A Study on the Optimization of High School Buildings for Evacuation Safety: Classroom Layout and Ramps in Korea

This study used the Pathfinder program to evaluate evacuation safety by assuming evacuation training in high school buildings and changing classroom layout. Analysis of the final evacuation requirements for Scenario 2, which currently has a concentration of classrooms on the third floor of the building, showed that Scenario 2 reduced 29.6 seconds to 173.9 seconds compared to Scenario 1's 203.5 seconds. However, the analysis of Scenario 3, in which 10 classrooms and personnel of three grades were placed equally on the left and right sides of the building, showed that the final evacuation requirements were reduced 3.9 seconds to 170.0 seconds compared to Scenario 2, but there was no significant difference. Scenario 3, which has more the efficiency of school year operation by placing classroom layout on the same floor by grade level than Scenario 2, in which more classrooms and students were placed downstairs. In each scenario, an analysis of the final evacuation requirements showed that the evacuation exit T1 on the left side of the building was 28 seconds or more shorter than T3 on the right side of the building. Therefore, it was analyzed that proper classroom layout and ramp facilities in high school buildings ensure evacuation safety

evacuation and various scenarios along the evacuation route in the situation of students' evacuation training as variables. Pathfinder is used as an evacuation simulation software. The study seeks to suggest ways to optimize classroom layout for evacuation safety.

Evacuation Simulation 2.1 Structure of the target building
The target building is OO high school building and OOO is also located in OO city. It is a 10 class-sized school in one grade with a total of 30 classrooms, 4 science rooms, and 2 creative convergence rooms on the first, second and third floors, and on the fourth floor, there are special rooms such as auditoriums, health rooms, math rooms, and computer rooms. The building is 126.9 meters wide and 28.2 meters long and has a floor height of 4 meters. The width of the central exit is 9m and the width of both exits is 4.8m, and the width of the corridor on each floor is 2.4m, which satisfies the rules on the standards for evacuation and fire prevention of buildings specified by the Building Act, and the installation criteria of Article 15 1st steps (the corridor is at least 1.2m, and two or more direct statistics (or ramps) that lead to the floor (or ramps) of 0.9m) [6].
The design drawings of the school building are shown in Figure 1.  The facility used in this study is an elderly care hospital located in OOO city in the OOO region that has a The "density of occupants by type of use according to the purpose of the building subject to the installation of the evacuation safety zone" was applied to the number of people assigned to the classroom.
The floor area of the classroom is 72m 2 , and the class with the largest number of students is 30(2.4m 2 /1), and the class with the smallest number is 25(2.9m 2 /1), so the number of students in the classroom satisfies the calculation criteria.
2.2 Classroom capacity The "density of occupants by type of use according to the purpose of the building subject to the installation of the evacuation safety zone" was applied to the number of people assigned to the classroom [7].
The floor area of the classroom is 72m2, and the class with the largest number of students is 30(2.4m2/1), and the class with the smallest number is 25(2.9m2/1), so the number of students in the classroom satisfies the calculationcriteria.

Composition of Scenario
The scenarios were set up in three different ways as shown in Table 3, where students took refuge using T1 on the slope to the left of the school building, T2 on the playground of the building's central entrance, and T3 on the stairway to the right of the building, and T4 on the back of the central entrance. In Scenario 1, the current classroom layout was set. Scenario 2 hypothesized that the lower the number of students on the lower floor, the shorter the time required for evacuation, leaving four classrooms on the third floor, two classrooms on the left and right, and the rest on the lower floor and setting up similar student numbers on the left and right sides. Scenario 3 sets the number of classrooms and the number of students on each floor to be the same for the efficiency of school year management. The criteria for total evacuation requirements were the time when all students finally passed the first floor ramps, stairs and four central front exits. The elevator was removed from the evacuation route by not using it.  The maximum compartment area of A = 8.5, since the floor area of the classroom is 72m2. Therefore, evacuation initiation time (min) = 8.5/30 = 0.28 minutes, which translates into 17 seconds.
However, since the evacuation training was notified in advance in this study, the detection time and recognition time of the fire detector should be considered in the event of a fire do not occur. Therefore, the evacuation start time was set at 30 seconds, including the time of evacuation after listening to the broadcast in 17 seconds of Form (1) because it was assumed that the person in charge was directly evacuated through the broadcast. The evacuation time is set at less than four minutes as shown in Table 4 [9]. office, commercial and industrial buildings, schools, universities(residents are familiar with the building's interior, alarms, escape routes, and always awake) 4 minutes, or less

