What was the project?

DrainsAid were recently tasked with rehabilitating a 300mm section of pipe on a steep incline, near a large supermarket retailer, in Stocksbridge. For this the team used a localised patch repair.

Why patch repair?

Patch repairs are a form of trenchless technology that are used when only a short section of pipe needs repairing. It enables localised damage to be effectively fixed in a cost effective manner. In this project a section of pipe was rehabilitated using a one metre patch.

The process

This project commenced by the team carrying out a point of work risk assessment and ensuring that all traffic and pedestrian management was correctly set out. In this project the entry manhole was located on a grass verge off the route of pedestrians and traffic. This enabled the pavement to be left in full use due to the small site footprint needed whilst the work was being carried out. The relevant signs and traffic management measures were displayed on the pavement to alert road users and pedestrians to the works that were being undertaken.

Once the team had established the site, they carried out a CCTV survey of the sewer that was to be lined, identifying and recording flow conditions and the exact location of the defect. Once this survey was completed, they cleaned the sewer using a high pressure water jet to ensure the pipe surface was in the correct condition for the patch to adhere to, before completing a second CCTV survey to confirm the cleanliness of the sewer.

packer being rolled around patch

The team then moved on to installing the patch lining system to repair the damage. A woven fibre chopped strand patch was cut to size. Formed of a three-ply construction, in accordance with the design criteria, the fibre matt was impregnated with a two-part resin mix which was evenly dispersed throughout the patch using scrapers. Following this, the fibre matting was wrapped around a ‘packer’ and secured by means of patching wire to prevent the patch from slipping. The packer was then lowered into the manhole and pulled into position at the required location. The packer was then inflated to the required pressure of 1.8 bar and left to cure. The packer was tied off at both ends in case the need arose to remove it in order to relieve flows.

It took an hour and a half for the patch to cure, the packer was then deflated and removed from the drain completing the localised repair.

A final CCTV survey was then undertaken as a quality control check.

To see more information about our range of CIPP techniques, including patch repair, please visit https://www.drainsaid.com/. Don’t hesitate to contact us if you have any drainage issues which we can help with.

patch being inserted into manhole