Bathtub Curve
The bathtub curve describes how an asset's failure rate changes over its life: high early failures from manufacturing or installation defects, a long flat period of low random failures, then a rising rate as wear-out sets in. Its shape guides maintenance strategy by life phase.
The name comes from the curve's profile. The early 'infant mortality' region argues for commissioning checks and burn-in to weed out defective units. The flat 'useful life' region has a roughly constant, random failure rate where condition monitoring and run-to-failure can be appropriate. The rising 'wear-out' region justifies time-based replacement before failures cluster. Recognising which phase an asset is in prevents both over-maintenance and surprise breakdowns.
In context and practice
Bathtub Curve is a foundational concept in industrial operations and reliability engineering. Understanding and properly implementing bathtub curve helps teams reduce downtime, optimize energy use, and improve equipment lifespan. It is often a key differentiator between plants running at industry-average efficiency and those achieving best-in-class performance.
Closely related terms include Weibull Analysis, MTBF (Mean Time Between Failures), RCM (Reliability-Centred Maintenance). These concepts often work together in industrial practice — mastering one usually means understanding all of them.
In your plant: When planning maintenance, reliability or efficiency projects, clarify your approach to bathtub curve. Ask vendors or consultants how they implement it. The specifics matter — two plants with the same definition of bathtub curve may execute it very differently based on their equipment, age, and operational culture. The gap between definition and execution is where real value (or waste) lives.
Measuring success: Bathtub curve programs succeed when you can measure their impact. Set a baseline, implement the practice, and track the outcome — downtime reduction, energy savings, cost avoidance, or compliance improvement. Most plants find that a 3–6 month pilot clarifies the true value and ROI of bathtub curve. Don't guess; measure.
Why it matters: bathtub curve is not an end in itself, but a lever in your plant's overall efficiency and reliability strategy. It works best when part of a system: clear ownership, investment in tools or training, executive sponsorship, and regular review. Isolated initiatives often fizzle. Embedded bathtub curve programs compound, delivering value year after year as the practice matures and spreads.
Related terms
Weibull Analysis · MTBF (Mean Time Between Failures) · RCM (Reliability-Centred Maintenance)