Underground asset location and condition assessment technologies

Beneath the surface of cities worldwide lies an extensive and complex network of pipes and cables providing the essential utility services that underpin modern civilised life. With the ageing of this buried infrastructure and growing demand for new underground utilities due to the expansion of the population and the development of new technologies (e.g. broadband), it is vitally important both to locate the existing underground infrastructure and to assess its condition. This paper reviews current locating technologies with an emphasis on describing their application and limitations, both inherently and as highlighted in a review of field trials conducted in the UK and US. Furthermore, the paper reviews condition assessment tools, which allow a proactive approach to pipeline maintenance. These two reviews were presented to a UK workshop in 2002 to provide a context for a discussion of the research needs; those considered to be of highest priority were specifically identified. The main outcome of the reviews and workshop is that there is no single technology which can locate all underground utility services with complete certainty or that can provide a means of condition assessment that is generally applicable. The development of multi-sensor tools is therefore advocated both for the location and condition assessment of pipelines. The research needs indicate that location without error of all the underground infrastructure is vital in today’s society where the disruption to everyday life by streetworks will no longer be accepted and alternatives, such as trenchless technologies, have to be advanced with minimal risk of failure. There is a parallel research need for an alternative approach to utility service provision in urban areas. Recommendations are made on ways to address the research needs, together with evidence of significant progress.