Pareto Chart for Downtime Causes — OEE Equipment & SRE Outage 80/20
A downtime Pareto chart ranks equipment or system outage causes by total lost minutes and plots the cumulative percentage curve ($C_k$) to target Total Productive Maintenance (TPM) and SRE reliability engineering.
Tip: Paste Excel or Google Sheets rows (Ctrl+V / ⌘V) directly into any cell.
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OEE Availability = (Planned Run Time - Total Downtime) / Planned Run Time. Top-k downtime share = sum_{i=1..k}(Min_(i)) / Total Downtime.
Chart Design & Use-Case Tips
- 01OEE Availability = (Planned Run Time - Total Downtime) / Planned Run Time. Top-k downtime share = sum_{i=1..k}(Min_(i)) / Total Downtime.
- 02Always chart downtime by total lost minutes (duration) in addition to event count—a single 300-minute mechanical failure impacts OEE Availability far more than ten 2-minute resets.
- 03Focus maintenance kaizen events on the causes to the left of the 80% threshold line.
- 04Track the Sum readout in the telemetry bar to watch total monthly unplanned downtime minutes trend down.
Frequently Asked Questions
Why measure downtime Pareto in minutes rather than incident count?+
Counting incidents treats a 30-second sensor trip equally with a 4-hour bearing seizure. Weighting by lost production minutes focuses engineering on true OEE and SLA recovery.
Can cloud SRE teams use this for SLA outage post-mortems?+
Yes—replace machine causes with cloud incident categories (e.g., DB Connection Pool, Bad Config Deploy, Third-Party API, DNS) and plot downtime minutes or error-budget burn.
Does the chart automatically calculate the cumulative 80% line?+
Yes, the right-hand axis plots 0% to 100% cumulative share with a dashed horizontal threshold at 80%.