With a total length of 32.8 kilometers, the Koralm Tunnel is the longest railroad tunnel in Austria and is a section of the pan-European railroad network. As a central section of the double-track high-performance line “Koralmbahn Graz-Klagenfurt”, the tunnel connects Styria with Carinthia. The AQUASYS high-pressure water mist system was installed to ensure the safety of the tunnel in the event of a fire.

This high-pressure water mist system from AQAUSYS protects the emergency stops in the middle of the tunnel and is designed to fight fires with a heat release of up to 200 MW. In close cooperation with Porr Verkehrstechnik GmbH, the complex challenges were overcome efficiently. Together, the two companies ensured the integration of the innovative fire protection system into the tunnel infrastructure.
Over 2,500 nozzles were installed and 8 km of piping laid. A major challenge was ensuring the safe evacuation of passengers in the presence of high voltage in the overhead lines and the simultaneous introduction of water mist. To this end, the safe operation of our firefighting system in the vicinity of high voltages of up to 65 kV was demonstrated in the run-up to the project through extensive tests in the high-voltage laboratory at Graz University of Technology.
The planned automatic maintenance represents a milestone, meaning that on-site maintenance by our specialist personnel is only required every 4 years.

This innovative project, which combines the expertise of both companies, shows how successfully technological solutions can be implemented in the infrastructure sector. The successful spray tests of the finished system once again confirm the high reliability of AQUASYS technology and underline our contribution to the safety of this pioneering infrastructure project.