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Cipp Patch Repair Systems

Localised pipe repair by positioning a short sleeve of resin-impregnated material within the host pipe and cured.

Patch repair techniques involve impregnating a fabric with a suitable resin and positioned in place within the sewer around an inflatable packer. The packer filled with water, steam or air under pressure, presses the patch against the existing sewer wall while the resin cures.

Both thermal-cure and ambient-cure systems are available. Resins are usually polyester (ambient temperatures) or epoxy (thermal cure). Patch repairs are short versions of cured-in-place liners, using polyester needle-felt on its own or in combination with glass fibre.

Safe working practices are essential particularly when impregnation of the fabric is carried out on site since the spillage of chemicals and good ventilation is needed as polyester resins give off styrene.

For both systems, it is necessary to limit the rise in temperature of the materials until the patch is inflated within the pipe and avoid premature cure, which can cause failure.

The curing time depends on the resin formulation, the thickness of the patch, the temperature within the packer (in thermal-cure systems) and the temperature of the existing pipe wall. A high ground-water table will cool the outer surface of the patch and additional curing time should be allowed for hot cured systems. Ambient cured patches may not have sufficient thermo-energy to ensure a full cure.

After curing, the packer is deflated and removed. The patch should then be inspected by CCTV, any lateral connections being re-opened using the same techniques available for full-length liners



lining on_packer

photo courtesy of WRc

Last Updated on Thursday, 25 April 2013 16:35

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