Inspection of a 24 inch slurry pipe

This line carried water-based slurry. It was not insulated and was at ground level, so that access for inspection was not difficult. However, the main concern was local high levels of internal erosion where eddies in the flow caused turbulence and consequent high impact of particles on the inside of the pipe.

Since service history had shown that these occurrences were difficult to predict, spot thickness measurements were ineffective in detecting thinned areas prior to leakage.

Teletest overcame this problem as 100% of the pipe wall is examined. During initial trials, a test was carried out on a section where a small leak had occurred. The result is shown on the graph. A strong signal, coinciding with the location of the leak, suggested extensive metal loss and it was found by subsequent examination that there was a band of erosion almost through the wall for the majority of the pipe circumference. The pipe was therefore at the end of its life.