Using Criticality in a Maintenance Strategy

Criticality analysis is an effective way to inform maintenance strategy, but only when it’s carried out properly. In this article, we’ll discuss two main points:

1. An explanation of criticality and how it can fit any business that has assets.

2. A process for carrying out criticality studies that focus not only on hardware, but also software, your people, and how they react to new ways of operating.

This article is based on a webinar "How Criticality Can Frame a Maintenance Strategy" with Andy Gailey. To view the recording of the webinar, click this link.

What Is Criticality?

To start off, we first need to know what we mean by “criticality.” Basically, criticality is organizing things into degrees of importance. The human body is a good analogy for this. Obviously, your heart and lungs are super critical, but parts like a finger, hand, or arm are of secondary criticality since you could conceivably live the rest of your life without them.

Tip: Criticality is not the same as risk. Risk analysis is a vigorous measurement of how different failure modes could impact your operation, whereas criticality is a more high-level overview of your assets.

Basics of Implementing Criticality Analysis

Essentially, criticality is an overall thought about how important things are. Engineers ask all kinds of critical thinking questions every day, such as:

• What happened?

• Why did it happen?

• How can we make it better?

• Do we take steps to renew that piece of equipment?

• Do we replace it, or can we rebuild it into a better state?

What these questions don't address is the overall view of what’s actually going on. Many organizations never set aside time to look at their assets in terms of how critical they are. If asked which of their assets out of a group is the most important, they’d answer “Everything is important.” The truth, however, is that there has to be something that's more important than the rest.

This often leads maintenance workers into a state where they’re only reacting to things going on around them. As long as they’re driven by reactive events, they’re going to be content with that way of doing things, especially if that’s the only way they’ve been told.

Focus on What’s Important

Because of this reactive-driven nature, when you introduce the concept of criticality to people, they’ll ask, “Well, what can it do for me?” They’re not that interested in the inputs and outputs of criticality; they’re just interested in what it can give them, such as what kind of revenue they can see returned to their business or what major benefits they might see.

These are actually the right kinds of questions to ask. Like anything in maintenance and reliability, you need to keep your eye on the prize. You shouldn’t do anything that isn’t proven to add outstanding value to your business, whether that’s in terms of production, safety, the environment, etc.

Create a Living Process

Conversely, many people who get criticality studies wrong are those who think it’s simply a thing to do. Often, somebody high up in the business says the company needs to do criticality, and the maintenance team struggles to do it. After all that effort, they end up making a file that they put on a shelf, never to look at it again.

In reality, criticality should be treated as a live process. As you embark on this process, your goals are to:

• Learn about your assets, your people, your inventory, etc.

• Use criticality as a tool to make things better

• Revisit that tool in the future to see if it worked

Once it’s carried out, it should be reviewed to gauge whether it has worked or if it needs to be changed. In addition, things in the industry can change over time. Some assets may disappear, and others will find their way up or down the hierarchy.

Don’t Forget About People

When we talk about criticality, we usually focus on hard assets and their components. People and their skills are often overlooked, not to mention their buy-in to actually involve themselves with asset care. As such, keep people in mind when performing criticality analysis.

Divide and Conquer

You’re going to have to invest some time into criticality analysis to get the return, and when you first start, it can seem like a major piece of work. However, if you pare it down into sections and components, it becomes much easier. Co-opting other people into the workflow can also help.

Read the Manual

By doing criticality research, you get people to read the manual rather than make assumptions about your assets. Instead of being considered an additional part of the resources for an asset, the manual should be one of the foremost resources. It helps you buy the right types of spares at the right time, and it can also give you a framework for your maintenance strategy by answering questions like:

• Where can we put our predictive tools?

• Where do we go when we have to make plans?

• Where are the bits that the law says we have to go and do first?

The manual also gives an idea of whether your people have the right skill level and tools to do planned maintenance.

Benefits of Criticality Analysis

When it comes to benefits, criticality analysis is paid for through the following:

• The reduction of spares in inventory, saving money on purchasing and storing parts

• The removal of planned maintenance that adds no value whatsoever

The main thing criticality does is revealing the unknowns. People often make assumptions about their assets, and criticality helps correct that.

Making Maintenance Choices

When it comes to your maintenance strategy, you have a few choices. Note that none of these are necessarily the right choice. All of the following can be part of a maintenance strategy, even reactive maintenance.

Reactive

The first maintenance choice is to have no strategy at all and just wing it. It’s waiting until something breaks before calling the original equipment manufacturer (OEM) and seeing if they have any spares, all while hoping the machine will never break. It’s a common strategy.

Planned

The second approach is to gather all your OEM manuals, methodically go through them, input all the planned maintenance into your CMMS, and get your technicians on board with performing it.

