Patterns Of Failure

Failures manifest in one of four primary patterns. They are described below, together with their approximate failure percentage when compared to the entire population of process machinery in industry.

Wearout – Constant hazard rate with a distinct wearout region.

Bathtub – Infant mortality, constant hazard rate, and distinct wearout.

Constant Failure Rate – Constant hazard rate with little or no changes over the life.

Infant Mortality – Infant mortality followed by a constant hazard rate. Infant mortality is clearly the primary failure pattern. Scheduled maintenance activities do little or nothing to defend against the portion of infant mortality failures. Assets where early life failures are a significant problem should be examined using root cause failure analysis.

See also Bathtub Curve.