FAQ

There may be limitations on how effective a survey is depending on the type of terrain or landscape.

For the most effective results the ideal conditions are:

• Full and complete utility records – the better the data at the start the better the survey outcome is likely to be.
• Free access to the survey area and its surroundings beyond the survey area – this is often a limitation in security-sensitive areas such as airports. The best results using EML methods come when you connect to a utility directly, either using clips or else an induction ring. To do this you must be able to access a pit or valve on the line, therefore free access is essential. The same applies to drainage and fibre where you need access to the pits along the line in order to be able to push a sonde or a flexi-trace through the pipe or duct. In the case of fibre optic ducts you also need the room in the duct to pass a flexi-trace through the duct being traced.
• Foreknowledge of any special requirements for accessing utilities.
  • The most common of these is the requirement for confined space entry, if this is known beforehand, we can ensure that we attend with the correctly qualified personnel and the right equipment.
  • Similar to and often hand in hand with confined space requirements, flooded or blocked pits can be allowed for at the planning stage and the correct equipment priced for and mobilised to make sure the survey goes smoothly.
    • Gullies and sewers need to be clean and free of debris which would stop the sonde being passed through them.
• As well as access to the chambers, we need access to all other points of contact.

Usually yes. Provided ground conditions are suitable, radar will pick up plastic utilities by detecting the interface between the plastic duct/pipe and the contents of the utility.

This is a radar set which uses more than one detection frequency at once. Best practice for GPR surveying requires the use of 2 frequencies. Older and cheaper radar systems only have a single frequency and as such it is necessary to perform each survey twice, thus taking twice as long to do each survey.

This is the current standard for utility detection, it provides a guide to the accuracies attainable by various detection methods, the survey types suitable for different environments and applications and the standards to which surveys should be conducted. All our surveyors are fully conversant with this standard and apply it to their work.

Generally the maximum depth for tracing a sewer is 15m by the usual method of introducing a radio transmitter called a sonde into the pipe and pushing or floating it along the length requiring tracing. (The sonde can also be towed by or built into a pipeline inspection cctv crawler) For large diameter pipes there is also the option of performing a traverse through the pipe using an EDM or laser scanner in the same way as you would carry out a topographical survey on the surface. Survey stations are set up in the pipe or culvert, referenced to control stations on the surface and the pipe surveyed accurately. Although this method is very accurate it is a large undertaking as a confined space entry by several people is required. Select surveys are qualified and highly experienced in both of these approaches.

With our large workforce based throughout the country we can carry out survey work throughout the British Isles and internationally if so required.

Yes, as most locations are traffic sensitive our surveyors are all qualified to provide basic traffic management to protect and manage their works. In addition we can provide far larger and more complex TM solutions as required on a project by project basis.