A crude oil pipeline in Canada presented a particularly challenging scenario for NDT Global. Short, branched axial cracks located close to the girth welds had been observed. But these attributes created depth-sizing complexity for ultrasonic inline inspection tools. The assessment of such atypical flaws called for highly innovative techniques and an out-of-the-box approach.  Against this background, experts from NDT Global worked closely with the customer to develop the best-fit solution. The goal was to gain greater insight into the nature of the cracks while overcoming the sizing limitations of conventional inspection technology. To this end, a series of analytical tests and experimental assessments were performed.

• In-depth insight into crack complexities which were found to arise from the short crack lengths and close proximity to girth welds

• Full-scale pull-testing program to establish the inspection tool’s sizing and detection capabilities

• Laboratory non-destructive experiments to better understand the impact of crack orientation on sizing