Measurement Principle
The basic element of the metal loss survey is the high-resolution Magnetic Flux Leakage (MFL) technology. The pipe wall is magnetized axially to saturation level using the very latest permanent magnets. 

High magnetization levels are necessary to differentiate corrosion from other pipeline features such as hard spots, stress and strain variations and to minimize the effects of remanent magnetization and velocity.

In a pipeline with no flaws, the magnetic flux travels undisturbed through the walls. In the presence of internal and external metal loss, the flux “leaks” out of the pipeline and is recorded by hall effect sensors, of which there can be hundreds. The sensor system and electronics developed and manufactured in-house guarantee high resolution and sensitivity with 360 degree full circumferential coverage. High magnetization levels between 10 - 30 kA/m ensure the validity of the results.