Earticle

Looking at the fire statistics related to dust explosions, the number of fires is small, but the damage to life and property is large. Among the substances of such dust explosion, food is used in our daily life, so we do not recognize the danger and cause even greater damage. Previous research on foods dust explosion studied the ignition and explosive properties of flour, sugar, and corn flour, based on this, in this study, not only the above substances, but also soybean flour and potato starch were carried out in-house dust ignition test and lower explosive concentration test using a Hartman type dust explosion device. As a result of the experiment, flour, sugar, and corn flour were ignited by the flame during the dust ignition test, and in the lower explosive limit(LEL) test, the LEL concentration(explosion probability) was 1.67g/L(33.3%) for flour, 4.17g/L(33.3%) for sugar, and 4.17g/L(66.6%) for cornstarch, respectively. However, in the case of soybean flour and potato starch, no explosion occurred even at a maximum of 10g.

Recently, public interest in electric power supply considering safety and environment is increasing. Among the available alternative energy sources including hydro, solar and wind power to mitigate greenhouse emissions, biomass is the only carbon-based sustainable option. However, wood pellets used in biomass power generation pose a risk of fire due to spontaneous combustion. Fires caused by spontaneous combustion of wood pellets have a significant impact on the environment and economy. Wood pellets are crushed during the process to become fine particles. In this experiment, the effect of particle size and quantitative difference of wood pellets on ignition was analyzed. Wood pellets were pulverized to 200㎛ size and the characteristics of wood pellets were investigated using an industrial analyzer and an elemental analyzer. The wood pellets were divided into 200㎛, 400㎛, 600㎛, 800㎛ sizes and a thermogravimetric analyzer (TGA) was used. The weight of wood pellets was classified into 3groups. The smaller the particle size of the wood pellets, the more rapid thermal decomposition occurred in the section where the volatile matter was burned and the higher the reaction rate. The smaller the amount of wood pellets, the faster the temperature rose, and the larger the amount, the slower it rose. Since the particle size of wood pellets is one of the biggest factors influencing spontaneous ignition, it is necessary to minimize the accumulation of fines and particulates in the bends of storage, piping and equipment, etc. in order to reduce the fire hazard caused by spontaneous ignition.

In this paper, we analyzed whether it is reasonable to classify fried dregs fires as spontaneous combustion. In the fire statistics and experiments, the frying dregs fires occurred in the process of handling the high-temperature carbonized frying dregs generated after frying. Fire didn’t occur in the frying dregs at room temperature, and the process of fire caused by careless handling of the high-temperature carbonized frying dregs was measured using a thermal image camera and a thermometer for frying. In the experiment, the temperature that could not be measured by the frying thermometer was measured by the thermal imaging camera, and the temperature of the carbonized residue was confirmed. The generalization error of spontaneous combustion, which is generally the cause of fire by fire investigators, was found out, and through the experiment, general frying crumbs generated during frying did not reach the flour ignition point and cooled naturally. However, the small grains of frying debris at the bottom of the fryer were carbonized by receiving direct heat from the fryer heat source while in the frying oil for a long time, and it was confirmed that the temperature reached a temperature higher than 300 ℃, which can carbonize flour at a temperature higher than the actual frying oil temperature.

In normal building fires, the main risk of combustion expansion is not only the combustibles materials in a building but also the risk to the spread of surface combustion of the interior finishing materials. Therefore, it is important to regulate the methods and standards for testing the performance of flame retardant in fire law and building ordinances. In this study, the fire characteristics of interior finishing materials are analyzed through the cone-calorimeter test, the flame retardant performance test and the VSR measuring test of building material. First, the results of the cone-calorimeter test confirmed that the ignition and flame combustion were started as soon as the radiant heat shield was removed, which could be a rapid propagation factor of the flame in the event of fire. Second, the results of the VSR measuring test showed that harmful gases for human body were released from the interior finishing materials. As observed from the result of examination, the interior finishing materials(five species including form blocks) should be used not only in the multi-use facilities occupied by unspecified majority but also in residences because of the sudden increase of the combustion in case of fire. Hence, it is urgent to limit the combustion characteristics of materials based on the use of interior finishing materials, the maximum thermal discharge rate and the emission of harmful gases.