• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.50-54
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• 2006

A fire in a subway station platform, completely isolated by screen doors, was numerically simulated to investigate problems in smoke control and find their countermeasures. A part of the platform, $40m{\times}5m$ floor and 3 m high, and a fire of 1 MW were considered, and the smoke extraction system was assumed to start operation at the onset of the fire. For three different values of the exhaust air flow rate, 0.1, 2, and $4m^3/min-m^2$, the distributions of temperature, concentrations of soot and carbon monoxide, and those of visibility were compared. The time-variations of the number of randomly distributed particles in the space were also investigated for the air flow rates to see the efficiency in smoke control. It was shown that smoke control takes time by lack of air supply. It was also confirmed that air supply from the railway to the platform at emergency is needed so that smoke is able to be controlled efficiently, and that opening the doors at the both ends of the platform is desirable until the fire is completely extinguished.

• Journal of the Korean Society of Safety
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• v.37 no.3
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• pp.71-78
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• 2022

The purpose of this study is to improve the National Fire Mobilization Plan. This plan is a national-level comprehensive response system aimed to compensate for scarce firefighting resources and minimize damage from large-scale disasters that exceed the response limits of city and province firefighting forces. As such, relevant literature and domestic and foreign firefighting mobilization standards were reviewed, and simulations of firefighting mobilization were performed using the QGIS program to compare and analyze cases. Results showed that, as opposed to the current method of issuing mobilization orders by dividing resources according to city and province, recognizing the entire country as a single entity and prioritizing the mobilization of adjacent firefighting resources is more effective in terms of minimizing time and distance and more quickly securing resources. Regarding national firefighting mobilization, recognizing the country's firefighting resources as a whole will allow adjacent firefighting resources to be mobilized with priority. However, the mobilization-related limits of each region need to be set to respond to local disasters. Once the scale of mobilization is determined, a system that can quickly calculate how to mobilize firefighting resources based on location and distance can be established. Additionally, it is necessary to create an integrated management system so the central government can directly organize and mobilize local firefighting resources.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.419-425
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• 2021

This study analyzed the safety of evacuation according to the number of exits and the direction of evacuation routes with evacuation simulations of the Pathfinder in case of a fire at a highway service area. It was also analyzed of the difference in RSET by comparing the single or double types of the exit of a facility. The results were as follows. When only one direction exit was opened, all of the RSET were exceeded. When two or more different directions were opened according to the general principle of evacuation, all results met the RSET. The simulations showed that two or more different directions were more shortened in RSET than the one same direction. The result of the types of doors showed that the single type door was shortened in RSET rather than the double type doors. For the evacuation safety in a fire at the highway service areas, firstly, it is necessary to secure two or more exits in a fire at all times. Secondly, the exits should not be same directions. Finally, it is suggested that the exit should be installed with a single type of door.

• Fire Science and Engineering
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• v.32 no.1
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• pp.33-39
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• 2018

When the fire in the high-rise building was not extinguished in its early stage and propagated over its origin, safe egress becomes one of the most important factor to minimize the casualties. Recently fire protection for high-rise building has been reinforced after experiencing the series of disastrous fires. But, we still find many high-rise buildings do not comply with those reinforcement. And also there is a possibility of failure of reinforced fire protection system. Under these situation safe egress guide would be the final layer of protection. In this study existing egress methods were identified and evaluated. According the result of study, priority in egress should be given to the tenants on the floor of fire origin and floors exposed to the risk of fire. Then, the rest of the tenants can be evacuated simultaneously. Floors exposed in fire risk shall be determined by fire tests and/or fire simulations. But, the result of fire monitoring shall override preliminary estimations. Egress time for each algorithm was estimated by egress simulation and the result was compared. There was a little difference in egress time between total egress and phased egress, and a big difference between using stairs only and using elevators and stairs together. to a constant thickness between layers constituting a firefighter's protective clothing should be considered in the future.

