Validating Selective Seam Weld Corrosion Classification Using ILI Technology

Although failures due to selective seam weld corrosion (SSWC) are rare, they can be catastrophic. To help mitigate risk, the Pipeline Hazardous Materials and Safety Administration (PHMSA) requires operators of hazardous liquid pipelines to schedule evaluation and remediation of corrosion of or along the longitudinal seam weld within 180 days of discovery, regardless of the threat posed. However, it has been difficult to detect, identify and size SSWC and to consistently distinguish it from lesser integrity threats, including general corrosion crossing the long seam (CCLS).

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In an effort to overcome this gap, T.D. Williamson (TDW) participated in a DOT project that resulted in the development of an SSWC classifier. The classifier leverages the data collected by the MDS™ platform, which incorporates six primary technologies (SMFL, MFL, IDOD, LFM, GEO, XYZ) that collect multiple data streams simultaneously.

TDW then validated the classifier on 700 SSWC calls made on 75 inline inspection runs over eight years. Dig feedback data available for 201 of these calls provided confidence that the classifier replicates the discrimination ability of the subject matter expert but avoids error-prone human input.

To date, the classifier has proven highly effective in discriminating SSWC.

In 2022, TDW published an industry-first specification that characterised the performance of the SSWC classifier. This white paper describes the statistical backing of the published specification, demonstrating the field data basis and validation.

Download this white paper from T.D. Williamson today to find out more.