The effect of technical installations on evacuation performance in urban road tunnel fires

Tunnels are separated from the ground by structural linings, and are enclosed and unfamiliar for occupants. In tunnel fires, occupants are faced with a dangerous environment and they need to evacuate. Conveying and obtaining information about the evacuation is the key issue for evacuees. Since tunnels typically have low lighting and little connection outside the tunnel, technical installations are the only approach to deliver information to occupants in order to guide their fast and safe evacuation. This is particularly an issue for urban road tunnels with large occupants’ flow in a large underground space. The present study explores the effect and role of technical installations (alarms, information signs, and lighting) on people’s evacuation performance in urban tunnel fires, through field experiments, questionnaires and interviews. Theory of affordance (sensory affordance, cognitive affordance and functional affordance) is taken into consideration and provides an integral evaluation for technical installations. Technical installations are useful in helping occupants notice the emergency, find exits and guide path, and information signs are regarded as the most powerful among those three. Besides, this experiment points out some side effect from alarms and ambiguity of signs which will result in serious consequence potentially. This study leads to guidance on improvement of technical installations on evacuation planning and procedures on urban road tunnels.