Pre-Insulated Pipes Provide Firewater and Drainage Solutions for a Major Railway Tunnel in Norway

27. January 2023 | 3 min read

A new double-track line from Drammen to Kobbervikdalen is under construction as part of a rail infrastructure development in Norway. To secure the project’s water supply in extreme weather conditions, Pipelife delivered a variety of pre-insulated pipes.

Close up of the construction works at the Strømsåsen tunnel | Pipelife © Bjarte Opofte, Bane NOR

The InterCity Initiative

The InterCity Initiative is a large-scale railway development in Eastern Norway that will provide more trains per hour between Drammen and Vestfold. This involves the reconstruction of existing train stations as well as the creation of new train lines.

The main obstacle to fast train travel between Drammen and Vestfold was the Strømsåsen hill that, until now, had to be circumvented. Equipped with 10 kilometers of new double tracks, the InterCity Initiative is constructing a tunnel through the hill to facilitate a more direct route between the two regions.

A Depth Dilemma

In countries like Norway, pipelines are often laid deep in the ground to benefit from a stable geothermal environment and avoid frost exposure. However, the groundwater levels near the Strømsåsen tunnel construction made this solution unsuitable.

Pipelife Norway was presented with this problem and tasked with finding custom firewater and drainage solutions that could be installed close to the surface, while also dealing with the challenging conditions of the project and the local climate.


A female worker attaching insulation to a fire hydrant for the InterCity project | Pipelife

Providing Frost-Proof Firewater Access Throughout the Tunnel

To secure firewater access throughout the 6-kilometer-long tunnel, Pipelife Norway provided a pre-insulated firewater system including 28 fire hydrants fitted with MDI-based polyurethane (PUR) insulation. This provided crucial protection from extreme outside temperatures.

Though insulated, the exposed hydrants are still vulnerable to frost over time as Norwegian winters can promise regular temperatures between -20 °C and -30 °C. To address this, the team additionally equipped the hydrants with a self-limiting heating cable that prevents internal stagnant water from freezing.

Two male workers attaching insulation layer to a fire hydrant | Pipelife
A worker is standing next to a pre-insulated fire hydrant at Pipelife Norway's plant | Pipelife

Pre-Insulated Pipes for Stormwater Management

Pipelife Norway was also tasked with providing a drainage solution that could divert stormwater away from a large housing estate situated over the tunnel.

As with the fire hydrant pipes, the project conditions required these pipes to be laid close to the surface, often underneath the rails. The team supplied 900 meters of PE pressure pipes and fitted them with PUR insulation as they were particularly vulnerable to influxes of cold air caused by trains traveling through the tunnel. Beyond this, the rigidity of the foam insulation provided extra support for the pipes running beneath the train line to withstand excess traffic loads, mechanical stress and vibrations.

Construction works at the Strømsåsen tunnel at night | Pipelife © Bjarte Opofte, Bane NOR

The Rail Ahead

This NOK 12.7 billion (EUR 1.2 billion) project is being developed by Veidekke, one of Scandinavia’s largest contractors, and Bane NOR, the Norwegian state enterprise responsible for the national rail network. The overall construction started in 2019, but the installation of the pipes and fire hydrants began in June 2022. Soon the development’s water supply will be protected against the Norwegian winters, ensuring the safe and successful completion of this much-needed infrastructure for the residents of Eastern Norway.

The project is an exciting example of designing custom solutions. The topographic restrictions involved were unique and required methods of supplying firewater and drainage that are rare in Norway.

Pipelife Norway provided a start-to-finish solution that included sourcing, insulating and delivering the products required to make this project a success. The clients appreciated working with a single supplier for this complex solution, as it was important that they could depend on us for quality and delivery.

Work installing the Pipelife insulated hydrants and pipes continues, and the overall development is planned to be under construction until 2025.

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