• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.37-45
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• 2019

The characteristic of fire and explosion related to electrostatic discharge is that it is difficult to reproduce the electrostatic charge and discharge phenomenon in addition to the large human and material damage. Therefore, in order to prevent accidents and disasters related to electrostatic in fire and explosion hazard areas, it is important to manage the level of electrostatic in a safe manner from the perspective of system between industrial facilities and human bodies. Rule 325 of the Occupational Safety and Health Regulations, "Prevention of Fire / Explosion due to Electrostatic", requires the use of grounding, conductive materials, humidification and electrification in order to prevent the risk of disaster caused by static explosion and electrostatic in the production process. In order to comply with these measures, related technologies, standards and systems are needed from the viewpoint of preventive measures related to electrostatic in fire and explosion hazard areas, but in Korea, it is still insufficient. Therefore, technical, institutional and managerial measures are needed as a precautionary measure to improve the level of ESD safety in fire and explosion hazard areas and prevent electrostatic related injury. In Korea, we analyzed the current status and characteristics of electrostatic related disaster by using the statistics of industrial accident and fire statistics of the Ministry of Employment and Labor. We also analyzed the current status and characteristics of electrostatic related disasters in Japan using JNIOSH accidents and disasters investigation cases and JNIOSH fire accident data of Japan Fire Bureau. The purpose of this study is to compare and analyze the current status of electrostatic related accidents and disasters in Korea and Japan in order to improve the safety management of electrostatic in fire and explosion hazard areas. In order to prevent accidents and disasters in the industrial field, The technical, institutional, and managerial measures to manage the level of electrostatic in a safe state were derived from the system point of view.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.229-236
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• 2022

An experimental investigation was conducted on the influences of median size, dust concentration, dust condition (cloud and layer) for the fire and explosion hazard assessment of dusts with the same powder property. For this purpose, tests have been performed in accordance with 20 L explosion sphere, thermogravi- metric analyze, combustion rate tester (UN method). We investigated the explosion characteristics and flame propagation velocity (FPV) in dust cloud and the flame spread velocity(FSV) over dust layer on 8 dust samples with different particle sizes of 4 types of dusts (Sugar, Mg, Al, Zr). An explosion hazard increased with decreasing particle size in Mg and Al dust clouds, but sugar did not show the effect of explosion hazard due to particle size change in dust clouds. The flame propagation velocity (FPV) of suspended dusts increased significantly when the particle size decreased from micro to nano than the variation of particle size in micro range. The flame spread velocity (FSV) over dust layer showed a tendency to increase over the inclined dust layers (30° slope) rather than the horizontal dust layers (0° slope). The flame spread rate (FSV) over dust layers increased on the inclined dust layer (30° slope) rather than the horizontal dust layer (0° slope) and was higher upward flame than the downward flame in condition of inclined dust layers(30° slope).

• Journal of the Korean Professional Engineers Association
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• v.45 no.6
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• pp.20-27
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• 2012

World has become interested in the development of new dean energy because of oil prices rise and global warming due to carbon dioxide emissions. This study evaluated the safety of the refueling infrastructure for hydrogen, CNG and HCNG(hydrogen blended natural gas) which recently take center stage as a clean fuel. The risk of fuel was evaluated by 3D computational fluid dynamics program for gas dispersion and explosion. Hydrogen is higher than the CNG explosion overpressure and shows rapid spread. On the other hand, CNG and 30% HCNG showed quite similar characteristics. HCNG slightly rises in risk than the CNG, but HCNG is safe compared to hydrogen.

• Journal of Powder Materials
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• v.10 no.6
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• pp.430-435
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• 2003

The phenomenon of electrical explosion of conductors is considered in the context of the changes in the energy and structural states of the metal at the stages of energy delivery and relaxation of the primary products of EEC. It is shown that these changes are related to the forced interaction of an intense energy flux with matter and to the subsequent spontaneous relaxation processes. The characteristics of nano-sized metal powders are also discussed. The preferential gas media during EEC is Ar+$H_2$. An increase in $e/e_s$ (in the range of values studied) leads to a reduction in the metal content. For reactive powders obtained with high metal content, it is necessary to separate the SFAP fractions, which settled on the negative electrode of the electric filter.

