Calculating and Improving Mean Time to Repair

Maintenance metrics make it possible to quantify maintenance program performance, which can provide the basis for data-driven continuous improvement. Mean Time to Repair is one especially crucial metric for gauging response times and the overall success of maintenance departments. 

What is Mean Time to Repair (MTTR)?

Mean Time to Repair (MTTR) is a widely used maintenance metric that provides a clear and actionable picture of how long it takes your technicians to complete specific maintenance tasks. Maintenance operations will often use MTTR data as a Key Performance Indicator (KPI) to determine how efficient maintenance teams are at diagnosing issues and restoring equipment to proper working order

What does MTTR mean?

The MTTR formula calculates the average amount of time needed to conduct servicing, complete a repair, or replace a component of a critical physical asset and return it to functionality. A lower MTTR score indicates a lower time to completion. It indicates that your maintenance team has been successful at completing tasks in a timely and efficient manner. This is also an indication that your maintenance operation is effective at minimizing downtime

A higher MTTR means your team has demonstrated a slow incident response time. This may be an indication that your maintenance team is not successful in optimizing its time or that they’re missing essential resources. 

In short, a low MTTR is usually a sign that your organization has a successful maintenance program, whereas a high MTTR suggests the need for improvements in your maintenance processes, training programs, or resource allocation strategies.

MTTR formula: how do you calculate MTTR?

Calculating MTTR is simple. You can calculate MTTR by dividing the total downtime due to repairs for a specific piece of equipment by the number of repairs performed over a specific period.

The MTTR formula

Follow these five steps to calculate MTTR:

Step 1

Select a period for measurement (i.e. one month, one year, 5 years, etc.).

Step 2

Calculate the total downtime for this asset throughout this period.

Step 3

Tally up the total number of incidents or outages and the repairs needed during the selected period.

Step 4

Divide the total time by the number of repair incidents for the selected period.

Step 5

Your formula should look like this:

  • Total maintenance time / Number of repairs = MTTR

An example of the MTTR formula in action

  • Selected Duration: 1 month
  • Number of repair incidents in 1 month: 3
  • Total downtime for 3 repairs: 3 hours + 2 hours + 4 hours = 9 hours
  • 9 (Total maintenance time) / 3 (Number of repairs) = 3 (MTTR)

In this sample MTTR calculation, we can see that the average time to repair the physical asset during this period was 3 hours.

How do maintenance teams use MTTR?

Broadly speaking, maintenance teams will use MTTR to evaluate and improve their performance in various critical areas including parts replacement, work order management, and even recruitment and hiring. 

Below, we’ll take a closer look at a few areas of incident management where MTTR is commonly calculated and used to aid in organizational decision-making. 

  • Benchmarking maintenance team performance and comparing internal MTTR figures against historical data or industry standards to identify areas that need improvement.
  • Settling repair versus replacement discussions. A higher MTTR for specific assets potentially indicates that the time and money spent on an asset may mean that replacement is a more cost-effective solution. 
  • Allocating resources including spare parts, tools, and personnel. A high MTTR may indicate the need for new hires, more equipment, or a new approach to specific processes.
  • Optimizing staffing levels and training needs in instances where consistently high MTTR suggests the need for new personnel or additional on-the-job training. 
  • Improving processes and streamlining workflows by using high MTTR to identify and resolve inefficiencies, bottlenecks, and recurring issues that may be contributing to protracted repair times.
  • Managing work orders more effectively by using MTTR to spotlight delays in the process of approving, executing, or completing work orders, as well as more effectively setting priorities based on the criticality of assets
  • Transitioning from reactive to preventive maintenance with the help of MTTR and other maintenance metrics to better predict likely equipment failures and plan preemptive maintenance activities based on these findings.  

10 tips for improving MTTR

Keeping track of your organization’s MTTR scores is an important preliminary step in improving the performance of your maintenance program. Identifying critical maintenance tasks with a high MTTR score can help you identify inefficiencies and set a benchmark for performance improvements.

Here are 10 actionable tips for improving MTTR in your organization with an emphasis on building a more strategic, data-driven, and efficient maintenance program. 

  1. Implement preventive maintenance by building scheduled and routine services into your maintenance calendar to address potential issues before they arise, preempt unexpected failures, and dramatically reduce the overall downtime used to calculate MTTR
  2. Invest in continuous training to enhance the knowledge and skills of your maintenance technicians, ultimately cultivating an in-house team with the ability to perform maintenance tasks faster, more efficiently, and more effectively. 
  3. Use advanced diagnostic tools and technologies such as condition monitoring sensors and machine learning to track equipment performance in real time, identify the root cause of issues before they lead to equipment failure, and perform repairs with little to no unplanned downtime
  4. Refine spare parts inventory management with the support of an advanced inventory management software system to ensure that critical spare parts, tools, and materials are always available as needed, and that equipment downtime is never prolonged by a shortage of these resources. 
  5. Streamline work order management to eliminate delays in approval, transmission, execution, or completion, ultimately ensuring that your MTTR is never elevated due to process inefficiencies
  6. Enhance communication and collaboration between maintenance team members, as well as between your department and other relevant departments such as inventory management and manufacturing, ultimately ensuring that team members across the organization have access to the same data, work orders, maintenance schedules, and more. 
  7. Conduct regular data analysis to better understand recurring performance issues and drive improvements in repair scheduling to increase equipment uptime across the board. 
  8. Establish Standard Operating Procedures (SOPs) for repairs, parts replacement, and other routine maintenance tasks to promote consistency and efficiency in all maintenance activities. 
  9. Conduct regular audits of critical assets, ensuring equipment, machinery, and facilities are in good, safe, and healthy working order as well as promoting early identification and resolution of potential issues.  
  10. Implement a Computerized Maintenance Management System (CMMS) to consolidate and automate activities such as work order management, inventory tracking, equipment performance monitoring, and maintenance scheduling on a single, easy-to-use, data-driven platform. 

Leading-edge CMMS solutions like Limble’s also help to streamline interdepartmental collaboration and communication, promote standardized repair procedures, and incorporate advanced diagnostic tools into your maintenance strategy. These functions are especially valuable for organizations looking to transition from largely reactive maintenance strategies to programs with a greater emphasis on preemptive maintenance and the prevention of equipment breakdowns 

Collectively, all of these improvements are likely to reduce your MTTR and promote a more efficient and cost-effective maintenance program. 

Learn more about essential maintenance metrics

MTTR is just one of several essential maintenance metrics. Any high-performing maintenance team will rely on a cross-section of illuminating tracking and reporting metrics for evaluation, decision-making, and continuous improvement.

Systematic and ongoing oversight of key performance indicators can help your maintenance team

  • Pinpoint inefficiencies and bottlenecks, delivering insights that can help you improve training, repair procedures, and other aspects of your maintenance processes.
  • Make data-driven decisions about how to schedule future maintenance activities, allocate physical resources, and delegate maintenance personnel.
  • Optimize your broader maintenance strategy by using monitoring metrics to anticipate potential issues with equipment, consequently engage in predictive maintenance actions, and ultimately reduce unplanned downtime and maintenance costs;
  • Improve the reliability of your physical assets by combining MTTR findings with additional maintenance metrics such as Mean Time Between Failures (MTBF), Mean Time to Recovery, and Overall Equipment Effectiveness (OEE), ultimately using these combined figures as baseline measures for improving equipment performance.
  • Boost your maintenance team’s performance through regular, transparent, and quantifiable evaluation, and consequent improvement initiatives. 

Want to learn more about the value of clear and measurable maintenance metrics? Check out our Ultimate Guide!

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