Underground Service Location and Drainage Investigation

Radio detection

Underground Service Location

Underground services and their locations can be a critical factor in any development - the cost and time scale factors in re-routing services or having non-existent services supplied can be the deciding factor on the viability of a scheme. We have many years experience and some of the best modern equipment to map these services without having to excavate.

By using the latest Radio Detection equipment along with signal generators and plans supplied by the utility companies we can locate metal objects to provide details of the service locations.

Ground Penetrating Radar (GPR)

If pipes are made of non-metallic materials such as plastic or asbestos cement we use Ground Penetrating Radar which indicates the presence of services and voids by timing the radar signal reflected from the ground.



Whilst we do our best to locate as many services as possible it is essential to note that it is not possible to trace all services on a site other than by physically exposing them. On sites which have a long history of different building phases and development or which are relatively restricted there are limitations due to the number of redundant services in the ground, the close proximity of different services and the number of times the ground has been disturbed. We would estimate that a 70-80% detection rate is probably the best anyone could achieve in this type of situation, with a detection rate of 90%+ on “Greenfield” sites. Whilst Radio Detection and Ground Penetrating Radar are very useful they both have their limitations, notably:

Radio detection

  • Can only trace metallic services.
  • Difficult to distinguish between services unless a positive trace signal can be applied at a stop valve or similar and even then signal can be transferred into adjacent pipes or cables.
  • Difficult to resolve signals within 1m of buildings, walls, parked cars etc.

GPR

  • Depth penetration limited to 3m and resolution is poor below 1.5m.
  • Resolution in made up ground, waterlogged ground or that which has been previously disturbed may be poor.
  • Unable to distinguish between services.
  • Unable to be used on rough ground