• Title/Summary/Keyword: Fire transition

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A Study on the Transition of Hydrogen-Air and LPG-Air Explosion to Fire (수소와 액화석유 가스의 공기혼합기의 폭발 후 화재로 전이 연구)

  • Oh Kyu-Hyung;Lee Sung-Eun;Rhie Kwang-Won
    • Journal of the Korean Society of Safety
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    • v.19 no.4 s.68
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    • pp.150-154
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    • 2004
  • Gas explosion characteristics of hydrogen and liquefied petroleum gas(LPG) were measured in 6L cylindrical vessel, and experiment for explosion to fire transition phenomena of the gases were carried out using the 270L vessel. Explosion characteristics were measured using the stain type pressure transducer and explosion to fire transition phenomena was analyzed with the hish-speed camera. Base on the experiment, it was found that explosion pressure was most high slightly above the stoichiometric concentration, and explosion pressure rise rate and flame propagation velocity were proportional to the combustion velocity. And we find that those kind of explosion characteristics affect the explosion-to-fire transition, in addition, explosion flame temperature, flame residence time, are important parameters in explosion-to-fire transition.

Development of Compensation-Type Fire Detector Using Metal-Insulator-Transition Critical-Temperature Sensor (금속-절연체 전이 임계온도센서를 이용한 보상식 화재 감지기 개발)

  • Jung, Sun-Kyu;Kim, Hyun-Tak
    • Fire Science and Engineering
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    • v.28 no.1
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    • pp.26-30
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    • 2014
  • A Compensation-type fire detector (CFD) is operated with two functions of a differential-temperature detector and as a fixed-temperature detector. The differential-temperature detector observes a rate of temperature increase, and the fixed-temperature detector measures a given fixed temperature. The differential-temperature detector does not observe the outbreak of fire in slowly increasing temperature conditions, whereas the fixed-temperature detector is not able to observe the outbreak of fire in conditions under predetermined temperature level. We developed a CFD to compensate for weaknesses of both detectors. To compensate for the disadvantages, a sensor of the sensor metal-insulator-transition critical-temperature sensor was used. Temperature coefficient of resistance is the sensitivity for sensor. At $55^{\circ}C$, temperature coefficient of resistance of metal-insulator-transition critical-temperature sensor was 14.15%. Temperature coefficient of resistance of thermistor was about 0.5%. This CFD was operated as two ways that fixed-temperature detector and differential-temperature detector in one sensor.

A Study on the transition of Explosion to Eire of LPG and Its' Prevention (LP가스 폭발 후 화재 전이 현상 및 전이 방지에 관한 연구)

  • 오규형;이성은
    • Fire Science and Engineering
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    • v.18 no.2
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    • pp.20-26
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    • 2004
  • The purpose of this study is to investigate the transition mechanism and prevention mechanism of gas explosion to fire. Transition phenomena of explosion to fire of LPG in the explosion vessel of its size of TEX>$100 cm {\times} 60 cm {\times} 45 cm$ was visualized using the high speed video camera and the mechanism was analysed from the videograph. Newspaper size of $30cm {\times} 20cm$ was used for combustible sample in this experiments and LPG-air mixture was ignited by 10 ㎸ electric spark. Experimental parameter was gas concentration, size of vent area and position of combustible solid. Size of vent area were varied as $10cm {\times} 9cm, 13cm {\times} 10cm, 27cm {\times} 20cm, 40cm {\times} 27cm$, and the position of combustible was varied in 4 point. Carbon dioxide was used to study the prevention mechanism of explosion to fire transition of LPG. Based on this experiment we can find that transition possibility of explosion to fire on solid combustible from explosion is depends on concentration of LPG-air mixture and the exposure time of solid combustibles in high temperature atmosphere of flame and burnt gas. And cooling or inerting of the atmosphere after explosion can be prevent the transition of explosion to fire on solid combustibles from gas explosion.

선박 화재안전과 SOLAS 협약

  • Ryu, Eun-Yeol
    • Fire Protection Technology
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    • s.17
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    • pp.24-32
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    • 1994
  • This article introduces the transition of SOLAS (The International Convention for the Safety of Life Sea) safety regulations for fire protection, fire detection and fire extinction in ships. And also the regulations and the related IMO fire test rules applied to products such as fire sep-arate walls and non-combustible materials for interior to prevent fire spread on the ship fire are summarized.

