Mean Time Between Maintenance

What is Mean Time Between Maintenance?

Mean Time Between Maintenance (MTBM) is a maintenance metric that measures the average time elapsed between maintenance actions on equipment or systems. Maintenance Managers use MTBM to measure the duration a piece of equipment operates without any need for intervention. Organizations commonly use MTBM to measure the maintenance reliability of an asset and its maintenance needs. Companies typically apply MTBM to both corrective and preventive maintenance actions.

How is Mean Time Between Maintenance Calculated?

MTBM is calculated by dividing the total operational time by the number of maintenance actions that occurred during that time. In the following formula, T denotes the total uptime and D indicates the number of downtime occurrences due to unscheduled and scheduled maintenance activities.

[MTBF = T / D]

To calculate Total Operating Time, take into account the time that equipment is fully operational and running, then subtract all planned and unplanned downtime.

For example, if a machine operates for a total of 1,200 hours over a certain period and during that period maintenance was performed 6 times, the MTBM would read as follows:

[ MTBF = 1,200 / 6; MTBF = 200]

How Mean Time Between Maintenance is Used: Practical Examples

Organizations rely on MTBM for a variety of purposes. Not only does this maintenance metric help in calculating total maintenance costs and the average value of maintenance activities, but MTBM also assists with these critical strategies and processes.

• Maintenance Scheduling: MTBM helps to inform maintenance planning and scheduling, optimizing equipment operation time.
• Reliability Analysis: The MTBM metric helps reliability engineers assess equipment reliability. A higher MTBM score typically indicates more dependable equipment.
• Resource Allocation: MTBM provides critical information that helps managers make informed decisions in delegating maintenance resources and forming a budget.
• Performance Benchmarking: Reliability engineers and managers can measure MTBM statistics against industry standards and manufacturer benchmarks to evaluate the performance of repairable systems and equipment.

For instance, a utility company might use MTBM data to create maintenance schedules for transformers. If the MTBM across all equipment is lower than expected, they might investigate potential causes and take steps to improve the reliability of their equipment or adjust their repair processes.

Ways to Reduce Maintenance Frequency and Increase MTBM

Increasing MTBM means reducing the frequency and average maintenance time without compromising the equipment’s reliability and safety. These strategies can help raise your facility’s MTBM and lower costs overall.

• Quality Parts and Equipment: Spending a bit more for more dependable parts and higher-quality equipment can significantly reduce the failure rate and increase total uptime.
• Root Cause Analysis: When maintenance is performed, identify the root cause of any failures and address them to prevent recurrence.
• Preventive Maintenance: Implement a robust preventive maintenance program that can catch issues before they escalate.
• Predictive Maintenance: Use condition monitoring tools to predict when maintenance is needed, allowing for timely intervention before incidents occur, typically extending the time between maintenance actions.
• Operator Training: Ensure that personnel are qualified to correctly operate the equipment. Improper use can lead to unnecessary wear and tear, decreasing the MTBF value.
• Design Improvements: Modify or upgrade equipment to improve its reliability and extend the time between necessary maintenance.

For example, a manufacturing plant may improve MTBM by investing in a predictive maintenance system that uses vibration analysis in its manufacturing processes to anticipate when a machine is likely to need maintenance. The system alerts the appropriate personnel when vibrations reach a certain threshold, allowing the maintenance team to make adjustments before major repairs are necessary.

FAQs

What kinds of assets require MTBM tracking?

Almost every industry uses mean time between maintenance and mean time between failures to track the maintenance needs of many types of repairable systems and equipment. MTBM is a valued maintenance metric for critical internal systems such as HVAC, as well as crucial peripheral systems like sump pumps. Manufacturers typically track MTBM values on essential production equipment and important ancillary assets.

How do companies track MTBM?

There was a time when managers had to manually track mean time between maintenance, mean time between failures, and other performance indicators. The process could take hours, often taking up a full workday. Thankfully, in modern times, organizations have moved to computerized maintenance management systems (CMMS), which can monitor several items, such as maintenance activities and equipment conditions. CMMS software can collect data, analyze information, and provide managers with in-depth information to improve maintenance and manufacturing processes. Facilities management platforms like ServiceChannel make calculating key maintenance metrics quick, easy, and accurate.

What’s the difference between MTBM and MTBF?

MTBM differs slightly from another commonly used metric — Mean Time Between Failures (MTBF). MTBM measures the average time between any need for maintenance, whether for a product, system failure, or any other reason. MTBF only denotes the time lapse between a product or system failure, which usually requires corrective maintenance or repairs. As with MTBM, a higher MTBF indicates better equipment reliability. The MTBF calculation is the operation time in hours (O) divided by the failure rate (F) — [MTBF = O / F].

What is MTTR?

Mean Time To Repair or Replace (MTTR) is another important metric commonly used in equipment and facility maintenance. MTTR measures the average time it takes to repair an asset or replace individual components after a failure occurs. Reliability engineers and managers use this metric to determine the effectiveness of current maintenance practices. MTTR is frequently used alongside MTBM and MTBF metrics to evaluate the overall reliability of a system or asset.

What other metrics are used in facility maintenance?

Facility maintenance managers employ a variety of metrics designed to monitor asset performance and improve maintenance processes. Average time to completion measures the average time it takes maintenance teams to complete work orders in a given period. Equipment downtime tracks the total actual time production stops due to equipment failures or other issues. Organizations might utilize several other metrics as well, covering everything from personnel efficiency on the shop floor to equipment reliability.

MTBM is a crucial metric for understanding and improving equipment and system reliability. By extending MTBM through strategic maintenance practices, maintenance teams can reduce the total maintenance required. MTBM provides companies with information that helps them determine the need for improvements, improve operational efficiency, and increase total uptime.