A Review of Building Evacuation Models - NIST Virtual Library

Models Not Yet Released
A.20 Spatial-Grid Evacuation Model (SGEM) Package
Developer: Lo, S.M. from the Department of Building and Construction, City University in
Hong Kong (primary developer).
Purpose of the model: The purpose of this model is to make use of CAD plans to generate
escape patterns from complex buildings 85, 86 .
Availability to the public for use: The model is not yet available to the public. The model has
been used for some consultancy projects; however the developers are still working on the
interface of the model, the CAD feature, and the simulation process.
Modeling method: Movement/Partial-Behavioral model
Structure of model: The structure of the model is ultimately a fine network model. Initially,
the model resolves the building into nodes that represent spaces/zones (unprotected, partially
protected, and fully protected) of the building with at least one arc (opening) between the zones,
which is labeled as a coarse network. Then, each zone is divided up into a finite grid of cells
each measuring 0.4 x 0.4 m in size to represent the amount of space taken up by one occupant,
which is the reason that the model is labeled as a fine network model. Additionally, only one
person occupies a grid cell at a time.
Perspective of model: Individual perspective. The model tracks individual occupants at each
time step throughout the building. Also, occupants’ movements throughout the building are
based not only on the distance to an exit but also on other conflicts that arise during the
evacuation.
Occupant behavior: None/implicit.
Individual behavior is simulated using a wayfinding function. The wayfinding function of the
model is affected by personal characteristics of the individual (age, gender, drive, patience, etc)
and the environmental stimuli in a zone (obstacles, conflicts, smoke, alarm signals, assistance of
a manager, etc.). This wayfinding function ultimately adjusts the directional adjustment of
individual’s movement (depending on obstacles and conflicts) and the individual’s speed
(slowing, stopping). However, the reference for the model 85 then states that “at present, we
merely consider three classes of behavioural effect and provide respective weightings,” without
going into more detail.
The route choice tendency alters the tendency of a direction an occupant takes to leave a zone.
On the other hand, the wayfinding function decides the direction the occupant will actually take
at each time step.
A-71