• 한국화재소방학회논문지
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• 제33권6호
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• pp.126-131
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• 2019

과열방지장치가 없는 가스레인지를 이용하여 동물성 식품의 실물 화재 실험을 실시하였다. 동물성 식품의 연소 초기에는 흰색의 연기와 수증기가 다량 발생했으나 물기가 없어지고 동물성 식품의 탄화가 시작되면 검정색 연기가 발생하였다. 가스레인지의 과열 시간이 5,400 s가 경과되어도 고등어, 명태 및 닭고기 등은 착화되지 못했다. 그러나 돼지고기는 2,643 s, 쇠고기는 2,819 s, 참치는 6,492 s에서 발화되는 것을 확인하였다. 동물성 식품의 화염 패턴은 층류와 난류가 혼합된 형태이며, 달무리 패턴(Halo Pattern)이 발생하는 것을 알 수 있었다. 주방 후드가 작동할 때의 화염은 모래시계 패턴을 형성하였고, 주방 후드가 작동하지 않을 때는 삼각형 패턴을 나타냈다. 냄비에 담긴 참치가 과열되면 6,492 s에 자연발화 되었고, 주방 후드의 표면 온도는 464.5 ℃로 급격히 상승하였다. 그리고 냄비 상부의 바깥 표면으로부터 6 cm 이격된 냄비 후면의 온도는 6,660 s에 복사열로 인해 869 ℃로 측정되었다. 화염에 의해 소손된 주방 벽면에는 모래시계 패턴이 형성되었으며, 주방 후드가 작동하지 않거나 천장 높이보다 화염이 작게 성장할 때는 삼각형 패턴을 나타내는 것이 확인되었다.

• 한국안전학회지
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• 제28권2호
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• pp.21-25
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• 2013

The purpose of this study is to provide basic data for the safety assessment of a water purifier when water leaks due to inappropriate maintenance and the examination of the cause of accidents related to the leak. Due to its inspection and management by non-specialists, if a leak occurs in a water purifier with the water level controller being inclined, it may result in the failure of the compressor, power supply line, PCB, etc. The analysis of the thermal diffusion pattern of water purifier compressors using a thermal image camera shows that its maximum temperature was approximately $80^{\circ}C$. In addition, its operating current was a maximum of 13 A and the system's operating current was approximately 1.7 A after the compressor was charged. It was found that the housing type power cable cover of the compressor had the effect of preventing electric shock but has poor flame resistance. Furthermore, the performance of the overload protector, PTC relays, etc., was excellent but they have potential for problems as metallic terminals were exposed, resulting in the potential of a safety related accident. The terminals and their surface damaged by the tracking showed a trace of carbonization and the resistance between terminals was measured to be approximately $8{\Omega}$. In addition, while the tracking was proceeding, the fuse and circuit breaker installed for system protection did not operate.

• 한국화재소방학회논문지
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• 제24권5호
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• pp.136-141
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• 2010

본 연구에서는 옥내 조명 설비의 전원을 ON/OFF 하기 위해 사용되는 저압용 스위치의 구조 및 발열 메커니즘을 제시하고, 에너지원의 종류에 따라 스위치의 고정금구 및 가동 접점 등의 소손패턴을 제시함으로써 향후 예상되는 PL 분쟁의 판단 근거를 확보하는데 있다. 스위치에 인가된 일반 화염은 한국산업규격(KS)의 난연성 시험 방법을 적용하였다. 또한 스위치에 공급된 전류는 대전류공급장치(PCITS)를 이용하였다. 실험이 진행될 때 주위의 온도는 $22{\pm}2^{\circ}C$, 습도는 40~60%를 유지시켰다. 스위치의 발열은 배선과 클립의 접속 불량, 가동 접점의 절연 열화 및 접촉 불량 등에 의해서 생성되는 것으로 판단된다. 일반 화염에 의해 소손된 스위치는 표면이 균일하게 탄화되었으며, 화원을 제거하면 자연 소화되었다. 일반화염에 의해 탄화된 스위치를 분해한 결과 고정금구 및 가동 접점 등은 비교적 양호한 형태를 보였으나 외함, 클립 지지대, 가동 접점, 표시램프 등에서 탄화 및 변색을 확인할 수 있었다. 과전류에 의해 소손된 스위치는 배선을 연결하는 클립 및 클립 지지대 등은 소손의 흔적이 거의 없으나 고정금구, 가동 접점, 표시 램프 등은 심하게 탄화되었다. 즉 접촉 저항이 큰 부분에서 집중적으로 소손되었고 내부에서 외부로 탄화가 진행되는 패턴을 나타냈다. 따라서 소손된 스위치의 탄화 패턴 및 금속 금구류의 특성을 분석하면 최초의 에너지원 판정이 가능하다.

