• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1545-1546
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• 2015

본 연구에서는 아직은 우리 주변에서 생소하지만 향후 사용 빈도가 높아질 중앙 집진식 청소기의 발생 가능한 화재원인을 연구하여 어떤 조건하에서 발화가능성이 있는지, 발화요인 제거와 화재조사시 과학적으로 명확하게 판단하여 원인불명의 화재가 발생하지 않도록 중앙 집진식 청소기의 화재 감식기법과 예방을 위한 개선방향을 제시하고자 한다.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.91-96
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• 2004

Overloading of electrical equipment results in excessive currents. As the heat developed in the cables is proportional to square of the current, they get overheated. The insulation on cables is generally made of materials which are damaged easily by excessive temperature. They may therefore lose their insulating properties and lead to short circuits. Since many insulating materials are combustible, they may even catch fire if the temperature rises to their ignition temperature. In this paper, we have simulated the thermal analysis for cable according to the value of current in a overload and a short with the cable of the L's company product(600 V, VV : Four Core) using the electro-thermal finite element method(Flux2D).

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.348-354
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• 2004

Hydrogen gas has several merits such as lower ignition energy, wide flammability and shorter quenching distance. It leads to high thermal efficiency but backfire occurrence. In this study, feasibility of expansion of BFL(Back-Fire Limit) equivalence ratio and combustion characteristics by a dilution of hydrogen fuel are experimently examined by using experimental heavy duty single cylinder hydrogen fueled engine. As results, it is found that BFL equivalence ratio is expanded to rich range and torque is increased.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2280-2283
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• 1999

Close to high power radio/radar transmitters, there is a possibility that electrical sparks may occur at discontinuities in metallic structures. If these structures are in an area where flammable mixtures are present, there is a danger that fire or explosion may happen by these sparks. Voltage may be induced on these metallic structures by the radio-frequency transmitter. In this case, a person who comes into contact with these structure may be undergone a severe electrical shock. In this paper, assessment of the these hazards was investigated through experimental and evaluation for actual tower cranes near AM radio transmitters.

• International Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.1-5
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• 2015

The powder propellant rocket which uses micron-sized particles as fuel is storable and costly. Functions like thrust control and multiple-ignition can be realized by changing powder mass flow rate. In this paper, we discuss the theoretical performance of bi-propellant and mono-propellant powder rocket. When used as the fluidization gas, helium can improve specific impulse dramatically. The stability of the powder feeding device is preliminarily quantified through metal/N2O powder rocket hot fire tests.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.24-30
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• 2010

An accurate information of the autoignition temperature(AIT) is important in developing appropriate prevention and control measures in industrial fire. This study measured the AITs of trichlorosliane and dichlosilane(DCS)-trichlorosliane(TCS) mixtures by using ASTM E659-78 apparatus. The experiment AITs of trichlorosliane, TCS(90wt%)-DCS(10wt%) and the TCS(70wt%)-DCS(30wt%) were $225^{\circ}C,\;250^{\circ}C\;and\;236^{\circ}C$, respectively.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.1-9
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• 1994

This study focuses on forest fires attributed to cigarette light, the main source of wild fires, by examining the characteristics of the fire types. It aims to present useful data for preventive measures. Statistics show that the average length of cigarette butts left after smoking is 30mm excluding filter for domestic cigarette smokers. Also the average thickness of litter layer in forests is 58.2mm throughout the nation. The value varies according to how often leaves were trodden by hikers : the accumulation amount of Mt. Sunchi. which is relatively protected from human disturbances, is 29.6% more than that of Mt. Kye-Ryong National Park. Aged trees such as Pznus rzgidu, Quercus acutissima and Larix leptolepis have relatively large inflammable contents, 2.43kg in 15 year-old stand and 2.55kg in 10 year-old stand. This study found out the following fact with regard to the start of lighting and the out-break of fire. Fire breaks out within five minutes in the sample(C), in which Zoysza gaponica and Populus X tomentiglandulosu has been tramped when the sample has 2~6 percent of moisture contents. Coniferous trees such as Pinus rigida and Larzx leptolepis do not burn easily while leaving charcoal. In contrast, deciduous trees with Zoysia japonzca and Populus X tomentiglandulosu are quick to catch fire. As a result of the experiments, it is proved that cigarette light is a very dangerous cause of wild fire especially for dry grass like Zoysia gaponica.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.634-643
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• 2023

Purpose: Underground common duct fires are steadily occurring, and the proportion of property damage is particularly large among property and human casualties caused by fires. Especially, cable fires that occur in common areas can spread vertically quickly and pose a great risk. This paper aims to scientifically analyze the nature of the fire by reproducing the fire through experiments. Method: To analyze the characteristics of cable fires in underground common duct, heat release rate and temperature changes were measured through Room-corner (ISO 9705) test, and the vertical and horizontal propagation of cable fires was quantitatively compared and analyzed. Result: The Room Corner Test (ISO 9705) was used to compare the temperature changes at each data logger point. The results showed that the time it took for the fire to reach the ignition temperature in the horizontal and vertical directions from the center point of the first-tier cable was 589 seconds and 536 seconds, respectively, which means that the vertical fire propagation is 53 seconds faster than the horizontal propagation. This proves that the vertical propagation of fire is relatively faster than the horizontal propagation. The horizontal propagation speed of the fire was also compared for each floor cable tray. The results showed that the third-tier cable propagated at 3.4 times the speed of the second-tier cable, and the second-tier cable propagated at 1.5 times the speed of the first-tier cable. This means that the higher the cable is located, the faster the fire spreads and the larger the fire becomes. Conclusion: This study identified the risks of cable fires and analyzed the risks of vertical fire propagation during cable fires based on the results of the Room Corner Test. Studies to prevent the spread of fire and fire response policies to prevent vertical fire propagation are required. The results of this study are expected to be used to assess the fire risk of common areas and other fires.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.697-703
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• 2018

In this paper, we analyzed the operation of the ignition circuit for electronic arm and fire device(EAFD), and investigated the sensitive elements of the circuit system. For reliability analysis, the EAFD ignition circuit was modeled using the PSpice simulation tool, and the output results of the circuit were examined by changing the tolerance of each circuit element. Monte Carlo simulation was used by maintaining the values of the observed sensitive elements at ${\pm}10%$ of the original values and adjusting the values of the other components according to a random distribution. The histogram results of the output peak currents and pulse widths were represented by Weibull and Burr type XII function fittings in three cases(element values are +10 %, 0 %, -10 % of original). For the output peak currents, mean values were 1.0028, 1.0034, and 1.0050, where the variance values were calculated as 0.0398, 0.0396, and 0.0290 using the Weibull function fitting, respectively. For pulse widths, the mean values of 0.9475, 0.9907, and 1.0293 with the variance values of 0.0260, 0.0251, and 0.0238 were obtained using the Burr Type XII function fittings.