Emergency Evacuation From Tunnels

Tunnel evacuation is uniquely challenging — there are limited exits, poor visibility, and long escape routes.
Fire in a tunnel fills the bore with smoke in seconds, reducing visibility to zero.
Gas ingress from the ground can create toxic or explosive atmospheres requiring immediate evacuation.
All tunnel workers must know the evacuation route, assembly points, and alarm signals before entry.
Refuge chambers or safe havens may be provided in long tunnels as intermediate points of safety.
Self-rescuer breathing apparatus provides 10-20 minutes of air for escape from a smoke-filled tunnel.
Communication systems — PA, radio, or hard-wired — must reach all parts of the tunnel for alarm purposes.
The Confined Spaces Regulations 1997 and CDM 2015 require documented evacuation procedures for tunnels.
Evacuation drills must be carried out regularly to test the procedure and train the workforce.
Emergency lighting powered by battery backup must illuminate escape routes throughout the tunnel.

Smoke fills quickly	Tunnel fires generate smoke that fills the bore in seconds, cutting off escape routes.
Limited exits	Tunnels typically have only two exits — if one is blocked, the other must be reachable.
Toxic atmosphere	Gas ingress or fire creates conditions incompatible with life within minutes.
Legal requirement	Confined Spaces Regulations and CDM mandate emergency evacuation plans for all tunnels.

Do

Don't

Learn the evacuation route, alarm signals, and assembly point before entering the tunnel.
Know the location of your nearest self-rescuer and how to don it within 30 seconds.
Attend all tunnel evacuation drills and take them seriously every time.
Follow the evacuation route markers and emergency lighting during an alarm.
Report to the assembly point and confirm your name on the tunnel register.
Carry a personal gas monitor and a cap lamp at all times in the tunnel.
Know the location of refuge chambers and safe havens along the tunnel route.
Evacuate immediately on hearing the alarm — do not wait for further instruction.
Move calmly towards the nearest exit, keeping contact with the tunnel wall if visibility is poor.
Check that communication systems are working before starting your shift underground.

DON'T enter the tunnel without knowing the evacuation route and alarm signals.
DON'T delay evacuation to collect tools, equipment, or personal belongings.
DON'T run during evacuation — move quickly but calmly to avoid trips and collisions.
DON'T re-enter the tunnel after evacuation until the all-clear is given.
DON'T block escape routes with materials, plant, or stored equipment.
DON'T ignore the evacuation alarm even if you think it is a drill.
DON'T remove or relocate self-rescuers from their designated positions.
DON'T smoke or create ignition sources inside the tunnel at any time.
DON'T assume the emergency will be short — use your self-rescuer if conditions deteriorate.
DON'T skip evacuation drills — they build the muscle memory needed in a real emergency.

See also: Tunnelling Safety Awareness | Tunnel Ventilation Requirements

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