• 전기학회논문지P
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• 제59권4호
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• pp.462-466
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• 2010

The purpose of this study is to evaluate the safety of a wire connector fabricated for the effective installation of a lighting fixture including its contact resistance, insulation resistance, withstanding voltage characteristics, etc., and to provide the basis for the analysis and judgment of PL(Product Liability) dispute by presenting a damage pattern due to a general flame and overcurrent. This study applied the Korean Standard (KS) for the incombustibility test of the connector using a general flame and performed an overcurrent characteristics test of the connector using PCITS (Primary Current Injection Test System). The contact resistance of the housing connector was measured using a high resistance meter and the insulation resistance was measured using a multimeter. In addition, a supply voltage of AC 1,500V for testing the withstanding voltage characteristics was applied to both ends of the connector. Measurement was performed on 5 specimens and the measured values were used as a basis for judgment. Since the connector is fabricated in the form of a housing, it can be connected and separated easily and has a structure that allows no foreign material to enter. In addition, since it has a structure that allows wires to be connected only when their polarity is identical, any misconnection that may occur during installation can be prevented. When the incombustibility test was performed by applying a general flame to the connector, it showed outstanding incombustibility characteristics and the blade and blade holder connected to the housing remained firmly secured even after the insulation sheath (PVC) was completely destroyed by fire. In addition, the mechanism of the damaged connecting wire showed a comparatively uniform carbonization pattern and it was found that some residual melted insulation material was attached to both ends. In the accelerated life test (ALT) to which approximately 500% of the rated current was applied, the connector damage proceeded in the order of white smoke generation, wire separation, spark occurrence and carbonization. That is, it could be seen that the connector damaged by overcurrent lost its own metallic color with traces of discoloration and carbonization. The contact resistance of the connector at a normal state was 2.164mV/A on average. The contact resistance measured after the high temperature test was 3.258mV/A. In addition, the insulation resistance after the temperature test was completed was greater than $10G\Omega$ and the withstanding voltage test result showed that no insulation breakdown occurred to all specimens showing stable withstanding voltage and insulation resistance characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.335-338
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• 2001

With the use of the electron microscopy and X-ray phase analysis the regularities of carbon deposit formation in process of methane and propane pyrolysis on the zeolites, Kazakhstan natural clays, chrome and bauxite sludge containing metal oxides of iron subgroup, have been studied. In process of over-carbonization the trivalent iron was reduced to metal form. In addition, the carbon tubes of divers morphology had been impregnated with ultra-dispersed metal particles. The kinetic parameters of carbon formation in process of methane decomposition on the zeolite CoO mixture surface were investigated by method of thermo-gravimetric analysis. The morphology and structure of formed carbon fibrils, with the metal particles fixed at their ends, have been investigated, the formation of branched carbon fibrils pattern, so called octopus, being found.

• 한국화재소방학회논문지
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• 제28권5호
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• pp.8-13
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• 2014

본 연구에서는 대전류공급장치시스템(PCITS)을 이용하여 열동전자식 배선용차단기(MCCB)에 과전류를 인가하였을 때 소손된 패턴을 해석하는 데 있다. MCCB의 트립바가 소손된 상태에서 PCITS로 과전류 150 A를 5 s 동안 흘렀을 때 우측에 위치한 온도 조절 장치의 표면이 심하게 탄화되었다. 동일한 조건에서 300 A의 과전류를 5 s 동안 흘렸을 때 온도 조절 장치의 전체가 열화(劣化)되어 납작하게 밀착되었다. 과전류 450 A를 5 s 동안 흘렸을 때 온도 조절 장치의 코일은 융융 및 단선이 발생하였다. 또한 접점, 외함 및 상부 덮개 등에서 탄화 흔적 및 변형이 확인되었다. 과전류600 A를 공급하고 3 s 정도가 경과되었을 때 MCCB의 내부에서 흰색 연기가 발생하였고, 불꽃이 외부로 방사되었다. 그리고 탁(딱)하는 소리와 동시에 과전류의 공급이 중단되었다. 동일한 MCCB를 일반 화염으로 소손시켰을 때 작동 손잡이, 단자, 소호 장치 및 온도 조절 장치 등의 표면에 탄화가 고르게 형성된 것을 알 수 있다. 또한 작동 기구부의 트립바는 녹아 흘러 내렸으며, 작동 금속핀은 트립 상태로 이동된 것이 확인된다.

• 한국화재소방학회논문지
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• 제25권6호
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• pp.21-26
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• 2011

