• Tunnel and Underground Space
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• v.16 no.6 s.65
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• pp.526-535
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• 2006

An experimental study was carried out on a reduced scale tunnel model to grasp the behavioral feature of fire-induced smoke in the long tunnels. Based on Froude modeling, the 1/50 scaled tunnel model (20 m long) was constructed by acrylic tubes and paraffin gas was released inside the tunnel to simulate the 20 MW fire-induced smoke. me test results show, that after approximately 2 minutes of fire generation, was descended from the tunnel ceiling through the decrease of buoyancy, then it was symmetrically propagated about 90 meters for 4 minutes before jet fans were operated. The smoke was effectively controlled when the jet fans were operated and an air stream velocity was getting closed to reach a critical velocity (the minimum air velocity that requires to suppress the smoke spreading against the longitudinal ventilation flow during the tunnel fire situations). It was also found out that a range of smoke was spreaded about 3 meters from the origin of fire but the range was not propagated to the escape direction anymore. The early stage of the In operation, however, showed that the smoke was hardly controlled. It means that the operation of emergency ventilation system has many dangerous factors such as an intercepting breathing zone.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.711-721
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• 2005

In order to design of emergency ventilation systems, the smoke movements in tunnel fire with natural and forced ventilation were investigated. Reduced-scale experiments were carried out under the Froude scaling with novel fire source consisting many wicks. Temperature profiles were measured under the ceiling and vertical direction along the center of the tunnel and poisonous gases were measured at emergency exit point in the natural ventilation case. In forced ventilation, temperature profiles were measured with various flow rate to obtain critical velocity. The results showed that the interval of emergency exit having 225m was estimated reasonably through the measurements of temperature variation and poisonous gas in the natural ventilation. In the case of forced ventilation, the temperature distribution near fire source is remarkably different from that of natural ventilation. Also, the critical velocity to prevent upstream smoke flow has the range of 0.57m/s between 0.64m/s. Finally, it was also identified that although the increase of flow rate can suppress the backward flow of smoke to upstream direction, brings about the increase of flame intensity near stoichiometric fuel/air ratio.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.308-315
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• 2014

In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a $1.1m{\times}0.5m{\times}50.4m$ tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.

• Fire Science and Engineering
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• v.23 no.3
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• pp.67-72
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• 2009

This paper is for response feature of fire detectors not only to analysis response feature of fire detector, but also to observe flame spread of inside-building and fire enlargement by using the row house which is supposed to be broken up. Many kinds of popular detectors such as heat type detector(differential type, fixed temperature type, Analogue type)and smoke type(light scattered type, Analogue type, single alarm type) were installed in the house in order to check for the change of temperature by installing of thermocouples. As a result, smoke detectors are better than heat detectors when it comes to making effective fire-detect system in the row house.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.201-210
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• 2019

Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

• Tunnel and Underground Space
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• v.15 no.6 s.59
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• pp.452-461
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• 2005

In a bidirectional tunnel, the accident rate is 1.5 times as high as that of one directional tunnel , the risk of a fire is increased. On fire, there is a problem that the jet fan should not be operated until completion of refuge. To be special, as the great damages occur owing to the expansion of smoke in long tunnels, there is a need to minimize fatality by constructing cross passage and smoke removal system. This study aims at verifying the efficiency of smoke exhaust system through fire propagation simulation as well as scale model test. The results show that completion of escape through emergency exit requires 335 seconds, while addition of smoke exhaust system reduce the escape time to 185 seconds. Also, near the fire source temperature decreased by about $60^{\circ}C$. Without the exhaust system, fire propagation speed was in the range of 0.36 and 0.82 m/s, and it dropped to $0.27\~0.58\;m/s$ with the exhaust system on. Taking into account the escape speed of tunnel users, usually $0.7\~1.0\;m/s$, the emergency exit built every 150m is sufficient for the safe egress. The ultimate goal of this study is to provide fundamental information for the smoke exhaust system in bidirectional tunnels.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8645-8652
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• 2016

Background: Consumption of tobacco in the form of a water pipe has recently increased, especially among young people. This study aimed to develop a scale which would be used in order to detect perceptions about the effects of water pipe smoking on health and to test its validity and reliability. Our scale named "a scale of perception about the effects of water pipe smoking on health" was developed in order to detect factors effecting the perception of adolescents about the effects of water pipe smoking on health. Materials and Methods: The sample consisted of 150 voluntary students in scale development and 750 voluntary students in the study group. Data were collected via a questionnaire prepared by researchers themselves and 5-pont Likert scale for "a scale of perception about the effects of water pipe smoking on health" which was prepared through the literature. Data evaluation was carried out on a computer with SPSS. Results: The findings of the study showed that "a scale of perception about the effects of water pipe smoking on health" was valid and reliable. Total score average of the adolescents participated in the study was $58.5{\pm}1.25$. The mean score of the ones who did not smoke water pipe ($60.1{\pm}11.7$) was higher than the mean score of the ones who smoked water pipe ($51.6{\pm}13.8$), the difference being statistically significant. Conclusions: It is established that "a scale of perception about the effects of water pipe smoking on health" was a reliable and valid measurement tool. It is also found out that individuals who smoked a water pipe had a lower level of perception of water pipe smoking effects on health than their counterparts who did not smoke a water pipe.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.244-249
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• 2004

Experiments were performed to investigate the characteristics of combustion of 7MW-3 air stages combustion system for a heavy oil firing boiler. Several fuel nozzles were developed for the purpose of lowering pollutions in another institute and ${\Phi}$-jet nozzle among them was equipped to the combustion system. A variety of combustion phenomena were observed as air stage ratio, air fuel ratio and load are changed for each nozzle. Main combustion characteristics are shape of flame, NOx and CO generations, smoke scale number. Through lots of adjustments, the combustion system reaches such goals as the low NOx of 160 ppm, CO of 300 ppm corrected at $O_2$ of 4% and dust of 150 mg/Sm3.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.289-296
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• 2010

This study is aiming at analyzing correlation between flashover's time and maximum smoke production rate's time on sandwich panel specimens. For this analysis, KS F ISO 137481-1 has been performed for 23 kinds of sandwich panels which mainly consist of EPS, PIR, PUR, Glass wool and so on. KS F ISO 13784-1 represents real scale reaction-to-fire test and focuses on measuring flashover phenomenon rather than other tests as like ISO 5660-1 and SBI.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1998.11a
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• pp.29-39
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• 1998

복도는 사무실용 건물, 호텔 등 공중이용 건물에서 중요한 피난경로의 일부이다. 화재로 복도에 연기가 확산되면 그 온도, 연층의 높이, 유해물질의 농도 등에 따라 피난에 심각한 장애를 가져올 수 있다. 본 연구는 이러한 복도에서의 연기의 확산 및 유동에 관하여 연구하기 위하여 길이 40m의 복도에서 pool fire로부터의 연기 유동에 관한 실제크기의 실험과 수치해석을 수행하였다. 화재실과 그에 접해있는 긴 복도가 있는 실험장치에 직경 15, 20, 30cm의 가솔린 pool을 화재실 중앙에서 점화 시켰다. 연기의 온도 및 이동을 측정하기 위해 전장 중앙선을 따라 열전대를 설치하였고 연층의 두께를 측정하기 위하여 수직방향으로 세곳에 열전대가 부착된 수직봉을 설치하였다. 아르곤 레이저 sheet 과 비디오 카메라를 이용해 연기의 유동을 가시화 하였다.