Abstract
This paper highlights a PHMSA-sponsored research project directed toward enhancing external corrosion direct assessment (ECDA) classification and prioritization for effective direct examinations. With ECDA, indirect inspections (IDI) techniques are used at grade to identify areas where external corrosion activity may have occurred , may be occurring or may occur on pipelines below grade. To objectively enhance classification and prioritization methodologies as outlined in NACE SP0502-2008, we developed improved self-consistent classification and prioritization tables. Suitable metrics are identified to accurately characterize external corrosion and IDI data in relation to operational environments, such as soils data, normally collected during the pre-assessment step of ECDA. Specifically, empirical relationships are identified involving rupture and leak failure threats due to external corrosion activity below grade, discovered by either in-line inspection (ILI) or direct examination (DE). The empirical models plus the classification and prioritization tables provide accurate classification and prioritization methodologies aimed at enabling pipeline operators to effectively, economically, efficiently and safely address the external corrosion threat to pipeline integrity.
