• Title/Summary/Keyword: fire accidents

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Analysis of Sheath Temperatures and Load Currents Dependent on Conductor Temperatures in Live 6kV CV Cables Operating at a Power Station (발전소에서 운전 중인 활선 6 kV CV 단심 cable의 도체온도에 따른 피복 표면온도 및 부하전류 특성 분석)

  • Um, Kee-Hong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.3
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    • pp.189-195
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    • 2017
  • The only method used in the power stations in order to deliver generated electric power is 6 kV XLPE (or CV) single core cables. Among many kinds of accidents happening in the power stations, the outbreak of fire due to the deterioration of live cables causes enormous socioeconomic losses. From the installation of the cables, the management and diagnose should be thoroughly made. Even though it differs depending on the installations and usage conditions, the cross-sectional area of cables is in shortage. The excessive allowable temperature caused from the current causes the deterioration of cables. In order to prevent an unexpected breakdown of live cables, we have invented a device to monitor and diagnose the status of cables. We have installed our device in the Korea Western Power Co., Ltd.. In this paper, we present our research results in situ that we have obtained by measuring the temperature of sheath, changing with the surrounding circumstances, especially ambient temperatures. We also show our study results of characteristics for temperature of sheath surface and load current at the ambient temperatures of $40^{\circ}C-10^{\circ}C$.

Secondary Traumatic Stress(STS) and related factors of Emergency Medical Technicians (응급구조사의 이차 외상성 스트레스 정도와 관련요인)

  • Choi, Hee-Jeong;Park, Jeong-Mi;Suh, Soon-Rim
    • The Korean Journal of Emergency Medical Services
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    • v.13 no.2
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    • pp.5-15
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    • 2009
  • Purpose : This study was to examine the secondary traumatic stress(STS) and related factors of emergency medical technicians. Methods : This study was conducted among 190 emergency medical technicians, over the age of 25, with the 1st or 2nd grade qualification, who serve at fire stations in U and P city of Korea. The collected data for this study was analyzed using SPSS 12.0. Result : The average character type of A-type personality technicians was 43.25 points and the average of B-type personality technicians was 37.82 points. It suggested that the former was higher than the latter. State anxiety did not show statistically significant difference between A-Type group and B-Type group with the score of 48.51 for A-Type and 47.91 for B-Type. Physical symptoms showed statistically significant difference between the two groups with the higher score of 28.45 for A-type group than that of 28.13 for B-Type group. The level of STS related to the volunteers' job characteristics was found to be low when the volunteers were satisfied with their job and didn't want to transfer to another division. Those on duty who had slept more than seven hours that day had the highest points. The number of points was highest when the frequency for the onset of trauma was between 20~30 times. Furthermore it was found that for most technicians, 71.05%, the period of symptoms lasted for a few weeks at most, and this was where the STS was the lowest, whereas on the other hand the highest STS occurred when the symptoms lasted for a period of up to six months. The findings showed significant correlations with a relation of r=.24 between STS and level of anxiety and r=.45 between STS and physical symptoms. However, no significant correlation was found between the level of anxiety and physical symptoms. Conclusion : The more emergency medical technicians are exposed to accidents, the more serious the STS are. Those with an A-type personality are especially prone to have higher STS. The higher the STS level is, the higher the level of physical states and anxiety is.

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Change of Statical Behavior and Ultimate Capacity of Steel Cable-stayed Bridges after Cable Failure (케이블 단선 후 강사장교의 구조 및 극한 거동 변화)

  • Kim, Seung-Jun;Choi, Jun-Ho;Won, Deok-Hee;Han, Taek-Hee;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.6
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    • pp.747-761
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    • 2011
  • This paper presents an investigation on the change in the statical behavior and the ultimate capacity of steel cable-stayed bridges after cable failure. Cable failure can occur due to fire, direct vehicle clash accidents, cable or anchorage fatigue, and so on. Moreover, the cable may be temporarily disconnected during cable replacement work. When cable failure occurs, the load, that was supported by the broken cable is first transferred to another cable. Then the structural state changes due to the interaction between the girder, mast, and cables. Moreover, it can be predicted that the ultimate capacity will decrease after cable failure, because of the loss of the support system. In this study, the analysis method is suggested to find the new equilibrium state after cable failure based on the theory of nonlinear finite element analysis. Moreover, the ultimate analysis method is also suggested to analyze the ultimate behavior of live loads after cable failure. For a more rational analysis, a three-step analysis procedure is suggested and used, which consisted of initial shape analysis, cable failure analysis, and live load analysis. Using this analysis method, an analytical study was performed to investigate the changes in the structural state and ultimate behavior of steel cable-stayed bridges.

