The old outfall pipe, which was installed in 1961, was made of wood. It had begun to break in some places and was springing leaks. The bands around the pipe had rusted and begun to crack after many years of friction against the seabed, and the related maintenance costs were increasing. As a result, Stora Enso decided to replace the outfall pipe. Stefan Johansson, a Construction Project Manager at Nymölla Bruk, contacted Uponor Infra during the marine installation of a stormwater pipe for the Glasbruket housing area in Limhamn. In the Limhamn project, no external concrete weights were used for sinking the pipes. A patented profile filling method was used instead.
A patented method for sinking the pipes
“Nymölla was very interested in avoiding the use of external concrete weights, because fishing activities occur in the area. Weholite was chosen because it could be profile-filled with grout. This was a crucial factor when choosing Uponor,” says Stefan Johansson. Nymölla chose Weholite for the new pipe due to its ability to withstand external wear such as friction against the seabed, which was so advantageous that alternatives were ruled out. In all, 3,500 metres of Weholite dimension DN/ID1,500mm were installed, consisting of 24-metre sections of pipe.
A dedicated team
“The project has involved several challenges, the greatest of which was the weather and ensuring that the old pipe would continue to function as the new one was being installed. In addition, connecting the new pipe could take no longer than 5 hours.” “In collaboration with us, Uponor Infra Project Services managed to handle all these challenges. Uponor Infra’s project service team is very dedicated, competent, perceptive, reliable and fun to work with. They clearly like their job and enjoy working together,” Stefan Johansson concludes. Uponor Infra Project Service’s work involved drawings, calculations of stability, corrosion and hydraulics, as well as project management and job descriptions. The field service work consisted of detailed engineering, project management, welding pipes into 265-metre sections, profile-filling by using the Uponor patented method, and the monitoring of sinkings.