According to industry legend, agricultural engineer Eric Wood was repairing a corrosion hole in an air duct on a mushroom farm when he conceived the concept behind CIPP – the use of fluid pressure to press the repair medium against the pipe wall whilst it cured in place to form a new pipe.

Whatever the truth of that story, the fact is that Mr Wood, ably supported by entrepreneurs Doug Chick and Brain Chandler started an industry with a far-reaching effect on the infrastructure business, which has endured almost forty years.

Wood, Chick and Chandler took the concept, sourced materials from resin producer Scott Bader and felt maker WE Rawson and developed what we know as Insituform. They took the idea to the Greater London Council’s Metropolitan Water Board as a means to restore ageing water mains and were given the opportunity to demonstrate the efficacy of their method by lining a 100-year-old brick egg-shaped sewer at their own expense.

In 1971 they impregnated a felt tube with polyester resin, wrapped in a plastic sheet, pulled the 70 m tube into the 1,175.675 mm Marsh Lane Sewer, inflated it and left it to cure. Tested in 1991, after twenty years in service, it met the 4-34-04 flexural modulus requirements – a research-based group of WRc – providing consultancy in the water, waste and environment sectors in the UK – by a margin of more than 20 per cent. This validated what many municipal engineers worldwide had already concluded: CIPP is here to stay.

Wood, Chick and Chandler registered the company Insituform Pipes and Structures Ltd (the first of many vehicles for patents and technology), and set about marketing their technology and developing improvements such as polymer coated felt and vacuum impregnation.

They tried steam and UV curing too, but concentrated efforts on the time-proven water inversion and hot water cure system.

By 1986, with licensed partners in the United Kingdom, they had completed over 400 projects for regional water authorities, municipal boroughs, power generators and commercial companies. As early as 1976 they lined pressure pipes, the first being a 600 mm force main for Thames Water in Reading.

In the late 1970s they licensed various companies including Entrepose in France, Olimb in Norway, Per Aarsleff in Denmark, Monier in Australia and started a company in North America. With no shortage of entrepreneurship for Eric, Doug and Brian, they established Insituform North America Inc and Insituform Group Ltd in Guernsey as a royalty collector.

These companies were floated on NASDAQ, an American stock exchange, and the proceeds invested in R&D and tube making in Wellingborough and Memphis, Tenessee. Both Insituform companies began to acquire back licensee businesses to vertically integrate and in 1991 merged to form Insituform Technologies Inc.

Strong patent protection

This remarkable growth story was fostered by strong patent protection and some remarkably good licensed partners. But the protection afforded by patents is transient and long before the expiry of the first layers of protection others had noted the extraordinary growth of the business.

In Japan in 1980, the Tokyo and Osaka Gas Companies, with their contractors, developed hose lining systems using woven polyester hose and epoxy and polyester resins. By 1983, PALTEM and Phoenix were well established and enhanced with felt for extra stiffness became used in water mains and sewers.

Phoenix was licensed in France and Switzerland and rapidly spread through Europe. Also in France, in the early 1980s the Copeflex process, a resin impregnated glass fibre liner developed by Coopetanche and subsequently acquired by SADE made inroads into the municipal sewer business.

In Germany, the sewer maintenance group Kanal Muller, once sales agents for Insituform, developed and licensed a felt liner system, InLiner, which is installed using a calibration hose, and in Sweden, Volmar Johnsson developed the glass fibre hose, UV light cured InPipe system.

In the 1980s, with initial patents reaching maturity, many developers looked at the lucrative licensing route for taking their processes to market, and the multiple CIPP technologies spread to the far corners of the globe – Korea, New Zealand, Taiwan, Venezuela and Argentina. Insituform, KMG and Ashimori, developers of PALTEM, set up in unlicensed territories.

In the late 1980s, Insituform’s felt supplier WE Rawson established Applied Felts to service the needs of the many users of the basic felt and resin liner systems and other smaller felt liner makers were established in Europe and America.

Prompted by the principles proven in the municipal market and the success of products such as the KMG Houseliner, other smaller contractors working with simple resin and felt systems began to work in local markets, servicing the needs of householders and other private sewer owners.

The size of this market is hard to quantify but some measure of it is indicated by the UK Government’s decision to take about half the private sewer, some 200,000 km, into public ownership. In the UK, franchised sewer maintenance contractors groups such as DynoRod have seized on the opportunity and provide distribution for some of the smaller vendors who have focussed on this market.

In the 1990s more UV light curing systems emerged in Europe with first Brandenburger, then BKP Berolina, Saertex Multiliner and Impreg entering the fray.

Their impact has perhaps been influenced by the technical demands of the German market and the efforts of IKT, an independent test laboratory in promoting its facilities and research initiatives since about 2004. The annual performance tables of IKT have caught the attention of owners and specifiers and now a number of European contractors and municipalities are involved in a pan European testing scheme which annually ranks the performance of contractors.

Confidence in CIPP

Technical guidelines and standards play an important role in the acceptance and growth of technologies, particularly in the municipal infrastructure business. The role of WRc in developing its Manual of Sewer Condition Classification and its Sewer Rehabilitation Manual in 1983 cannot be understated. These together with the WRc Information and Guidance Note (Water Industry Standard) 4-34-04 have influence the adoption of sewer rehabilitation techniques in general, and CIPP in particular, throughout the English-speaking world and beyond.

The WRc Approval, an independent view on performance against accepted standards is also useful and many countries have similar systems. The Japan Institute for Wastewater Engineering Technology is a particularly good example of a systematic evaluation program in the public interest. Following on from WIS 4-34-04 in 1985 came ATSM F1216 in 1979, EN 13566-4 in 2002 and now ISO 11296 in 2009; all serve to build confidence in the CIPP concept but require that the utility owners and their contractors implement proper systems for product acceptance, quality control and assurance.