Emergency evacuation
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Concept
Emergency evacuation is the movement of persons from a dangerous place to a safe refuge. Examples are the evacuation of an apartment, a house, a district during or after a catastrophic event like floods, fires or bomb alarms. The duration of the evacuation is called evacuation time. There are several methods to forecast evacuation times like full scale trials, calculations based on the flow of persons (hydraulic models) or evacuation simulations.
Evacuation Plans
In areas threatened by disasters evacuation plans are established to prepare for an efficient evacuation and to avoid panic. Evacuation simulations, trials, and emergency plans are further measures of preparation.
Evacuation plans are addressing the procedure and are therefore part of the procedural measures of fire protection.
Sequence of an evacuation
Schematically, the sequence of an evacuation can be divided into the following phases:
- detection
- decision
- alarm
- reaction
- movement to an area of refugee or an assembly station
- transportation
The time for the first four phases is usually called pre-movement time.
The particular phases are different for different objects, e.g., for ships a distinction between assembly and embarkation (to boats or rafts) is made. These are separate from each other. The decision whether to enter the boats or rafts is thus usually made after assembly is completed.
Evacuation of districts or areas
The evacuation of whole areas can be necessary after natural disasters like
- eruption of a volcano
- floods
- earthquakes
Other reasons are accidents:
- industrial accidents
- traffic accidents, e.g., trains or airplanes
- fire
- bomb threats
- terroristic attacks
The evacuation of whole areas is part of civil defense.
Evacuation of buildings
Since the evacuation of buildings is part of the evacuation of areas, it is triggered by the same events. The strategy of individuals was investigated by Abrahams (1994). The independent variables where the complexity of the building and the movement ability of the individuals. With increasing complexity and decreasing motion ability, the strategy changes from "fast egress" via "slow egress" and "move to safe place inside building" (like a staircase) to "stay in place and wait for help". The last strategy is the one of motion impaired persons, which must be safed by nursing staff or first responders.
Evacuation of ships
The main difference between the evacuation of buildings and the evacuation of ships is the availability of an area of safety. The first phase, i.e., the assembly phase, of a ship evacuation is to some extent comparable to building evacuation. The evacuation to the boats (embarkation) starts after the assembly (at least for one assembly station) is completed.
References
- Abrahams, John: Fire escape in difficult circumstances, chapter 6, In: Stollard, 1994, Design against fire.
- Gershenfeld, Neil, Mathematical Modelling. OUP, Oxford, 1999.
- Hubert Klüpfel, A Cellular Automaton Model for Crowd Movement and Egress Simulation. Dissertation, Universität Duisburg-Essen, 2003.
- Stollard, P. and L. Johnson, Eds., Design against fire: an introduction to fire safety engineering design, London, New York, 1994.
- http://www.traffgo.de/downloads/eintraege_pedevacbib.pdf - A literature review (PDF)
External links
- http://www.traffgo.com/show_text.php?mid=11&umid=0 - TraffGo and PedGo (pedestrian simulation and evacuation dynamics)
- http://fseg.gre.ac.uk - Fire Safety Engineering Group at the University of Greenwich
- http://www.traffic.uni-duisburg.de - PESOS and BYPASS, reasearch projects "Evacuation of Passenger Ships" (University Duisburg-Essen, Germany)
- http://www.germanlloyd.org/aeneas.html - Simulation of Ship Evacuation at Germanischer Lloyd
- http://www.tiems.org - The International Emergency Management Society
- http://angel.elte.hu/~panic - Panic Simulation (Budapest University)
- http://www.helbing.org - Dirk Helbing's homepage