Below Ground Utility Tracing/GPR PAS128

Utilities Tracing Overview

SDS have been supplying a PAS 128 utilities tracing service to the industry for over 20 years.

Underground utility tracing is the locating and mapping of all types of subsurface features using a variety of methods and technologies.

By combining GPR with electromagnectic detection methods and with the benefit of many years of training and experience SDS look to provide clients with a comprehensive overview of all buried services.

Using the latest Radiodetection electrolocation equipment, IDS GPR antenna and the latest CCTV drainage survey equipment. A full picture of all underground services is possible.

In 2014 regulations for tracing utilities were introduced in the PAS 128 document, this gives guidance into tracing utilities from desktop studies to fully traced surveys with GPR verification. The PAS 128 also gives guidelines to the degree of accuracy that can be expected with each level of survey undertaken.

A thorough and accurate utility survey is viewed as an important tool for any designer, planner, contractor or owner of underground services proving vital for worksite safety, accurate planning and detailed record keeping.

Traced services can be delivered in a comprehensive range of digital formats from full 3D BIM/Revit drawings, cad and pdf.

Click here to see examples of sample utilities surveys

Ground Penetrating Radar Surveys

SDS have been providing ground penetrating radar (GPR) surveys for over 10 years using a range of market leading ids geo-radar ground penetrating equipment and software, in that time GPR has become a powerful tool in the field of underground utility investigation.

GPR is a geophysical method of survey that uses radar pulses to image the subsurface, reflected radar signals build up picture of the subsoils ground make.

GPR grids are surveyed and the results can either be post processed for greater accuracy and added to cad or marked/flagged out on site as an aid to construction.

The huge benefits of GPR include its non-intrusive nature and accurate way of mapping below ground features.

3D visual taken during GPR Survey
  • Radio detection techniques are unable to detect non-metallic buried services such as plastic water and gas pipes, fibre-optics and drainage pipes that we cannot introduce a sonde into. With this potential hazard of the unknown location of services Ground Penetrating Radar (GPR) can be used to supplement the Radio detection results in the location of these services.
  • GPR is able to detect non-metallic as well as metallic pipes. It will also give an indication of the location and depth of buried services but will not identify them.
  • GPR can also be used for the detection of voids and tree roots.
  • GPR does NOT trace services, but indicates the presence of voids, disturbed ground, trenches, pipes and cables under the surface. GPR works by emitting a short pulse of energy into the ground. Echoes are returned from the different interfaces between different materials in the ground. The Survey Results can be temporarily marked on the ground for immediate use on site.
  • It has become common practice to survey in the results with a Total Station for fast production of accurate drawings. This information may be added to an existing Topographical Survey or overlaid onto Ordnance Survey Background .

GPR Surveys Can Be Used For

  • Tracing utilities depth and position
  • Mapping of services
  • Void and tunnel location
  • Archaeological investigation
  • Rebar analysis
  • Borehole clearance