Engineers VS covid-19

Опубликовано: 27.10.2021

At the first stage of the team competition in the “Design and Modeling” direction, the participants had to develop a BIM model of the SPbPU research building in the Autodesk Revit system.

In the second stage, participants used CFD modeling in the Autodesk CFD system to re-arrange the classroom or office space to reduce the risk of infection spreading among students, students and employees.

In connection with recent events in the world, the issue of protecting people from various infectious diseases is particularly acute. There is a need to design new buildings and modernize existing ones with a new approach. The main objective of our work is to simulate the air flow in an existing room in such a way as to minimize the risk of infection spreading. It is also necessary to complete this task by spending the minimum possible amount of money. To find the optimal solution, the following goals were set:

Initially, we must understand what criteria can be used to analyze the premises in terms of protection against the spread of viral diseases. According to the recommendations of the World Health Organization, people should stay at least a meter apart in public places. Rospotrebnadzor imposes even more stringent conditions for people to stay indoors: it is necessary to maintain a distance of 1.5 meters. Thus, the first requirement for the investigated premises is the distance between employees. This is where the direct documented instructions about the layout end. To determine the second criterion, we turned to the studies of doctors of viral infections. Sources of infection can be transmitted by airborne droplets. And an infection like coronavirus is heavier than air, therefore, you need to block the direct path between people in the room. Based on a software package that can simulate the movement of air flows from supply ventilation to exhaust, we have formed the second criterion. Its essence lies in the arrangement of workplaces in such a way that the trajectory of air movement does not cross 2 people at once. By fulfilling this requirement, we will ensure that a person does not infect colleagues.

Original model

With the initial arrangement of furniture in a given room, a distance of 1.5 meters between employees was observed. The result of the calculations, in which the sets of particle traces correspond to the places of placement of people (agents # 1-10), indicate that the initial placement of people in a given room is not safe in the presence of the possibility of spreading infection.

In 8 out of 10 cases, air flows have a trajectory passing through several agents at once, which is unacceptable in terms of the generated requirements and safety criteria.

Protective screens and ventilation

The result of the calculations, in which the sets of particle traces correspond to the places of placement of people (agents # 1-10), shows the effectiveness of installing protective screens and two vents, as well as partial rearrangement. The idea of this option is the symmetry of the arrangement of ventilation and holes along the axis of the cabinets

In all ten sets of traces, the airflow passing through any agent did not fall with its trajectory to the locations of other agents. Thus, the likelihood of spreading infection is reduced to a minimum. The distance between people meets the requirements of Rospotrebnadzor and is at least 1.5 meters. The absence of intersection of the air flow trajectories of several agents at once is given in Table 3 below.

Stage 3

In the final part of the competition, it was necessary to simulate the movement of people in various scenarios using the AnyLogic simulation system and propose solutions to improve the level of security. Participants offered their solutions based on the recommendations of Rospotrebnadzor, WHO and the results of their own research

In 2020, the COVID-19 pandemic hit, leaving a mark on every area of ​​people’s lives. Education was no exception: schoolchildren stopped attending schools because of the likelihood of getting sick. In the near future, educational institutions will reopen, which means that it is necessary to develop models of people’s behavior in the current conditions. And do it in such a way as to exclude or at least minimize the likelihood of the spread of infection. The main task of our work is to conduct simulation modeling in the AnyLogic software system. The purpose of this simulation is to generate solutions to reduce the concentration of people in the areas under consideration in order to increase the organization’s resilience to the spread of COVID-19. We have received 4 scenarios for the development of events, for which it is necessary to build a simulation model: entrance, recess, canteen and evacuation. To solve the problem, you must perform the following steps:

  • recreate the model in the AnyLogic program according to all the conditions specified in the terms of reference;
  • assess the level of concentration of people in the areas under consideration;
  • in the presence of an increased concentration of people, develop security measures to achieve the norm;

School entrance

The number of students arriving cannot be distributed without the formation of long lines and crowds. Moreover, any targeted measures also failed to bring results. Therefore, it was decided to delimit the arrival of students in half with a shift by an hour. Our next step was to simulate the arrival of the 1st shift of students. The longest place to stay at the entrance is the wardrobe. According to the terms of reference, students must be in the cloakroom for 5 minutes. Therefore, to optimize the influx of students, 75 people were allocated who arrive at the cloakroom in the first place. It is assumed that these are students of the 11th grade.

After 3 minutes 20 seconds, the rest of the students begin to arrive at a rate of 13.5 students per minute. Measures were also introduced to delimit the flow in the school yard to minimize contact between students. To prevent people from crowding in front of the cloakroom, a waiting area was introduced in which students stay when the cloakroom is full

Summing up, we can conclude that the best option would be to divide the students into 2 shifts with an hour difference in arrival time. This measure will minimize the risk of infection transmission. If you try to organize the entrance of all students within one hour, then the risk of getting infected increases several times. The optimal number of arriving people is 700.

Change at school

The next step was to introduce restrictions and conditions into the plan according to the scenario. This explanatory note was made for the task “Change”. The following actions are envisaged to reduce the concentration of people:

  • flow demarcation
  • creation of waiting areas
  • shift in schedule
  • delimitation of exit time from classes

The next point in working out the task is to set the conditions prescribed in the terms of reference and run the model. Students must exit the classrooms within the first 3 minutes and head to the waiting area before the next lesson. The total change time is 15 minutes. In the last 3 minutes, students must proceed to their classrooms. The following are drawings of the simulation area:

We see that there is a huge excess of the permissible concentration of people in the corridors. Also, the allotted time is not enough for people to have a good rest and move to the right office.

Summing up, we can conclude that this option of moving students around the classroom puts them at risk of getting infected. The essence of the problem lies in the movement of people between floors, sometimes it is necessary to pass more than 2 spans. To optimize the work of the school, it is necessary to reduce the vertical movement of schoolchildren to a minimum, and, if possible, conduct all classes for grade 1 on one, maximum two floors. Thus, using simulation modeling in the AnyLogic software system, it was possible to identify the impossibility of solving the problem of reducing the concentration of people in the areas under consideration in order to increase the organization’s resilience to the spread of COVID-19

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