Condition Monitoring Location(CML)

A measured wall thickness value obtained at a CML using non-destructive examination techniques, typically ultrasonic thickness gauging. Thickness readings are the primary quantitative data for calculating corrosion rates and remaining life of static equipment. Each reading is recorded with the CML identifier, measurement date, measured value, measurement technique, and the technician.

The rate of material loss due to corrosion or erosion, typically expressed in millimeters per year (mm/yr) or mils per year (mpy). Short-term corrosion rate is calculated between the two most recent thickness measurements; long-term corrosion rate is calculated from the original (or earliest) thickness to the most recent measurement. The more conservative (higher) rate is typically used for remaining life calculations.

The calculated time until the wall thickness at a CML or the minimum measured thickness on a component reaches the retirement thickness, based on the current measured thickness and the applicable corrosion rate. Remaining life is the inspection-data-driven equivalent of Remaining Useful Life (RUL), specifically calculated from thickness data for static equipment.

The wall thickness specified at the time of design and fabrication, before any in-service degradation. Nominal thickness is the starting point for remaining life calculations and is the thickness that should be measured at a CML immediately after construction. It includes the minimum required thickness plus the corrosion allowance plus any manufacturing tolerance.

A position in the asset hierarchy that describes a function or location within a technical system, independent of the specific physical equipment installed at that position. Functional locations are permanent — they represent where a function is performed — while the equipment occupying that location may change over time. This separation enables tracking of maintenance history by location even when equipment is replaced.