IMO 8: Counterflow: two rooms connected by a corridor

1. Definition

Two rooms of 10 m by 10 m are joined by a corridor 10 m long and 2 m wide. The corridor starts and ends at the centre of one side of each room. The population is 100 persons with instant response and Table 3.4 speeds (males 30 to 50). Step 1: 100 persons in room 1, packed from the left wall at the highest possible density, walk to room 2. The time the last person enters room 2 is recorded. Step 2: the run is repeated with 10, 50 and 100 additional persons of the same characteristics who walk from room 2 to room 1. Both groups start together, and the time the last room-1 person enters room 2 is recorded.

Source: IMO MSC.1/Circ.1533, Annex 3, Appendix 2, Test 8, paras. 12-14, p. 11, Fig. 2. This is a paraphrase, not the text of the standard.

Reference: International Maritime Organization (2016). Revised guidelines on evacuation analysis for new and existing passenger ships. MSC.1/Circ.1533, 6 June 2016. https://edocs.imo.org/Final%20Documents/English/MSC.1-CIRC.1533%20(E).docx (Page numbers are the printed page numbers of Annex 3 (“Annex 3, page n”). Tests are cited by test number and paragraph of Appendix 2.)

2. Scenario

Scenario picture not available.

3. What to expect

The recorded duration increases as the number of persons in counterflow increases. IMO gives no size for the increase.

Our criterion: Counterflow increases evacuation time

4. Our result

Status: PASS

Test cases of this row

• test_counterflow_increases_time: bound: agents_remaining = 0 in both runs; comparison: measured[0] (counterflow, 40 agents) > measured[1] (one-way, 20 agents)

5. Our implementation

Deviations from the standard:

• The scenario has 20 agents per room, spread over the left 8 m of room 1 (and the right 8 m of room 2), not 100 packed from the left wall.
• One counterflow level (20 persons) is run against one one-way run, not the levels 10, 50 and 100. The test cannot show that the duration rises with the count.
• The recorded time is the total evacuation time of the run, with exits as 2 m strips at the far walls, not the time the last room-1 person enters room 2. The counterflow run also has twice as many agents as the one-way run.
• The pass rule is the suite’s own: both runs complete, and the counterflow evacuation time is longer than the one-way time.
• Constant desired speed 1.2 m/s instead of Table 3.4 speeds; default body radius 0.15 m; one seed (42). The room and corridor dimensions match Fig. 2. The scenario is built in code (tests/vv/test_imo.py).

Model: CollisionFreeSpeedModel

• Test function: tests/vv/test_imo.py::test_counterflow_increases_time

6. Our notebook

No notebook for this test yet.