The installation and maintenance of all the pipes and cables is quick and easy to perform inside the utilities tunnel. There are concrete chambers inside the Infra Culvert at regular intervals for branching and connections.

In cooperation with the Swedish company Tekniska verken i Linköping AB, Uponor Infra Oy has developed an underground passage into which all the infrastructure of a residential area is gathered. Infra Culvert has been patented in the Nordic countries and a patent is pending also elsewhere in Europe.

The district of Vallastaden in Linköping, Sweden, is the first place that the Infra Culvert has been installed. All the district’s electricity and data cables, as well as water, sewage, waste and district heating pipes travel underground along a Weholite pipe that is 1.8 kilometres long and 2.2 metres in diameter. Built two years ago, the utilities tunnel has already proven its usefulness when changes were made to the public utility services inside it without having to dig holes in roads.

“The ease of modifications and repairs to cables and pipes without any digging is the most noticeable improvement to the old way of doing things. Any defects in the cables and pipes inside the utilities tunnel are also quick and easy to pinpoint and repair,” says Christian Vestman, Head of Project Services at Uponor Infra.

“Inside the tunnel, cables and pipes are protected from the wear and tear and damage that both the dampness of the earth and any vibrations may cause, which increases their service life.”

Swedish cities are eager to try

Infra Culvert is especially well suited for densely populated areas and places with challenging terrain. For example, a high water table causes the erosion of underground pipes and cables, especially their connections. In densely populated areas, digging up pipes and cables for repair and installation causes traffic jams and other inconveniences for the area’s residents.

Inspired by Vallastaden’s example, many Swedish cities are now interested in installing these utilities tunnels. Currently, 12 Swedish cities are at the budgeting stage with their Infra Culvert plans and the building work of at least one site will begin next year. Some cities in Southern Finland are also looking into the possibility of installing Infra Culverts.

“Compared to burying cables and pipes underground the traditional way, the initial investment of an Infra Culvert is unfortunately higher, which is hindering speedier adoption. On the other hand, the service life of an Infra Culvert is up to 100 years, and the owner of the structure can charge rent from the companies using or installing the pipes and cables in the passage, which is why the investment costs cannot be directly compared,” Vestman says.

Will Vaasa become a utilities tunnel trailblazer?

“The design and installation of the Infra Culvert is performed by Uponor Infra’s Vaasa unit and the components are ordered from the nearest Uponor production unit,” Christian Vestman explains.

Vestman would be very happy to see Vaasa as the first Finnish city to build an Infra Culvert, for example in the new Ravilaakso district. This would make the district a trailblazer of public utility services, as well as new energy solutions. And the design and installation of the Infra Culvert represents Vaasa-based know-how as much as many of the energy solutions there!

“The possibility of building a utilities tunnel in Ravilaakso has been discussed for a long time, but the final decision depends on many factors. We would like to see the district, for example, utilising a local low-heat district heating network and seasonal thermal energy storage in bedrock,” says Head of Site Pertti Onkalo from the City of Vaasa’s Real Estate Department.

Ravilaakso will be fairly densely built-up and the plan is to include some other solutions based on regional know-how there too. These highlight how well the utilities tunnel would lend itself to the area. Of course, the final decision also depends on the construction budget for the district.

“Uponor is involved with the Cleantech Kvarken project where we seek to find local innovations that could be used, for example, in urban infrastructure construction projects in Finland and elsewhere. The Infra Culvert is an excellent example of an innovation like that. It would be great if it could be utilised also here where it was created,” says VASEK's Project Manager Mauritz Knuts.

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Cleantech Kvarken is a project implemented in Västerbotten and Örnsköldsvik in Sweden and the Vaasa region in Finland. Its aims include cross-border business cooperation and the export of products and services from the energy and environmental sectors. The project is funded by the Botnia-Atlantica Interreg programme..

Text: Johanna Haveri
Translation: Taina Pemberton
Photos: Uponor, Johanna Haveri, Mauritz Knuts