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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Occupants can also be introduced into the simulation at a certain time and place, after the<br />
evacuation has begun. When family groups are specified in STEPS, the family moves<br />
throughout the simulation to meet at a certain position in the building before evacuating.<br />
Output: STEPS output includes the total evacuation time, numbers <strong>of</strong> occupants in certain<br />
areas, planes, paths, and the entire simulation and the number <strong>of</strong> people that have left these<br />
different fields vs. time.<br />
Use <strong>of</strong> fire data: None.<br />
Import CAD drawings: Yes, CAD drawings are input in DXF file format.<br />
Visualization capabilities: 3-D visualization.<br />
Validation studies: STEPS<br />
simulations have been compared to<br />
the method <strong>of</strong> evacuation<br />
calculations outlined by NFPA<br />
130 21 . This report outlines two<br />
examples that demonstrate STEPS’<br />
applicability to station geometries.<br />
The first case, shown in Figure A.6,<br />
involves a center-platform station in<br />
which the platform is raised above<br />
the concourse (at grade level) as<br />
shown in the figure. By using the<br />
NFPA calculations for Case 1, the<br />
total time to clear the platform is<br />
190.7 s and the total time to<br />
evacuate the station is 239.9 s.<br />
21, p. 130-30<br />
Figure A.6: Case Study 1<br />
When the identical model <strong>of</strong> this station is simulated with STEPS, the mean time to clear the<br />
platform is 212.4 s and the mean evacuation time is 257.4 s. This case shows a difference <strong>of</strong> 7.3<br />
% to 11.4 % between NFPA 130 and STEPS. Also, STEPS is able to model the natural<br />
imbalance <strong>of</strong> exit use, while NFPA 130 calculations assume that all exits are used optimally.<br />
Case 2 involves a more complex station with a side-platform. As shown in Figure A.7, the<br />
concourse is below grade level and the platform is below the level <strong>of</strong> the concourse. Using<br />
NFPA 130, the total time to clear the platform is 179.8 s and the total evacuation <strong>of</strong> the station is<br />
369.8 s. Also, when recalculating NFPA evacuation times using a different, more realistic split,<br />
the result is found to be 306.3 s. When modeled in STEPS, a mean platform clearing time <strong>of</strong><br />
181.4 s is achieved and a mean total evacuation time was 313.2 s. This shows a 0.9 % to 2.3 %<br />
difference between STEPS and NFPA 130 calculation methods.<br />
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