Earticle

Machining center(MCT) which is operated at night without any operator is utilized widely. Its shaft and other elements rotate with high speed and high temperature is generated, due to the friction. Also, gas generated by cutting fluids and metal dust mix up together, which become the ignition source. The combustion process which leads to the ignition is investigated by measuring the rising time of the frictional heat and the safety standards applied to the electric discharge machine are reviewed. Frictional heat temperature variations in the process of metal machining are surveyed for the machining methods, metals and rpm, which will be very useful to make fire protection policy.

Two cases of explosion fire are surveyed, which take place in the process of utilizing the ion exchange resin. Reactor temperature rises up from 90°C to 170°C and then valves are opened to avoid temperature rising. But 10 minutes later, temperature also goes from 170°C to 300°C abruptly and the sight glass is broken and fierce explosion happens. The fire occurred due to the sudden temperature rise in the reactors of the large-scale silicon production process plant. Several sample cases are analysed and the exact remedies to prevent similar explosion accident in the process of utilizing ion exchange resin are suggested.

When unsaturated polyester resin and hardener are mixed up in FRP ship building process, temperature goes up and finally the fire happens. According to the ratio of unsaturated polyester resin and hardener(100:1~50), the possibility of ignition is reviewed and the optimal ration which minimizes the possibility of fire is analysed. Also, other environmental effects, like weather, humidity and temperature on the artificial ignition are obtained through re-enactment experiments. Temperature variation after mixing work of resin and hardener is reviewed. When the ratio of hardener is over 10%, temperature is over 25°C and no flammable gas generated.

In this study, we focused on understanding the fire behavior of electric vehicles which became an issue recently among the undeveloped fire investigation area. Pouch-type Li-ion batteries were examined for the different conditions, exposed to fire and overcharged. As a result, we revealed that there existed the evidence to distinguish the internal fault and external fire. Therefore, it is promising that the application of this study makes it clear to decide the origin of the fire.

In the tourism submarine, there exist no explosive materials, but two fire cases are reported. Hydrogen emitted from the lead-acid battery of submarine is filed up for a long time and causes an explosion. Frictional sparks generated by grinding work start the ignition. In the experiment, the amount of hydrogen generated from the battery is calculated and the pressure to cause the explosion is proved. Since the minimum ignition energy of hydrogen is small(0.02mJ), ignition starts even for the small spark of grinder. Providing a suitable ventilation system and battery storage system is the most useful methods to prevent the explosion fire of the tourism submarine. Way to prevent explosion by hydrogen inside the submarine by providing a ventilation and detection system of hydrogen that causes explosion.

The event data generated by the thermal detector of security system installed in the fire target and the fire space is analyzed, which is used as the basic data for determining the initial firing point. The operation principle, detection distance, detection angle, and effects of the thermal detector are checked, and the direction of combustion is verified by analyzing the data of the heat-sensor event due to the flow of flames and smoke. The reproducibility test of the fire case proves that the ignition point and fire behavior, by reinterpreting the sensor operation event data according to the detection range and blind range of the thermal detector, and confirms that the thermal detector can be an important factor in determining the firing point during the fire investigation.

This paper is a numerical study of the structure of the supply/exhaust pipe for safe cooling inside the heat treatment chamber at high temperature. The chamber of this study maintains the internal temperature at over 400°C. The cooling and exhaust pipe structure is essential for the cooling process to be efficient, safe and fast. Against this background, this paper compares the results according to the shape of the supply/exhaust pipe through the flow analysis and experiments inside the chamber, and compares Deriving the exhaust structure. Through the study of this paper, it was confirmed that the vertical air exhaust system exhibits the most uniform flow and temperature distribution, and the structure will be applied to chamber development and production. The temperature distribution was improved from about 130°C to 80°C. The reliability of the test results is within 6.14%.