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Hazard
Inaccurate situational awareness: Underground structures

Hazard Knowledge

Incidents in underground structures may present significant challenges in gathering information and establishing accurate situational awareness. The seriousness of the incident in a tunnel or underground structure may not be immediately apparent and there is potential for the incident to rapidly escalate. Underground environments are varied and fire and rescue personnel may encounter a range of complex and unfamiliar conditions that may include:

  • Long travel distances
  • Complex workings and uncharted layouts
  • Dead end conditions
  • Pressurised workings
  • Complex and unfamiliar machinery
  • Highly restricted working areas

Consideration should be given to the likely resource and time requirements to establish, initiate and maintain an effective intervention and the likely development of the incident during that time. Initial considerations should include:

  • Identifying appropriate bridgeheads or equipment staging areas
  • Position of any ventilation outlets where the products of the incident may affect those on the surface or remote from the incident
  • Direction of any mechanical forced ventilation, so that safe areas for members of the public and operational bridgeheads can be provided
  • Gradient of any passageway allowing run off, liquid contamination or flowing fuel fire to spread, or the potential for inclined surface 'trench effect'.
  • Method of containing run off or contaminated liquids, and their environmental impact
  • Stability of the structure and its effect on the surface
  • Risk of inundation of the infrastructure
  • Identifying the possible spread of flood water and its predicted effects on the wider community.

Some infrastructures will contain large numbers of people, unfamiliar with their surroundings or emergency procedures. The responsibility for their evacuation in an emergency rests with the infrastructure managers, however fire and rescue services will undertake rescues of staff and/or members of the public where they are in imminent danger.

Incident commanders should attempt to identify the progress and success of managed evacuation. If it appears that people are, or may be, imminently exposed to harm then the situation becomes a rescue and the incident commander will take appropriate action.