As specialists in Ground Penetrating Radar, GPR Pro is able to provide the GPR part of a utility survey, in accordance with PAS128.
We provide this service for all contractors, councils, utilities and surveying companies, who can combine our results with their EML survey to deliver a fully PAS128 compliant service.
Why use GPR for utility detection
GPR is a particularly useful technology for detecting near surface underground features and utilities, not only because it is able to detect most types of utility (including non-metallic), but also because GPR can recover additional information about the below surface environment, including the location and extents of reinforced concrete, underground features and structural information.
Ground Penetrating Radar technology
GPR technology takes more education than EML* to use; in comparison with EML, GPR is able to detect non-metallic pipes (PVC plastic gas and water pipes and some fibre optic cables) and does not require access to the service in order to detect it, a GPR signal is also not influenced by electromagnetic fields and targets detected will usually be more accurate in horizontal positioning. GPR is also able to recover other information about the survey area including the presence of other underground features, rebar and structural information.
GPR survey methodology
– On site detection
Similar to EML, the ground is marked with paint in the locations where a utility is detected.
– Post Processed
GPR data is collected onsite and returned to the office for interpretation (now erroneously referred to as post processing), it is generally accepted that a post processed GPR survey will yield superior results to an on-site survey because more information and time is available for decision making. However, this is not appropriate for all survey conditions.
Final survey output
GPR data is exported to a drawing which is provided to the customer in dwg and pdf formats. Where applicable, a report is also produced.
If a fully PAS128 compliant survey is required, after both geophysical surveys have been completed, the data from GPR and EML should be compiled into one final drawing which draws on the strengths of both methods to produce a high quality output.
*EML (ElectroMagnetic Location) is a geophysical survey method that can be used to detect electricity cables and metallic targets, as well as some non-metallic targets with manhole access. EML is a good method for detecting utilities, but does suffer from some limitations: it is confused by some ground conditions and cannot detect plastic or utilities with no manhole present. In some cases, magnetic fields interact with each other and services could be detected in the incorrect locations.