Underground Utilities Surveying
Vital Cost-Saving Process
Knowing where underground services are located helps mitigate risk for developers, engineers, constructors and utility owners. This knowledge minimises potential project delay, damage to third party assets, and risk to the safety of public and workers.
Our qualified and RICS-accredited utility surveyors have proven ability of reducing financial and H&S risk for many private and public sector construction, transport and utility projects. We are competent and experienced in delivering accurate, up-to-date and comprehensive utilities site plans and use the latest location tools and technologies to map natural and man-made features to build comprehensive below-ground pictures.
In our experience, we find that working closely and collaboratively with our clients and alongside other disciplines helps us achieve successful outcomes. We are flexible in our approach and draw on our broad surveying expertise to deliver more comprehensive and useful results.
What Lies Below?
We use a combination of tools (depending on location and requirements) coupled with more than 25 years' experience to map cables, pipework, gas and sewer lines, cavities, culverts and land drain systems. We produce 2D plan outputs, 3D wireframe and model drawings, GIS outputs, photography, section views and more and deliver in DWG and PDF formats. We believe the best platform for utilities data is a current and comprehensive topographical survey.
Whilst we have a variety of tools at our disposal, the key systems used are Ground Penetrating Radar (GPR), Cable Avoidance (CAT), and Signal Generator (Genny) Tools. These tools have the potential to determine both service plan and service depth data.
Ground Penetrating Radar (GPR) - also known as Ground Probing Radar, Ground Radar, and Georadar.
Ground Penetrating Radar (GPR) sends radio signals into the ground to create an image of the features of the subsurface without drilling or digging. GPR transmits radio pulses through a transducer or antenna which is moved along the ground by the operator. Any buried objects or different materials under the ground reflect these pulses or signals which are then stored in the GPR's control unit.
Ultimately these signals are shown as different bands that allow our surveyors to assess the complete below-ground picture.
Soil type and frequency will dictate the depth penetration of the radio waves and therefore the detail returned by the GPR - so each survey and the requirements of each survey will be different depending on location. GPR can detect objects through dense material including concrete and can even detect the rebar within the concrete.
Radio Frequency Cable Avoidance (CAT) and Signal Generator (Genny) Tools
The CAT and Genny can be used together or individually to help locate cable services below ground and avoid damage to buried cables and other utility lines. The CAT operates in three modes; power, radio and Genny.
In radio mode, the CAT traces naturally radiating signals from conductive metallic services. In power mode, it traces power signals radiated by loaded cables to detect and avoid below-ground electricity cables. In signal generator or Genny mode, the CAT traces a tone generated by the Genny to avoid services connected to the source; water valves, plug sockets or gas valves for example.
How are we different?
Whilst no underground utility survey can guarantee 100% what type of utility is found, our surveyors are highly experienced in interpreting GPR signals and have a high success rate of providing detailed information that has positively influenced projects and saved developers significant cost and time.
Standards of Work
Our underground utility surveys are carried out to PAS128 specifications. PAS128 sets out provisions for all those working in utility surveying to provide clarity on surveying methods, data capture, data classification and accountability for work undertaken - ensuring clients receive a consistent and reliable service.
We also incorporate TSA (The Survey Association) Guidelines for Utility Surveying in our work which sets out best practice for specific professional utility surveying tasks. However, we cannot guarantee locating all buried utilities, as the local environment and conditions will influence the results.
Service Data (Stats) is sometimes unavailable, incomplete or out of date; a utilities survey therefore is a vital, non-intrusive method of investigation.
CCTV drain surveys provide a clear and unequivocal record of pipe condition; both service (covering the deterioration of the system due to external factors such as silting or root infestation) and structural (covering physical pipe condition such as cracks or open joints).
A CCTV survey can fulfil several functions, by providing amongst other things:
- A clear and comprehensive report with anticipated remediation schedules to help plan drainage maintenance in the most cost-effective way.
- Data for allowing assessment of system capacity and condition, informing connection risk in advance for new developments.
- Dilapidation reports to assess condition before and after adjacent construction projects, to help prove that development has not left the system in a worse condition than before work started.
Where safe, we lift all covers to obtain data on drainage and other services. Drainage details normally include invert level and depth, pipe sizes where obtainable - whether foul surface or combined - and connectivities between chambers.
Review the Benefits
Construction in increasingly limited space puts greater demand on developers to design effectively. High quality underground utilities surveying allows our clients to maximise the total land space, and design with full knowledge of below-ground constraints.
In addition, utility surveys offer developers, engineers, constructors and utility owners the chance to:
- Obtain a complete record for future development
- Achieve confirmation of existing as-built records
- Reduce utility and asset damage
- Reduce project delay
- Better plan utility diversions
- Reduce need for intrusive investigation
- Save cost and time by working with the full picture of below-ground utilities
- Reduce safety risk to workers and public