Pipeline Rehabilitation
The future is trenchless Concern about the state of the United Kingdom’s underground pipe networks emerged in the 1970s with the reorganisation of the Water Industry and the publication of the NWC’s National Assessment’ in 1977. It became clear that a substantial proportion of the UKs 234,278 km of sewers and 318,415 km of water mains were more than 50 years of age and in need of attention. Annual renewal costs for sewer and water mains estimated at £215.3M sent shock waves through government and ultimately triggered discussions leading to privatisation. NWC urged accurate determination of the scale of problems underground and development of new methods for repair and maintenance prompting investment in CCTV inspection and rehabilitation techniques. Thames Water’s Graham Cox, at the 1981 ICE Conference ‘Restoration of the Sewerage Systems’, spoke of ‘making use of the hole’ describing new techniques for sewer renovation including slip lining, cured in place lining and GRP panel lining. In 1985 the institution of Public Health Engineers, now CIWEM, hosted ‘Trenchless Construction for Utilities’. The event, styled ‘No Dig 85’, attracted 378 delegates from 21 countries and 66 exhibitors, was a signal moment for pipeline rehabilitation. Speaker
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of renewal and replacement and should drive innovation towards more and better trenchless methods. No Dig 85 prompted establishment of an International Society for Trenchless Technology, a series of annual awards for trenchless innovation, various trenchless publications and a succession of international No Dig conferences; the 38th International No Dig will be held in Helsinki in October 2022. There are now 27 affiliated national or regional trenchless societies affiliated to ISTT, providing representation for more than 3000 corporate and individual members. Pipeline condition assessment and rehabilitation are the primary focus for at least half of the current membership.
James Thompson of Jason Consultants detailed the scale of opportunities for renovation and renewal in the UK and overseas. He introduced the notion that the costs of the social and economic disruption associated with open cut construction would be many times the direct engineering cost
Cured in place pipe, originally pioneered in the UK in 1971 by Eric Wood, developer of the Insituform method, is unquestionably the primary process for renovating sewer pipe. Wood’s company and its contracting partners have subsequently lined more than 65,000kms of gravity sewer. The annual worldwide investment in cured in place pipe in all its forms is thought to be running close
WATER INDUSTRY JOURNAL SEPTEMBER 2021
