Evacuation using Familiar Routes

During an evacuation, “… familiar entry routes are more likely to be used for evacuation than egress routes that have never been experienced before. Consequently, routes that are being counted on to “drain” the building of its occupants may be disregarded in an actual evacuation.” (SFPE Handbook of Fire Protection Engineering). One way to represent this is to assign some fraction of occupants to use an exit door (or doors) with which they are familiar, while other occupants can use any exit.

Let us demonstrate with a simple example. In Figure 1 we show a room that has one familiar Entry and two Exits. The room is 10×10 m and we will place 200 occupants in the room. We want 70% of the occupants to evacuate using the Entry and 30% using either of the two Exits.

Figure 1: A room with a familiar Entry and two Exits.
Figure 1: A room with a familiar Entry and two Exits.

To do this, we define two Behaviors. For the first behavior, we edit the Exits and choose only the Entry door. For the second, we edit the exits and choose both Exit 1 and Exit 2.

Figure 2: Select the exit door to be used by the Use Entry behavior.
Figure 2: Select the exit door to be used by the Use Entry behavior.

Now we right-click on the room and select Add Occupants. In the Add Occupants dialog, we click on the Behavior and assign 70% to Use Entry and 30% to Use Exit 1 or 2, Figure 3.

Figure 3: Add occupants using a distribution of behaviors.
Figure 3: Add occupants using a distribution of behaviors.

Finally, we assign a different color to the occupants using the exits by right-clicking on the Use Exit 1 or 2 behavior and clicking Select Referencing Objects. We change the color of those occupants to red.

When we view the results, we see that the blue occupants (140 persons) exit using the familiar Entry and the red occupants (60 persons) use either of the two Exits.

Figure 4: Results showing blue occupants exiting the familiar Entry and red occupants exiting the two Exits.
Figure 4: Results showing blue occupants exiting the familiar Entry and red occupants exiting the two Exits.

A couple of comments:

  • If you are working with a model where you have already created the occupants, you can right-click the Occupant Group and select Properties to assign a distribution of behaviors.
  • Any behavior can have any combination of exits. The default behavior allows the occupants to use any exit.

Download Pathfinder Model

assign-familiar-exit-doors.pth

Comments or Questions

This post was written by Daniel Swenson. For comments or questions, send email to support@thunderheadeng.com.


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