TUN/General/TBT-TUN-008

Tunnel Fire Prevention

Tunnelling & Shafts › General › Tunnel Fire Prevention

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Fire in a tunnel is one of the most dangerous construction emergencies due to confined escape routes.
Smoke in a tunnel reduces visibility to zero within seconds and contains lethal toxic gases.
Heat from a tunnel fire can exceed 1,000°C, making the environment unsurvivable within minutes.
Common ignition sources include hot works, electrical faults, diesel plant, and flammable material storage.
The ventilation system becomes critical during a fire for smoke management and maintaining escape routes.
Fire detection systems, alarms, and suppression equipment must be installed before tunnel work begins.
Flammable materials including fuel, hydraulic oil, timber, and waste must be strictly controlled underground.
Emergency evacuation procedures must account for smoke direction, refuge areas, and rescue team access.
Self-rescuer devices providing breathable air for escape should be carried by all tunnel workers.
The Regulatory Reform (Fire Safety) Order 2005 and the Joint Fire Code apply to tunnel construction.

Unsurvivable conditions	Tunnel fires generate lethal temperatures and toxic smoke in an enclosed space with limited escape routes.
Rapid escalation	Fires in tunnels escalate far faster than surface fires due to confined airflow and concentrated fuel loads.
Escape difficulty	Tunnel workers may be hundreds of metres from the portal. Smoke fills escape routes within seconds of ignition.

Don't

Install fire detection, alarms, and suppression systems before tunnel work begins.
Carry a self-rescuer breathing device at all times when working underground.
Control flammable materials; store only minimum quantities needed inside the tunnel.
Maintain fire extinguishers at regular intervals and at every hot works location.
Know the evacuation route, refuge locations, and emergency assembly points.
Ensure the ventilation system is designed for smoke management during fire events.
Report any electrical faults, fuel leaks, or overheating equipment immediately.
Practise tunnel evacuation drills regularly so all workers know the escape procedure.
Use diesel particulate filters on all plant to reduce fire ignition risk.
Keep escape routes clear and illuminated with emergency lighting at all times.

DON'T store unnecessary flammable materials inside the tunnel at any time.
DON'T carry out hot works in the tunnel without a specific hot works permit.
DON'T block or obstruct tunnel escape routes with plant, materials, or equipment.
DON'T ignore fire alarms in the tunnel; evacuate immediately towards fresh air.
DON'T work underground without a self-rescuer breathing device on your person.
DON'T leave diesel plant running unattended inside the tunnel overnight.
DON'T smoke or use naked flames anywhere inside the tunnel construction zone.
DON'T skip evacuation drills because they disrupt the construction programme.
DON'T disable fire detection or suppression systems during construction work.
DON'T fight a tunnel fire beyond using an extinguisher on a small fire; evacuate.

See also: Tunnelling Safety Awareness | Emergency Evacuation From Tunnels

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