• 한국안전학회지
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• 제39권2호
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• pp.9-21
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• 2024

Static-electricity-induced fires and explosions persistently occur every year, averaging approximately 80 and 20 cases annually according to fire statistics provided by the National Fire Agency and industrial accident statistics provided by the Ministry of Employment and Labor, respectively. Despite the relatively low probabilities of these accidents, their potential risks are high. Consequently, effective risk assessment methodologies and accident investigation strategies are essential for efficiently managing static-electricity hazards in fire- and explosion-prone areas. Accordingly, this study aimed to identify the causal variables essential for accident investigations, thereby facilitating risk assessments and the implementation of effective recurrence prevention measures to mitigate static-electricity hazards in fire-and explosion-prone regions. To this end, industrial accident statistics recorded over the past decade (2012 to 2021) by the Ministry of Employment and Labor were analyzed to identify major fire and explosion incidents and related industrial accidents wherein static electricity was identified as a potential ignition source. Subsequently, relevant investigation reports (63 cases) were thoroughly analyzed. Based on the results of this analysis, existing electrostatic fire and explosion risk assessment techniques were refined and augmented. Moreover, factors essential for investigating electrostatic fire and explosion disasters were delineated, and the primary causal variables necessary for effective risk assessments and scientific investigations were derived.

• 항공우주시스템공학회지
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• 제17권1호
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• pp.51-58
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• 2023

별도의 점화원 없이 스스로 점화가 가능한 접촉점화 추진제는 부식성과 독성으로 인하여 취급의 어려움이 있다. 따라서 독성이 적거나 없는 친환경 접촉점화 추진제의 개발이 필요하며, 본 연구에는 친환경 접촉점화 추진제의 기초 연구를 수행하였다. 산화제로 95%의 과산화수소, 연료로 CNU_HGFv1를 사용하였으며 액적 낙하 시험, 점화 시험 및 연소 시험을 통하여 추진제의 점화 및 연소 특성을 확인하였다. 액적 낙하 시험 결과 점화지연 시간은 9.7ms 이며, 점화시험에서는 약 27ms로 추진제로 사용하기에 충분히 빠른 것을 확인하였다. 연소시험 결과 약 11.7bar에서 연소 효율 95.4~98.1%를 달성하였으며, 하드스타트 및 연소 불안정 없이 빠르고 안정적인 연소가 가능함을 확인하였다.

• 한국안전학회지
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• 제26권3호
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• pp.15-22
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• 2011

Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.

• 한국안전학회지
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• 제32권6호
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• pp.16-21
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• 2017

Fire or electrical problem while DC electric traction vehicle operation caused by various reasons can lead to not only suspension of the operation, but also severe aftermath such as massive casualty. In this paper, fire analysis on DC electric traction vehicle caused by electrical breakdown on line breaker, which is in connection with the power supply, is presented. When the electric arc, the by-product of frequent line breaker operation, is not fully diminished, it leads to electrical breakdown and fire. Especially, electrical breakdown can be easily induced by the open-and-close operation of inner contractor inside line breaker, eventually followed by ground fault and generation of transient current. Electric arc is consequent on the ground fault and acts as possible ignition source, leading to fire. Also, during the repetitive operation of the line breaker, the contactor is separated each other and some copper powder is generated, and the copper powder provided breakdown path, resulting in fire.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.208-213
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• 2010

In this study CFD(Computational Fluid Dynamics) analysis of the steady fire-driven fuid flow for the performance test of ventilation at railway tunnel between Heuksok and Nodeul Station from Seoul Metro 9 is performed. There were fans with exhaust and intake modes and each was installed at the middle and both ends of the tunnel. For this test, the pool fire source of methyl alcohol with 1.5MW and smoke generators were installed between the middle of tunnel and Heuksok Station. In this test, the smoke behavior from natural convection was observed for 10 minutes from the ignition of pool fire and then fans with intake-modes at both sides of Heuksok effect of fan-on with intake mode located in the opposite side of the tunnel nearby Heuksok Station on fire-driven fluid flow is studied on when the boundary conditions of fan-on at the tunnel between Heuksok and Nodeul Station are the same as test. FLUENT, a commercial CFD code, is used for this analysis.

• 한국안전학회지
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• 제38권6호
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• pp.9-15
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• 2023

Hydrogen is gaining attention as a sustainable and renewable energy source, potentially replacing fossil fuels. Its high diffusivity, wide flammable range, and low ignition energy make it prone to ignition even with minimal friction, potentially leading to fire and explosion risks. Workplaces manage ignition risks by classifying areas with explosive atmospheres. However, the effective installation of a blast wall can significantly limit the spread of hydrogen, thereby enhancing workplace safety. To optimize the wall installation of this barrier, we employed the response surface methodology (RSM), considering variables such as wall distance, height, and width. We performed 17 simulations using the Box-Behnken design, conducted using FLACS software. This process yielded two objective functions: explosion likelihood near the barrier and explosion overpressure affecting the blast wall. We successfully achieved the optimal solution using multi-objective optimization for these two functions. We validated the optimal solution through verification simulations to ensure reliability, maintaining a margin of error of 5%. We anticipated that this method would efficiently determine the most effective installation of a blast wall while enhancing workplace safety.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.330-334
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• 2004

