Top 10 Essential Maintenance Metrics Every Reliability Engineer Must Track

In today’s competitive business world, it’s very important for equipment to be up and running, reliable, and perform well. Tracking, optimizing, and improving maintenance operations are key to keeping productivity high in any type of business, whether it’s a factory, a utility company, or a facilities management company. Maintenance KPIs, or maintenance metrics, let businesses measure how well their maintenance plans are working and make better decisions.

The following guide goes into great detail about the most significant maintenance metrics used in all industries, using the attached infographic as a reference. It also discusses how each one is essential for ensuring operational excellence.

1. Mean Time Between Failure (MTBF)

Definition:
MTBF is a way to find out how long a system or part can run without stopping or failure. For a repairable system, it’s the average amount of time that passes between two failures.

Formula:

Explanation:
This measure lets you figure out how reliable the equipment is by nature. A system with a greater MTBF is less likely to fail and is more reliable.

Importance:
Keeping track of MTBF helps maintenance crews see how equipment is doing over time and plan repairs that will keep it running well. If a pump usually breaks down every 335 hours, for example, maintenance can be planned before that time runs out to avoid having to stop working unexpectedly.

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2. Mean Time to Repair (MTTR)

Definition:
MTTR is the average time it takes to find out what’s wrong with a broken part or system and fix it so it works again.

Formula:

Explanation:
This indicator measures how soon repair crews can get broken equipment back in working order. It covers the time it takes to fix something after it breaks down and get it back to full operation.

Importance:
A reduced MTTR means that maintenance can respond more quickly and effectively, which cuts down on downtime and productivity losses. Regularly checking MTTR can also show where procedures aren’t working well or where people need further training.

3. Failure Rate (?)

Definition:
The failure rate indicates you how often a part or system fails in a certain amount of time. It’s the opposite of MTBF.

Formula:

Explanation:
This tells you how likely it is that something will fail in a certain amount of time (for example, the hourly failure rate).

Importance:
Knowing the failure rate helps engineers and reliability experts figure out how risky an operation is. A higher failure rate can make it necessary to rebuild, update, or change maintenance programs.

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4. Reliability (R)

Definition:
Reliability is the chance that a system will work without breaking down for a set amount of time under certain conditions.

Formula:

Explanation:
In this case, the chance that the system will work without breaking down for 20 hours is 94.21%.

Importance:
Systems that need to be available all the time or meet safety standards must be reliable. It also helps with life cycle cost analysis and helps make the case for spending money on condition monitoring or redesigning a system.

5. Planned vs. Unplanned Maintenance

Definition:
This measure keeps track of the number of planned (scheduled) maintenance tasks compared to the number of unplanned (emergency or corrective) maintenance tasks.

Explanation:
Planned maintenance is proactive and helps keep things from breaking down. Unplanned maintenance often happens because of reactive work that needs to be done when a system fails.

Importance:
An company that has a lot of unexpected maintenance is usually less efficient and has higher operational risks and costs. The goal is to get the most out of planned maintenance.

Ideal Benchmark:
A good benchmark is that at least 80% of the maintenance should be planned. Anything below shows that there is room for strategic improvements.

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6. Preventive Maintenance (PM) Compliance

Definition:
PM Compliance is a way to measure how successfully a company sticks to its plan for preventative maintenance.

Explanation:
This is commonly figured up by taking the percentage of preventive tasks that were done on time within a certain range of time (for example, ±10% of the scheduled interval).

Importance:
Following PM guidelines closely lowers the chance of unplanned breakdowns. It makes sure that maintenance plans are being carried out as planned.

Target Compliance:
World-class maintenance operations aim for more than 90% compliance. For instance, a PM assignment that is due every month must be done within three days of the due date.

Take Control:  What is proactive maintenance?

7. Planned Maintenance Percentage (PMP)

Definition:
The planned maintenance percentage is the number of hours spent on planned chores compared to the overall number of hours spent on maintenance.

Formula:

Explanation:
This displays how much of your maintenance plan is proactive instead of reactive.

Importance:
A maintenance department with high PMP values is doing a good job. Organizations are less likely to have unexpected failures or downtime if more than 90% of their maintenance activity is planned.

8. Inventory Turnover

Definition:
This number shows how often inventory is utilized and restocked over a certain amount of time.

Formula:

Explanation:
It shows how well your stock is being handled. High turnover shows that the inventory is being used well, whereas low turnover means that there is too much or old goods.

Importance:
If you don’t manage your inventory well, you could lose money because you have too much stock that you don’t need or have to pay for downtime because you don’t have the right parts.

9. Overall Equipment Effectiveness (OEE)

Definition:
OEE is a measure of how well a machine is being used. It is made up of three main parts: availability, performance, and quality.

Formula:

Explanation:
It shows the percentage of time spent on manufacturing that is actually

Importance:
A low OEE could mean that there are difficulties like machines that break down often, cycles that take a long time, or errors in quality. A world-class OEE is 85% or greater.

10. Maintenance Backlog

Definition:
This is the entire amount of maintenance work (in man-hours or tasks) that has been approved but hasn’t been done yet.

Explanation:
It serves as a workload indicator for the maintenance team.

Importance:
A lot of backlog means that there aren’t enough resources or planning. Most businesses think a backlog of one to two weeks is okay.

