COMPREHENSIVE OVERLINE DIAGNOSTICS TO DETERMINE ACTUAL PIPELINE AND PROTECTIVE COATING CONDITION

摘要

Overline electrochemical survey techniques are routinely used by pipeline owners and operators and specialist contractors alike to meet applicable operating regulations by assessing the levels of cathodic protection (CP) on pipelines [1]. Some of these techniques have also been used to identify locations where repairs may be required [2]. Unfortunately most of these techniques possess certain inherent limitations [3] that can be misleading, and could result in unnecessary remedial actions being taken. Rather than rely on a single technique, combinations of these commonly-used techniques have previously been applied [4] in an attempt to assess the condition of a failing coating systems. Unfortunately the survey results did not always correspond with the findings at exploratory excavations [5]. In the meanwhile, the techniques have been substantially refined and this paper demonstrates how the improved results can be used to create an economical multi-year rehabilitation plan.