Estimation of Safety in Railway Tunnel by Using Quantitative Risk Assessment (QRA를 이용한 철도터널 방재 안전성 평가)

  • Kim, Do-Sik;Kim, Do-Hyung;Kim, Woo-Sung;Lee, Du-Hwa;Lee, Ho-Seok
    • Tunnel and Underground Space
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    • v.16 no.5 s.64
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    • pp.357-367
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    • 2006
  • Recently, as the construction of new railway and the relocation of existing line increase, tunnel structures grow longer. The railway fire accidents in long tunnel bring large damages of human life and disaster. The interest of safety in long tunnel have a growing and the safety standard of long tunnel is tightening. For that reason, at the planning of long tunnel, the optimum design of safety facility in long tunnel for minimizing the risks and satisfying the safety standard is needed. For the reasonable design of long railway tunnel considering high safety, qualitative estimation for tunnel safety is required. In this study, QRA (Quantitative Risk Assessment) technique is applied to design of long railway tunnel for assuring the safety function and estimating the risk of safety. The case study for safety design in long railway tunnel is tarried out to verifying the QRA technique for two railway tunnels. Thus, the inclined and vertical shaft for escape way and safety facilities in long tunnel are planned, and the risks of tunnel safety for each case are estimated quantitatively.

Efficient Safety Management in Inland Waters: Focused on Water Relief and Water Safety (효율적 내수면 안전관리 : 수난구호 및 수상안전을 중심으로)

  • Chung, Chul-Min;Yang, Gi-Geun
    • The Journal of the Korea Contents Association
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    • v.15 no.3
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    • pp.101-113
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    • 2015
  • This study aims to prepare countermeasures to prevent and minimize drowning accident in inland waters by examining the current status of inland water safety management in Korea and diagnosing the defects. The defects in current inland water safety management is analyzed in four aspects. First is the legal defect that includes the absence of legislation that directs the inland water safety management. Second is the instructional defect such as the absence of educational program for prevention of inland water accidents and lack of professional water rescue experts. Third is cooperation defect such as dispersed reporting system and lack of private-public partnership in accident response. Fourth is the defect of emergency response ability, professionalism and accident response skills due to the dispersion and overlaps of safety management systems. In order to improve these defects, this study finds the countermeasures based on the survey of water sports professions and users and its analysis as follows: legislation of '(tentatively named) special act for water safety management in inland waters' is suggested in the legal aspects. A development of inland waters safety education program and training of water accident experts are suggested in the instructional aspects. Integrated operational system for water accident management, activation of safety network and re-establishment of private-public partnership are suggested in the cooperation aspects. Systematic and efficient inland water safety management plans such as enhancement of accident response skills and expertise and integrated inland water safety management with fire department-centered system were suggested in the aspects of emergency response ability.

Implementation of a Dual-mode Power Strip Controller Cooperating with Smartphones Based on Environmental Sensors (환경센서에 기반한 스마트폰 연동형 듀얼모드 전원 스트립 제어기 구현)

  • Lim, Jae-Hyun;Kim, Jong-Hyun;Jang, Min-Jun;Choi, Yeon-Seung;Cheong, Ho-Young
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.465-467
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    • 2015
  • This paper implements a dual-mode power strip controller (PSCtrl) with environmental sensors which cooperates with Android-based smartphones. According to the statistics on fires in housing facilities, unidentified electrical fires account for 23.4%. In order to reduce these fire accidents caused by user carelessness and protect life and property, smart power control techniques with improved user convenience are required. For this reason, the implemented dual-mode PSCtrl controls ON-OFF operations of a power strip in two ways (e.g. manual and automatic modes) by cooperating with Android-based smartphones provided with environmental data from light, temperature, and humidity sensors. In manual mode, users check environmental data displayed on Android-based smartphones, forcibly controlling the ON-OFF operations through the dual-mode PSCtrl, and in automatic mode, when environmental data exceeds the threshold set by users in advance, the dual-mode PSCtrl automatically controls the ON-OFF operations. Some experimental tests verify successful dual-mode operations of the implemented dual-mode PSCtrl.

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A Study on Lightweight Design of Cantilever-type Helideck Using Topology Design Optimization (위상 최적설계를 활용한 캔틸레버식 헬리데크 경량화 연구)

  • Jung, Tae-Won;Kim, Byung-Mo;Ha, Seung-Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.5
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    • pp.453-460
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    • 2017
  • In the offshore industry, helicopters are mainly used for transportation of goods or operating personnel between offshore sites and onshore facilities. A helideck is a structure that is required for landing and take-off of helicopters on the offshore structure. There are several shapes of helidecks depending on the type of offshore structures or installation location. Among them, cantilever-type helidecks usually provide more space on the topside of offshore structures and it is safer against potential accidents like fire or explosion. In this paper, the cantilever-type helideck is selected for the research object and topology design optimization is applied for lightweight design of the helideck. A finite element model is then created from the optimal layout of truss structures of the helideck, and structural analysis is performed under various landing conditions and wind loads. Based on the analysis results, the detailed section dimensions of structural members are determined so that the maximum stress at each structure member does not exceed the allowable stress of the structural material. Also, the final optimal design shows significant decrease in the total weight of the helideck.