In this paper, we studied on the fire dispersive patterns and the fire progress at the power cord sets for low voltage appliances in the wall-model. For the experiment, we manufactured a wall-model and applied the external flame at the power cord sets. From the results, short-circuit of the power cord sets was haunted by the external flame it was disconnected with the flashing and the scattering. The fire progress on the polyvinyl chloride insulated flexibel cords is not observed because the ignition energy decreases. In case of rubber insulated flexible cords, however, the fire was progressed continuously. Molten marks were formed at a two electric wire by continuous electric discharge in power source part. A large molten mark was formed in load part. And the columnar structure and voids were observed in molten wire.

• 한국안전학회지
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• 제36권1호
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• pp.64-71
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• 2021

Experimental and analytical investigations are performed to explore the explosion characteristics of a hydrogen-air mixture in open atmosphere. A hydrogen-air mixture tent of total volume of 27 m³, with 40% hydrogen volume, is used to observe overpressure at a distance from the ignition source. Vapor cloud explosion analyses are performed using the TNO multi-energy model and Baker-Strehlow-Tang model. The results of these analyses are compared with experiment done from this study and references. The experimental results with and without obstacles indicate that the overpressure values measured at a distance of 4.5-21.5 m from the ignition source are about 9.4-3.6 kPa and 6.5-2 kPa, respectively. This implies that the overpressure with obstacles is approximately 1.7 times greater than that without obstacles. Analytical observation indicates that the results obtained with the Baker-Strehlow-Tang model with M_f = 0.2-0.35 are in good agreement with those of most of the previous studies, including that obtained from this study. Moreover, the TNO multi-energy model with a volume of 27 m³ well predicts the overpressure obtained from this study. Further studies should considered explosions in semi-confined spaces, which is more suitable for hydrogen refueling stations.

• 한국안전학회지
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• 제20권4호
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• pp.171-179
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• 2005

건물의 마감재료가 화재에 노출될 때 그 마감재료의 역할을 이해하는 것은 필수적이다. 실물화재실험을 통해서 재료의 성능을 평가하는 것이 가능하다. 그러나 실물화재 실험 시 소요되는 시간과 높은 비용으로 인해 실물 화재 실험이 수행되는 경우는 드물고 대신 컴퓨터 화재 시뮬레이션이 개발되어 왔다. 컴퓨터 화재 시뮬레이션에서는 초기입력 데이터로서 점화 버너의 화염으로부터의 Heat Flux Map이 요구된다. 현재까지의 연구에서는 열전대 혹은 열유속 센서와 같은 실험장치의 제한으로 인해 $10kW/m^2$간격의 Heat Flux Map이 나와있을 뿐이고 공간적으로 더 상세한 Heat Flux Map은 없는 실정이다. 화재 시뮬레이션의 성능을 증가시키기 위해서는 점화 버너로부터의 정확하고 상세한 Heat Flux Map이 필요불가결하다. 본 연구의 목적은 적외선 카메라로부터 얻어진 표면온도를 이용하여 벽에서 점화 버너 화염에 대한 Heat Flux Happing Procedure를 개발하는 것이다. 높은 수준의 공간적 해상도는 적외선 카메라로부터 제공된다. 개발된 Heat Flux Mapping Procedure를 증명하기 위해서 ISO 9705 점화버너를 이용해서 실험이 행해졌다. 실험 결과를 통해 개발된 Heat Flux Mapping방법의 열유속 해상도와 공간적 해상도가 얻어졌다. 또한 그 실험 결과가 현재 쓰여지고 있는 Heat Flux Map과 비교되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제37권8호
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• pp.946-952
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• 2013

선박의 Ro-Ro 구역이나 특별범주구역의 화재방호를 위해 설치하는 고정식 수계소화설비의 개발 및 실용화를 위해, 특히 방수량이 적으며 관련기준에서 요구하는 성능요건을 만족하는 미분무 노즐을 개발하고자 실물화재실험을 수행하였다. 본 설비의 화재시나리오는 크게 두 가지로 트럭화물화재와 승용차화재로 구분되며, 각각 고정 설치된 미분무 노즐과 화원과의 세 가지 위치에 대한 시나리오로 이루어져 있다. 모든 화재실험은 30분간 진행되었으며 천장부의 가스온도와 우드펠릿의 손상율, 타깃합판의 착화여부로 판단되었다. 본 논문은 두 가지 화재실험 중 조건이 더욱 까다로운 트럭화재용 미분무 노즐의 결과를 위주로 방수압력과 방수량, 미분무수의 유동특성에 따른 화재실험결과와 화재진압특성을 고찰하였으며, 수십 회의 반복실험 결과 분당 약 40 L의 유량을 가지는 저압 미분무 노즐로 Ro-Ro구역의 화재진압이 가능한 것으로 나타났다.