• Journal of Powder Materials
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• v.23 no.3
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• pp.213-220
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• 2016

In this study, bulk nickel-carbon nanotube (CNT) nanocomposites are synthesized by a novel method which includes a combination of ultrasonication, electrical explosion of wire in liquid and spark plasma sintering. The mechanical characteristics of the bulk Ni-CNT composites synthesized with CNT contents of 0.7, 1, 3 and 5 wt.% are investigated. X-ray diffraction, optical microscopy and field emission scanning electron microscopy techniques are used to observe the different phases, morphologies and structures of the composite powders as well as the sintered samples. The obtained results reveal that the as-synthesized composite exhibits substantial enhancement in the microhardness and values more than 140 HV are observed. However an empirical reinforcement limit of 3 wt.% is determined for the CNT content, beyond which, there is no significant improvement in the mechanical properties.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.45-50
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• 1996

Wood chips of oak(Quercus mongolica) and larch(Larix leptolepis) were treated with low pressure steaming explosion. Main components of exploded wood were separated with hot water and methanol extraction. Crude lignin separated from those extractives were purified and those chemical characteristics were investigated. And also, lignin adhesive was prepared from crude lignin and studied those chemical characteristics. The results can be summarized as follows ; 1. The purified lignin by Bj$\ddot{o}$kman's method from crude lignin is about 30% in exploded oak wood and is about 11% in exploded larch wood as a low amount. 2. The phenolic hydroxyl groups in the purified lignins are little higher than those of MWL and molecular weight distributions of the purified lignins are some lower than that of MWL. 3. Alkaline nitrobenzene oxidation products are very low in the clude lignin but those are increased in the purified lignin 4. The gravity of lignin resins(1.15 and 1.13) are a little lower than that of phenol resin(1.16) and the compressive shearing strength of lignin resins are higher than those of phenol resin.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.6
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• pp.1-11
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• 2003

For an accurate shock response analysis of a floating structure such as a naval surface ship subjected to an UNDEX(UNDerwater Explosion), the cavitation effects due to reflected wave at free surface and wetted structural surface should be considered. In this study, for the consideration of cavitation effects an effective method using LS-DYNA/USA and its theoretical background were presented. Through the application of the analysis of bulk cavitation phenomena in the free field, it could be confirmed that almost the same results were obtained between LS-DYNA/USA code and the analytical method. for the investigation of cavitation effects from the structural shock response characteristics, three dimensional UNDEX shock response analysis of an idealized ship model was also carried out It could be found that the cavitation Phenomena gave significant effects on the structural shock response characteristics, and especially that the shock loadings calculated at the installed location of shipboard equipment were underestimated in the case of no consideration of the cavitation effects, which might cause the severe mistake in its shock-resistance design.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.4
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• pp.406-414
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• 1987

As one of the explosion suppression methods of LPG tank exposed to hot environment by an accident or fire, some material which has large heat capacity and thermal conductivity can be installed inside the LPG tank in order to suppress the temperature increasement of tank wall. In the present study, theoretical model for the horizontally locating cylindrical LPG tank with and without the aluminum explosion suppression material has been developed to predict the characteristics of system. As a parametric study, effects of two major parameters, thickness of material filling and initial vapor volume fraction, on the time variation of wall temperature, temperature and pressure in tank are numerically examined. The results of present study show that the thickness of material filling does not give big differences in the suppression characteristics when the thickness of filling is larger than three inches. In case of material filling, there are marked suppression effects to the increase-ment of wall temperature, average vapor temperature and pressure in tank compared with the case of no filling.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.121-125
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• 2000

This study was executed by dust explosion experiment of terephthalic acid which was widely used for various purposes of food packing material and film etc. and the demand was rapidly increasing. The particle size and concentration of dust affected the minimum ignition energy largely and the lean concentration and the minimum ignition energy in the range of this study were obtained 50$g/m^3$ and 19mJ respectively. Minimum ignition energy was shown at the 4 and 5mm gap distance of discharge electrode, and when the gap distance was below 2mm the explosion could not generated although the sufficient energy was given. It was also found that the ignition energy decreased linearly with the decreasing of dust mean particle size.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.83-88
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• 2012

For the safe handling of n-tridecane, the lower flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. Also lower explosion limits by the lower flash points were calculated. The lower flash points of n-tridecane by using closed-cup tester were experimented $92^{\circ}C$ and $96^{\circ}C$. The lower flash points and fire point of n-tridecane by using open cup tester were experimented 100 oC and 103 oC, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-tridecane. The experimental AIT of n-tridecane was 223 oC. The calculated lower explosion limit by using measured lower flash point 92 oC for n-tridecane was 0.6 Vol.%.