Due to damage caused by root ingress, a vitrified clay sewer line in Lancashire required proactive rehabilitation works to prevent further deterioration. DrainsAid were tasked with the manhole to manhole installation of a 225m x 300mm Hot CIPP Liner.
Planning & Preperation
The sewer line resided under a privately owned field in the countryside of Barnoldswick, which had limited access for vehicles. Therefore, road management procedures were required on Kelbrook Road to allow our Recycling Jet Vac and Lining Vans parking availability. Two way traffic lights were assembled by NRASWA trained operatives, as well as pedestrian management to segregate the working area from a nearby public bridleway.
With the site established, a CCTV survey was conducted to establish flow conditions. Following investigation and root cutting operations, our highly efficient Recycling Jet Vac Tanker was then utilised to cleanse the sewer line. The robotic cutter was then launched to record the chainage and orientation of all lateral connections, which would be used once the liner was insitu, to reopen all connections at their pre-measure locations.
Scaffolding was designed and erected above the inversion manhole to a sufficient height, to facilitate the head of water required for the 225m liner being inverted. The team also prepared the liner by securing the ‘stop’ end with banding straps, rope and a burp tube to ensure all trapped air could escape prior to immersion.
Hot CIPP Liner Process
Firstly, a pre liner was inserted into the pipe, followed by a 6mm thick, Type II structural lining. The process uses water pressure from our Recycling Tanker to fill the liner to capacity with the hydraulic force of water pushing the liner to the desired position at the downstream manhole. This process inverts the liner leaving the resin impregnated side to cure to the existing pipes internal walls, and the smooth coating to become the inner pipeline.
Throughout curation, heater hoses were passed through the liner and a boiler was used to heat the circulating water at a temperature of 90 degrees. To complete the installation mechanical end seals were installed to stabilise the liner against the wall of the pipe, ensuring a watertight seal. Finally, lateral intersections were reopened using the Hachler HF 200 Milling Robot.
Utilising a hot water cure method in combination with a polyurethane coated liner (for heat resistance) allowed DrainsAid to successfully rehabilitate the pipe, repairing damage and extending its life expectancy by a further 50 years.