Wall Loss

Wall loss is the reduction in a pipeline’s original wall thickness caused by internal or external corrosion, expressed either in absolute units or as a percentage of the nominal wall thickness. It is the primary quantity that in-line inspection tools are built to measure, because remaining wall thickness relative to MAOP is what determines whether a given corrosion feature is a monitoring item or an immediate repair. Wall loss data only becomes actionable when it is tied to a precise location and compared against a prior measurement at that same location - without that pairing, a single wall-loss reading tells you a defect exists but not whether it is stable or actively growing.