What is Repair Time?

This is a key performance indicator that represents the average time it takes to repair equipment or an asset. Also commonly known as time to repair, mean time to recovery, and mean time to repair or replace (MTTR) the terms for these maintenance KPIs are frequently used interchangeably.

By definition, it includes the amount of time spent diagnosing the issue, acquiring parts, and performing the actual repairs to return the equipment from system failure to fully operational status. This metric helps understand the efficiency of current maintenance team activities and the reliability of equipment.

How is it Calculated?

The time to repair clock starts ticking the moment an equipment failure occurs until the time the asset resumes normal operations. Calculate the following to determine the time to repair average value:

1. Record each instance of equipment failure and the time it takes to restore its functionality.

2. Add the total repair time for all failures over a specified time period to obtain the total repair time value.

3. Divide the total repair time value by the number of repairs carried out during the specified period. 

With TTR representing the time to repair, N as the number of repairs over a period, and T as the total repair time value, the formula would look like this:

[TTR = T / N]

To illustrate for practical application, over the course of a month, a facility experienced 5 equipment failures. It took 2, 1, 3, 2, and 3 hours respectively, giving you five total repairs with a total repair time value of 11. Written out as a formula, the result would be as follows:

[TTR = 11 / 5; TTR = 2.2]

You receive a repair time value of 2.2 in this example. The lower the total time to repair, the more efficiently maintenance teams are doing their job and the more reliable the specific asset is.

Practical Examples of How Repair Time is Used

Facility managers and maintenance teams use mean time to repair measurements to calculate a wide vareity of other metrics as well as informing higher-level decisions. 

• Maintenance efficiency: Tracking MTTR and analyzing the results helps determine system reliability and the efficiency of the maintenance team.
• Scheduling: Mean time to repair results help predict unplanned downtime due to system failures and empowers facilities to schedule operations accordingly.
• Cost analysis: Extended times to repair can factor into higher labor costs and potential production loss, which impacts budget planning.
• Vendor performance: If you outsource repairs, the MTTR metric can help assess vendor reliability and efficiency.

To illustrate a practical use of time to repair, consider a transportation company. This outfit might use MTTR to schedule bus maintenance. Knowing the average time it takes to get a vehicle back on the road, the company can reduce downtime during off-peak hours and minimize disruption to services.

Ways to Reduce MTTR

Several factors go into reducing the average time to repair in any given period. Employing one or more of these strategies can help increase equipment availability, reduce downtime costs, and improve the repair process as well as the mean time to repair to avoid a high MTTR.

• Training: Provide continuing education courses for maintenance personnel to keep their skills up-to-date and improve their efficiency.
• Standardization: Develop operating procedures for common repairs to improve repair times and streamline repair processes. 
• Inventory management: Keep critical spare parts and materials in stock on-premises to avoid repair delays when equipment failure occurs. 
• Tools and Equipment: Ensure you have the proper tools and equipment on hand to conduct repairs at a moment’s notice to reduce unplanned downtime and lost productivity.
• Root cause analysis: After repairs are complete, examine the source of the failure and consider actions to prevent similar issues in the future.
• Maintenance planning: Incorporate a commprehensive maintenance plan into your standard operating procedures. Sound maintenance strategies can dramatically reduce downtime and extend the lifespan of equipment.

FAQs

Is mean time to repair (MTTR) the same as mean downtime (MDT)?

Mean time to repair or mean time to recover communicate the same information. However, mean downtime represents a slightly different metric. MTTR strictly expresses the average amount of time an asset is non-operational due to repair processes or replacement. Mean downtime (MDT) represents an average of all instances of an asset’s time not in use, regardless of the reason.

What is an acceptable mean time to repair?

This can vary by equipment type, manufacturer, and many other factors. Check with your manufacturer for recommendations, because calculating MTTR is key to prevent unplanned maintenance and future failures. Many equipment makers provide references that sum up expected times on their equipment by task.

What other maintenance metrics do facilities commonly use?

Other measurements frequently used in maintenance include mean time between maintenance (MTBM) and mean time between failures (MTBF). MTBM represents the average time a piece of equipment operates before having to be shut down for upkeep tasks. This differs slightly from MTBF, which counts the average time a piece of equipment lasts before it loses functionality, whether it’s been shut down for maintenance or in operation.

In conclusion, this vital metric that helps facilities manage and improve their maintenance processes. By effectively measuring and working to reduce failure rate, unplanned downtime and the time it takes to fix a system, facilities can enhance operational efficiency and total uptime, reduce costs, and improve overall equipment effectiveness (OEE).