Electrical Field Signature Method (EFSM)

The original development of this technique was largely directed at oil and gas production. The technique measures corrosion damage over several meters of an actual structure, clearly distinguishing it from other smaller sensor systems. An induced current is fed into the monitored section of interest and the resulting voltage distribution is measured to detect corrosion damage. An array of pins is attached strategically over the structure for measuring purposes. Increased pin spacing implies lower resolution for localized corrosion. Typical applications involve pin attachment to the external surface of a pipeline, to monitor corrosion damage to the inside of the pipe walls.