아케이드형 재래시장의 화재특성에 관한 수치적 연구

Abstract

A fire simulation using FDS on the arcade type Busan Bupyeong Market was carried out to find out its optimum roof height by computing the temperature and visibility when a fire was broken out. The fire was assumed to locate at the center of market passageway with a 1MW heat release rate. Four roof heights of 4.5m, 6m, 8m and 10m were selected. The temperatures and visibilities, at a point of 5m distance from fire source and at the ceiling along the longitudinal centerline of the space, were compared. Following conclusions were obtained from the results.

1) The average temperature at the respiration line (1.5m high from the floor) was the highest when the roof height was 4.5m, and decreased with increasing roof height. The temperature difference was very small between the two roof heights, 8m and 12m. This confirms that the roof height is an important factor in the determination of average temperature due to a fire.

2) The temperature in the ceiling area above the passageway centerline was 250℃ for the roof height 4.5m, and 110℃ for 6m. The both roof heights 8m and 12m yielded were approximately the same temperature, 95℃.

3) The temperature at a point of the respiration line for the roof height of 4.5m was also higher than that for 6m. There was no temperature difference in the cases of 8m and 12m. From these results, It is confirmed that this is due to the size of the space, and hence a higher roof is desirable.

4) The visibility analysis at the respiration line showed that, in the case of roof height 4.5m, the visible distance was less than 3m within a few seconds from the fire start. This is caused by the small size of the space. The visible distance gradually decreased with time in the cases of 6m, 8m and 12m. These results also show that the roof height should be as high as possible so that the people in the market may escape safely.

5) The higher temperature and shorter visible distance for lower roof heights implies that a market with a higher roof height is desirable for safe evacuation and efficient firefighting operation. In this study, it was found the height of arcade should be at least 8m to meet the minimum visible distance 5m for safe evacuation.