Technical visit to Nam Wan Tunnel and West Tsing Yi Viaduct of Route 8 - tunnel ventilation system
By Ir Elmen CHU
A technical visit to Nam Wan Tunnel and West Tsing Yi Viaduct of Route 8 - tunnel ventilation system organised by the FE Division was successfully held on 30 May 2009 with over 30 participants attended. The Route 8 Highway Scheme will link Lantau Island with Shatin. The North Lantau Highway section was completed in 1997. The remaining 15.5 km section is from Tsing Yi, through Stonecutter Bridge to Cheung Sha Wan, then to Shatin. Nam Wan Tunnel will provide a link between West Tsing Yi Viaduct and Stonecutter Bridge.
During the visit, Ir Richard C C Lau, Resident Engineer of Ove Arup & Partners Hong Kong Ltd, gave an overview of the project. The Nam Wan Tunnel consists of two tunnel tubes (EB and WB) and each tunnel tube is 1.25 km long, 12 m wide and 5.1 m height of twin three-lane tunnels. There are 12 numbers of cross passages inside the tunnel for emergency escape. The project was commenced in April 2003 and substantially completed in November 2007.
Mr Jackie S C Lau, Senior Engineer and Mr Gary S W Kwok, Project Engineer of Shinryo (HK) Ltd, then briefly introduced the tunnel ventilation fire and smoke control system. The system consists of two sets of 660V 920 kW smoke extraction fans which is installed in East Portal Building at eastern end of the tunnel. Both fans are connected with stainless steel durasteel smoke extraction duct along each tunnel. There are 28 numbers of jet fans installed along each tunnel. The main control room is located in the West Portal Building at the western end of the tunnel. Each tunnel is divided into six fire zones. Mr Lau explained the operation principles of the system, including the normal mode and fire mode, and the condition if fire breakout in each zone of the tunnel. The presentation ended with a fruitful discussion during the question-and-answer session.
After the presentation, Ir Lau and his colleagues guided the participants into Nam Wan Tunnel. The participants visited the main control room in West Portal Building and the function of remote manual operation panel (tunnel ventilation system) was explained. The participants then travelled along the tunnel to East Portal Building. In the tunnel, the participants visited the cross passages and briefed on the fire services installation. Arriving at East Portal Building, participants saw the 660V 920 kW smoke extraction fan and motor control centre system. Then participants walked and viewed inside the stainless steel durasteel smoke extraction duct. The visit ended after taking a group photo at the east end of the tunnel.
On behalf of all participants, we would like to express our sincere gratitude to Ir Lau, Mr Lau, Mr Kwok and their colleagues for their hospitality.
Presentation of souvenir (L to R): Mr Jackie S C Lau, Ir Richard C C Lau, Ir Elmen Chu, Mr Gary Kwok and Ir Simon Tsang
Participants at the east end of Nam Wan Tunnel