CMMS: The Digital Backbone for Maintenance Metrics

eMaint, Fiix, and SAP PM (Plant Maintenance Module) are all examples of modern computerized maintenance management systems (CMMS) that let you keep track of, manage, and analyze important maintenance parameters all in one place. These digital tools help maintain plans based on data by providing automation, real-time dashboards, and strong reporting features.

With a well-implemented CMMS or SAP PM system, maintenance teams can:

• keep an eye on important metrics like Mean Time Between Failures (MTBF) and Mean Time to Repair (MTTR).
• Keep an eye on Planned Maintenance Percentage (PMP) and Preventive Maintenance (PM) compliance.
• Use inventory turnover rates to predict how many extra components you’ll need.
• Use failure rate analytics to find patterns in failures that happen again and over again.
• Use Overall Equipment Effectiveness (OEE) to get ideas about how to improve your long-term maintenance plan.

SAP PM Module Integration

The SAP ERP ecosystem includes the Plant Maintenance (PM) module, which is a strong CMMS. It lets industries that use a lot of assets:

• Automate work order management and maintenance notifications
• Plan maintenance jobs that are both preventative and predictive
• Connect asset hierarchies to functional areas and equipment information
• Keep track of and look at the history of your equipment to find the core cause.
• Connect with materials management (MM) to keep track of spare parts without any problems.
• Make reports that are ready for audits and inspections that show compliance.

Importance:

Companies that use CMMS platforms or SAP PM modules say that they have seen big gains in:

• Reliability and uptime of assets
• Control of maintenance costs by making the best use of manpower and parts
• Following the rules by keeping accurate records and schedules
• Making decisions based on real-time data and past experiences

Using digital maintenance tools like SAP PM and new CMMS platforms makes it easier to do proactive, predictive, and performance-based maintenance management.

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Leading vs. Lagging Indicators

There are several different types of maintenance metrics:

• Leading indicators are measurements that assist you forecast future changes by showing you how likely they are to happen (for example, PM Compliance and Planned Maintenance %).
• Lagging indicators are metrics that demonstrate how well something did in the past (for example, MTBF and MTTR).

The finest maintenance programs use both types to keep getting better.

What are the 5 Ms in maintenance?

For context, effective maintenance also addresses these five pillars:

1. Man: Skilled workforce with proper training
2. Money: Adequate budgeting for tools and replacements
3. Materials: Timely availability of quality spares
4. Methods: Proven procedures and documentation
5. Machine: Reliable and well-monitored equipment

These are very important for Total Productive Maintenance (TPM) and getting world-class results.

Knowing and using important maintenance parameters like MTBF, MTTR, OEE, and PM Compliance gives businesses strong tools to lower expenses, cut down on downtime, and boost productivity. Digital tools like CMMS may help maintenance teams go from putting out fires to managing assets proactively.

By keeping an eye on these KPIs and making sure they are in line with business goals, companies not only make their equipment more reliable, but they also get a strategic edge in operational excellence.

Refer the below link for What is maintenance and Types of Maintenance

What is maintenance? Types of Maintenance

FAQ in Maintenance Metrics

What Are Maintenance Metrics in Industrial Operations?

Key performance indicators (KPIs) for maintenance are numbers that show how well and efficiently your maintenance work is being done. Organizations may keep an eye on the health of their assets, measure the effectiveness of their upkeep, and push for ongoing improvement with these quantitative metrics. Companies can find gaps, improve maintenance plans, and cut down on downtime by looking at maintenance indicators like Mean Time Between Failures (MTBF) or Overall Equipment Effectiveness (OEE).

Boost Reliability: What is Predictive maintenance (Pdm)?

What is a Maintenance KPI (Key Performance Indicator)?

A Maintenance KPI is a specific goal or standard that is used to measure how well maintenance plans are working. Metrics give you raw statistics, like failure rates and downtime hours. KPIs, on the other hand, give you performance goals, like raising asset uptime by 10%. A good KPI for improving asset reliability, for instance, may be lowering Mean Time to Repair (MTTR) by 15% during the next quarter.

What are the 4 Core Maintenance Performance Metrics?

The following four metrics are very important for judging how well IT and industrial maintenance systems work, especially when they are used with DevOps or reliability-centered maintenance (RCM) frameworks:

1. Deployment Frequency: This tells you how often new modifications or upgrades are successfully put into production.
2. Lead Time for Changes: This is the time it takes to make a change and then put it into the live environment.
3. Change Failure Rate: The change failure rate is the percentage of modifications that cause problems in manufacturing.
4. Mean Time to Restore Service (MTTR): Mean Time to Restore Service (MTTR) is the average amount of time it takes to fix a problem and get things back to normal.

These metrics help organizations assess responsiveness, stability, and overall maintenance efficiency.

Deep Dive: What is Reliability Centered Maintenance (RCM)?

What Is PMO (Planned Maintenance Optimization) in Maintenance Management?

Planned Maintenance Optimization (PMO) is a way to make existing preventive maintenance (PM) programs better and more effective. PMO means looking at the history of equipment failures, how often maintenance tasks need to be done, and how important the assets are to change maintenance schedules, get rid of unnecessary jobs, and make things more reliable. The goal is to find a cost-effective balance between preventive and corrective maintenance that keeps unplanned downtime to a minimum while extending the life of assets.