In-Line Inspection (ILI / Smart Pig)

In-line inspection uses an instrumented tool - commonly called a smart pig - that travels through a pipeline under product flow, recording sensor data (typically magnetic flux leakage or ultrasonic) along the full internal length of the line. ILI is the industry standard for finding internal and external wall loss, dents, and cracks on pipe that can accommodate a pig, and it remains the most direct way to measure metal loss anywhere along a pipeline. Its limitations are practical rather than technical: it requires launcher and receiver infrastructure, is typically run on a multi-year cycle rather than continuously, and cannot be used on unpiggable lines with tight bends, varying diameters, or no pigging infrastructure - which is a meaningful share of older distribution and gathering pipe.