MTBF & MTTR Data Collection Worksheet

What the worksheet is designed to capture

The template separates period-level exposure data from individual failure-event evidence. This prevents operating hours from being repeated and accidentally summed once for every failure.

• PERIOD_SUMMARY row: one row for each asset group and reporting period. Enter the reporting dates and total operating hours here. Leave failure-event and repair-stage fields blank.
• FAILURE row: one row for each event that meets the agreed qualifying-failure definition. Enter the event timing, failure mode, delay categories and restoration evidence. Leave period operating hours blank.

Use a stable, non-confidential Asset_Group_ID and the same reporting dates to connect the summary and event rows. Do not use personal names, access credentials, restricted asset identifiers or confidential work-order narratives.

Recommended setup before recording data

1. Define the asset population: one machine, a group of comparable machines or another clearly stated boundary.
2. Define a qualifying failure: state whether it includes only functional failures, production-stopping breakdowns or another consistent rule.
3. Define operating time: use actual or consistently defined scheduled running hours; do not alternate between calendar and operating exposure.
4. Define the repair clock: document the start and stop events and which delay categories remain inside total restoration time.
5. Set the reporting period: use dates long enough to produce meaningful exposure and retain zero-failure periods instead of discarding them.

Field guide

Period and event identity

• Record_Type: enter PERIOD_SUMMARY or FAILURE.
• Asset_Group_ID: a consistent generic identifier for the selected asset population.
• Reporting_Period_Start / End: the common period used for operating hours and failures.
• Failure_Event_ID: a non-confidential unique reference that prevents duplicate counting.
• Qualifying_Failure_Y_N: record whether the event meets the agreed definition; calculate failure count from Y events only.
• Failure_Mode: a concise functional description, not merely a symptom or replaced part.

Repair-time breakdown

• Response_Hours: recognition, notification and maintenance response before safe access begins.
• Safety_Access_Hours: approved isolation, PTW/LOTO, cooling, draining, depressurization, production release and physical access preparation.
• Diagnosis_Hours: evidence gathering, testing, drawing review and confirmation of the failed function.
• Logistics_Hours: waiting for approved spares, tools, lifting equipment, contractors or OEM information.
• Active_Repair_Hours: removal, correction, installation, adjustment and reassembly.
• Test_Release_Hours: inspection, functional testing, safeguards restoration, documentation and operational handback.
• Total_Included_Restoration_Hours: the duration between the agreed clock start and stop. It should reconcile with included stage durations.

Action and verification

• Clock_Start_Definition / Clock_Stop_Definition: record the rule so later reviewers can confirm that periods are comparable.
• Corrective_Action: the specific improvement selected after reviewing the dominant verified delay or failure mode.
• Verification_Method: how later comparable evidence will show whether the action worked.
• Reviewer / Review_Date: optional governance fields; use a role or approved identifier where privacy rules require it.
• Notes_No_Confidential_Data: short interpretation notes only. Keep private, personal, security-sensitive and proprietary information out of this public template.

Map the worksheet to the KPI formulas

Choose either active repair time or total included restoration time for MTTR and label the result clearly. Do not mix definitions between periods. A zero-failure period provides useful exposure evidence but does not produce a finite observed MTBF by simple division; carry the operating hours into a longer observation window rather than inventing a result.

After validating the records, enter the period operating hours, qualifying-failure count and chosen total repair hours in the MTBF, MTTR & Availability Calculator.

Data-quality checks before calculation

• Check that each event ID appears once and belongs to the stated asset group and period.
• Confirm restored time is later than failure-start time and that units are hours throughout.
• Reconcile total included restoration time with the delay stages included by your definition.
• Investigate blank timestamps, negative durations, overlapping events and reopened failures.
• Confirm incomplete repairs are not counted as completed restoration events.
• Review whether night-shift, contractor and repeat failures are captured consistently.
• Retain the failure count and individual durations beside the average so a small sample remains visible.

Interpretation and safety limitations

This worksheet supports education and preliminary reliability analysis. It is not a CMMS replacement, audited business record, competency certificate or basis for declaring equipment safe. A lower MTTR does not prove safer or better maintenance if required controls, permanent repair quality or functional testing were reduced.

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