Work commences to install new fans in Heysen Tunnels, as refurbishment continues

Tuesday, 19 December 2023

Work to install 23 new exhaust fans in the Heysen Tunnels has begun, as part of the ongoing upgrade of the tunnel’s systems.

The work is part of the South Eastern Freeway Upgrade Project, which is jointly funded by the Australian and South Australian governments. The tunnel refit work will address current 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 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 (ITS) 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 the event of an emergency incident; 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 tunnel’s 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 any traffic.

McConnell Dowell Constructors (Aust) Pty Ltd are the managing contractor for the works and local sub-contractors and suppliers are being used wherever possible. While the 23 ‘Half-Banana Jet Fans’ have been built in Germany, their support frames have been fabricated locally. The term ‘Half-Banana’ refers to the slight bend in the fans, to direct airflow along the curved roof of the tunnels . Similar fans have been used previously in the O-Bahn City Access Tunnel.

The first of the fans have been installed during December, with the remainder to be lifted into place in the first half of 2024.

As work continues on the tunnel refurbishment, traffic conditions will change for three weeks in January to allow for vital electrical upgrades. The temporary change in traffic conditions will be from 2 January to 25 January, which is traditionally the quietest time of the year for traffic through the tunnels.

Between 6am and 7pm during this period (7 days a week), the left-hand lane of the Adelaide-bound tunnel will be closed, while speeds will be restricted to 60km/h for the remaining two lanes. The Crafers-bound tunnel will operate as normal.

Then, between 7pm and 6am (7 days a week), the Adelaide-bound tunnel will be closed completely, with traffic to operate in a single-lane each way using the Crafers-bound tunnel.

Drivers heading through the tunnels are encouraged to allow extra time for their journey, or to seek an alternative route. In the event of a bushfire, other emergency, or on catastrophic fire days, all lanes will be open in both tunnels and speed limits will be reinstated to normal. The works will also not have a direct impact on Tour Down Under events in the hills  , and public transport will continue to operate as usual. Safety ramps will be accessible at all times.

For more information on the project, or to register for updates, visit the South Eastern Freeway Upgrade Project website.