Phase recently carried out a utility tracing survey at a brownfield site in London. The site was approximately 55 m by 20 m and we were able to survey it in a single day utilising radio frequency location (RFL) and ground penetrating radar (GPR). A variety of metallic and non-metallic apparatus was located, including high and low voltage electricity cables, communication cables, drainage pipes and metallic fuel pipes. The latter were associated with buried underground fuel tanks which were also located by the GPR.
All utility apparatus traced by the RFL survey was marked up on site and was also tied-in to an existing topographic survey using a one-man total station. The GPR data was processed off site and provided depth information on some utility apparatus, as well as identifying several other possible sub-surface features including the fuel tanks, an area of reinforced concrete and a possible sub-surface structure. The RFL results and GPR interpretation were presented on a CAD plan, overlain on to a topographic survey.