Advances in utility location

There are over four million kilometres of buried assets in the UK. At present, utilities make information about their buried assets available in a variety of methods including via websites, through telephone or written application, with a paper plan sent in response, or by marking out the location onsite. Collating these records can be a time consuming exercise and often the information has to be transferred by hand to another CAD system.

Even when a utility company uses the latest techniques to map its new assets, information on legacy services – which may have been installed decades earlier by a predecessor organisation – may be inaccurate or even non-existent. Pipes in older cities may be over 150 years old. Poor mapping techniques used at the time of installation and the practice of recording the pipe’s location relative to a physical feature that may no longer exist means the exact location of many of today’s networks are unknown. Although current surface location and detection techniques have improved in recent years, they are still of limited use, being both unreliable and slow to operate. As a result the only way to reliably identify the accurate position of any buried service is to excavate a trial hole.

Economic disruption

The direct cost of trenching and reinstatement work of UK highways for utilities is in excess of £1.5 billion per year. Part of this is attributable to holes excavated in the wrong location and damage to third party assets, which is estimated to be as high as £150 million. Although direct costs are high they are significantly lower than the societal costs, such as delays to road users, disruption to businesses and environmental damage which may be as high as £5 billion per year.

These costs will continue to rise unless better information and more effective technologies can be made available to those doing the work. Today there is a boom in cable laying. The UK Government is actively promoting the use of broadband and the fibre optic cable networks required for this are vast. Today over three million kilometres of fibre optic are laid under the streets of the UK, with 60,000 new connections each week.

Many utilities are reaching the end of their design lives. National Grid, for example, has a program to replace all their iron mains within 30 metres of properties over the next 30 years. Thames Water will replace over 1,600 kilometres of iron mains in London over the next five years.

The introduction of competition into utility services and increasing customer demand for essential services has brought with it a greater number of excavations in the streets in order to supply these services. The increase in the number of utilities licensed to lay mains and cables within our streets brings with it the increased potential for conflict between the utilities and a greater need for readily accessible accurate records. There is also a need to develop better ways to display the information. Utility plans can become so complicated it is difficult for site operatives to identify what they will actually find below the ground, illustrated in Figure 2.

This problem is not limited to the UK. Countries in Europe, USA and increasingly in Asia report that they are having problems with locating and accessing their buried utilities and the disruption that causes, particularly in urban areas.

Mapping the underworld

The UK’s Engineering and Physical Sciences Research Council (EPSRC) announced in 2004 that it would establish a program as an initial attempt to tackle these issues. It organised an ‘ideas factory’, whereby invited academics, industrialists and EPSRC got together in the autumn of 2004 to review the problems and agree priority research topics. Out of this a £1 million research program was identified with four projects funded;

• Buried asset location, identification and condition assessment – a multi-sensor approach;
• Enhanced methods of detection of buried assets;
• Mapping and positioning; and
• Knowledge and data integration.

The first project investigated the feasibility of several novel approaches alongside enhanced existing approaches to be combined into a single multi-modal unit which would locate, identify and condition assess buried assets. These techniques include developing ground probing radar, acoustic and electro-magnetic techniques as well as considering the interaction of the utility with the surrounding soil to develop tools which can both operate from the surface and through in pipe systems. They are now being taken forward under the second phase of the project – visit www.mappingtheunderworld.ac.uk for more information.

The second project is developing low cost detectable labels which can be affixed to pipes, cables and ducts that can be remotely interrogated from a surface based unit to give information on the location and nature of the asset.

The final two projects have laid the foundation for a further project funded by the DTI, ‘Visualising Integrated Information on Buried Assets to Reduce Streetworks’ (VISTA).

VISTA

This project, lead by UK Water Industry Research (UKWIR) brings together the University of Nottingham and the University of Leeds as well as 20 other organisations including various utility companies, highways organisations, contractors, consultants and survey companies.

The research for this project focuses on the enhancement and integration of existing legacy asset information together with dynamically acquired accurately geo-referenced data in the street. Novel techniques will be developed to display the information to digging teams and network designers. The work will include field trials to confirm issues and trial solutions.

Mapping and positioning

The research conducted by the University of Nottingham is through their Institute of Engineering Surveying and Space Geodesy (IESSG). The team has developed techniques that allow satellite technology to be used in densely built up areas with ‘urban canyons’ – places with insufficient visible sky to provide sufficient satellite sightings. The team also used laser technology to identify pipe materials and developed an ‘augmented reality’ system, which overlays the buried asset network on the surface background.

Data integration

The University of Leeds has investigated the various data issues related to buried asset records and has developed a schema which can be used to allow organisations to access varied digital records via the web.

This has required drawing up a core list of attributes which is common to all data sets and a thesaurus to translate the variety of asset names into common terms. Three trials have been carried out by different data organisations, all of which have successfully made integrated data available via the web. Plans are now being developed for a wider trial in Scotland with a view to developing a national system there.

The future

Traffic management regulations are likely to require all utilities to improve the information they currently hold about their buried assets. This has been supported by the results of a review of the current process carried out recently by the National Underground Asset Group (NUAG), a group of stakeholders from utility companies, local authorities, contractors, government departments and industry organisations, which was established in 2005. NUAG’s role is to fully represent all industry views to support the Department for Transport’s decision making associated with the Traffic Management Act. Acting under the Department’s governance the group are currently developing and implementing standards on recording, storing and sharing underground asset data across Great Britain. The research described above will facilitate this and help ensure that any excavation carried out is minimised. It will also allow the UK to become a leader throughout the world in the field of managing buried assets.