Input variables and input values
In this study, the input variables reflected in the Pathfinder evacuation simulation [10] were divided into walking speed, evacuation initiation time, and shoulder width and applied as shown in Table 5. Among the input variables, the shoulder width reflects the body size of 20 Korean body measurements based on the standard body type by gender and age [11]. Therefore, the shoulder width was based on 39.8 cm for boys and 35.7 cm for girls. The walking speed was calculated by applying 1.19 m/s to the average adult walking speed [12].

Simulation Results
In each scenario, the evacuation zone was set to T1, T2, T3 and T4, as shown in Figure 2, and the results were analyzed.  Figure 3~4 shows the change in occupancy and flow of evacuation equipment according to scenario 1 until the evacuation is completed, starting evacuation 30 seconds after the evacuation drill is started using 4 evacuation zones, leaving the classroom layout of the current building intact.

.1 Comparison of Evacuation Time by Scenario
The initial and final evacuation time for each evacuation zone in each scenario is analyzed and the evacuation requirements are shown in Table 5. Depending on the conditions of the scenario, the evacuation request time in Scenario 1 is 203.5 seconds and the evacuation request time in Scenario 2 is 173.9 seconds, indicating that the evacuation request time is reduced when the classroom and students are distributed to the first and second floors compared to when the classroom and students are concentrated on the third floor. Scenario 3, 170.0 seconds less than the evacuation requirements in Scenario 2, was reduced by 3.9 seconds, making no significant difference. However, Scenario 3, which is efficient in operating the school year by arranging classrooms for the same grade, is the best classroom layout.

Comparison of evacuation time between ramps and stairs
The analysis of each scenario showed that T1 had shorter evacuation requirements than T3, as shown in Table 6. The reason for T1's reduction in the evacuation requirements compared to T3 is that, under the conditions of Scenario 3, the difference in the escape velocity between the ramps and the stairways was changed to the ramps in order to add Scenario 4, as shown in Table 7, and compared with Scenario 3, the evacuation requirements for both slopes were compared.  In figure 9, the inclination angle of 34° of the right staircase was reflected, and the walking speed was slower than the left ramp with the inclination angle of 15°, so the bottleneck phenomenon was severe and the final evacuation time was analyzed to be different. .

Conclusions
In this study, evacuation safety and evacuation time were analyzed by setting the location of classrooms or the number of students in the evacuation training situation in high school buildings using Pathfinder evacuation simulation. Scenario-specific results are as follows: (1) A comparative analysis of Scenarios 1 and 2 suggests that the design of classrooms downstairs is suitable for evacuation safety as a result of an analysis that reduces the evacuation requirements time in Scenario 2, which is 29.6 seconds shorter than Scenario 1, which has more classrooms and students located on the second and third floors.
(2) Evacuation time in Scenario 3, with the same number of classrooms and students on the left and right sides of the building for each grade, is 3.9 seconds shorter than Scenario 2, which focuses on the layout of classrooms downstairs, ensuring the efficiency of each school year's operation and evacuation safety.
(3) In all three scenarios, the Ramp is considered suitable for evacuation safety as a result of shorter evacuation requirements of T1 than T3. Scenario 4, which changed Scenario 3, required 36.3 seconds more of T3's evacuation time. In Scenario 4, the evacuation requirements of T3 took 64.8 seconds more than T1, indicating that the walk speed varies depending on the slope angle.
In conclusion, it was analyzed that the RSET did not exceed the evacuation possible time at all places in the building when the proper classroom arrangement centered on the shelter was made. It was also shown that the ramp with a gentle ramp than the stairs reduced the shelter demand time. Research is needed on the required safe egress time according to the slope of the ramp in the future.