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  • Writer's pictureTime To Reline

What is Pipe Relining? A question we get asked all of the time.

Updated: May 31

To put it simply, pipe relining is a pipe we install inside an existing pipe. At Time to Reline we are experts in this innovative plumbing solution and have broken down some of the different techniques and key considerations.

How does it work?

There are numerous ways to reline a pipe. Depending on what exactly needs to be done, will influence the method we recommend at Time to Reline.

Most issues are located in one section in the pipework such as a misaligned pipe or roots growing through an old inspection opening. In this instance we would install a sectional pipe repair. We install a section of cured-in-place-pipe onto a tool long enough to cover the length of the repair as required by AS3500.2. We then pull it into place using ropes and check with our Industry leading CCTV drainage cameras to ensure it is in the right place. The tool is then inflated under high pressure to compress the relining materials and push the resin into the broken pipe or damaged joints. The resin is then allowed to cure before removing the tool and leaving a brand new pipe inside the old one. The section is now much stronger as the original pipe is still in place with a structural liner multiplying the strength of the pipework and faulty section sealed.

Another method of relining is called inversion. This is more suited to longer lengths of pipework or sections of pipework in which a rope cannot get into place. A large drum type piece of equipment is used with air pressure as the installation medium. The liner is rolled onto an axel inside the drum which turns as we place it inside, creating a kind of spiral. We then pull the liner through the "nose" of the drum and turn it inside out, clamping it to the front piece. When air pressure is applied it pulls itself from the centre and inverts (turns resin facing out) the liner then slides through itself until completely inverted and collapses on itself. A calibration hose is then inverted through the centre of the liner which forces it to the shape of the "host" pipe. Then, there is a tube which we seal at the end with special knots and flat rope. In the flat rope we tie a rope and hose which is dragged to the furthest end away from the relining drum. The air is then replaced with hot water through the hose until it returns to the drum. We then circulate the hot water until the liner is cured, before cooling the water back down to ensure the resin has completely set. Once we remove the calibration hose the pipe is ready to use with no extra waiting time required. We may be required to reinstate some junctions as the liner seals everything. To do this we use a state of the art robotic cutter.

Junctions also require attention sometimes. To repair these we use a satellite junction repair; a specialist tool that requires a lot of experience to get perfect. It is similar to a sectional pipe repair but it has an arm that inverts out once in place. It is usual for a number of reasons most commonly to seal two liners together like the final piece of the jigsaw. However, they can be installed alone to seal a pesky root infested inspection opening that many older clay junctions have.

Why pipe relining over traditional methods such as excavation?

The strength of the host pipe and the new lining is over 10x stronger than new PVC piping alone.

Then add the speed and minimal disruption to the surrounding area such as foundations, walls, landscaping, and vegetation.

To be honest, not all pipework can be relined but we will not know until we have completed an inspection. We provide a free service to come out and inspect your sewer and stormwater lines. As long as the pipework is clear enough to get the information we need i.e. length, pipe diameter, number of junctions and bends, we can give you a competitive quote then and there. We also won't force you to try and sign anything while on site as it is a no obligation quote. We just know our experience and expertise will shine through.

Pipe Relining Drum

Is there a standard for relining materials and installations?

Yes! AS3500.2 stipulates what materials must be used and the correct lengths needed to repair broken pipework. Below is an extract which shows the standard of relining materials that must be installed. Materials should only be installed if watermarked and tested. Relining systems are tested together and should only be used as per manufacturers' instructions.

F2 Liner

CIPP liners shall conform with WMTS-518. When measured in accordance with ISO 7685 for thermosets (CIPP), or with ISO 9969 for thermoplastics, the minimum ring stiffness of an unsupported structural liner for below ground applications shall be 4 kN/m/m. For above ground applications the minimum pipe stiffness of the unsupported liner shall be in accordance with the appropriate product specification.

Key things to remember when choosing a pipe relining provider:

  1. That the products being installed are watermarked.

  2. That the products (resin and liner) are approved to be used together.

  3. Check what exactly is being repaired and how.

  4. Make sure to get a recording after the works are completed for your personal records.

  5. Check everything works after relining is completed. If it worked before, it should work after.

Time to Reline: Pipe Relining

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