One of our CIPP lining gangs were in Sheffield recently. The team were tasked with rehabilitation of a section of 125mm x 225mm vitrified clay sewer pipe in a busy residential area. For this they chose to use a UV Lining rehabilitation method.
Why UV Lining?
UV Lining was the preferred repair option due to the gradient of the pipe, the need to keep the site footprint to a minimum and the need to minimise disruption as much as possible.
The sewer under repair had 13 lateral connections which would require re-opening once the CIPP (cured in place pipe) liner has cured. To ensure the exact location of these connections are recorded a CCTV survey was undertaken prior to the liner installation to accurately record the chainages. This will allow our engineers to revisit these exact locations with the robotic cutter after lining in order to re-open the lateral connections and restore full service to the residents drains.
Our Jet Vac Tanker was utilised to cleanse and desilt the pipe in preparation for the lining process. Over pumping was also set up in order to keep the pipe free from flows during the repair process.
A 125m x 225mm x 3mm UV sensitive resin impregnated liner (provided by RSM Lining Supplies) was winched into place between two existing manhole chambers. The liner was then slightly inflated in order to install the UV light train and fix the ‘end cans’ to the liner. Once this was done the liner with then slowly inflated to the size and shape of the host pipe.
The UV light train was then pulled through the liner to cure it using UV light, the speed of which was mechanically determined, as was the power output of the UV lamps. Readings were sent back to our control unit every 2 seconds to ensure guidelines were followed and a full and precise cure was achieved. This method has an advantage over the alternatives as it has a significantly lower carbon footprint with a minimum expenditure of energy required.
Upon curation of the liner, we used our Hachler HF 200 robotic cutter to re-open the 13 lateral connections. This robust, powerful robot can travel up to 90m away from the manhole or access point.