Pipeline companies often are required to evaluate the integrity of existing pipelines. The
integrity of existing pipelines is important for assessing asset integrity, public safety and
environmental safety.
Pipeline integrity can be evaluated using in-line inspection (ILI) tools, hydrostatic pressure
testing, and direct assessment (DA). Depending upon the threat, three forms of DA can be
used. These three forms of DA are external corrosion direct assessment (ECDA), dry gas -
internal corrosion direct assessment (DG-ICDA), and stress corrosion cracking direct
assessment (SSCDA).
Three direct assessment (DA) methodologies are available to the pipeline operator to assess
the integrity of a pipeline segment. External Corrosion Direct Assessment (ECDA), Internal
Corrosion Direct Assessment (ICDA) and Stress Corrosion Cracking Direct Assessment
(SSCDA) all require risk assessments to determine the need, locations, and potential for
corrosion. When possible all three Direct Assessment techniques can be applied
simultaneously to the same segment of pipeline.
Selection of indirect inspection test methods and direct examination sites can be very
complicated. Test methods used for direct examination may combine test methods for ECDA,
ICDA and SSCDA.