This paper summarizes the results of ten years of External Corrosion Direct Assessment (ECDA) application on more than 100 projects and includes a number of important lessons learned during the process.
The large majority of the ECDA projects resulted in “clean bills of health” for the assessed pipelines. The actual number of direct examinations seldom exceeded the minimum number of digs required by NACE Standard SP 0502-2010.
Topics like selection of the ECDA regions, influence of pipe depth and local soil resistivity in classifying and prioritizing Direct Current Voltage Gradient (DCVG) indications, dealing with “clipped” gradients and dealing with “false” severe Close Interval Potential Survey (CIPS) indications are discussed in detail in this paper.
