Earticle

In this paper, in order to understand the characteristics of ignition caused by overload and overheating of motor among various factors of electric fire, we studied through ventilator used in various places such as restaurants and houses.It was able to identify the type of the ventilator by sampling the old ventilator which is used in various places, and it was possible to identify many kinds of ventilators which are damaged by the disconnection of the motor and the potential of the winding protection film and the interlayer short circuit,Experiments were conducted to forcibly restrain the rotating blades by using foreign substances to produce realistic situations and collect data such as the heat of the motor, the change of the current value, and the process of interlayer short-circuit and proved the fire hazard.And to utilize it as a basic data for the cause identification and as a fire investigation identification data.

In this study preceding tests are designed to determine the cause of the fire on #72 cable of Seohae Bridge, and the results are as follow. (1) It is confirmed molten marks located on the point 56 m apart from a installation part of #72 cable-main tower are composed of the zinc by EDS test. (2) It is confirmed the HDPE cover burnt by external gas torch is dissimilar to the burnt HDPE cover in the site. (3) It is discovered the Dimple which is the characteristic of ductile fracture from the break end of the #72 strand. (4) It is confirmed the Dielectric Breakdown of the HDPE by artificial lightning of 100 kV ~ 200 kV from a impulse voltage generator. (5) It is confirmed the P.C strand cable’s HDPE and wax are discontinuously ignited by short-circuit current approval test. Based on these results, The cause of the fire is estimated at lightning currents. And reenactment experiment that approves overcurrent to a HDPE P.C strand cable which used in the bridge is designed to verify the conclusion of the tests. The result is that the cable can be discontinuously ignited by currents of 2.0 kA for 0.15 seconds or by currents of 1.5 kA for 0.20 seconds. These current values are less than the limit that LINET system of KMA is able to dectect. the fire on #72 cable of Seohae Bridge can be caused by the small currents lightning with long strokes of IEC 62305-1.

In this paper, we conducted experiments with similar tpyes of starting capacitors identified in the fire site. We tested heat from starting capacitors energized continuously with working voltage and it was observed that starting capacitors could be exploded. We confirmed experimentally that old and degraded starting capacitors could be ignited if energized continuously. Also we confirmed that it could be identified by observing appearance of starting capacitors' debris whether starting capacitors were exploded by internal electrical energy or external flames.

In this study, we realized a determination method for the area of fire origin by using an angle between object and its shadow which is projected on the floor from the CCTV visual display not directly taken fire origin. This method use the transformation process that the distortion calibration and calibrated display of CCTV are converted to top view display. The area of fire origin is determined by the distance between and object and a fire origin. To predict a fire origin through transformation of CCTV visual display expand the application of CCTV and the scope of evidence. Because of no additional conditions, this method can be recognized as being more valuable than traditional ways.

This study describes the techniques to analyze the components of carbonized paper wallpapers in fire scenes and estimate the ignition point. The conventional ignition point estimation methods include a number of techniques from the US' NFPA 921 and Japan's TFD Materials Information, such as wood carbonization depth measurement, gypsum boards calcination measurement, and metal deformation analysis. In the United States and Japan, these techniques can be applied well to various fire scenes because most housing buildings are finished with gypsum boards and paints. However, in the case of Korea, there are limitations in applying the above techniques as most buildings are finished with wallpapers on fire- resistant substances or mortar. Wallpapers are carbonized in a fish scale shape by the radiant heat generated at the ignition point, and the carbonized wallpapers show differences according to their locations. The amounts of the soot left on the wallpapers also vary. Nonetheless, there are no academic theories or studies conducted in relation to this. The purpose of this study is, therefore, to analyze the components of carbonized wallpapers collected from fire scenes and tests, and to establish ignition point estimation techniques that can be applied to fire cases in Korea

In this research, we decided to clarify the cause of the fire caused by the adsorption facility installed in the factory and to do research to prepare an alternative plan. Understanding the structure of the adsorption facility used in the main factory and analyzing the danger of fire and its relevance according to the characteristics of each type of activated carbon. In order to investigate the cause of the fire caused by heat of adsorption, static electricity and external heat source, we made a model of adsorption device and conducted a replay experiment. It is the purpose of this research to recognize the fire hazard of the adsorption facility, prepare a scheme to improve safety, and provide a fire prevention policy.

The expectancy about the personal safety is rising as mush as our society is developing. Nevertheless the explosion fire because of the oil vapor diffusion, that is one among the careless fire, is happening constantly. We are trying to calculate the arrival time of the fire risk because of the oil vapor diffusion on the workplace using the VOCs and thinner. For this, we measured the first ignition time through the explosion test and we compared with the theoretical time of lower explosion limit. Through the result, we expect to provide the standard in which the worker using the VOCs can recognize a danger by oneself.