MTBF Explained: Use Failure History to Improve Asset Reliability

MTBF means Mean Time Between Failures.

It is a maintenance metric used for repairable assets. It helps teams understand the average operating time between one failure and the next.

For plant maintenance teams, MTBF is useful because it shows whether asset reliability is improving, getting worse, or staying the same. But MTBF should not be treated as a magic number. It becomes useful only when connected with failure history, asset criticality, PM quality, operating conditions, and corrective actions.

What MTBF means

MTBF answers this question:

How long does this asset usually run before it fails again?

A simple way to calculate it is:

Total operating time divided by number of failures.

For example, if a pump runs for 1,000 hours and fails 5 times, the MTBF is 200 hours.

That does not mean the pump will always fail exactly after 200 hours. It means the average time between failures has been 200 hours during the reviewed period.

Where MTBF is useful

MTBF is useful for repairable assets such as:

• Pumps
• Motors
• Compressors
• Conveyors
• Gearboxes
• Packaging machines
• HVAC equipment
• Refrigeration systems
• Production machines
• Utilities equipment

It is less useful for assets or components that are not repaired after failure, or where usage data is not reliable.

A good asset management software setup helps because failures must be linked to the correct asset.

Why MTBF matters

MTBF helps teams identify reliability problems.

A falling MTBF may indicate:

• Poor repair quality
• Wrong spare parts
• Inadequate lubrication
• Misalignment
• Overloading
• Weak PM tasks
• Poor operating conditions
• Repeated temporary fixes
• Aging equipment
• Design or installation issues

A rising MTBF may show that preventive maintenance, operator care, improved spares, or corrective actions are working.

MTBF needs clean failure data

MTBF becomes misleading when failure records are poor.

Common data problems include:

• Breakdown not recorded as a work order
• Same failure split into many records
• Multiple different failures grouped as one
• Asset selected incorrectly
• No clear failure code
• Downtime not captured
• Temporary repair not identified
• Operating hours not available

A work order management software process helps create cleaner failure history.

Do not use MTBF alone

MTBF should be reviewed with other metrics.

Use it together with:

• MTTR
• Breakdown frequency
• Downtime hours
• Repair cost
• Spare usage
• PM compliance
• Failure codes
• Asset criticality
• Production impact

For example, an asset with moderate MTBF but very high downtime impact may need more attention than an asset that fails often but is easy to repair with no production impact.

Use MTBF to improve PMs

MTBF can help improve preventive maintenance.

Ask:

• Are failures happening before the next PM is due?
• Did MTBF improve after changing PM frequency?
• Are PM tasks detecting early signs?
• Are technicians reporting abnormal findings?
• Are failures linked to lubrication, alignment, cleaning, inspection, or operation?
• Should the PM be time-based, meter-based, or condition-based?

A preventive maintenance software system helps teams adjust PMs based on actual reliability history.

Use MTBF in reliability review meetings

MTBF is useful when reviewed regularly.

Discuss:

• Top assets with lowest MTBF
• Assets where MTBF is decreasing
• Assets with repeated failure codes
• Assets where PMs are not reducing failures
• Assets that may need replacement or redesign
• Corrective actions that improved MTBF

Analytics and reporting software helps make these trends visible.

Bottom line

MTBF helps maintenance teams understand how often repairable assets fail, but it is valuable only when the underlying data is reliable.

MaintBoard helps teams capture breakdowns, asset history, work orders, failure causes, spare usage, downtime, PM compliance, and reliability reports. That gives maintenance managers better visibility into which assets need attention and whether reliability is actually improving.