Transporting People with Limited Mobility

It is necessary to determine the estimated time for rescuing people who are unable to independently evacuate (people with limited mobility) from medical and social institutions using stretchers.

The estimated time for transporting people with limited mobility from a certain floor of a building is determined by the formula:

where:

$t_1$ — time to place a person on a stretcher (9 sec);

$t_2$ — time to transfer a person from a stretcher to a prepared surface (9 sec);

*$N_{нм}$* — number of people with limited mobility;

*$N_{перс}$* — number of staff;

$L_1$ — horizontal length of the escape route;

$L_2$ — length of stairs for the escape route;

$V_1$ — movement speed of medical staff horizontally with a stretcher without a person being rescued;

$V_1^c$ — horizontal movement speed of medical staff with a person being rescued lying on a stretcher;

$V_2$ — movement speed of medical staff up the stairs with a stretcher without a person being rescued;

$V_2^c$ — movement speed of medical staff down the stairs with the person being rescued lying on a stretcher.

One rescue team trip consists of the following stages:

1. The team goes to the person with limited mobility from the safe zone.
2. Places the person with limited mobility on a stretcher.
3. Transports the person with limited mobility to a safe area.
4. Transfers the person with limited mobility to a prepared surface.

These actions are repeated until all people with limited mobility have been transported to a safe area, or until the number of trips exceeds the maximum number of trips the team can make.

- this is the number of trips that each pair of staff members (rescue team) participating in the rescue of people with limited mobility must make to evacuate all people with limited mobility from the floor.

The calculation of trips for rescuing people involves a number of simplifications and assumptions as compared to real-life situations:

1. The length of the rescue path for each person with limited mobility is the same.
2. All people with limited mobility from one floor are transported to the same safe zone.
3. The staff rescues people with limited mobility only on the same floor as themselves.
4. The rescue team is located near the person with limited mobility it will transport first (the last variable in the formula with a minus sign).
5. It is not specified, what happens to a staff member who does not have a partner on their floor: whether they pair up with another such staff member who also lacks a partner on their floor, or not.

Solution prompted by the application

The algorithm for determining the estimated transportation time, used in the application, allows you to eliminate the assumptions in the formula proposed by the methodology, and consists of the following steps:

All staff members are divided into rescue teams. The dividing method is set in the evacuation simulation parameters. See section Evacuation Simulation Parameters.

1. 1. The team that finishes transporting a person with limited mobility first is automatically selected for the rescue of the next person with limited mobility.
2. From the number of people with limited mobility who have not been evacuated, a person who can be transported by the chosen team is selected (taking into account the number of trips already made by the team). If there are several such people, the person with limited mobility whom the team can reach the fastest is chosen. Priority is given to those people with limited mobility who are on the same floor as the staff making up the team.
3. The travel time of the team from its current location (effectively, the safe zone where the last person with limited mobility was transported to) to the location of the selected person with limited mobility is calculated.
4. The time it takes to transport the person with limited mobility from their current location to the safe zone is calculated.
5. The sum of the travel time (item 4), the time for moving the person to and from the stretcher, the transportation time (item 5), determines the moment when the team finishes transporting the selected person with limited mobility.
6. Steps 2-6 to be repeated until there are no unevacuated people with limited mobility and teams capable to evacuate them.

To enable the calculation of transportation time, it is necessary to:

1. Add people with limited mobility (people categorized as People with Limited Mobility).
2. Add personnel (people categorized as Staff).
3. Select the required option for forming rescue teams. Refer to the section Evacuation Simulation Parameters.
4. Conduct an evacuation simulation. See section Starting and Stopping Evacuation Simulation.

Estimated rescue time is not included in the estimated evacuation time.

The estimated rescue time does not affect the probability of evacuation and the severity of individual fire risk.

The simulation of the rescue pair movement, both with and without stretchers, does not occur: during the visualization of people’s movement, people categorized as Staff and People with Limited Mobility do not move.

Calculation results

To view the simulation results, navigate to the simulation results viewing tab and then switch to the Estimated Time for Transporting People with Limited Mobility tab.

The General Rescue Results tab displays the final results of the algorithm’s operation.

The Rescue Diagram (by teams) and Rescue Diagram (by people with limited mobility) tabs graphically display the rescue process of people with limited mobility. Each block on the diagram represents one of the rescue stages at a specific moment through which the team or a person with limited mobility goes: trip to reach the person, ,moving the person to a stretcher, transporting, and moving the person with limited mobility from the stretcher.

The color of the rectangle indicates the rescue stage type, and its length indicates the duration. To obtain detailed data for each rescue stage, you need to hover the mouse cursor over the relevant block on the diagram.