A Review of Building Evacuation Models - NIST Virtual Library
A Review of Building Evacuation Models - NIST Virtual Library
A Review of Building Evacuation Models - NIST Virtual Library
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<strong>Models</strong> No Longer in Use<br />
A.25 Takahashi’s Fluid Model<br />
Developers: Takahashi, Tanaka, and Kose, Ministry <strong>of</strong> Construction, Japan<br />
Purpose <strong>of</strong> the model: The purpose <strong>of</strong> this model is to predict and evaluate the evacuation time<br />
<strong>of</strong> people in a fire, mainly from a low level hazard 106, 107 . The assumption <strong>of</strong> this model is that<br />
people move like a fluid.<br />
Availability to the public for use: According to one <strong>of</strong> the authors, the model was published<br />
for general use about 15 years ago from the <strong>Building</strong> Center <strong>of</strong> Japan and was used for a while in<br />
research and practical fire safety design <strong>of</strong> actual buildings. However, because hand calculation<br />
methods have been widely used among building designers for the estimation <strong>of</strong> evacuation time<br />
lately, the model has not become as popular in use.<br />
Modeling method: Movement model<br />
Structure <strong>of</strong> model: This is a coarse network system. The 6 space elements are room, path,<br />
stair, vestibule, hall, and refuge area. The two “imaginary spaces” are link and crowding.<br />
Perspective <strong>of</strong> model: The model views the occupants globally as a homogeneous group with<br />
the ability to move like a fluid with a constant speed in each space element. The occupants view<br />
the building globally as well, since they are moved throughout the building through the most<br />
optimal route.<br />
Occupant behavior: No behavior.<br />
Occupant movement: Occupants are uniformly distributed in rooms and given delay times by<br />
the user. Takahashi’s fluid program models the movement <strong>of</strong> the occupants throughout the room<br />
using two different approaches, depending on the obstacles in a room. The L-shape approach is<br />
used for rooms where obstacles are present, which allows the occupants to approach the exit in<br />
an L-shaped or indirect manner. For rooms without obstacles, the occupants approach the exit<br />
directly using the centripetal approach, as shown in Figure A.26.<br />
Figure A.26: Occupant movement in a room following the centripetal approach<br />
106, p. 554<br />
For both methods, the number <strong>of</strong> evacuees arriving to the exit after a time (t) is affected by the<br />
length and width <strong>of</strong> the room, the user specified walking speed, and the density <strong>of</strong> the evacuees<br />
in the room. Any crowding at the exits from rooms is redistributed to achieve the minimum or<br />
optimal evacuation time from each space. The fluid movement equations used for the simulation<br />
A-91