Earticle

In this paper, as there are many cases of fires occurring due to the failure or inoperability of the thermostat of electronic products, the purpose is to test and analyze the risks and probabilities through fire cases and reproduction experiments, and suggest countermeasures. Among electronic products, water purifiers are composed of a refrigerant system with a compressor to make cold water, a heating device to make hot water, and an electric device used as an energy source. Due to the nature of the water purifier manufacturing, these devices are subject to a lot of moisture and dust. etc. exist in large quantities and use electrical energy, so there is a possibility of fire due to short circuit in the wire, electrical abnormal overheating (tracking phenomenon) in the thermostat, electronic board, starting relay, etc., and overheating of the heating device (Band Heater). there is. Therefore, in order to prevent fires from these devices, a system to remove foreign substances inside the water purifier is necessary, the use of heat-resistant (fire-resistant) wires for electrical devices is essential, and the use of non-combustible materials (semi-combustible materials) for each part is necessary to prevent fire. The risk must be eliminated through prevention and combustion expansion prevention devices.

다양한 재료와 제작 조건으로 만들어진 유리들은 일부 서로 다른 물성을 지니고 있으며, 이로 인해 고대의 유리 제작 과정에서 각기 다른 특장점을 가졌을 가능성이 있다. 따라서 고대 소다 유리의 화학조성에 기반하여 유리 시편을 제작하고, 물리적 특성을 분석하였다. 시편은 안정제인 석회(CaO)와 알루미나(Al2O3)의 비율을 조절하여 6종의 소다 유리를 제작하였다. 실체현미경 관찰 결과, 석회가 많이 함유될수록 가지상의 균열이 자주 발생하며, 알루미나가 많이 함유될수록 작은 균열이 불규칙한 형태로 나타나고, blister가 많이 발생하는 경향을 확인하였다. 주사전자현미경 관찰 결과, LCHA 계열의 유리가 HCLA 계열의 유리보다 크기가 큰 seed가 더 많이 관찰되며, seed의 수도 더 많았다. 색도 측정 결과, LCHA 계열의 유리는 알루미나가 많이 함유될수록 명도가 높아지는 경향을 보였으나, 종합적으로 안정제 종류의 차이로 인한 색도 변화의 경향성은 확인되지 않았다. 따라서 자외선-가시광선 분광분석을 실시하여 안정제 함량 변화에 따른 흡광도 차이를 확인한 결과, LCHA 계열의 유리는 HCLA 계열의 유리보다 338, 437, 486, 573, 735, 740, 848, 939 nm에서 흡광도가 상대적으로 낮게 나타났으며, 따라서 미세하게 백색도가 더 높을 것으로 추정된다. 결론적으로, LCHA 계열의 유리가 HCLA 계열의 유리보다 미세 기포의 영향으로 투명도는 낮지만 점도는 높을 것으로 추정되며, 냉각 과정에서 균열 등의 파손이 적게 발생될 것이다. 유리 제작기법의 측면에서 살펴보면, 유리 구슬 제작 시 가장 많이 쓰인 Drawn기법은 상온에서의 작업 시간이 상대적으로 긴 공정인데, 급격한 온도 감소에 취약해 다량의 균열이 발생하여 제품에 결함이 생길 가능성이 높은 HCLA 계열의 유리보다 팽창률이 상대적으로 낮은 LCHA 계열의 유리가 drawn 기법에 유리했을 것으로 판단된다. 반면에 HCLA 계열의 유리는 기포가 적게 발생하며 투명도가 높으므로 작업 공정이 상대적으로 짧고 간단한 주조(Moulded)기법에 유리했을 것으로 판단된다.

Glass made with various materials and manufacturing conditions has some different properties, which may have different features in the process of making glass in ancient times. Therefore, glass specimens were produced based on the chemical composition of ancient soda glass, and physical properties were analyzed. Six types of soda glass were produced by adjusting the ratio of lime (CaO) and alumina (Al2O3), which are stabilizers. Stereo microscopy has confirmed that the more lime (CaO) is contained, the more often cracks occur and cracks on the branches, and the more alumina (Al2O3) is contained, the smaller the cracks appear in irregular form, and the tendency to develop a lot of blisters. As a result of scanning electron microscopy, more seeds were observed in the LCHA series of glasses larger in size than in the HCLA series, and the number of seeds was greater. As a result of chromaticity measurements, the glass of the LCHA series tended to increase brightness the more alumina it contained, but overall the tendency to change the chromaticity due to the difference in stabilizer type was not confirmed. Therefore, as a result of the ultraviolet-visible light spectroscopy to confirm the difference in absorption rate due to the change in stabilizer content, the glass of the LCHA series showed a higher reflectance at 338, 437, 486, 573, 735, 740, 848, 939 nm, especially than the glass of the HCLA series, and it is estimated that the whiteness is finely higher. In conclusion, it has been confirmed that the glass of the LCHA series appears to have a lower transparency to the naked eye due to the influence of microbubbles than the glass of the HCLA series, but the viscosity is high, and it is found that less breakage such as cracking occurs during the cooling process. The drawn technique most commonly used in the production of glass beads in Korea is a process in which the working time at room temperature is relatively long, and the glass of the HCLA series is vulnerable to rapid temperature reduction, which is likely to cause a large amount of cracking and defect in the product, and it is believed that the LCHA series of glass, which has a relatively low expansion rate, may have been advantageous to the drawn technique. On the other hand, HCLA-based glass generates less bubbles and has high transparency, so it is believed that the work process would have been advantageous for a relatively short and simple moulded technique.

This paper recognizes the risk of ignition of air fryer (machine that can cook fried dishes with hot air without oil) that is far exceeding the sales rate of microwave ovens, which is necessary to modern household kitchen, and identifies fire risk through the operation principle of the process of heat transfer, and the main structure of the machine. The fire test that we conducted is to observe the risk of ignition of the machine due to the damage to the safety system and the possibility of igniting oil paper along with food, to experiment with the possibility of ignition due to blockage of the exhaust due to obstacles, and accumulation of oil stains on the hot wire, and to present the method of fire control and devise countermeasures.

본 연구에서는 숭례문 화재를 재현하기 위한 실물 모형을 제작하여 화재의 전이과정 및 붕괴에 이르는 과정을 추론하여 보고자 하였다. 실험결과 시너의 폭발력에 의한 화염이 천정의 적심부분에 직접적인 화재 원인임을 예측 할 수 있었으며, 이에 따른 적심부의 계속적인 훈소과정을 거쳐 숭례문의 천정내부에 화재가 성장하였을 것으로 판단되었다.