Direct Current Potential Drop (DCPD) surveys are a non-destructive pipeline inspection technique used to evaluate cathodic protection (CP) effectiveness and detect coating.

Direct Current Potential Drop (DCPD) surveys are a non-destructive pipeline inspection technique used to evaluate cathodic protection (CP) effectiveness and detect coating defects along buried pipelines. By applying a low DC voltage and measuring potential variations along the pipeline, DCPD identifies areas where protective systems may be underperforming.

DCPD surveys help pipeline operators pinpoint coating holidays, insulation degradation, and CP system anomalies — enabling targeted maintenance and reducing external corrosion risk. Results integrate into ECDA (External Corrosion Direct Assessment) programs and pipeline integrity management systems.

For comprehensive external corrosion assessment, DCPD surveys are often combined with DCVG surveys, ACVG measurements, and advanced aboveground inspection methods like EMPIT's Current Magnetometry Inspection (CMI), which provides direct corrosion detection and coating condition data without excavation.