Height equivalent to an apartment building, diameter of 22 meters and volume of 3,500 cubic meters of water - The FishGLOBE V5 fish farm in Stavanger, southwest Norway, is the world's largest ever built PE plastic structure designed for marine conditions.

Plastic has numerous advantages in marine conditions

The highly durable Wehopanels and Weholite pipes developed by Uponor Infra can be dimensioned and equipped individually for countless applications, such as tanks, foundation slabs, support structures, underground pumping station chambers and floating or submerged marine structures. In recent years, many innovative new products and structures have been developed using Wehopanel. “This project is the only one of its kind in the world. No PE plastic structure of this size has ever before been designed and built for use in marine conditions,” says Kari Karjalainen, Export Manager at Uponor Infra. Karjalainen says that the project has been very interesting and challenging. “The design, manufacturing and construction processes have all been extremely demanding. We got the opportunity to really make the most of our expertise and decades of experience in plastic construction.” Karjalainen says that a Wehopanel profile was customised for FishGLOBE, as no panels this strong and large had been produced before. “The calculation results ran to hundreds of pages, to ensure the durability of the structure in marine conditions with rough waves and currents.” Karjalainen believes that FishGLOBE will revolutionise not only marine fish farming, but also the future of other plastic structures designed for marine conditions. “Success in the project opens the door to new opportunities to build a variety of large-scale plastic applications for marine conditions. Plastic has undeniable advantages – it’s a durable material with a lifespan of over a hundred years. Thanks to its flexibility, it doesn’t develop cracks that lead to breakage – and there is not at risk of corrosion, either.”

A fully automated facility

At its Vaasa plant, Uponor Infra manufactured robot-welded Wehopanels measuring as much as 3 x 8 metres from 250 x 200 x 20 mm profiles for use as the functional shell and internal structures of the globe. A Weholite pipe with an internal diameter of three metres was made to serve as its central pipe. “The panels were also sawn to their correct dimensions before transport to Norway.” Its six water feed pipes, which also serve as the support structures of the facility, are 1,100mm pressure pipes. The water feed pipes supply the facility with seawater – which is then treated and discharged back into the sea through the central pipe. FishGLOBE is a closed and fully automated fish farming system. Technical equipment and an integrated feeding unit are installed in the upper section of the facility. FishGLOBE also differs from other closed systems in that the upper section is also enclosed. This ensures that waves cannot introduce salmon lice and other parasites into the habitat – the fish can thus live their first year in safe conditions. In the FishGLOBE, young salmon – smolts – are grown from a size of 100 grams to one kilo, after which they are moved to the next facility.

A massive welding and construction project

The panels and pipes were delivered to Stathelle in southwestern Norway in December 2018. Welding and construction then got under way. “The construction project was a massive undertaking. In addition to Uponor Infra’s own team, a Norwegian subcontractor OPD AS worked on it,” says Kari Karjalainen. The facility was lifted into the sea in July 2019 and towed to its final location in Lysefjord, near Stavanger in southwestern Norway. The final welding work, completion of the technical equipment and facility testing were then carried out. The facility was anchored to the seabed with 12 anchor points made of PE plastic that have been designed to withstand more than 25 tonnes of force.

A much larger FishGLOBE is already being designed

The customer, RyFish, introduced the first fish into the facility in November. They are expected to grow to a size of one kilo by April 2020. "Two FishGLOBE facilities of the same size are planned to be delivered to Lysefjord in 2020. The design work has already begun and the manufacture of profiles and panels can get under way in Vaasa as soon as everything is finalised.” The development of FishGLOBE will not end here. The much larger FishGLOBE V6 is already being designed. “It will have a volume of 31,000m3, with capacity for 2,000 tonnes of fish. Its diameter will be 44 metres and its height 30 metres. The system will weigh 1,000 tonnes,” says Karjalainen.