• 한국화재소방학회논문지
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• 제32권5호
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• pp.67-76
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• 2018

소화활동설비 중 연결송수관설비는 출동한 소방대가 소화용수를 공급하는데 화재현장 활동에서 그 어떤 설비보다 중요하다. 본 연구에서는 연결송수관설비 화재안전기준(NFSC 502)을 바탕으로 연결송수관설비가 설치된 아파트에 대한 연결송수구 설치 위치를 조사하였다. 소방대원이 아파트에 설치된 연결송수관설비 송수구를 알고 있는 경우와 모르고 있는 경우 그리고 주간과 야간을 나누어 연결송수관설비 송수구 발견 시간을 측정하여 보았다. 실험결과를 바탕으로 소방대가 출동하여 활용하는 본격 소화설비인 연결송수관설비의 활용 극대화를 위하여 연결송수관 설치 위치에 대한 명확화 및 위치안내도 표지판 설치 등 연결송수관설비 화재안전기준(NFSC 502)에 대한 개선안을 제안하고자 한다.

• 국제초고층학회논문집
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• 제7권4호
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• pp.343-362
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• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.

• 대한안전경영과학회지
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• 제18권4호
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• pp.11-17
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• 2016

Currently, the number of a shopping center building is increasing because most people want to go a shopping center building easily for buying many things and eating some foods. That are a normal trend these days. However, the increasing number of shopping center buildings has been increasing the number of shopping center building fires which also have been making social problems. Therefore, this study was conducted for the fire department connection among other fire facilities because it is important for fire suppression. The research subject is on the fire department connections that are on 70 shopping center buildings of more than 5 years old constructed. Survey and analysis were conducted for 70 fire department connections. The result of this study is that all installed fire department connections have a type that includes one or two holes each at 65mm wide, and the average distance between fire department connections and access roads is 4.85m. The total average percentage of insufficiency conditions such as drive ways for fire trucks, visibility, accessibility, pressure range sign, installed height, cover of the hole, etc. is 45.3%. So improvement of law and systems, that are fire facility construction and maintenance implementations, will be needed in my opinion.

• Safety and Health at Work
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• 제7권4호
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• pp.284-292
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• 2016

Background: In Ghana, fire incidents have become a regular occurrence, with thousands of lives and millions of dollars lost every year. Hardly a day passes without news of a fire outbreak in some part of Ghana, causing fear and panic among the people. This generates much discussion centering on rumors relating to politics, sabotage, misfortune, religious differences, etc. This article seeks to discuss the trend of fire incidents occurring in Ghana from 2000 to 2013 and the different ways to prevent these incidents. Methods: The pattern of fire incidence in Ghana as a whole as well as in each region is discussed. The study took into consideration the causes, mechanisms, as well as preventive measures against the fire menace. Data were obtained from the head office of Ghana's national fire service. Results: It was noticed that in general the rate of fire incidence increased each year. This increase was attributed to several factors: rate of population growth and industrialization, unstable electricity, urbanization, negligence, illegal electrical connection, etc. The cause of fire was categorized into domestic, industrial, vehicular, institutional, electrical, commercial, bush, and others. Among these causes, domestic fire accounted for 41% of the total number of fire incidents in the country. Conclusion: Finally, this study presents several recommendations to help prevent and mitigate fire incidents in Ghana.

• Steel and Composite Structures
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• 제5권2_3호
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• pp.193-202
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• 2005

This paper describes recent developments in composite construction and their effect on codified design procedures in the UK. Areas of particular interest include: rules on shear connection, design of beams with web openings, serviceability limits, such as floor vibrations, and fire safe design. The design of cellular beams with regular circular openings now includes generalized rules for web-post buckling, and for the development of in-plane moment in the web-post for asymmetric sections. Closed solutions for the maximum shear force due to limits on web-post bending or buckling are presented. The fire resistance of cellular beams is also dependent on the temperature of the web-post, and for closely spaced openings. It is necessary to increase the thickness of fire protection to the web. For serviceability design of beams, deflection limits and natural frequency and response factor for vibration are presented. It may be necessary to use stricter limits for certain applications.

