pathfinder 疏散软件入门教程 教程实例

403 Poyntz Avenue, Suite B
Manhattan, KS 66502
USA
+1.785.770.8511
SFPE Example 2
Pathfinder 2011
SFPE Example 2
This is the second example in the SFPE Engineering Guide - Human Behavior in Fire (SFPE, 2003). The example determines the total movement time for a 5-story building with the following characteristics:
1.There are 200 people on each floor above the ground floor.
2.Each floor is served by two 44 inch (1.12 m) wide stairways. The doors leading into and from the
stairway are 32 inches wide (0.81 m). The stair design uses 7 inch/11 inch risers and treads.
3.The floor to floor distance is 12 feet. Floor to landing distance is 6 feet.
ndings between the floors are 4 x 8 feet (1.22 x 2.44 m).
5.Handrails are provided on both sides of the stairways 2.5 inches (64 mm) from the wall.
The model is shown in Figure 1. Obviously, a real building would have a different arrangement of landings, but this model captures the geometry as described in the example. Consistent with the SFPE description of the problem, additional exits are provided on the first floor such that the flow of 400 people (each stairway takes ½ the occupants) from the upper floors through each stairway is the controlling component.
In the problem description we use the floor naming convention with the first floor meaning the main floor at Z=0.
Figure 1: SFPE Example 2 geometry and occupants
Create Geometry
To select English measurements:
1.On the View menu, click Units and select EN to display measurements using the English system. To specify snap grid spacing:
1.On the View menu, click Edit Snap Grid....
2.In the Specify snap grid spacing menu, type 2.0. By default, length units will be in feet,
however, you can type a value followed by a unit (e.g.: "in" or "m") and the length will be
converted to feet.
3.Click OK.
To define the default floor height:
1.In the Floor Height box, type 1
2.0.
To create the room:
1.In the View toolbar, click Top View ( ).
2.In the Tools toolbar, click Add a Rectangular Room ().
3.In the Z Plane box, type 0.0.
4.In the coordinate boxes enter the following values: X1:0.0, Y1:0.0, X2:60.0, Y2:40.0.
5.Click Create.
Replicate the room to create five floors.
1.In the View toolbar, click the Selection Tool icon .
2.Select the room.
3.In the Tools toolbar, click the Move Objects icon .
4.Select Copy Mode.
5.In the Copies box type 4.
6.In the Move Z box, type 12.0.
7.Click Copy/Move.
8.Click the Zoom Fit icon to rescale the view.
Your model should now look like Figure 2.
Figure 2: The floors in the model
To define the landings:
1.Create the first landing at Z=6.0 ft. In the View toolbar, click Top View ( ). In the Tools toolbar,
click Add a Rectangular Room (). In the Z Plane box, type 6.0. In the coordinate boxes enter the following values: X1:-13.5, Y1:16.0, X2:-9.5, Y2:24.0. Click Create.
2.Replicate the landing. In the View toolbar, click the Selection Tool icon . Select the landing. In
the Tools toolbar, click the Move Objects icon . Select Copy Mode. In the Copies box type 3.
In the Move Z box, type 12.0. Click Copy/Move.
3.Repeat for the landing on the opposite side. In the View toolbar, click Top View ( ). In the
Tools toolbar, click Add a Rectangular Room (). In the Z Plane box, type 6.0. In the
coordinate boxes enter the following values: X1:69.5, Y1:16.0, X2:73.5, Y2:24.0. Click
Create.
4.Replicate the landing. In the View toolbar, click the Selection Tool icon . Select the landing. In
the Tools toolbar, click the Move Objects icon . Select Copy Mode. In the Copies box type 3.
In the Move Z box, type 12.0. Click Copy/Move.
Your model should now look like Figure 8.4
Figure 3: The floors and landings in the model
To add the first stairway on the left side of the building:
1.In the Tools toolbar, click Create Stairs between two edges ().
2.In the Stair Width box, type 44.0 in. In the Door 1 Width box and the Door 2 Width box, type
32.0 in.
