In a first for the construction industry, TBE United Kingdom has proved that accuracy is truly the key to successful design, planning and consultation of projects thanks to the pioneering civil engineering process, ‘Subsurface Utility Engineering’ or ‘SUE’. The innovative underground utility mapping and detection procedure, which has just been launched across the UK, has been utilised for the first time in this country up to its highest quality standard by leading construction firm, Carillion plc on a London city centre site.

SUE is unique in the UK market as it incorporates civil engineering, surface geophysics, surveying and mapping, as well as non-destructive vacuum excavation and asset management technologies. Combined, these can identify and classify quality levels of existing subsurface utility data and map the locations of the underground utilities. It is so accurate, that unlike general locating and mapping services, TBE UK will certify its findings.

Carillion used SUE for a high profile project taking place on London’s South Bank, adjacent to one of the Capital’s most celebrated tourist attractions, Tate Modern. Four residential blocks are currently being constructed, but in order to know where constructors could pile for a basement secant wall without hitting subsurface utilities (and to see if any utilities discovered could be relocated) the SUE process was employed to map the project’s vicinity.

TBE UK was initially awarded the contract to conduct a SUE Quality Level B (QL-B) survey. The QL-B standard is the first level where up-to-the-minute designating information is used and verifies QL-C and QL-D data – the most basic and common methods of utility detection. It also addresses the problems caused by inaccurate utility records, abandoned or unrecorded facilities, or lost references. The resulting two-dimensional horizontal mapping information is useful during a project’s preliminary design phase, when slight adjustments to the design or utility location can produce substantial cost savings.

James Lewis, TBE UK’s Business Unit Manager explained:

“Once the QL-B survey was complete, we issued the results to the client with a number of cross-sections showing the location of all the existing running services and most importantly, the clear space where the high voltage cables could be diverted. Based on the investigation results, it was agreed that the cables could be safely moved for construction works to progress as originally planned.”

However to verify the survey, TBE UK was then asked to perform the most accurate process of SUE, Quality Level A (OL-A), before the diversion took place.

This is a key recommendation of TBE UK’s, as although QL-B is horizontally informative, it still cannot be described as accurate. Subsequently QL-A provides precise 3D horizontal and vertical mapping of underground utilities and related structures with accurate information on depth, horizontal position, diameter, material and if required, condition. TBE UK is the only firm in the country qualified to provide this information by using the non-destructive vacuum excavation technique safely and efficiently.

“The second phase of the project ran smoothly with every excavation completed successfully. We were able to expose the required utilities to determine and confirm their exact location and horizontal position by using the vacuum excavation process. These accurate details were then transferred to a 3D plan and given to the project engineers to assist them in their future works.”

It is hard to put a value on the contribution SUE has made to this project, however Carillion has confirmed that prior to using this innovative technique, it was thought that all the high voltage cables in the project’s vicinity would require relocation at a cost of well over £100,000.

The SUE information showed that in reality only half the cables needed to be moved and that there was sufficient space on-site for the affected cables to be diverted rather than totally relocated. In short, SUE allowed Carillion to make more informed decisions which saved them time, worry, lost progress and money. Plus, this is just the tip of the iceberg. The additional savings enjoyed by not striking utilities in the first place can only be imagined.

Email: fiona@manifestcomms.co.uk