You might also buy all the OEM recommended spares. However, the thing to bear in mind with OEMs is that they build assets, but hardly ever run them. Once you’ve taken the key and they walk away, their responsibility is zero (unless you’re in a highly regulated industry). As such, they’re likely one of the worst parties you can ask for how your asset is going to be used.

Tip: With planned maintenance, it’s easy to put in lots of time-based tasks and still have breakdowns. It can create a snowball effect where once something breaks, somebody puts in a weekly or monthly PM for it, resulting in a mass of labor hours you can never cover.

Proactive

There’s yet another way to look at things, and that is proactively. Proactive maintenance involves creating lubrication regimes, checking on aligned components on a regular basis, and ensuring they’re not vibrating excessively. It’s more detailed and more focused on your given application.

Predictive

Finally, you can use predictive tools. The first predictive tool you should use is people. Training your people to use their eyes and ears is often the best place to start.

In some ways, predictive maintenance (PdM) is just the earliest form of reactive maintenance. You need a signal to take actions, and that’s what PdM will give you.

Moving From Reactive to Predictive

It’s not really possible to take people from reactive or planned maintenance to proactive / predictive without training them to think differently. There’s a human aspect you need to be aware of, so you’ll need to take your people along with you on your journey from one sphere to the next.

While criticality can help you make the change, it can still take a long time to help people get on board.

Four Ways Criticality Can Benefit a Maintenance Strategy

As you implement criticality in your maintenance strategy, there are a number of benefits. These include the following.

1. Revealing Unknowns

The first benefit of criticality is it reveals the unknowns. Specifically, it can reveal what you didn’t previously know about your equipment, your people, and your ways of operating.

2. Restoring Order and Confidence

Over time, criticality can restore some order and confidence, particularly from operations. The operations part of your business may not understand what your maintenance team does. However, if you can get some higher figures of throughput and availability, it can restore confidence and order with your operations and maintenance. The end result is engineering and maintenance working hand-in-hand with operations.

3. RCM and FMECA

You also need to understand that one of your primary goals is to work toward the level of production you require. You’re not doing criticality for the sake of criticality; you’re working toward an overall goal. As such, criticality can help inform reliability-centered maintenance (RCM) and FMEA/FMECA.

To do things like predictive maintenance, you need to know about failure modes and their effects on the risk and consequence for your business. Criticality can help inform FMECA and RCA, which in turn can inform your maintenance team on the types of maintenance they need to perform.

4. Knowledge and Training

Finally, you need to know what your people know and understand about your assets. Teach them that there is a predictive way of doing things and that lubrication on a robust mobile system is part of that journey.

Asset Criticality Process

Now that we know the basics of criticality and how to implement it, here's a process to follow to carry out a criticality study.

Gather Information

Before starting out, you need some inputs. It’s like baking a cake—you need ingredients. The ingredients for your criticality study include.

• A full asset list

• A complete set of OEM manuals

• A critical spares list from the OEM

• Recommended planned maintenance routines

• A history of any planned events on existing lines

• A list of parts you already have (to prevent duplication)

• A CMMS or Asset Operations Management system, which you’ll keep open during this process

• Any condition monitoring

• A skills matrix, along with the availability of those skills

You’ll need people to come along to gather information. At this stage, it’s important to get the following people involved:

• People involved in health and safety

• Operations manager

• Production managers

• Operators

• Maintenance technicians

You'll start from a macro level where you’ll look at high-level assets across your whole asset group, then choose which one is the most critical. That will usually be the one that generates the most revenue for your business.

Tip: This may seem like a lot of information to gather. It may take anywhere from a couple hours to a couple days to get together, depending on your information management.

Level One

In level one, you’re going to be looking at your head line asset. For instance, in the food industry, it could be an oven, a fryer, or a packaging machine. Note that it’ll have multiple subcomponents (motors, gearboxes, bearings, chains, etc.) which you’ll get to later. Record the asset (or a whole line of assets if they’re not particularly complex) and list its description and replacement value.

You’ll also score the asset on these areas:

• Safety

• Downtime

• Production

• Quality

• Existing maintenance tasks

• Financial impact

You’ll add those together into an overall score. Again, at this stage you’re either scoring one very complicated asset, or half a dozen or a dozen less complicated assets.

Tip: An asset’s criticality depends on its operating context. For instance, if you have two identical pumps but one is only used in an auxiliary fashion, the one more in demand will be more critical.

Level Two

In the second level, you’re going to look at component levels. In the example of an oven, you’ll drill down and list that the oven has motors, gears, bearings, pumps, and other auxiliary drives. This is the point where you’ll need information from your OEM about their costs.

