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