3.Click on the lower landing and position the stair towards the front side of the landing. Click on
the lower floor to create the stairs from the landing to the lower floor, Figure 4.
e the Move Objects tool to make three copies of the stair, separated by 12 ft in the Z
direction.
5.Add the stairs that go up from the landing. Click on the lower landing and position the stair
opposite the first stairs. Click on the second floor to create the stairs from the landing to the
second floor.
e the Move Objects tool to make three copies of the stair, separated by 12 ft in the Z
direction.
7.Repeat on the other side of the model. This time, position the first stairs on the back side of the
landing.
Figure 4: First stairs on left side of building
Add the exit doors:
1.Select the door tool () and in the Max Width box, type 120.0 in.
2.Place a door adjacent to both stairs on the lowest floor. These doors are wide enough that exit
from the first floor does not affect the egress time.
the doors Right Exit and Left Exit to aid in later plotting of the exit rates through
each door, Figure 8.7.
Figure 5: The Left Exit
The SFPE problem description assumes that evacuation of the first floor does not affect evacuation from the higher floors. Therefore, we add four more exits to the first floor, Figure 6.
Figure 6: Additional exits on first floor
Define Profiles
Profiles describe the characteristics of the occupants, including the walking speed, delay times before movement, size, display image, and base color. We will use a different color for each floor, so that we can identify occupants in the graphical display of their egress. To define the profiles:
1.On the Model menu click Edit Profiles. Click Rename and change the name of the default profile
to Floor 1.
2.Click the Color box, click the Palette tab, and select a red color. Click OK. Click Apply.
3.Click New to create a new profile, give it the name Floor 2, and give it an orange color.
4.Repeat for floors 3, 4, and 5, giving colors yellow, green, and blue.
Add Occupants
To add occupants:
1.Select the first (lowest) floor. On the Model menu click Add Occupants. For the Profile select
Floor 1. For Occupant Count select By Number and type 200. Click OK.
2.Repeat for each floor, selecting the corresponding profile for each floor.
When finished, your model should look like Figure 7.
Figure 7: Pathfinder model with occupants
Run Simulation
To run the simulation:
1.Save your document to a new folder. Use the name sfpe
2.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. The total time required for evacuation is approximately 410 seconds. 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, Figure 8.
Detailed information for each room is provided in comma-separated value (CSV) files that can be imported to a spreadsheet.
Figure 8: Display of results
Another useful way to view the data is to plot either floor occupancy or door flow rates. These options are available under the Results menu. Figure 9 shows a graph of floor occupancy as a function of time This is a good time to recognize the naming floors can help in their later selection.
Figure 9: Display of floor occupancy
Select SFPE Mode
Pathfinder provides the option to select different simulation modes. By default, the occupants act as agents with a steering behavior that seeks to reach a goal while avoiding other occupants and boundaries. 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
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.On the Simulation menu, click Simulation Parameters....
2.Click the Behavior tab.
3.In the Behavior Mode box, select SFPE.
4.In the Door Boundary Layer box, type 6 in.
5.Click OK.
Before running the analysis, save the model using the name sfpe2_sfpe_mode.pth. The total time for all occupants to exit is approximately 607 sec.
Compare Results to SFPE Calculation The SFPE solution to this problem is given below.
The Pathfinder solution gives the time to exit the stairs as 607 sec, compared to the SFPE solution of 617 sec (10.29 minutes).
Adding Collision Avoidance to the SFPE Mode
The SFPE mode does not prevent multiple occupants from occupying the same space. A collision handling option can be added to the SFPE calculation. Flow rates through doors and walking speeds are still calculated using the SFPE To run with this movement option:
1.Open the sfpe2_sfpe_mode.pth model created above. On the File menu, click Save As...
and give the name as sfpe2_collision.pth.
2.On the Simulation menu, click Simulation Parameters....
3.Click the Behavior tab.
4.In the Behavior Mode box select SFPE.
5.Click to select Add Basic Collisions.
6.Click OK to close the Simulation Parameters dialog.
7.Run the simulation.
In the new solution, the time to exit the stairs is 632 sec. These times are similar to the standard SFPE solution, but the appearance of the solution is improved, since the occupants form queues at the doors.
References
[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.。