There are basically two types of fire life safety provisions – passive and active. Passive measures cover details of the design and layout of the tunnel itself to aid the escape of the those trapped and to minimise both the intensity of the fire and its impact on the structure. Such measures include:

  • Providing a roadway cross fall to a suitably designed drain to minimise the surface area of any spilt liquid available to burn

  • Using a low porosity material for the pavement to minimise fire and explosion risks from combustible materials accumulating within the roadway

  • Designing the reinforced concrete to be more resistant to spalling at high temperatures

  • Using materials which are non-combustible and which do not produce large quantities of toxic fumes when heated

  • Uninterruptible power supply for emergency lighting just above pavement level

  • Easily understood signs to direct those trapped to places of safety, located at low level to ensure they are not hidden by smoke

    • Active provisions have the same aims and can include:

  • Fire and/or smoke detection system, closed circuit television system

  • Hand-held fire extinguishers and a wet or dry hydrant system with hose reels

  • Sprinkler or deluge system (although not generally recommended for use in road tunnels) is required by the fire authorities in a few countries

  • Emergency ventilation to control smoke spread and exhaust it from the tunnel

  • Communications facilities including emergency telephones, radio and loudspeakers