• Title/Summary/Keyword: The causes of fire

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Temperature Characteristics on Cooking Equipment Materials of Portable Gas Ranges (이동식부탄연소기의 조리기구재질에 따른 온도 특성)

  • Kim, Dae-Hyun;Lee, Keun-Oh
    • Journal of the Korean Society of Safety
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    • v.29 no.3
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    • pp.8-13
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    • 2014
  • Accidents involving portable ranges occurred total 133 cases for the last five years(2008~2012). It accounted for 18.0% of all gas accidents(739 cases). Major causes of accidents are using of excessive hot grill, leaving a butane can near fire and overheating of a butane can during cooking. In this study, it is a desire to investigate the relationship between thermal behavior mechanism depending on characteristics of cooking equipment materials of portable gas ranges. It shows that slope of temperature change curve correlates with difference of heat capacity on thermal behavior characteristics experiment depending on materials of cooking equipment. In conclusion, temperature characteristics appear differently depending on variables such as materials of cooking equipment. Especially, it is necessary to restrict using cooking equipment made of stones, because it is very dangerous that temperature of can is rapidly increasing caused by high heat capacity of stone.

Bacterial Shoot Blight of Apple Caused by Pseudomonas syringae (Pseudomonas syringae에 의한 사과나무 가지마름병의 발생)

  • 서상태;원선영;박덕환;김영숙;허장현;임춘근
    • Plant Disease and Agriculture
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    • v.5 no.1
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    • pp.46-49
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    • 1999
  • Bacterial blight occurred on the flowers, leaves, twigs and branches of apple trees (Malus domestica Borkh) in Chunchon, Kangwon-Do. Infected flowers and leaves turned brownish black, and they were fallen down or remained hanging in the trees. Under humid conditions during postblossom period, the casual bacterium spreaded along twigs and killed them. However, killing of branches was very rare. The symptoms on apple trees were very similar to symptoms of fire blight. But the causal organism isolated from the lesions was identified as Pseudomonas syringae based on physiological and chemical characteristics. This is the first described bacterium that causes apple shoot blight in Korea.

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Strength Properties of Cement Matrix using Phytoncide (피톤치드를 혼입한 시멘트경화체의 강도 특성)

  • Kim, Hyeon-Sung;Kim, Sun-A;Park, Sun-Gyu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.23-24
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    • 2018
  • Most finishing materials are vulnerable to durability, humidity resistance and fire. And those products used formaldehyde to protect, during the manufacturing process. Also most finishing materials used adhesives to construction process indoor. All of these elements are major causes of releasing formaldehyde. In this study, concrete used by phytoncide was examined to remove the formaldehyde. As a result of the experiment, we found that compressive strength was increased and formaldehyde effectively removed by using mixture of cement matrix and phytoncide.

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AFCI algorithm design without sensor (센서없는 AFCI 알고리즘 설계)

  • Ban, Gi-Jong;Choi, Sung-Dai;Ho, Yoon-Kwang;Kim, Sang-Hoon;Nam, Moon-Hyon;Kim, Lark-Kyo
    • Proceedings of the KIEE Conference
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    • 2006.04a
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    • pp.231-233
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    • 2006
  • Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, arc current control algorithm is designed for the interruption of arc fault current which is occurred in the low voltage network. This arc is one of the main causes of electric fire. General arc current sensor has troubles for detecting arc currents, thus we would like to propose the arc current detection method without current sensor. In this paper, arc discharge currents within power lines are being detected through the arc current control algorithm.

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Problem considerations and expectations in applying vegetable oil to power transformer (식물성 절연유의 전력용 변압기 적용에 따른 문제점 고찰 및 전망)

  • Park, Hyun-Soo;Kim, Ji-Ho;Lee, Hyang-Beom
    • 한국정보통신설비학회:학술대회논문집
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    • 2009.08a
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    • pp.184-186
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    • 2009
  • In past, transformer connection study was concentrated on efficiency improvement and life time broadening. But environmental side began to become important recently. In existing, quick transaction of mineral oil used to insulation oil of transformer is possibility to be difficult and causes environmental pollution in case of was outpoured and there is worry of fire occurrence. Accordingly, nonflammable performance becomes many interest in excellent vegetable oil because ignition point is high than mineral oil and environment friendly material. But, vegetable oil is cooling of transformer and insulation problem of insulating paper for cause of insulation oil special quality. Therefore, in this paper, special quality of vegetable oil that there are being a lot of mineral oil and the latest interest examined about problem and consideration item to be solved to analyzed comparison and applies vegetable oil to transformer for electric power.

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Heat of Combustion Experiment Based on the Ratio of Moisture Content of Infected and Non-Infected Bursaphelenchus Xylophilus (재선충 감염 소나무와 비 감염 소나무의 수분함유율에 따른 연소열 실험)

  • Kwon, Hyuk;Kong, Ha-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.2
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    • pp.443-451
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    • 2021
  • This study compared and analyzed the thermal characteristics based on the ratio of moisture content of infected and non-infected Bursaphelenchus Xylophilus by heat of combustion experiment. The experiment results are as follows. The analysisresult of the ratio of water content shows that 19.92% on average for infected Bursaphelenchus Xylophilus and 26.27% for non-infected which decreases water content as the size of conduction, convection, and radiant heat increases in case of fire. As the vaporization of the moisture content accelerates, the average moisture content is reached, and the result is contrary to the thermal characteristics of the wood that the moisture content is not ignited by a heat source when the moisture content is under 15%. The combustion heat analysis result showed that infected and non-infected Bursaphelenchus Xylophilus had no significant difference in combustion heat at about 3%. However, it shows that combustion heat is higher than other species. In conclusion, decreasing in moisture content based on the increasing conduction, convection, and radiant heat is one of the direct causes of ignition, and the lower the moisture content, the faster the fire spreads.

