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IMO Test 11
Staircase
Pathfinder 2011
IMO Test 11, Staircase
This example describes International Maritime Organization Test 11: a room connected to a stair via a
corridor. 150 people start in the room, with walking speeds evenly distributed from 0.97 to 1.62 meters
per second. The expected result is the formation of congestion leading into the hallway and at the base
of the stairs. This example is written in a somewhat abbreviated form, assuming that you have already
created the previous examples to learn how the tools function.
The instructions for this example are written in a somewhat abbreviated form, since it is assumed that
you have already created the previous examples and have learned the use of Pathfinder tools.
Figure 1: Geometry of the IMO Test 10 problem
Create Geometry
To select Metric measurements:
1. On the View menu, click Units and select SI.
To specify snap grid spacing:
1. On the View menu, click Edit Snap Grid....
2. In the Snap grid spacing box, type 1.0 m .
3. Click OK.
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Begin by creating a rectangular area 8 meters by 5 meters in the space from (-3, 0) to (5, 5). Create the
hallway with another rectangular area (0, 5) to (2, 17). Merge the two areas by selecting both and
selecting Merge from either the model or right-click menu.
Figure 2: The room and corridor
To create the stairs, begin by creating a second floor. Add a new floor from the floor drop down menu,
Figure 3.b. In the New Floor dialog, input 2 meters, select Set as active floor, and click OK.
a. Add a new floor
b. New floor dialog
Figure 3: Adding a new floor to the model
On the new floor, create a rectangular area from (0, 22) to (2, 24) for the upper landing.
Right-click on Floors in the tree display and select Show All , Figure 4.
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Figure 4: Model with landing
To place the stairs, click Create Stairs between two edges ( ). Click-drag the entire width of the lower
corridor then click the edge of the top landing to finish defining the stair. To define the exit, select the
Add a new Door tool (
)and click-drag across the edge of the top landing, Figure 5.
Figure 5: The completed geometry
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Define Profiles
Profiles describe the characteristics of the occupants, including the walking speed, delay times before
movement, size, display image, and base color. To define the profile:
1.
2.
3.
4.
5.
On the Model menu click Edit Profiles.
In the Speed drop-down list, choose Uniform.
In the Min box, type 0.97 m/s and in the Max box type 1.62 m/s.
Click OK to close the Uniform Distribution dialog.
Click OK to close the Edit Profiles dialog.
Add Occupants
To add the occupants, click the Add Rectangular Group of Occupants (
Uniform and add 150 occupants, Figure 6.
) tool. For Placement, select
Figure 6: The occupants in the room.
Run Simulation
To run the simulation:
1. Save your document to a new folder. Use the name imo11.pth.
1. On the toolbar, click Run Simulation ( ). By default, the problem will be solved using the
Steering behavior mode.
2. A summary report is provided in the analysis dialog. It provides FIRST IN and LAST OUT times for
each room and door.
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View Results
When the simulation is finished, the 3D Pathfinder results window will display.
To view results:
1. Click the Play button. This will display the occupants as cylinders with their direction indicated
by a triangle.
2. At any time click the Pause or Stop button. You can drag the time line to control the animation.
3. To view occupants as people, click the Stop button, on the Agents menu, click Show as People,
then click the Play button.
Detailed information for each room is provided in comma-separated value (CSV) files that can be
imported to a spreadsheet.
Figure 7: The 3D results with steering behavior
Compare Steering Mode Results with Expected Result
The calculated evacuation time is 74 seconds. Congestion is observed at the room exit, but no significant
congestion at the base of the stairs. The reason is that although the walking speed on the stairs is
reduced by 23%, there is still sufficient flow capacity on the stairs to avoid congestion at the base.
Select SFPE Mode
Pathfinder provides the option to select different simulation modes. The SFPE movement mode is
consistent with the assumptions used in the SFPE Engineering Guide - Human Behavior in Fire (SFPE,
2003). Assumptions include:
1. The occupants move toward the exits using the shortest path
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2. The maximum occupant speed is a function of room density
3. Occupants move independently and can occupy the same space as other occupants
4. Queues form at doors, with the flow rate through the door as specified by SFPE guidelines.
Because multiple occupants can occupy the same space, a queue may appear as a single
occupant.
To select the SFPE mode:
1.
2.
3.
4.
On the Simulation menu, click Simulation Parameters....
Click the Behavior tab.
In the Behavior Mode box, select SFPE.
In the Door Boundary Layer box, type 0 cm. This removes the boundary layer from the flow
calculation of the door
5. Click OK.
Save the model using the name imo11_sfpe_mode.pth and run the analysis.
References
(IMO, 2002) Interim Guidelines for Evacuation Analyses for New and Existing Passenger Ships. June 6,
2002. International Maritime Organization. 4 Albert Embankment London Great Britain . MSC/Circ.1033.
(SFPE, 2003) Engineering Guide - Human Behavior in Fire. June, 2003. Society of Fire Protection
Engineers. 7315 Wisconsin Avenue, Suite 620E Bethesda Maryland USA 1-301-718-2910.
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