본 논문에서는 에너지원에 따른 이동전화기(SCH_W830) 배터리의 소손 패턴을 제시함으로써 소비자분쟁 해결의 자료로 활용하고자 한다. 실험이 진행될 때의 주위 온도는 $22{\pm}2^{\circ}C$, 습도는 40~60 %를 유지함으로써 신뢰성을 확보하였다. 실험에 사용된 이동전화기의 배터리 전압은 양극(+)과 음극 (1)(-) 사이의 전압은 4.19 V이며, 양극(+)과 음극 (2)(-) 사이의 전압은 4.18 V로 측정되었다. 일반화염 인가에 의한 이동 전화기의 난연성 시험은 한국산업규격(KS)을 적용하였으며, 일반화염이 30 sec 동안 외함에 인가되어도 내장된 배터리의 소손은 없는 것으로 확인되었다. 생리 식염수(NaCl, 0.9%)에 이동전화기를 180 sec 침수시킨 결과 배터리 단자 사이에 누설전류에 의한 발열로 탄화 및 용융이 발생한 흔적을 확인할 수 있었다. 전자레인지(MWO)를 이용하여 70 sec 동안 이동전화기를 가열하면 금속홀더, 충전용 커넥터, 안테나 등이 내장된 부분에서 용융 및 변색이 확인되며, 그 밖의 부분은 특이사항이 없는 것을 알 수 있다. 즉, 인가된 에너지원의 종류에 따라 이동전화기 외형의 탄화, 내장된 금속 및 유전체, 배터리 단자대의 손상 및 변형 등이 다르게 발생하지만 전압은 비교적 일정한 특성을 보이는 것으로 보아 연소의 확산 패턴, 금속의 용융 및 변형 부분의 특성을 종합적으로 고려하여 해석하면 소손 원인 판정이 가능하다.

• 한국안전학회지
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• 제28권3호
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• pp.69-73
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• 2013

The purpose of this paper is to analyze the carbonization pattern and operation characteristics of an MCCB. The MCCB is consisted of the actuator lever, actuator mechanism, bimetallic strip, contacts, up and down operator, arc divider or extinguisher, metal operation pin, terminal part, etc. When the actuator lever of the MCCB is at the top or the internal metal operation pin is in contact with the front part, the MCCB is turned on or off. It means trip state if the actuator lever or the internal metal operation pin moves to back side. In the UL 94 vertical combustion test, white smoke occurred from the MCCB when an average of 17~24 seconds elapsed after the MCCB was ignited and black smoke occurred when an average of 45~50 seconds elapsed. It took 5~6 minutes for the MCCB surface to be half burnt and took an average of 8~9 minutes for the MCCB surface to be entirely burnt. In the UL 94 test, the MCCB trip device operated when an average 7~8 minutes elapsed. If the MCCB trip has occurred, it may have been caused by an electrical problem such as a short-circuit, overcurrent, etc., as well as fire heat. From the entire part combustion test according to KS C 3004, it was found that the metal operation pin could be moved to the MCCB trip position without any electrical problems.

• 한국안전학회지
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• 제30권6호
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• pp.40-47
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• 2015

In this study, temperature characteristics and fire damage form were analyzed to investigate flame spreading form and fire probability from ignition sources subject to drivit component materials which is finishing material in architecture. Ignition sources were limited to a gas torch and exterior panel board fire, and the size of the sample was manufacture in 30 cm length ${\times}$ 50 cm height ${\times}$ 5cm thickness size. Marble (inner wall) + 3 mm drivit (outer wall), marble (inner wall) + 4 mm plaster stone (outer wall), sandwich panel + 3 mm driver bit (outer wall), sandwich panel + 3 mm driver bit + insulation (outer wall), and gypsum board (inner wall) + 3 mm drivit (outer wall) were prepared for the sample. As result of the research for temperature characteristics, large temperature difference by each material was shown in $218^{\circ}C{\sim}995^{\circ}C$ at 30 seconds and $501^{\circ}C{\sim}1078^{\circ}C$ at 300 seconds. Especially when the inner wall was a plaster board, lowest temperature of $501^{\circ}C$ was shown at 300 seconds and marble inner wall showed the following lowest temperature of $900^{\circ}C$. Temperature rising over $1000^{\circ}C$ was shown in other materials. Regarding fire damage form, drivit or gypsum board outer wall parts exposed to fire showed combustion and carbonization to show calcination(breaking phenomenon) and influence of heat exposure was higher as calcination became more severe.

• 한국안전학회지
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• 제25권6호
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• pp.86-91
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• 2010

The purpose of this study is to analyze the damage patterns and metal structure of 3 phase mold transformers collected from places where accidents have occurred. Compared to an oil-immersed transformer, a mold transformer has the advantage of requiring a smaller installation area and can be kept clean, while its disadvantages include the fact that abnormal symptoms of an accident are difficult to discover and its repair is impossible. The capacity of the mold transformers collected from places where accidents have occurred was 200kVA with primary voltages being F23,900V, R22,900V, 21,900V, 20,900V, 19,900V, etc., as well as secondary voltages being 380V, 220V, etc. It was found from the analysis on the diffusion of combustion in the damaged mold transformers that fire occurred first inside the U-phase primary winding and that carbonization and heat were diffused to V-phase and W-phase in V-pattern. In addition, from the analysis on the cross-sectional structure of the metal of the melted high voltage winding using a metallurgical microscope, it was found that the boundary surface, voids, and columnar structure were formed when an interlayer short-circuit had occurred Therefore, even though it is not possible to find the cause for the occurrence of an interlayer short-circuit at the inner side of the primary winding, it is thought that, due to the thermal energy generated when the short-circuit occurred, the heat source was diffused to the upper side and outside, causing a secondary accident.