Characteristics of Saturation and Circulating Current Based on Winding and Iron Core Structure of Grid-connected Transformer in Energy Storage System (ESS 연계용 변압기의 결선방식 및 철심구조에 따른 순환전류와 포화특성에 관한 연구)

  • Tae, Dong-Hyun;Lee, Hu-Dong;Kim, Ji-Myung;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.4
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    • pp.39-48
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    • 2020
  • Since the fire accident of ESS (energy storage system) occurred at Gochang KEPCO Power Testing Center in August 2017, 29 fire cases with significant property losses have occurred in Korea. Although the cause of fire accidents have not been identified precisely, it should be considered battery and PCS (power conditioning system) as well as unbalance issues in the distribution system. In particular, circulating currents in a neutral line of a grid-connected transformer, which can affect a magnetized current, may have a negative effect on the ESS with unintentional core saturation and surge voltages at the secondary side of the transformer. Therefore, this paper proposes the modeling of the distribution system, which was composed of a substation, grid-connected transformer, and customer loads using PSCAD/EMTDC S/W, to analyze the phenomena of circulating current and surge voltages of the transformer with unbalanced currents in the distribution system. This paper presents a countermeasure for a circulating current with the installation of NGR (neutral grounding resistor) in grid-connected transformer. From the simulation results, it is clear that exceeding the circulating current and surge voltage at the secondary side of the transformer can be one of the causes of fire accidents.

Tracking Propagation Mechanism on the Surface of Polyvinyl-Chloride-Sheathed Flat Cord based on Electric Field Analysis and Gas Discharge Physics (전계해석과 기체방전 이론을 기반으로 한 Polyvinyl-Chloride-Sheathed Flat Cord 표면의 트래킹 진전 메커니즘)

  • Lim, Dong-Young;Park, Herie;Jee, Seung-Wook
    • Fire Science and Engineering
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    • v.33 no.2
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    • pp.30-38
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    • 2019
  • Tracking, which is one of the main causes of electrical fires, is perceived as a physical phenomenon of electrical discharge. Hence tracking should be explained based on electric field analysis, conduction path by electron generation, and gas discharge physics. However, few papers have considered these details. This paper proposes a tracking mechanism including their effects on tracking progress. In order to prove this mechanism, a tracking experiment, an electric field analysis for the carbonization evolution model, and an explanation of the tracking process by gas discharge physics were conducted. From the tracking experiment, the current waveforms were measured at each stage of the tracking progress from corona discharge to tracking breakdown. The electric field analysis was carried out in order to determine the electric field on the surface of a dry-band and the high electric field region for electron generation during the generation and progress of carbonization. In this paper, the proposed tracking mechanism consisted of six stages including electron avalanche by corona discharge, accumulation of positive ions, expansion of electron avalanche, secondary electron emission avalanche, streamer, and tracking by conductive path. The pulse current waveforms measured in the tracking experiment can be explained by the proposed tracking mechanism. The results of this study will be used as the technical data to detect tracking phenomenon, which is the cause of electric fire, and to improve the proof tracking index.

Structure Improvement of Preaction Valve to Reduce the Pressure Drop (압력손실을 줄이기 위한 준비작동식 유수검지장치 본체 구조 개선)

  • Hong, Seung-Tae;Jeong, Jae-Han;Nam, Jun-Seok;Kwon, Young-Kyu;Han, Chul-Su;Yoo, Seung-Joon
    • Korean Chemical Engineering Research
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    • v.53 no.1
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    • pp.16-21
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    • 2015
  • The body structure of diaphragm type preaction valve was improved in order to reduce the pressure drop. The pressure drop must be kept within 20.7 kPa to pass the revised (2012. 2. 9) standard for alarm valve and preaction valve. The pressure drop test was carried out by KFI (Korea Fire Institute) standard. The pressure drop of a preaction valve was higher than that of an alarm valve. Causes for increasing the pressure drop were investigated with the fluid flow in the valve. The preaction valve had more pressure drop factors (changes in velocity and direction) compared with the alarm valve. Inner structure of the preaction valve was changed to the clapper type to remove the pressure drop factors. In 80A and 100A size of preaction valves, the pressure drop was reduced from 80.9 and 171.0 kPa to 14.4 and 14.2 kPa respectively, after the change of the structure.

A Study on the Characteristics of Organic Insulating Materials Carbonized by a Leakage Current (누설전류에 의하여 탄화된 유기절연재료의 특성에 대한연구)

  • Park, Sang-Taek;Roh, Young-Su
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.2
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    • pp.161-167
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    • 2009
  • Organic insulating materials which are utilized as insulating materials for the low voltage show unique carbonization characteristics when they are carbonized by a leakage current. Therefore the use of the carbonization characteristics makes it possible to examine the electrical fire which is caused by a leakage current flowing on the surface of the organic insulating material. In order to understand such carbonization characteristics, in this paper, experiments have been done to carbonize typical organic insulating materials such as phenol resin, PVC, and acrylic resin, and the carbonization patterns and the IR absorption spectrum of specimens have been analyzed. According to the analysis of the carbonization patterns, the phenol resin shows the so-called 'spider-leg' carbonization pattern due to a thermosetting property. In contrast to the phenol resin, the thermoplastic property makes it difficult to observe a clear carbonization pattern to verify carbonizing causes on the surfaces of PVC and acrylic resins. In this case, the IR absorption spectrum can be analyzed to examine the specimen carbonized by a leakage current. The analysis result shows that absorption peaks appear at the wave numbers of $3,400[cm^{-1}]$ and $1,618[cm^{-1}]$, which can be an important factor to verify the carbonizing causes.