Abstract
This paper provides an overview of the external corrosion direct assessment (ECDA) process by presenting the practical application of the process to a gas transmission pipeline owned by Company A. The paper describes each of the indirect inspection techniques used to assess the condition of the external coating on the buried pipeline, and then compares those results to results from direct examinations of selected sections along the pipeline. In addition, comparisons are also made to results from in-line inspections of that same pipeline. Note that the results from the in-line inspection results were not made available until after the selection of the locations for excavation and direct examinations. Close agreements were found between the location and severity of damage to external coatings, based on indirect inspections and direct examinations. Additionally, close agreements were found between the severity of external corrosion, as determined from direct examinations, and that indicated by in-line inspections. As such the ECDA process was validated by these studies on Company A’s pipeline.
The Pipeline Research Council International (PRCI) has overseen the validation of the ECDA process, based on the studies of multiple pipelines. This paper provided an overview of just one of these studies. When competent personnel follow the ECDA process, it will provide an accurate assessment of the condition of possible external corrosion on buried pipelines.
