Cured-in-place-pipe (CIPP) lining is the common name given to the installation of a resin impregnated liner (tube) into a deteriorated pipe and curing it in place to produce a new structural pipe within a pipe.

The installation process can be carried out using various methods such as pulling in and inversion using air or water pressure. The curing of the resin can be carried out using steam, hot water, UV light and there are some resins that will cure under ambient conditions.

Liner construction has also become incredibly advanced with a range of materials available, from standard polyester tubes to glass fibre reinforced tubes. One of Insituform’s latest award winning innovations, iPlus Composite™, utilises advanced sandwich laminate construction incorporating glass and/or carbon fibre to produce a high strength liner with a reduction in wall thickness of up to 60 per cent when compared to a standard liner.

Lining resins have also come a long way over the past 35 years with formulations being specifically designed and tested for the pipe rehabilitation market. However, it is critical that the tube/resin combination be thoroughly tested as a composite to ensure compatibility and long term performance. This is why Insituform develops and manufactures its own liners, followed by a stringent process of resin supplier accreditation and licensing to ensure compatibility and consistency across its worldwide operations.

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Despite the above advances, a number of myths still exist within the industry regarding to CIPP liners.

Myth 1 – All CIPP liners are the same

While there are some conceptual similarities between systems, it is clear from the information above that a large number of variants exist to suit different site conditions and challenges. Each liner will have its own specific installation method and finished properties. Myth 2 – CIPP liners cannot be installed where there is infiltration

"Insituform’s CIPP lining range is extremely robust when it comes to installation under infiltration conditions" said Mr Gamba, "Over the past 35 years, we have not only worked on the improvement of our materials and systems, but we have also developed proprietary methods to allow us to install our liners under difficult situations. Our capabilities have been well proven on projects in the Hunter region and North Coast of NSW."

Mr Gamboa said that, once installed, CIPP liners have been proven to be the most effective on the market when it comes to reducing or eliminating further infiltration into the lined pipe due to the tight fit nature of the finished product and the migration of resin into pipe defects.

Myth 3 – CIPP liners cannot be installed in damaged pipes

CIPP liners are extremely versatile for the rehabilitation of damaged pipes as they are installed in a flexible state prior to curing. This means that the liners can negotiate significant defects such as holes or missing sections, and are particularly advantageous when dealing with large joint displacements or pipe bends/deflections, which are common where ground movement has occurred. When the liner is inflated/pressurised in position, it has the added benefit of supporting the pipe during curing to limit the risk of further pipe collapse. Conclusions

In summary, CIPP liners have come a long way since their inception almost 40 years ago and remain the most widely used and tested liners in the world said Mr Gamboa. Continued development has ensured that the technology remains at the forefront of the industry and is able to be applied under more varied and difficult situations.