End of Life(EOL)

The estimated time from the present until an equipment item reaches a condition where it can no longer perform its intended function safely and must be repaired, replaced, or retired. For static equipment, RUL is typically calculated from the current measured wall thickness, the minimum required thickness, and the corrosion rate. For rotating equipment, RUL may be estimated from degradation models fitted to condition monitoring data.

The complete span of an asset's existence from initial conception through design, procurement, construction, commissioning, operation, maintenance, modification, and eventual decommissioning and disposal. Asset lifecycle management optimizes the total cost of ownership by making informed decisions at each stage that consider the full remaining lifecycle, not just the immediate cost.

An engineering assessment methodology used to determine whether equipment with identified flaws, damage, or degradation can continue to operate safely and reliably for a defined future period. FFS evaluations quantify the remaining structural capacity of degraded equipment using the procedures in API 579-1/ASME FFS-1, considering the specific type and extent of damage relative to the design margins.

The minimum acceptable wall thickness below which equipment must be retired from service, repaired, or re-rated. Retirement thickness equals the minimum required thickness for pressure containment plus any additional thickness required by the applicable code (such as structural minimum for external loads, corrosion allowance for future service, or minimum for NDE reliability). When measured thickness reaches retirement thickness, the equipment has exhausted its design margin.