ThermaSmart® PRO Insulation Protects Pipelines in S-1 Expressway Tunnels

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A milestone in Polish infrastructure

In southern Poland, a major step forward to improved regional interconnectivity has been taken – the construction of the S-1 expressway. The stretch of the Gdańsk–Vienna transport corridor, which extends into Slovakia as the D3 motorway, was commissioned by GDDKiA and supervised by contract engineers from DTŚ S.A. and INKO Consulting.

The route is expected to be completed in the second half of 2026. However, our role in the project already ended.

On the 8.5-kilometre stretch between the two villages Przybędza and Milówka, the Mirbud/Kobylarnia consortium has built not only striking flyovers but also two tunnels through the Barania and Białożyński Grań massifs in the Beskid mountain range. Together, these tunnels measure more than 1,800 metres. With flyovers exceeding 30 metres in height and significant elevation differences, this project stands out as one of the most visually impressive engineering achievements in Poland.

A pipeline with a blue connection end is insulated with ThermaSmart PRO and runs along the side of a concrete tunnel foundation. The pipe is securely placed and insulated, ensuring long-term protection and energy-efficient heat transfer.

Tunnel construction with proven technology

The tunnels were excavated using the NATM method, a trusted technology also applied in other projects across the country, often alongside tunnel boring machine (TBM) systems. On this stretch of the S-1, Slovak partners worked closely with the Mirbud Group to deliver the complex underground works.

Thermaflex as an insulation partner

Inside the tunnels, reliable pipeline protection was essential. That is where Thermaflex came in. Our ThermaSmart® PRO system was chosen to safeguard water mains, hydrants, and sewage pipes against freezing. Its high thermal insulation performance, combined with fire-retardant properties, makes it an ideal solution for demanding environments such as tunnels.

Where additional security was needed, the system was complemented with heating cables and accessories. In total, more than 3,500 m² of ThermaSmart® PRO insulation was installed by the Mirbud Group together with SAN-NIK Tomasz Abucki. Thanks to its flexibility and simple installation, construction times were reduced. The insulation’s resistance to water vapour also means pipelines are better protected against corrosion, ensuring long-term durability.

Lasting impact

For Thermaflex, collaboration was key. Working alongside the Mirbud Group and its partners, we contributed to a project that is both technically advanced and strategically important. Once completed, the S-1 expressway will improve connectivity and, consequently, will lead to regional development.

More projects like this one

Insulation for Poland’s Longest tunnel

Zwierzyniecki (Zoo) Bridge Renovation

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