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A platform for research: civil engineering, architecture and urbanism
Study for safety at a relatively short tunnel when a tunnel fire occurred
Progress in vehicle exhaust control has greatly improved environments in road tunnels in recent years. Consequently, we discuss the downsizing or removal of tunnel ventilation systems formerly installed to secure the environments in road tunnels. On the other hand, tunnel ventilation systems are also used as smoke control systems in case of fires. So it is also important to discuss safety from tunnel fires. We studied factors that affect the safety of tunnel users in a relatively short road tunnel (around 500m, without a ventilation system) when a tunnel fire has occurred. The examination was analysed by a three-dimensional simulation (Large-Eddy Simulation model) to reproduce the smoke spread and by a one-dimensional evacuation simulation. We evaluated the number of people requiring help (NPRH) who cannot evacuate from a tunnel fire. Among the results of the study without a ventilation system, we found some conditions related to safety when a tunnel fire has occurred. The conditions were the fire source point, road longitudinal gradient, presence or absence of wind velocity and a bus. Especially when evacuating from a bus, people need more time to evacuate. This case has an increased risk of someone being left behind in the bus. And we confirmed that many passengers cannot evacuate from a bus because of the smoke from the fire when the bus is close to the fire source point. The second factor influencing safety is the natural wind in the tunnels. Even in a small natural wind of about 1.0 m/s case, smoke catches up to tunnel users when the direction of the natural wind matches the evacuation direction. In this case, we have confirmed that many evacuees cannot evacuate, even there is no bus.
Study for safety at a relatively short tunnel when a tunnel fire occurred
Progress in vehicle exhaust control has greatly improved environments in road tunnels in recent years. Consequently, we discuss the downsizing or removal of tunnel ventilation systems formerly installed to secure the environments in road tunnels. On the other hand, tunnel ventilation systems are also used as smoke control systems in case of fires. So it is also important to discuss safety from tunnel fires. We studied factors that affect the safety of tunnel users in a relatively short road tunnel (around 500m, without a ventilation system) when a tunnel fire has occurred. The examination was analysed by a three-dimensional simulation (Large-Eddy Simulation model) to reproduce the smoke spread and by a one-dimensional evacuation simulation. We evaluated the number of people requiring help (NPRH) who cannot evacuate from a tunnel fire. Among the results of the study without a ventilation system, we found some conditions related to safety when a tunnel fire has occurred. The conditions were the fire source point, road longitudinal gradient, presence or absence of wind velocity and a bus. Especially when evacuating from a bus, people need more time to evacuate. This case has an increased risk of someone being left behind in the bus. And we confirmed that many passengers cannot evacuate from a bus because of the smoke from the fire when the bus is close to the fire source point. The second factor influencing safety is the natural wind in the tunnels. Even in a small natural wind of about 1.0 m/s case, smoke catches up to tunnel users when the direction of the natural wind matches the evacuation direction. In this case, we have confirmed that many evacuees cannot evacuate, even there is no bus.
Study for safety at a relatively short tunnel when a tunnel fire occurred
Mikame, Y. (author) / Kawabata, N. (author) / Seike, M. (author) / Hasegawa, M. (author)
2014
7 Seiten, Bilder, Tabellen, 4 Quellen
Conference paper
English
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