An accurate base plan is essential for the plotting of underground utility services.
Information taken from record plans covering underground services is often incomplete, may be of doubtful accuracy and should usually be regarded only as an indicator.
Electronic tracing is a more reliable method of locating buried services.
Plan accuracies of the order of 6 150mm may be achieved but this figure will depend on the depth of the service below ground level.
Geophysical exploration techniques such as ground penetrating radar (GPR) will be used wherever possible and will compliment existing locating techniques.
Services that may be locatable with ground penetrating radar:
Plastic gas mains
Plastic water mains
Underground storage tanks
Non-metallic pump mains
Services that we include in our survey:
Metallic gas mains of 38mm dia and greater
Metallic water mains of 38mm dia and greater
Electricity supply cables of 440v to 66KV that are live
Electric cables to street lighting
Drainage runs of 100mm dia or greater where access to the pipe is possible
Telephone, communications and computer cables
Metallic fuel lines
Metallic pumping mains
Empty ducts of 100mm or greater
Underground heating pipes
Metallic services that are capable of transmitting a signal
We shall provide experienced personnel to locate, wherever possible, manhole covers, either visually or using locater equipment. Chamber and pipe details shall be obtained from the surface.
Connectivity shall be proved where possible by sonding.