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Research on FARSITE for introducing a Forest fire simulator (산불확산 시뮬레이션 도입을 위한 FARSITE 고찰)

  • Lee, Si-Young;Park, Houng-Sek
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.161-164
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    • 2008
  • We studied a basic concept and application about FARSITE, which is a forest fire spread simulator for preventing and predicting fire in United States Department of Agriculture(USDA). And, we researched a problem in the transition for introducing, so we serve the basic method for prevention and attacking fire. For this transition, we compared the behavior of the 2005 Yangyang forest fire with the result of a simulation. The spread direction is similar to real data. But, while mean spread of rate was 0.65km/hr on real data, it was 0.3km/hr on simulation. As Damaged area is 1,387ha on real, it was 5,368ha on simulation. Therefore, it is necessary to establish a fuel concept for more accurate simulation.

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A Study on the Explosion to Fire Transition Phenomena of Liquidfied Petroleum Gas (LP가스 폭발로부터 화재로의 천이에 관한 연구)

  • 오규형;이춘하
    • Journal of the Korean Society of Safety
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    • v.8 no.4
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    • pp.107-113
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    • 1993
  • Small rectangular explosion chamber of its size 25cmX25cmX32cm with a circular bursting diaphram at the top was used to study the mechanism of gas explosion to fire transition phenomena, the process of ignition of solid combustibles during a gas explosion. To visulize the explosion to fire transition phenomena, transparent acryl window and high speed camera system were used. The test piece of solid combustible in this experiments was a 5cm$\times$5cm square sheet of newspaper which was placed in the explosion chamber filled with a LPG-air mixture. The mixture was ignited by an electric spark at the center of the chamber. Explosion to fire transition phenomena and the behavior of out flow and in flow of gas through the opening yielded by bursting the diaphram was visualized with shlieren system and without shlieren system. Diameter of a bursting dlaphram at the top of the explosion chamber was varied 5cm, 10cm, and 15cm, and the position of test piece were varied with 6 point. Explosion pressure was measured with strain type pressure transducer, and the weight difference of the test piece before and after each experimental run was measured. By comparing the weight difference of solid combustibles before and after the experiment and the behavior of out flow and inflow of gas after explosion, it was found that the possibility of ignition was depends on the LPG-air mixture concentration and the exposure period of test piece to the burnt gas. Test result of this experiments it was found that the main factor of this phenomena are that heat transfer to the test piece, and the pyrolysis reaction of test piece. Based on the results, the mechanism of the explosion to fire transition phenomena were inferred ; gas explosion- heat transfer to solid combustibiles ; pyrolysis reaction of solid combutibles : air inflow ; mixing of the pyroly gas with air ignition.

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Experiment for the Improvement of Fire Resistance Capacity of Reinforced Concrete Flexural Member Strengthened with Carbon Fiber Reinforced Polymer (CFRP로 보강된 철근콘크리트 휨부재의 내화성능 개선을 위한 실험)

  • Lim, Jong-Wook;Seo, Soo-yeon;Song, Se-Ki
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.33 no.12
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    • pp.19-27
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    • 2017
  • This paper is a study to improve the fire-resistance capacity of reinforced concrete (RC) members strengthened by fiber-reinforced-polymer (FRP). The fire resistance of the RC members strengthened by FRP was evaluated through high temperature exposure test. In order to improve the fire resistance of the FRP reinforcing method, a fire-proof board was attached to the reinforced FRP surface and then the high temperature exposure test was carried out to evaluate the improvement of the fire resistance performance. It was confirmed that the resistance to high temperature of NSMR could be improved somewhat compared with that of EBR from the experiment that exposed to high temperature under the load corresponding to 40% of nominal strength. When 30 mm thick fire-resistance (FR) board is attached to the FRP surface, the surface of the reinforced FRP does not reach $65^{\circ}C$, which is the glass transition temperature (GTT) of the epoxy until the external temperature reaches $480^{\circ}C$. In particular, when a high performance fire-proof mortar was first applied prior to FR board attachment, the FRP portion did not reach the epoxy glass transition temperature until the external temperature reached $600^{\circ}C$.

Latest passenger vehicle fire trend and case study based on field investigation data (차량화재 사고경향 및 사례분석)

  • Shin, Junho;Won, Eugene;Hong, Ilmin
    • Journal of Auto-vehicle Safety Association
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    • v.6 no.2
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    • pp.67-71
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    • 2014
  • Based on the analysis of the actual passenger vehicle fire cases for recent four years (2010~2013), the passenger vehicle fire is increasing annually. Main root cause was analyzed as an electric problem as a 39%. Vehicle fire case by electric problem was mainly caused by use of Non-genuine part. Vehicle fire case by mechanical problem was mainly caused by various oil system maintenance. Vehicle fire case by smoking material was mainly caused by cigarette and disposal lighter. And external fire transition issue and towing mistake fire cases was also confirmed.