New fans installed in Heysen Tunnels refurbishment

The work is part of the upgrade of the South Eastern Freeway, the most direct connection between Adelaide and Melbourne. It is also a key corridor connecting Adelaide and the Adelaide Hills. The A$150m (£79.8m) tunnel refit will address elements that are at the end of their service life, to improve safety, traffic management and incident response capabilities.

The scope of the project work, being undertaken by McConnell Dowell Constructors (Aust) Pty Ltd, includes:

• upgrades to the tunnel lighting to a new LED system;
• installation of a new automated fire suppression system;
• upgrades to the tunnel ventilation system;
• repairs to the tunnel lining and installation of monitoring equipment;
• upgrades to the Intelligent Transport System equipment, including thermal incident detection systems, new and replacement CCTV, electronic speed and messaging signage and over height vehicle detection;
• upgrades to the traffic management system to restrict access to the tunnels in an emergency; and
• upgrades to emergency communication systems, including public address, radio rebroadcast, in-tunnel signage and help phones to improve safety and network reliability.

The new exhaust fans – eight in the Crafers-bound tunnel and 15 in the Adelaide-bound tunnel – form part of the tunnels’ fire suppression system to disperse smoke in the event of an incident. They will also provide ventilation, control exhaust fumes and clear any fog in the tunnel. The Adelaide-bound tunnel requires a greater number of fans to allow for smoke or fog to be pushed downhill ahead of traffic.

The fan installation is due to be completed in the first half of next year.

Initial activities and tunnel lining repairs started in March and the refurbishment is expected to be finished in the second half of 2024.