Prysmian Sky Project

We are building a tower to produce marine cables for Prysmian Group's production facility in Kirkkonummi. At the end of 2023, the building claimed the title of the tallest building in Finland, proof of our professionals' expertise in demanding industrial construction projects.

We are building a tower intended to hold submarine cables for Prysmian Group's production facility in Kirkkonummi. The tower has reached its highest point and is currently the tallest building in Finland.

High Technology in the Tower

Prysmian Group implemented a new, higher vertical vulcanization line in the tower, which is state-of-the-art in cable manufacturing. The tower has two vertical vulcanization lines that isolate high-voltage submarine cables. Vertical vulcanization is an important part of the manufacturing process of high-voltage cables. The production technology had to be installed on the tower from top to bottom, layer by layer, as the construction work progressed. In addition, the production lines of the cable tower require exceptional stability for the building: for the entire height of 185 meters, the tower must not bend by more than 20–30 millimeters.

The tower's frame was implemented with sliding casting technology, and the work proceeded uninterrupted 24 hours a day. The weather conditions, especially the wind speed, affected the casting process and the crane's lifting. During the lifting of the crane, the wind speed had to be less than ten meters per second, and during the sliding casting, the limit was 15 meters per second.

In addition to the new cable tower, the investment includes several other new production facilities. In addition to the tower project, YIT has started a contract that includes expanding four hall buildings and constructing a new material storage facility in the area. The new premises will have an area of 26,000 m². The contract includes a lot of demanding foundation construction work, concrete and steel construction work, as well as technical building work.

Promoting the Green Transition

By investing in Kirkkonummi, Prysmian Group is responding to the growth in demand for land and sea cables spurred by the energy transition and related technology. High-voltage submarine cables are used for the electricity transmission of green transition investments, such as offshore wind farms.

YIT was selected as the implementation partner for the cable tower project in the summer of 2023. The tower reached its ridge height of 185 meters by the end of 2023. The tower was completed and the 185-metre tower was commissioned in May 2025. The entire agreed contract is estimated to be completed in June 2026.

Facts:

The volcanization tower has a diameter of 24 meters
On average, the tower increased in height by 2.4 meters per day
The outer wall of the tower has a thickness of 600 mm
11,500 cubic metres of concrete were used for the tower and 1,600 cubic metres for the foundations
The tower weighs approximately 30,000 tons