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A Review of Building Evacuation Models - NIST Virtual Library

A Review of Building Evacuation Models - NIST Virtual Library

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factor,” the current goal is changed. Examples <strong>of</strong> goal modifiers are alarms, smoke<br />

detectors, usual noises, firefighter arrival, an impaired person, and smoke tolerance.<br />

• Goal generator: The model is provided with goals and their probability <strong>of</strong> occurring. Then,<br />

each goal is assigned an action set from the action library. An example provided by the<br />

model developer is that if a goal <strong>of</strong> firefighting was chosen, actions such as go to fire area,<br />

fight the fire, etc. may be assigned to this goal. The same action can be assigned to more<br />

than one goal.<br />

• Fire event: The user introduces information about the fire environment into the model. The<br />

information involves the location <strong>of</strong> the fire and the spread <strong>of</strong> smoke throughout the space.<br />

Subevents are scheduled into the model, such as spread <strong>of</strong> smoke to a location at the fire<br />

floor, spread <strong>of</strong> smoke to another floor, alarm goes <strong>of</strong>f, fire fighters arrive, etc. While these<br />

events are scheduled, local spread rates are entered interactively during the simulation. The<br />

developer describes the simulation as interactive, allowing the user to point to areas on the<br />

screen and provide different values for the environment.<br />

• Physical environment: The user also enters into the model a description <strong>of</strong> the building and<br />

the fire protection aspects, such as location <strong>of</strong> alarms, status <strong>of</strong> doors, etc. The building<br />

configuration is also sketched interactively and the output is graphical.<br />

• Route modifier library: The model assigns preference levels to spaces along different routes<br />

in the building. The criteria existing for these preference levels are the following: high<br />

priority is given to spaces with “architectural and functional differentiation” because <strong>of</strong> the<br />

belief that occupants have created stronger mental images <strong>of</strong> these areas; simple paths<br />

(instead <strong>of</strong> complex) are associated with a high probability <strong>of</strong> making a rational decision;<br />

higher preference is given to exits with perceptual access; and priority is indifferent to the<br />

introduction <strong>of</strong> exit signs.<br />

• People characteristics: Cognitive properties, such as preference levels, are assigned to each<br />

occupant group. Other characteristics include walking speed, asleep or awake at time <strong>of</strong> fire,<br />

and smoke tolerance.<br />

• Goal Initiator: This is the central unit that checks the goal modifiers to see if a goal change<br />

is needed for each individual at each time frame. If so, the next goal is chosen stochastically.<br />

Then, the goal is passed to the action generator.<br />

• Action Generator: The individual person is moved by this generator according to the action.<br />

The effect <strong>of</strong> the individual action on the fire event, building, and other individual is<br />

transferred to the goal modifiers.<br />

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