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.
Key words: ECDA, Severity Ranking, Severity Classification, Severity Prioritization