Causal Relationship between the Risk-inducing Factors and Safety Inspection and Accident Reduction in Small Construction Sites (소규모 건설현장에서 위험유발요인과 안전점검이 재해 저감 대책에 미치는 인과 관계)

  • Moon, Pil-jae;Kong, Ha-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.2
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    • pp.55-70
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    • 2020
  • This study aims to identify the influence of risk-inducing factors and safety inspection on the measures of reducing accidents among workers of building structures in small construction sites. The result can be summarized as follows: First, as for the influence of risk-inducing factors on human factors, preparation for work, disintegrating molds, taking follow-up measures, and keeping records, have statistically significant influences. Therefore, it can be said that safety inspection has a partial mediating effect in the relationship between risk-inducing factors and human factors. Second, as for the influence of risk-inducing factors on facility factors, preparation for work, and taking follow-up measures influenced significantly. This indicates that safety inspection has a partial mediating effect in the relationship between risk-inducing factors and facility factors. Third, as for the influence of risk-inducing factors on management factors, the installation of shores and risk assessment are found to have significant effects. This shows that safety inspection has a partial mediating effect in the relationship between risk-inducing factors and management factors. Fourth, the influence of risk-inducing factors on work factors was significant only in the installation of shores. This indicates that safety inspection has a completely mediating effect in the relationship between risk-inducing factors and work factors. Finally, in the relationship between risk-inducing factors and accident reduction measures, preparation for work, installation of shores, and taking follow-up measures showed significantly positive influences. In contrast, keeping records has a significant negative influence. Thus, safety inspection has a partial mediating effect in the relationship between risk-inducing factors and management factors.

Experimental Evaluation of Bi-directionally Unbonded Prestressed Concrete Panel Blast Resistance Behavior under Blast Loading Scenario (폭발하중 시나리오에 따른 2방향 비부착 프리스트레스트 콘크리트 패널부재의 폭발저항성능에 대한 실험적 거동 평가)

  • Choi, Ji-Hun;Choi, Seung-Jai;Cho, Chul-Min;Kim, Tae-Kyun;Kim, Jang-Ho Jay
    • Journal of the Korea Concrete Institute
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    • v.28 no.6
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    • pp.673-683
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    • 2016
  • In recent years, frequent terror or military attack by explosion, impact, fire accidents have occurred. Particularly, World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. Also, nuclear power plant incident on Mar. 11 of 2011. These attacks and incidents were raised public concerns and anxiety of potential terrorist attacks on major infrastructures and structures. Therefore, the extreme loading researches were performed of prestressed concrete (PSC) member, which widely used for nuclear containment vessel and gas tank. In this paper, to evaluate the blast resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, blast tests were carried out on $1,400{\times}1,000{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PSC), prestressed concrete with rebar (PSRC) specimens. The applied blast load was generated by the detonation of 55 lbs ANFO explosive charge at 1.0 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included displacement, acceleration, and strains at steel, concrete, PS tendon. The results can be used as basic research references for related research areas, which include protective design and blast simulation under blast loading.

A Study on the Confirmation of non-flammabikity of the Cast Resin Mold Transformer in Subway Substation (지하철 변전실용 진공주형형 몰드변압기의 난연성 확인에 관한 연구)

  • 정용기;장성규;곽희로
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.12 no.2
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    • pp.99-107
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    • 1998
  • This dissertationhas confirmed the non-flam mability of cast mold transformer that is increasingly used lately. As a research progress, the investigation has been performed on the installation status and each line of the subway system which have the most mold transformer accidents, and the impediment status of the transformer for rectifier and the high-voltage distribution transformer per each manufacturer. Then, a high voltage mold of the actual mold transformer has been installed in the horiwntal heating furnace and the heat has been applied by the standard heating temperature curve of KSF 2257(Fireproof testing meth od of the construction structures: 1993). Accordingly, the combustibility of the mold transformer based on the test results has been found that 78 minutes has been required for the complete burning per the KSF 2257 combustion test curve and that, after stopping the heat application of the horizontal furnace after ignition, the flame progress has not been made but shown as the self-extinguishing characteristics when the flame progress has been checked. Thus, the non-flammability and self-extinguishability of the mold transformer have been confirmed. The result of this dissertation has indicated that the accident involving mold transformer has been progressed and expanded by the dielectric breakdown or void due to the crack in the mold rather than a fire accident caused by a short-circuit or an overload.r an overload.

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