Knowing supply costs can allow you to compare them against your own existing component supplier. In some cases, you might be able to make an arrangement with the manufacturer rather than the OEM, saving as much as 10% on procurement.

Of course, some parts can only be obtained from the OEM, so you need to keep the OEM as part of your journey. You might still be able to negotiate a better deal, though. For example, if they recommend a list of 50 components and you only need 20, they may be able to accommodate your needs with a lower price.

Level Three

At level three, you’ll put down any condition monitoring and lubrication strategies you need. During this stage, you’ll ask questions like:

• What are the lubrication needs of this unit?

• What grease are we going to use?

• What time schedule are we going to put it on?

• Can we use some condition monitoring on it?

This information often becomes a go-to resource for deciding what to do with your assets after your criticality study.

Level Four

Level four is the criticality for the actual components, such as bearings, chains, gearboxes, motors, seals, etc. Be careful that you don’t put everything on this list, though. Door handles, wheels, or other things that you can just look at don’t need to be on your list. Typically, you’ll look at the rotating parts of equipment first. Some of this information can be transferred directly from level two to level four.

You’ll have a weighted score for all of the attributes of a particular component. These include:

• The probability of it failing (by experience or from data in your CMMS or Asset Operations Management platform)

• The severity or impact of how much time you’ll lose if it fails

• Whether there are alternative parts

• The types of detection methods (automatic detection alert, warning signs, monitoring)

• The criticality of the asset it belongs to

With the last point, consider items such as whether it’s a subcomponent of an asset group you can do without, whether it stops just the machine or line, or whether it might stop the plant as a whole.

Tip: Often, the more unpredictable a failure is, the higher its criticality will be. That said, don’t get so caught up in the nitty-gritty of the process that you lose sight of the main goal.

Level Five

At level five, you’ll look at what kind of maintenance you can perform on the components in step four. Answer these questions:

• Can we use an operator, or is a technician necessary?

• Are we going to do it on a time basis?

• What’s the condition monitoring type that we’re going to use? Vibration, ultrasound, or aural samplings?

This step sometimes flushes out your training needs. For instance, you might find that your operators carry out temperature measurements without any training in how to use thermography equipment, resulting in false results. Level five is part of revealing these kinds of unknowns.

Level Six

With this last step, you’ll determine what kind of planned work you need for your assets. Get together with your maintenance team on this one, as well as the planning team and some of the operators. Look at the skills each task requires. Do your people need support? Can they be buddied up to do certain low-level operations?

It’s important to get people involved. Often, the most effective maintenance that takes place comes from the practices of your maintenance group. If you can get somebody to come up with a way of maintaining equipment, they’ll own that. This ownership will instill some additional support in looking after your assets.

Remember, you can only expect your operator group to engage if you give them the tools and training to do so. To get them on board, you’ll need to support them.

How Criticality Can Frame a Maintenance Strategy

Criticality delivers on many levels. It can enable you to come up with a framework for your maintenance strategy in the following ways.

Produce a Single Document

Criticality puts everything into a single document. Once you’ve done the work, you have a document on your database that people can use for future reference.

On an annual basis, you’ll go back to it and look in your CMMS or Asset Operations Management system at what happened with your planned events and determine if it delivered what you wanted. If it didn’t, you can refer to your criticality study and see where you need to alter it.

Tip: It’s usually best to review your criticality analysis once per year or whenever something in your process changes.

Reveals the Unknowns

Probably the biggest impact of criticality is it reveals unknowns and truths about your equipment. With that extra knowledge, you’ll be in a better position to make decisions about how to go about maintaining it.

Builds Knowledge of Assets

One way in which it builds knowledge of your assets is it gets you to read the manuals and determine whether they’re actually fit for use. Often, manuals are woefully lacking in terms of being fit for an asset being operated in your specific environment.

Tasks Are Decided on Added Value

Under criticality, the tasks and instructions are decided based on the value they add to the business. They’re not decided as a reaction to something else that happened. As such, the input you receive from maintenance and operations is vital.

Skills Gaps Are Revealed for Action

Yet another way criticality helps frame maintenance strategies is it reveals the skills gap. All of a sudden, you find out the things you need to do to support your people.

Identify Critical Spares

Finally, criticality identifies the critical spares you actually need, not the ones the OEM says you need. As you go through the process of failure modes and RCM analysis, you can determine whether you actually need to hold each part.

This is important because if you have hundreds of items, it can cost a lot of money to put them all on stock, let alone manage that stock.

Conclusion

Remember, criticality is not about the process, but what it delivers. It’s about what it brings to your business. Be careful not to get so wrapped up in the process that you forget the end goal is delivering value.