A Non-Destructive, Continuous Inspection Technique Applied to Cast Iron Pipes

In the Netherlands the condition of cast iron (CI) pipes is assessed using destructive techniques (Rosenthal and Slaats, 2000). Consequently, CI pipes are normally inspected only after failure, and the assessment is limited to small sections of the worst affected pipes. Due to the irregular pattern of deterioration of cast iron pipes, the overall condition of a distribution network cannot be based on results from destructive inspection. Non-destructive inspection techniques have multiple advantages. Firstly, the condition assessment takes place on the whole length and circumference of the pipe. Secondly, water supply can in most cases continue undisturbed during the inspection. And, finally, there is no need to dig up the pipe or take samples out of it. To gain better understanding of the possibilities and difficulties, research on various non-destructive inspection techniques is being conducted in the joint research program of the Dutch and Belgian water companies. The Remote Field Technique was applied on a cast iron pipe of the Belgian water company Pidpa during a field test, after which the pipe's condition was assessed with conventional, destructive techniques. The results of both methods are compared and discussed in more detail in this paper. The comparison shows that the Remote Field Technique is both a useful inspection technique (delivering comparable results) and has added value to the destructive technique by showing the deterioration along the length and circumference of the pipe.