The Harbour Tunnel

the northern entrance and about 35 metres The tunnel ventilation system is managed from the southern entrance to its deepest to ensure carbon monoxide levels within point, 25 metres below sea level. the tunnel are kept within approved levels and that visibility for drivers is maintained The tunnel joins the at safe levels. at North Sydney, and the at the entrance to the Domain Tunnel. It has two lanes in each direction and Air quality monitoring carries around 90,000 vehicles per day. The tunnel operator carries out routine testing of the air quality in the tunnel and Sydney Harbour How is air quality managed in the ventilation building. The air quality in the Sydney Harbour Tunnel? is monitored 24 hours a day to ensure levels stay within the goals set by the former The Sydney Harbour Tunnel was completed Air quality in the tunnel is managed Minister for Planning and opened to traffic in August 1992 to with a ventilation building located in the The tunnel is fitted with carbon provide a second crossing of Sydney northern pylon of the . monoxide monitors as well as visibility Harbour and to alleviate congestion on In addition to air being expelled via the and air velocity monitors. the Sydney Harbour Bridge. ventilation building, air is expelled through the tunnel portals (tunnel entrances and The tunnel is made up of three sections: exits). Air is circulated through the tunnel twin 900-metre land tunnels on the north by a combination of vehicle movements and shore, twin 400-metre land tunnels on the use of axial fans. Fresh air can be drawn the south shore and a 960-metre immersed into the tunnel via a duct located on the top tube. The tunnel falls about 55 metres from or side of each tunnel.

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