Evacuation simulation is a method to determine

evacuation Evacuation or Evacuate may refer to: * Casualty evacuation (CASEVAC), patient evacuation in combat situations * Casualty movement, the procedure for moving a casualty from its initial location to an ambulance * Emergency evacuation, removal of per ...

times for areas, buildings, or vessels. It is based on the

simulation A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the ...

crowd Generally speaking, a crowd is defined as a group of people that have gathered for a common purpose or intent such as at a Demonstration (people), demonstration, a Sport, sports event, or during looting (this is known as an acting crowd), or ...

dynamics and

pedestrian motion Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults o ...

. The distinction between buildings, ships, and vessels on the one hand and settlements and areas on the other hand is important for the simulation of evacuation processes. In the case of the evacuation of a whole district, the

transport Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipel ...

phase (see

emergency evacuation Emergency evacuation is the urgent immediate egress or escape of people away from an area that contains an imminent threat, an ongoing threat or a hazard to lives or property. Examples range from the small-scale evacuation of a building due to ...

) is usually covered by

queueing models Queueing theory is the mathematical study of waiting lines, or queues. A queueing model is constructed so that queue lengths and waiting time can be predicted. Queueing theory is generally considered a branch of operations research because the ...

(see below). Simulations are not primarily methods for

optimization Mathematical optimization (alternatively spelled ''optimisation'') or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfi ...

. To optimize the geometry of a building or the procedure with respect to evacuation time, a target function has to be specified and minimized. Accordingly, one or several variables must be identified which are subject to variation.

Classification of models

Modelling approaches in the field of evacuation simulation: * Cellular automaton: discrete, microscopic models, where the pedestrian is represented by a cell state. There exist models for ship evacuation processes, bi-directional pedestrian flows, general models with bionics aspects * Agent-based models: microscopic models, where the pedestrian is represented by an agent. The agents can have human attributes besides the coordinates. Their behavior can integrate stochastic nature. There exist general models with spatial aspects of pedestrian steps * Social Force Model: continuous, microscopic model, based on equations from physics * Queuing models: macroscopic models which are based on the graphical representation of the geometry. The movement of the persons is represented as a

flow Flow may refer to: Science and technology * Fluid flow, the motion of a gas or liquid * Flow (geomorphology), a type of mass wasting or slope movement in geomorphology * Flow (mathematics), a group action of the real numbers on a set * Flow (psyc ...

on this

graph Graph may refer to: Mathematics *Graph (discrete mathematics), a structure made of vertices and edges **Graph theory, the study of such graphs and their properties *Graph (topology), a topological space resembling a graph in the sense of discre ...

. * Particle swarm optimization models: microscopic model, based on a fitness function which minimizes some properties of the evacuation (distance between pedestrians, distance between pedestrians and exits) * Fluid-dynamic models: continuous, macroscopic models, where large crowds are modeled with coupled, nonlinear, partial differential equations

Simulation of evacuations

Buildings (train stations, sports stadia), ships, aircraft, tunnels, and trains are similar concerning their evacuation: the persons are walking towards a safe area. In addition, persons might use slides or similar evacuation systems and for ships the lowering of life-boats.

Tunnels

Tunnels are unique environments with their own specific characteristics: underground spaces, unknown to users, no natural light, etc. which affect different aspects of evacuees behaviours such as pre-evacuation times (e.g. occupants' reluctance to leave the vehicles), occupant–occupant and occupant–environment interactions, herding behaviour and exit selection.

Ships

Four aspects are particular for ship evacuation: * Ratio of number of crew to number of passengers, * Ship motion, * Floating position * The evacuation system (e.g., slides, life-boats). Ship motion and/or abnormal floating position may decrease the ability to move. This influence has been investigated experimentally and can be taken into account by reduction factors. The evacuation of a ship is divided into two separate phases: assembly phase and

embarkation Embarkment (sometimes embarcation or embarkation) is the process of loading a passenger ship or an airplane with passengers or military personnel, related to and overlapping with individual boarding Boarding may refer to: *Boarding, used in the ...

phase.

Aircraft

The American

Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...

requires that aircraft have to be able to be evacuated within 90 seconds. This criterion has to be checked before approval of the aircraft. The 90-second rule requires the demonstration that all passengers and crew members can safely abandon the aircraft cabin in less than 90 seconds, with half of the usable exits blocked, with the minimum illumination provided by floor proximity lighting, and a certain age-gender mix in the simulated occupants. The rule was established in 1965 with 120 seconds, and has been evolving over the years to encompass the improvements in escape equipment, changes in cabin and seat material, and more complete and appropriate crew training.

References

Literature

* A. Schadschneider, W. Klingsch, H. Klüpfel, T. Kretz, C. Rogsch, and A. Seyfried. Evacuation Dynamics: Empirical Results, Modeling and Applications. In R.A. Meyers, editor, ''Encyclopedia of Complexity and System Science''. Springer, Berlin Heidelberg New York, 2009. (to be published in April 2009, available at arXiv:0802.1620v1). * Lord J, Meacham B, Moore A, Fahy R, Proulx G (2005). Guide for evaluating the predictive capabilities of computer egress models, NIST Report GCR 06-886. http://www.fire.nist.gov/bfrlpubs/fire05/PDF/f05156.pdf * E. Ronchi, P. Colonna, J. Capote, D. Alvear, N. Berloco, A. Cuesta. The evaluation of different evacuation models for road tunnel safety analyses. Tunnelling and Underground Space Technology Vol. 30, July 2012, pp74–84. {{doi, 10.1016/j.tust.2012.02.008 * Kuligowski ED, Peacock RD, Hoskins, BL (2010). A Review of Building Evacuation Models NIST, Fire Research Division. 2nd edition. Technical Note 1680 Washington, US. * International Maritime Organization (2007). Guidelines for Evacuation Analyses for New and Existing Passenger Ships, MSC/Circ.1238, International Maritime Organization, London, UK. * R. Lovreglio, E. Ronchi, M. J. Kinsey (2019). An online survey of pedestrian evacuation model usage and users. Fire Technology. https://doi.org/10.1007/s10694-019-00923-8 Emergency simulation Stochastic simulation Social physics