How To Calculate MTTR In 4 Easy Steps (Tips To Reduce It)

By Indeed Editorial Team

Published 29 September 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Unplanned downtime is one of the biggest reasons for operational inefficiencies and loss of revenue in an organisation. Companies use metrics like the mean time to repair (MTTR) to monitor and reduce unplanned downtime. If you are working in the manufacturing sector, knowing how to calculate this metric can help you minimise downtime and improve the efficiency of your manufacturing team. In this article, we discuss what MTTR is, explain how to calculate MTTR with a step-by-step guide, discuss its benefits and share strategies to reduce it.

What Is MTTR?

The mean time to repair represents the average time to repair a piece of machinery. Also known as mean reactive maintenance time, it is the time taken by repair personnel or maintenance teams to restore machinery to a fully functional state. The MTTR indicates how easy or difficult it is to repair a piece of equipment. Calculating and reducing the MTTR can help minimise unplanned downtime and improve operational efficiency.

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How To Calculate MTTR

Use the following steps to learn how to calculate MTTR:

1. Familiarise yourself with the formula

The mean time to repair is calculated in hours using the formula:

Mean time to repair (MTTR) = Total unplanned maintenance time / Total number of failures of an asset over a specific period

This formula assumes that trained personnel carry out the repair and maintenance tasks sequentially, as and when they occur. It does not consider planned downtime or routine maintenance tasks.

2. Determine the total repair time

You can determine the repair time in two ways. First, you can calculate the overall time to repair all equipment. Alternatively, you can track the total repair time for a particular piece of equipment. For example, consider a manufacturing company that tracks the repair time for their core machine, which is critical for production. If the repair personnel carry out five repair jobs on this machine in a year, with each task requiring three hours, the total repair time is 15 hours per year.

3. Calculate the total number of repairs

Determine how often the repair and maintenance team fixes specific machinery or parts. In the previous example, the total number of repairs the maintenance team completed in a year was five. Companies often maintain a logbook that tracks the number of repairs done by the maintenance team. You can refer to the logs to find the frequency of repairs on specific machinery.

4. Divide total repair time by the total number of repairs

Apply the formula for MTTR by dividing the total repair time by the total number of repairs. In the above example, the mean time to repair is:

MTTR = 15 / 5 = 3 hours

The MTTR helps in evaluating performance, efficiency and productivity. You can use the MTTR results to improve operational efficiency and reduce the average unplanned maintenance time. Depending on the project you are tracking the MTTR for, you can implement the right strategies to identify and fix repairs quickly. It is important to note that MTTR is not an objective value. It varies depending on the machinery type, its age and usage frequency. Often, companies aim for a lower MTTR to reduce unplanned downtimes.

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Benefits Of MTTR

Periodic MTTR analysis helps organisations make informed and data-driven decisions while maximising available resources. Here are the top benefits of calculating MTTR:

Make proactive repair or replacement decisions

When equipment ages, the MTTR usually increases as it takes longer to find suitable spare parts and repair the asset. If you notice an increase in MTTR for equipment over time, you can decide if repairing or replacing the machinery is the better choice. MTTR helps you predict future spending on the asset and calculate the revenue due to lost production. You can compare these values with the cost of new machinery to determine whether purchasing new equipment helps you save money, as it runs with fewer breakdowns and is easier to repair.

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Refine the work order process

Tracking the mean time to repair metric helps you discover problems in the work order process and implement suitable measures to correct them. The MTTR helps manufacturing teams identify inefficiencies in the production process. It can help teams identify delays in notifying repair personnel, the availability of repair tools and resources, the level of training the repair team needs to take corrective measures to eliminate inefficiencies.

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Organise spare parts

While the mean time to repair metric does not consider the time waiting for spare parts, it does account for the time spent locating spares that your team already has. Finding the correct spares for machinery is time-consuming and adds to the overall downtime. Disorganised storerooms with mislabeled parts increase the time to repair and resume production. A high MTTR can indicate improper inventory management, providing teams with critical insights to implement a better system to organise spare parts.

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How To Reduce MTTR

Here are a few strategies for organisations to reduce MTTR:

1. Monitor equipment and machinery to reduce failure detection time

The first step to reducing the mean time to repair is to identify issues fast. Equipment monitoring systems help you identify problems quickly as soon as they occur and provide appropriate metadata to identify the source of the issue. An updated monitoring and alert setup can help you monitor the performance of equipment, machinery and systems in real-time.

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2. Leverage automated solutions to improve real-time monitoring

Automated monitoring solutions track the health and performance of machinery and equipment in real-time. These intelligent systems alert you to machine performance variations, helping you proactively identify and eliminate issues, even before they occur. Apart from identifying the issue, these tools can suggest suitable remedies for standard repairs and identify the right personnel to solve the problem, reducing the response time even further.

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3. Prioritise high-impact incidents

In the case of a single issue, the repair process is straightforward. The maintenance team identifies and resolves that specific issue. In real-life scenarios, multiple problems co-occur and it is crucial for repair personnel to prioritise incidents before acting. Instead of resolving issues in the order of occurrence, you can prioritise fixing critical incidents that cause the maximum impact. Alternatively, you can also sort incidents based on the tentative time to fix them, helping restore normalcy quickly and efficiently with minimum impact.

4. Create a reliable incident response plan

An incident response plan includes several processes, like surveillance, diagnosis, ordering spares, communication, resolution and other activities associated with incident resolution. Ensure that you pay attention to all aspects of incident resolution to respond and resolve problems faster. There are several types of incident response plans, including:

• Ad hoc: This approach relies on figuring out the action plan after a problem occurs. This method is suitable for organisations that do not have resources for a dedicated in-house repair and maintenance team.

• Rigid: In this method, companies have a large in-house maintenance team who responds to and resolves any unexpected issues.

• Flexible: This approach combines both ad hoc and rigid methods. While the on-call incident response team is smaller than the in-house maintenance team in the rigid approach, they are highly skilled and experienced in handling various issues.

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5. Define distinct roles in the incident response hierarchy

Besides the right incident response plan, having a well-defined team with established hierarchies helps reduce the mean time to repair. The best way to begin is by assigning a personnel lead, the employee responsible for handling the incident. Assigning a direct responsibility helps resolve issues quickly, as in most cases, team members are hesitant to take the lead voluntarily. Also, establishing the team hierarchy helps avoid conflicts that prevent faster resolutions.

6. Provide adequate training to the incident response team

Now that you have an incident response plan and team, the next important step is to ensure that they are knowledgeable in handling repairs quickly. Provide the team with ample training to be experienced in resolving different issues. You can use simulations to train the team on different scenarios. Ensure that multiple team members undergo training to handle a specific issue so that even if a critical team member is on leave, the others can address the problem quickly without waiting for the absent team member.

7. Implement chaos engineering

Chaos engineering is an incident response technique where team leaders intentionally inject problems into the equipment. This checks the robustness and preparedness of the incident response team to handle the repairs and resolve the issues in as little time as possible. Chaos engineering helps the incident response team proactively identify areas of improvement, reducing the MTTR in real time.