of replacing a seized engine.
That's true for most assets. But there are some where maintenance costs are high enough and repair costs are low enough that it makes more sense to just run to failure.
What are the benefits of run to failure?
If you do the math correctly, you should end up saving money. With something that shares a lot of the same qualities as a light bulb, it's always cheaper and easier to let it fail than try to maintain it.
On top of that, letting it run to failure guarantees you're getting as much value from it as you can. You never have to worry that you're throwing parts out too early.
What are the drawbacks of run to failure?
If you don't do the math correctly, you might be creating costly headaches for yourself.
And even if your math is perfect, there are still headaches. With run to failure, you're sacrificing predictability. Instead of maintaining or swapping out parts on a set schedule, you never know when the team needs to swing into action. It might be first thing Monday morning or just before you're ready to start the weekend late Friday afternoon.
And to compensate for the increased unpredictability, you're forced to carry more in inventory. Instead of being able to match your inventory levels to predetermined dates when you've scheduled PMs, you need to carry certain inventory all the time because you never know when you need to use it.
How does CMMS help with run to failure?
When you're looking at run to failure, you first need to know how your assets tend to fail. Without a solid understanding of the various failure modes, there's no way for you to match assets with maintenance strategies.
Once you know where to implement it, you then need a reliable way to react quickly to failures with the right instructions and inventory. You need to be able to tell the maintenance techs exactly what they need to do and then make sure they have the parts and materials.
Modern CMMS solutions make it all possible. From one central system, you can review maintenance requests and then generate, prioritize, assign, and track work orders.
And the work orders you send out to the team come packed with everything they need to close out efficiently, including:
- Comprehensive asset maintenance and repair histories
- Step-by-step instructions
- Customizable checklists
- Associated parts and materials
- Digital images, schematics, and O&M manuals
They can even include interactive site maps and floor plans.
Because the software helps you control inventory with real-time counts, you can make sure the right parts are there, right when the team needs them.
Although it tends to have a bad reputation, there are many situations where the best maintenance strategy is run to failure. Basically, you let the asset or equipment run until it fails. Generally, you only implement this strategy for assets that are similar to light bulbs. They're non-critical, expensive or impossible to maintain and repair, cheap to carry in inventory, and everyone on the maintenance team can swap them out for new ones. However, there are cases where you might find the cost of the scheduled downtime needed for maintenance is greater than the cost of repairs. The advantages of run to failure are that you save money and get maximum value from your parts before throwing them out. However, you lose a lot of predictability, and to compensate, you need to carry more parts and materials in inventory. Modern CMMS solutions help you with run to failure by streamlining work order management, delivering the instructions techs need to work well, and controlling the required inventory.