A Review of Building Evacuation Models - NIST Virtual Library

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