Addressing the complexity of safety inside tunnels

Each tunnel provides its own unique safety challenges, based on where it is located, its layout, height, and traffic volumes and patterns. However, effective tunnel safety should improve two key aspects: incident prevention (and particularly fire) and the mitigation of their consequences. With nearly 50 years of experience in tunnel fire safety, Siemens understands the impact that the confined environment of tunnels, their critical economic role and the regulations have on fire safety performance requirements, today and in the future. As your partner of choice, we help you establish a future-proof fire safety technology strategy, tailored to each tunnel and translating into an overall system that will deliver consistently high performance in the long term.

Fire prevention through automatic incident detection

In tunnels, even seemingly minor events can quickly escalate. Though not compulsory for tunnels under 3000 metres in the context of the European Directive 2004/54/EC, automatic incident detection (AID) systems have proven their worth in shorter road and rail tunnels. AID systems are typically video-based, and use algorithms to analyse video images and detect deviations from "normal" patterns, automatically alerting operators of non-routine situations. Automatic incident detection using Siveillance™ from Siemens reliably identifies, monitors, and reports objects and situations that can lead to accidents and potentially fires. This universal video application platform generates alarms when defined safety rules are violated, e.g. slow or stopped traffic, wrong way drivers or lost loads. The system can be integrated with the traffic signalling system and automatic barriers, automatically alerting drivers to the incident before they enter the tunnel.

Incident and damage mitigation with precise fire location

As in all fire situations, identifying the source quickly is a significant success factor in effective incident mitigation in tunnels. A first line of defense can be found in the latest video smoke detection systems, such as used in Siveillance, which improve the fire risk assessment capability of tunnel operators and intervention forces by enabling them to remotely gather valuable information on smoke characteristics and changes inside the tunnel.  Linear heat detection systems, such as FibroLaser™ from Siemens, complement video analytics efficiently. These systems “take over” from video cameras inside the tunnel – eventually engulfed in smoke – or smoke detectors (increasingly used alongside linear heat detection systems), indicating the exact location of a heat spot and the direction and size of the fire – all important information to trigger appropriate smoke extraction, direct firefighting efforts, and improve escape conditions inside the tunnel.

Optimised response with quick alarming and evacuation

Self-rescue of people is a prime objective in tunnel incidents. Evacuation has to take place before conditions deteriorate (toxic smoke, visibility, structural collapse). Yet, recent events have shown that tunnel users are often reluctant to abandon their car – and therefore leave the tunnel – because they don’t always recognise the seriousness of the incident or think rescue will reach them quicker than realistically possible. Communication systems enabling immediate emergency messages to be broadcast are therefore vital to minimise the risk to tunnel users, enabling appropriate escape instructions to be given. The E100 voice evacuation system from Siemens is activated on alarm, sending out prerecorded instructions or live announcements at the same time as flashing evacuation lights are lit up along the escape route. This ensures users are instantly aware of the danger and know to evacuate immediately.