NorthConnex will install a state of the art emergency smoke extraction outlet at the Trelawney Street compound to ensure the safety of motorists in the rare event of a fire.

Heat detectors inside the tunnel would trigger the in-tunnel water deluge system to protect motorists. The ventilation system will then extract smoke through the portals and/or the tunnel support facilities and high-power fans would push the smoke high into the atmosphere.

During low speed traffic conditions, additional fresh air may be drawn into the tunnel from the tunnel support facilities to ensure air quality is maintained.

This facility will be accessed by workers about four times a year during planned tunnel maintenance shutdowns. It will not be permanently staffed. The emergency smoke extraction outlet, air intake system and a substation will be housed within buildings to minimise any noise impact and the perimeter of the site will be landscaped to reduce visual impact.