• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.516-525
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• 2010

전기화재란 전기를 사용함에 있어 불안전하게 사용하여 전기가 점화원이 되어 발생하는 화재를 총칭하는 것으로 그동안 발생한 전기화재의 주요원인을 살펴보면, 단락(短絡 Short), 과부하(過負荷 Over load), 누전(漏電, Leakage current), 접속불량(接續不良, Bad connection), 정전스파크(spark), 트래킹(Tracking)이 주요원인으로 분석되었다. 전기화재에 의한 현장조사는 통전을 입증하는 것이 제일 중요한 관건이 되는 것이지만 화재로 많은 것들이 소실된 현장에서 이를 규명하기란 결코 쉬운 일이 아니다. 따라서 본 논문에서는 전기화재가 일반화재와 다른 주요 특징을 고찰하고 전기화재를 입증하기 위해 필요한 주요 발생요인에 대하여 관찰요령을 고찰하였다.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.20-27
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• 2014

Cooling equipment is the frequent occurrence of fire despite the absence of the heating element. National fire statistics in 2013 show that a total of 263 fires occurred in the cooling equipment and the number of electric fan has 145 fire cases. This is accounted for 55.1% of the whole. Electric fan is the electrical appliance that the heat is generated on the winding wire and the iron core. If such characteristic is not controled properly, fire would break out at the electric fan. also there is a gap filled with an insulator between connection terminals of the capacitor in the electric fan. But in case that the gap on the capacitor is covered with some conductive material such as dust, there would be a fire as well caused by electrical heating locally. Although many studies related with those have been conducted, electric fan fire is continuously occurred. In this study, thermal characteristics and current signal in various conditions such as the heat generation of windings including iron cores of the motor and the dielectric breakdown of terminals on the capacitor connected to the motor were detected. In order to measure the maximum temperature, "third level" wind velocity button was pushed and the time selection switch to "continuation" was set. Analyzed data would be available for the fire safety of the electric fan.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.26-31
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• 2015

This paper describes the characteristics of voltage drop and thermal for poor connection on electrical connector of circuit breaker in control box of small size pulverizer. In order monitor, we did the changes of RMS in voltage and temperature value with video and made normal state over $2.5N{\cdot}m$ and poor connections state below $0.2N{\cdot}m$ by screw gage. In case of voltage signal, the voltage drop was increased when the current was increased due to poor connections. In case of temperature signal, the temperature difference indicates ten times at 5A and fourteen times at 15A in the normal state. According to increase thermal energy, the insulation of electrical wiring and connector of circuit breaker can be carbonized. The results of this study will be useful to the development of preventive devices and system for electric fire by poor connection at small size pulverizer.

• Fire Science and Engineering
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• v.32 no.3
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• pp.134-139
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• 2018

Extremely fine particles seriously affect people and are becoming a social problem. Conventional methods using the type of beta ray absorption are difficult to have real-time measurements and miniaturization for the acquisition of fine dust. In this paper, a light scattering method was used. The sensors were configured internally with semiconductor laser diodes for miniaturization, low cost and lightweight. The use of the FFT method makes it easier to separate fine dust according to size compared to conventional light scattering sensors. Bluetooth communication also allows the connection, monitoring and control of devices using smart phones.

• International journal of steel structures
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• v.18 no.4
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• pp.1139-1152
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• 2018

Many studies on the application of stainless steels as structural materials in buildings and infra-structures have been performed thanks to superior characteristics of corrosion resistance, fire resistance and aesthetic appeal. Experimental investigation to estimate the ultimate strength and fracture mode of the fillet-welded connections of cold-formed austenitic stainless steel (STS304L) with better intergranular corrosion resistance than that of austenitic stainless steel, STS304 commonly used has carried out by authors. Specimens were fabricated to fail by base metal fracture not weld metal fracture with main variables of weld lengths according to loading direction. All specimens showed a block shear fracture mode. In this paper, finite element analysis model was developed to predict the ultimate behaviors of welded connection and its validity was verified through the comparison with test results. Since the block shear behavior of welded connection due to stress triaxiality and shear-lag effects is different from that of bolted connection, stress and strain distributions in the critical path of tensile and shear fracture section were investigated. Test and analysis strengths were compared with those by current design specifications such as AISC, EC3 and existing researcher's proposed equations. In addition, through parametric analysis with extended variables, the conditions of end distance and longitudinal weld length for block shear fracture and tensile fracture were suggested.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.54-64
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• 2006

