Ultrasonic in-line inspection (ILI) tools are commonly used to assess pipeline condition, detect wall loss, monitor geometry changes and report pipeline features. While ILI data can be highly detailed, the way the findings are interpreted during a field verification often leads to misunderstandings.
This case study illustrates such scenario. The ILI tool correctly reported a 33 mm by 33 mm off-take, measuring the hollow element of the feature. However, field verification documented the external diameter as 60 mm, seemingly inconsistent with the ILI results. The difference arose from measurement perspectives: the ILI recorded the internal opening, while the field verified the external dimension.
Such misunderstandings highlight the gap in interpreting ILI results. Clients often assume ILI pipe tally data directly mirrors field measurements, overlooking the perspective and representation of the data. Without this knowledge, ILI report and field verification discrepancies can likely be categorized as errors, raising doubts about tool reliability and the overall inspection results. Misinterpretation of ILI results can encourage unnecessary excavations or even affect the vendor's reputation.
To prevent this, it is essential to understand how ILI data is collected, what it represents, and its limitations. Effective communication between vendors and clients is key to anticipating how results might be interpreted and ensuring proper support before field verification.
By clarifying data perspectives and fostering stakeholder communication, trust in ILI results can be strengthened. This approach promotes accurate interpretation, informed decision-making, and higher success rates in pipeline inspections.