LÄNSIMETRO STATIONS | HElsinki, Finland
Halton designed supply air units for four Länsimetro stations, integrating them directly into platform benches. The result is an efficient, draught-free and unobtrusive ventilation system that blends seamlessly into the modern station architecture.
Fresh Air Underground
Länsimetro
Project: Four Länsimetro Stations
Construction period: 2009–2022
Client: Länsimetro Oy
Products: Approximately 190 bench diffuser elements. Also BRD pressure-relief dampers and BLD non-return dampers.
Supply air capacity: 1,500–2,000 l/s per bench
The Challenge
The ventilation for Länsimetro stations had to align with the architect’s vision. Visible ductwork was out of the question, and embedding it into the bedrock would have been too costly and labour-intensive.
The ventilation needed to be effective, yet fresh air had to reach passengers silently and without any sensation of draught. At the same time, a smoke extraction solution for emergency situations had to be incorporated.
The Solution
Halton’s designers integrated supply air units into the bench structures. Approximately 190 bench diffuser elements (950 × 400 mm) were installed across four stations: Espoonlahti, Finnoo, Matinkylä and Urheilupuisto. Air volumes are substantial, reaching up to 1,600 l/s per bench.
To ensure draught-free performance, Halton tested the concept in a full-scale mock-up at its Kausala factory Innovation Hub. Using a plywood bench model, engineers tested how low-velocity panels distribute airflow beneath the seats without creating any draught. Sound levels were also measured during testing. In emergency situations, the same units can operate at boosted capacity to supply replacement air during smoke extraction. In addition, Halton delivered BRD pressure-relief dampers and BLD non-return dampers to the stations.
Customer Benefit
Supply Air to Passengers Draught-Free
The bench-integrated ventilation delivers the required supply air to passengers draught-free, unobtrusively and quietly. With the ventilation equipment hidden from view, the architect’s vision of a unified station space was fully realised. Full-scale mock-up testing and its documentation gave the client confidence in the outcome from the outset of the design stage.
The same supply air units serve dual duty for both normal ventilation and smoke extraction. The bench diffuser elements are also easy to detach for cleaning. Halton’s production was flexibly scheduled to match the Länsimetro construction timeline. The products were manufactured in Kausala, ensuring reliable delivery and environmentally friendly logistics.
Juhani Penttilä, Property and Infrastructure Director, Länsimetro Oy
“The solution meets all technical and architectural requirements. The ventilation was integrated into the station space unobtrusively, and the end result serves both the design intent and operational needs.”
Halton Buildings References
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