A Review of Building Evacuation Models - NIST Virtual Library

higher potential for a short time during the alternative route. These actions also tie in with the
patience option in the occupant submodel.
On the stairwells, the occupants view all nodes on the stairs as equally attractive, but if an
occupant is within 5 nodes of the edge of the staircase, he/she will move to the edge as an
attempt to use the handrails. Occupant travel speeds on stairs are based on work done by Fruin.
Exiting is based on two factors, the exit width and flow rate per unit width. These values
determine the maximum amount of occupants allowed to exit at the same time and the number of
nodes assigned to the exit. The user specifies an upper and lower limit of flow rate at each exit.
The user can manipulate aspects of the occupant submodel, for instance, the mobility and agility
attributes can be modified so that disabled or slow moving occupants can be simulated.
The toxicity submodel determines the effects of the toxic products on the occupants in the
building. The effects on the occupants are given to the behavioral submodel which transfers the
information to the movement submodel. To determine the effects of the fire hazard, including
the newly added radiative effects, on the occupant, EXODUS uses the Fractional Effective Dose
(FED) model developed by David Purser, BRE 61 . The FED model considers the effects of
radiation, temperature, HCN, CO, CO2, and low O2 to estimate the time to incapacitation. Also,
other effects to occupants are staggered and slowed movement, based on data from Jin 52 .
Occupants may choose to travel a different route when faced with a barrier of smoke, depending
upon their individual characteristics 53 .
Output: In order to interpret the results, data analysis tools have been developed to use once the
simulation have been completed. These tools allow for the output files to be searched and for
specific data to be extracted. The program is labeled as “askEXODUS.”
Use of fire data: Yes, the hazard submodel determines the thermal and toxic environment.
buildingEXODUS can accept data from other fire models or experimental data. A software link
is established between buildingEXODUS and the CFAST model.
Import CAD drawings: Yes, CAD drawings can be imported into the model. In addition, the
user can also input the geometry of the building via the geometry library or by interactively
using the tools provided in buildingEXODUS. This information is stored in the Geometry
submodel.
Visualization capabilities: 2-D (low detail and person shape) and 3-D capabilities (Virtual
reality interface).
Validation studies: According to developer, the model has undergone several forms of
qualitative and quantitative validation. The model developer claims that this includes direction
comparison of model predictions with past experimental data, comparison of “blind” model
predictions with experimental data, and comparing the nature of human behavior with
expectations of the model. Although many of the validation studies are performed on
airEXODUS using experimental trials from the aviation industry, the developers claim that both
airEXODUS and buildingEXODUS are based on the same principles.
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