A plant can complete every preventive maintenance task on schedule and still be sliding toward a reliability problem — if no one is tracking how long assets actually run between failures, how fast the team responds when they do fail, or whether that PM program is being executed at the rate the schedule claims. PM compliance below 90% predicts a measurable MTBF decline 60 to 90 days later. The gap between doing the work and measuring the work is where most reliability programs quietly lose ground. Sign up to calculate EFOR, EAF, MTBF, MTTR, and PM compliance automatically from your live work order data.
Why It Matters
When a turbine fails without warning, the question that follows is never just "why did it fail" — it's "what number would have told us three weeks ago." A scorecard built from spreadsheets, shift logs, and institutional memory can't answer that in time. A scorecard built from standardised, auditable work order data can. The five core metrics — EFOR, EAF, MTBF, MTTR, and PM compliance — aren't reported in isolation either; PM compliance is a leading indicator for the others, which is what makes tracking all five together more useful than watching any single number.
The Five Numbers That Define Reliability
Each metric answers a different question about the plant, and together they describe the health of the maintenance organisation more accurately than any one alone.
EFOR
Equivalent Forced Outage Rate — the share of time a unit is unavailable due to unplanned failures, the classic industry benchmark for unreliability.
EAF
Equivalent Availability Factor — the share of maximum possible generation the unit was actually available to produce, across planned and unplanned time.
MTBF & MTTR
MTBF tells you when things tend to break; MTTR tells you how fast the team gets them back running once they do.
EFOR and EAF describe generation-level reliability that regulators and offtakers see, while MTBF and MTTR describe the maintenance-level performance that actually drives those two numbers up or down over time.
Formulas And Best-In-Class Targets
| KPI |
Formula |
Target |
| MTBF |
Operational uptime ÷ number of failures |
Critical rotating equipment: over 2,000 hrs |
| MTTR |
Total repair time ÷ number of failures |
Lower is better, tracked by asset class |
| Availability |
MTBF ÷ (MTBF + MTTR) |
Plant and equipment specific |
| PM Compliance |
PMs completed on time ÷ PMs scheduled |
Above 90%, since below that MTBF decline follows |
Stop Calculating KPIs By Hand
Oxmaint computes EFOR, EAF, MTBF, MTTR, and PM compliance directly from your work order and asset data, live, with no spreadsheets and no end-of-month scramble. Sign up for a free trial to run it on your own fleet, or book a demo to see it configured for your plant.
Where KPI Scorecards Break Down
Numbers Calculated By Hand
Two engineers spend days each month pulling data from separate systems
Reports Are Weeks Stale
A gradual trend goes unnoticed for months because the report only updates monthly
Free-Text Failure Codes
Work orders closed with notes instead of a controlled list, so events can't be grouped
Timestamps Not Mandatory
Reported, work-started, and work-completed times missing from too many work orders
PM Compliance Watched Alone
Schedule adherence tracked without connecting it forward to the MTBF it predicts
One Dashboard For Everyone
Control room, management, and executive audiences all shown the same cluttered view
Frequently Asked Questions
Q
Why does PM compliance matter more than it looks like it should?
PM compliance is a leading indicator, not just a scorecard entry — data shows compliance dropping below 90% tends to predict a measurable MTBF decline 60 to 90 days later. It measures whether the maintenance program is actually being executed, not just whether it exists on paper.
Q
What's the difference between EFOR and EAF?
EFOR isolates unplanned, forced unavailability — it's the classic measure of unreliability. EAF is broader, covering the full share of maximum possible generation the unit was actually available to produce across both planned and unplanned time, so a unit can have a strong EAF while still having an EFOR problem worth investigating.
Q
What does a CMMS need to produce trustworthy KPI numbers?
Mandatory reported, work-started, and work-completed timestamps on every work order, a controlled list of failure codes instead of free text, and required resolution fields capturing the fix and parts used — without that discipline, MTBF and MTTR numbers can't be defended in an audit.
See The Trend Before It Becomes A Failure
Oxmaint keeps EFOR, EAF, MTBF, MTTR, and PM compliance tied to their evidence in one live, auditable dashboard, so proving your reliability program works doesn't mean three days of manual reporting every month. Sign up for a free trial to run it on your own fleet, or book a demo to see it configured for your team.
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