• Fire Science and Engineering
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• v.33 no.1
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• pp.121-129
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• 2019

In Korea, life safety assessment through simulation are mandatory in performance-based design. Generally, there are three types of methods for simulation-based life safety assessments: the non-coupling method that compares available safe egress time (ASET) and required safe egress time (RSET) at a specific point through conducting fire and assessment simulations independently; the semi-coupling method that compares fire and evacuation simulation results by overlaying the result screens; and the coupling method that compares the results of fire effect simulation to an evacuation simulation. Of these methods, all designers in South Korea have used the only non-coupling method. In the non-coupling method, it is important to determine the location of a specific point to compare ASET and RSET. However, without any defined regulation, setting the location is determined based on the designer's experience and knowledge. The number of specific locations and the locations themselves differ with each designer, which can produce contrasting results in a life safety assessment. Therefore, this study conducted a life safety assessment based on the three methods (non-coupling, semi-coupling and coupling) and compared each of the results. Furthermore this study suggests a improvement way in particular for the computer simulation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.17-20
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• 2008

Numerical simulations were performed for the prediction of the flame structure of a hydrocarbon flame interacting with a hydrogen flame. Methane was used as a hydrocarbon fuel in this study. The interaction of two 1D premixed flames established in counterflow geometry was investigated. The temperature of the flame interacting with each other was much higher and the flame thickness was wider at a global strain of $1000\;s^{-1}$ than normal methane flame.

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.101-106
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• 2015

Gas leakage and dispersion in the underground LNG power plant can lead to serious fire and explosion accident. In this study, computational fluid dynamics simulation was applied to model the dynamic process of gas leakage and dispersion phenomena in a closed space. To analyze the risk assessment factor, such as the flammable volume ratio, transient simulations were carried out for different scenarios. The simulation results visualized the gas distribution with time in the closed space. The flammable volume ratio was introduced for quantitative analysis the fire/explosion probability.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.3
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• pp.368-377
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• 2012

Most tunnel simulations have been focused on the thermal field and the critical velocity for suppression of hot back-layering flow in case of fire and on the characteristics of a tunnel fire in terms of the flame propagation and the toxic gas generation. In this paper, a comparative study of the flow characteristics of polluted air with no heat source in a tunnel model opened and closed at both end sides is implemented into a recognized CFD simulation code. The model is used to investigate the flow characteristics depending on the three different Reynolds numbers of 640, 1270 and 2120, which have been chosen by the flow velocities of 0.3, 0.6 and 1.0 m/s through the inlet. The results of this study have shown that the CFD predictive and experimental approaches are available in qualitatively studying the correlation of flow behaviors for a better tunnel design.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.255-258
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• 2008

본 연구에서는 이전의 연구를 통해 계단형 공동주택 화재 시 재실자 피난특성 및 연기거동에 관한 연구를 실물실험을 통해 수행한 바 있으나 이때 야기된 문제점들을 적절한 방재설비를 도입함으로써 일부 해소하고자 하였다. 따라서 본 연구에서는 이전의 연구와 동일한 대상 건물과 조건에서 수치해석을 수행하며 특히 계단실에 방재설비(배연팬 등) 설치 유 무에 따른 독성가스의 전파 특성 및 최상층까지의 도달시간등을 비교 검토하였다. 계단형 공동주택에서 층간에 배연팬이 설치되어 작동되는 경우가 배연팬이 없는 경우보다 약 45%의 CO 방출량을 줄일 수 있을 것으로 판단되지만 1층 출입구를 통해 유입되는 공기량은 배연팬이 없는 경우가 배연팬이 설치되어 작동되는 경우보다 약 23% 크기 때문에 이로 인해 제연풍속의 증가를 가져올 수도 있을 것이다.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.73-83
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• 2021

The door open time, resulting from occupants evacuating from apartments, is an important parameter when assessing the performance of smoke ventilation systems in high-rise apartment buildings. However, the values recommended in UK design guidance appear to have limited substantiation. Monte Carlo simulations have been carried out considering variabilities in door swing time, flow rate and number of occupants. It has been found that the door open time can be represented by a lognormal distribution with a mean of 6.6, 8.7 and 11.1 s and a standard deviation of 1.7, 3.2 and 4.7 s for one, two and three-bedroom apartments, respectively. For deterministic analyses, it is proposed that the 95th percentile values may be adopted in line with recommended practice for other fire safety design parameters such as fuel load density and soot yield, giving door open times of 10 s to 19 s, depending on the number of bedrooms.