Pipe defect characterisation by multi-sensor systems

Worldwide, pipeline systems differ in age, manufacture, length and system configuration. However, in all cases they require a large infrastructure investment, which for many cities and towns is one of their largest capital investments. Pipe leakage for these towns and cities can be a major problem, both from an environmental point of view, as well as the costs that are incurred due to overdesign of the sewerage systems and the treatment of additional potable water, lost due to leakage. It is essential to maintain pipelines to guarantee that they operate correctly and that external costs (i.e. contamination of ground water) associated with exfiltration and infiltration are minimised. To minimise these problems, damaged pipelines have to be replaced or repaired. Pipeline repair and rehabilitation methods can provide utility owners with cost effective alternatives to total replacement. However, making the correct choice of a repair or rehabilitation method is critical as it can significantly affect the total lifecycle cost of the system. A key issue governing the selection of correct rehabilitation technologies is the availability of adequate information concerning the condition of existing infrastructure. Current assessment technologies like closed-circuit television systems (CCTV) do not provide adequate detailed information of the entire interior pipe surface, wall damage and the condition of the soil surrounding the pipe. In order to overcome this problem a range of new sensors have been developed and tested for pipeline leakage detection and sewer assessment. These sensors have been mounted on the experimental platform SAM (Sewer assessment with multi-sensors) and connected to a commercial CCTV. This paper presents the first results for SAM and a comparison to other inspection systems.