An effective In-line Inspection (ILI) program must provide a prioritized excavation response plan to address anomalies identified as being of particular concern.
Locations that show potential for imminent or short term failure are prioritized under Phase 1 and Phase 2 responses respectively. Anomalies that could grow to become a severe risk for pipeline integrity prior to the next ILI are prioritized as Phase 3 excavations.
This paper describes the use of External Corrosion Direct Assessment (ECDA) principles in prioritizing Phase 3 anomalies on a gas pipeline in northern Ontario, resulting in a more effective excavation program.
A type of ECDA prioritization criterion, based on the results of an integrated Close Interval Potential Survey/Direct Current Voltage Gradient (CIPS/DCVG) survey in conjunction with the results of Phase 1 and Phase 2 digs, is proposed.