Rapid development of Information Technology(IT) requires new changes in overall official sections, and government also makes effort to promote the productivity and efficiency of official sections with IT. Objectives of this research are to evaluate the management of Electronic Approval System and to present the efficient way of using Electronic Approval System. In this research, we presented that the efficient use of Electronic Approval System requires systematic education, improvement of approval procedure, stability of system, improvement of system operation speed and connection with other official department.

• The Korean Journal of Emergency Medical Services
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• v.17 no.3
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• pp.29-37
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• 2013

Purpose: The purpose of this study is to investigate how empowering leadership effects on growth needs and turnover intentions to emergency medical technicians. Methods: The study was based on seventy six paramedics and seventy EMTs-basic who were working at the fire stations. A survey questionnaire was used to prove connection between empowering leadership, growth needs, and turnover intentions. Results: There was a positive correlation between empowering leadership and growth needs, and negative correlation between empowering leadership and turnover intentions. There was a positive correlation between emergency medical technicians growth needs and turnover intentions. Conclusion: This analysis is empirically applied to study the empowering leadership focused on the empowerment act of leader to a leading role to empowerment in fire service organization.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.1-10
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• 2008

A transient 3-D numerical simulation was performed to analyze the fire safety in a railway tunnel equipped with a mechanical ventilation system. The behavior of pollutants was studied for the emergency operation mode of ventilation system in case of fire in the center of the rescue station and near the escape route. Various schemes of escape route construction for connection angle($45^{\circ}$, $90^{\circ}$, 135^{\circ}$) and slope($10^{\circ}$) were evaluated for the ventilation efficiency in the fire near the escape route. From the results, it was shown that the mode of the ventilation fan operation which pressurizes the tunnel not under the fire and ventilates the smoke from the tunnel under the fire is most effective for the smoke control in the tunnel in case of the fire occurrence. It was also shown that the blowing of jet fan from the rescue tunnel to the main tunnel should be in the same direction as the flow direction in the main tunnel arising from the traffic and the buoyancy.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.435-443
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• 2020

The objective of this study was to determine the effective compressive strength of a column-slab connection with different compressive strengths between the column and slab concrete. A total of eight column specimens were fabricated, among which four specimens were restrained by slabs while the others did not have any slab, and the test results were compared with current design codes. According to ACI 318, the compressive strength of a column can be used as the effective compressive strength of the column-slab connection in design when the strength ratio of column concrete to slab concrete is less than 1.4. Even in this case, however, this study showed that the effective compressive strength decreased. The specimen with its slab-column connection zone reinforced by steel fibers showed an increased effective compressive strength compared to that of the specimen without the reinforcement, and the interior column specimens restrained with slabs reached the compressive strength of the column.

• Steel and Composite Structures
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• v.2 no.4
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• pp.247-258
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• 2002

The high-temperature material properties of steel are very important to the fire resistance analysis of high-strength bolt connections. This paper reports on the results of the experimental studies on the high-temperature properties of 20 MnTiB steel which is widely used in high-strength bolts, and the friction coefficient of 16Mn steel plates at elevated temperature which is a necessary parameter for bolted frictional connection analysis. The test data includes yield strength, limit strength, modulus of elasticity, elongation and expansion coefficient of 20MnTiB steel at elevated temperature, and the friction coefficients between two 16Mn steel plates under elevated temperatures and after cooling. Based on the data from the tests, the mathematical models for predicting the mechanical properties of 20MnTiB steel and friction coefficients of 16Mn steel plates have been established.