A hole success for drain pipe repair

A new method of replacing failed drain pipes relies on technology to open out the failed drains followed by a novel way of making replacement plastic pipe sections with moulded threads that can be screwed together and pushed into the holes. The process is exclusively licensed to Dyno-Rod by its creators, Ken and Elizabeth Scott, who are Dyno-Rod Franchisees in St Just, Cornwall. Ken Scott told us that he started work on the idea 12 years ago and the most crucial part of the development is the moulding process to make the pipe sections with their moulded on threads. The pipes are made of polyethylene (PE) or polypropylene (PP), are 100mm or 150mm in diameter, but only 4mm thick, in order not to reduce flow. Since the pipes may have to be pushed into the holes against some resistance, and in order to maintain a good seal when installed, machine cut threads were not an option. The pipe moulding technology is apparently the crucial breakthrough that makes the process possible and while Mr Scott and Dyno-Rod declined to give details, we can reveal that it is an injection moulding process that took three and a half years from inception to successful production of the first pipe. The Scotts, in typically British fashion, had to raise the £240,000 to purchase the moulding machine and £60,000 for the mould tool entirely from their own resources. The resulting "in2 no dig replacement system" allows failed pipes to be replaced in only a few hours, even when access is only possible from one manhole. If access from two manholes is available, it is possible to first pull through a re-rounding head, but if not, a head may be forced through by hydraulic rams, and then collapsed and retrieved. The service is to become available throughout the United Kingdom from the end of December, following general training of technicians on a special rig. PE will be the usual material offered, but the PP option is available for commercial and industrial applications because of its greater strength and chemical resistance. It is planned to develop the system to include 225mm pipes in the near future. The technology is covered by 11 patents. Other no dig technologies available include cured-in-place pipes (CIPP), pipe bursting and sliplining with continuous and discrete pipes. The CIPP 'Brawoliner' process involves blowing in a tubular mesh followed by resin. It is more expensive and requires higher levels of skill than the in2 process but can be applied to vertical pipes, can go round bends, and allows the easy location and cutting of lateral connections. Pipe bursting and sliplining require access from both ends. Pipe bursting involves the application of high pressure and so cannot be used if the pipe is less than 750mm deep and may damage third party services but does allow pipe capacity to be maintained or even increased. Dyno-Rod franchisees will offer whatever technology is most appropriate, but the new in2 system looks likely to best meet the need of a large number of cases. Dyno-Rod Pointers * Strength and integrity of joints is ensured by using special pipe sections with moulded on threads * in2 can be installed without excavation and in confined spaces, even when there is access only from one manhole. It involves no use of hazardous resins or chemicals and has a predicted life of more than 50 years.