ECDA for Unique Threats to Underground Pipelines

Overview

Main Objective

There are two primary objectives of the proposed research: The first objective of the proposed research is to complement ECDA protocol by including assessment of threats posed by alternating current and excessive cathodic protection. The second objective of the proposed research is to establish the limitations to applicability to the ECDA indirect assessment techniques under stray current conditions.

Public Abstract

External corrosion direct assessment process (ECDA) implemented in accordance with the NACE Recommended Practice RP0502-02 relies on above ground DA techniques to prioritize locations at risk for corrosion. There is a need to address the threats, which either currently are unaccounted for by the ECDA process or are associated with the process' existing deficiencies, specifically, the threat of corrosion caused by AC current, the threat to pipelines from high cathodic protection potentials, and establish the extent to which stray currents impact at-grade measurements using common ECDA techniques (such as, CIS, DCVG, PCM). While adverse effects of AC current and CP overprotection are left out of the ECDA scope, there is presently sufficient evidence that these phenomena affect the pipelines and may pose considerable integrity risks and thus should be included in ECDA assessment. There are two primary objectives of the proposed research: The first objective of the proposed research is to complement ECDA protocol by including assessment of threats posed by alternating current and excessive cathodic protection. The second objective of the proposed research is to establish the limitations to applicability to the ECDA indirect assessment techniques under stray current conditions. The research will result in three sets of deliverables guidelines for the pipeline operators. The guidelines will describe the proposed procedures, explain the meaning of the measurements, and provide instructions regarding the augmented indirect assessment to assess the pipeline integrity threats from AC corrosion and CP overprotection. The guidelines will also address the use and limitations of common above-ground ECDA techniques in presence of stray current activity. The research effort is co-funded by Southern California Gas.

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