• Advances in concrete construction
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• 제6권2호
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• pp.177-197
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• 2018

This paper presents a case study about the damages on the structural elements of a cast in place reinforced concrete (RC) building after a big fire which was able to be controlled after six hours. The fire broke off at the $2^{nd}$ basement floor of the building, which has five basements, one ground, and two normal floors. As a result of intensely stocked ignitable materials, it spread out to the all of the upstairs. In visual inspection, most of the typical fire damages were observed (such as spalling, net-like cracks, crumbled plasters, bared or visible reinforcement). Also, failures of the $2^{nd}$ basement columns were encountered. It has been concluded that the severity failures of the columns at the $2^{nd}$ basement caused utterly deformation of the building, which is responsible for the massive damages on the beam-column connections. All of the observed damages were categorized related to the types and presented separated regarding the floors. Besides to the visual inspection, the numerical analysis was run to verify the observed damaged on the building for columns, beams, and the connection regions. It is concluded from the study that several parameters such as duration of the fire, level of the temperature influence on the damages to the RC building. Also, it is highlighted by the study that if the damaged building is considered on the overall structural system, it is not able to satisfy the minimum service requirements neither gravity loads nor earthquake conditions.

• 한국안전학회지
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• 제38권3호
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• pp.27-34
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• 2023

With the technological development of the semiconductor industry, the roles of electrical and thermal energy supply and control of semiconductor equipment in ultrafine processes have become very important. However, instances of electrical fires in the chiller heater, which is used for cooling in the semiconductor manufacturing process, are increasing. A fire occurs in combustibles due to high heat at the connection part of the chiller heater, that is, when the number of electrical wires in the connection part is reduced or when the wires are completely disconnected. In this study, the temperature characteristics were compared and analyzed through experiments and 3D simulations. The number of electrical wires, which is the connection part of the chiller heater, was reduced by 90%, 50%, 30%, 10%, and 5%, and the wires were completely disconnected. When the number of electrical wires was reduced by 5%, heat of up to 80℃ was generated, which is a relatively high temperature but insufficient to cause a fire in combustibles. Complete disconnection occurred due to the vibration of the motor and other components, and sparks and arcs were generated, resulting in a rapid increase in temperature to up to 680℃. When completely disconnected, the temperature increase was sufficient to cause a fire in the combustibles covering the terminal block. Therefore, in this study, the causes of electrical fires in chiller heaters were investigated and preventive measures were proposed by analyzing abnormal signals and thermal characteristics caused by the electrical wiring being reduced and completely disconnected.

• 한국안전학회지
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• 제27권3호
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• pp.57-62
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• 2012

The purpose of this paper is to find dangerous factors of a water purifier when water leaks due to inappropriate use and analyze the patterns of damaged parts in order to provide data for the examination of the cause of the problem. If the water purifier is inspected and managed by a non-specialist, when the FLC(Float Level Controller) at the top is inclined, water leakage may occur to the water purifier. The leaked water flows onto the cables and hoses and enters the thermostat terminal, heater, PCB, power supply connection connector, etc., becoming a dangerous factor that may cause a system failure, fire, etc. Due to the water that entered the input terminal, low noise and white smoke were generated at first. However, the flame gradually propagated due to the continuous inflow of moisture. It was found that when moisture reached the PCB, a carbonized conductive path was formed at the varistor terminal, input terminal, semiconductor device terminal, etc., and the flame became larger, which might result in a fire. From the metal microscope analysis of a damaged condenser terminal, it was found that the amorphous structure unique to copper cable disappeared, and voids, boundary surface and disorderly fine particles occurred. Also, in the case of the connector into which moisture penetrated, fusion and deformation occurred at the cable connection clips. The result of analysis of the power supply cable connector using a thermal image camera showed that most of the heat was generated from the cable connection clips and the temperature at the connection center was normal.

• Steel and Composite Structures
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• 제8권3호
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• pp.243-264
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• 2008

This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

• Earthquakes and Structures
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• 제26권1호
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• pp.49-58
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• 2024

The purpose of this study was to develop a system capable of restoring the seismic performance of a precast concrete (PC) connection damaged by an earthquake. The developed PC connection consists of a top-and-seat angle, post-tensioning (PT) tendons, and U-shaped steel. The PC beam can be replaced by cutting the PT tendons in the event of damage. In addition, the seismic performance of the developed PC beam-column connection was evaluated experimentally. A PC beam-column connection specimen was fabricated, and a quasistatic cyclic loading test was conducted to a maximum drift ratio of 2.3%. Subsequently, the PC beam was replaced by a new PC beam, and the repaired PC connection was loaded to a maximum drift ratio of 5.1%. The structural performance of the repaired PC connection was then compared with that of the original PC connection. The difference in the load at the drift ratio of 2.3% between the original and the repaired PC specimens was only 0.2%. The residual drift ratio in the repaired PC specimen did not exceed 1.0% at the 2.0 % drift ratio cycles, which satisfies the life safety performance level specified in ACI 374.2R-13. When the developed PC connection system is used, structural performance can be restored by rapidly replacing the damaged elements.