• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.109-114
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• 2001

Explosive characteristics of the city gas were determined by using the gas explosion apparatues. The explosive range is determined between lower explosive limit of 5.0% and upper explosive limit of 15.3% at atmosphere and even though the oxygen concentration is decreased, lower explosive limit is not changed, but upper explosive limit is rapidly decreased. The minimum oxygen for combustion is determined 10%. The maximum explosion pressure is determined 5.72$\textrm{cm}^2$ and the maximum rate of explosion pressure rise is oxygen concentration of 12% to determined 160.12$\textrm{cm}^2{\cdot}$sec.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.71-77
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• 2000

The aim of this study is to investigate the temperature dependence of the lower explosive limit(LEL) at elevated temperature. The temperature dependence of the lower explosive limit is one of the significant indices of flammability and combustibility. By using the literature data, the new equations for predicting the temperature dependence of the lower explosive limits for paraffinic hydrocarbons are proposed. The values calculated by the proposed equations were a good agreement with the literature data. It is hoped eventually that this proposed equations will support the use of the prediction for the lower explosive limit and the flash points of the flammable mixtures.

• Fire Science and Engineering
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• v.26 no.4
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• pp.1-9
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• 2012

We have examined In order to compare each other from explosion and combustion characteristics about the dusts which collects from manufacturing process of wheat flour and cosmetics manufacturing process of functional Keratin removal soap at the small and medium enterprise style. We measured explosive pressure and explosive lower limit which follows in change of concentration change at the time of talc addition uses Hartman dust explosion apparatus, also measured weight loss and endothermic quantity uses DSC and TGA. The explosion test results show that increased explosive lower limit concentration and explosive pressure decreased by the increased ratio of the talc dust. And the DSC results show that heat flux and temperature decreased by the increased ratio of the talc dust. Also increased in raising temperature causes initial smoldering temperature to move towards low temperature section and the endothermic quantity increased on a large scale. Together the TGA results show that weight loss decreased by the increased ratio of the talc dust. From this research we have assured the successive dust explosion mechanism study will play a key role as a significant safety securing guideline against the dust explosion.

• Journal of the Korean Institute of Gas
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• v.9 no.2 s.27
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• pp.1-7
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• 2005

The thermochemical parameters for safe handling, storage, transport, operation and process design of flammable substances are explosive limit, flash point, autoignition temperature, minimum oxygen concentration, heat of combustion etc.. Explosive limit and autoignition temperature are the major physical properties used to determine the fire and explosion hazards of the flammable substances. Explosive limit and autoignition temperature of methane fur LNG process safety were investigated. By using the literatures data, the lower and upper explosive limits of methane recommended 4.8 vol$\%$ and 16 vol$\%$, respectively. Also autoignition temperatures of methane with ignition sources recommended $540^{\circ}C$ at the electrically heated cruicible furnace (the whole surface heating) and recommended about $1000^{\circ}C$ in the local hot surface. The new equations for predicting the temperature dependence and the pressure dependence of the lower explosive limits for methane are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.91-97
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• 2005

The research on the explosive limits is one of fundamental fields of combustion process, and information on the explosive limits of mixture of fuel and oxidant, with or without additives, is very important for the prevention in industrial fire and explosion accidents. Explosive limits of all compounds and solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Batten, Le Chatelier and MRSM(modified response surface methodology) model. In this study, the reference values of lower explosive limits(LEL) of the ethanol+toluene+ethylacetate system were compared with the calculated values by using the solution thermodynamics and the MRSM model, respectively. The values calculated by the proposed equations were a good agreement with literature data within a few percent. By means of this methodology, it is possible to evaluate reliability of experimental data of the lower explosive limits of the flammable mixtures. Also, from given results, it is possible to predict explosive limits of the other flammable liquid mixtures used in the chemical process by the use of the proposed equations.

• Fire Science and Engineering
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• v.15 no.3
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• pp.14-20
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• 2001

The flash points are one of the most important fundamental properties used to determine the potential for fire and explosion hazards of flammable substances. A classification of the flash points is important for the safe handling of flammable liquids which constitute the solvent mixtures. Basic to all flash points behavior are vapor pressure and explosive limits(lower explosive limit and upper explosive limit). The flash points of flammable solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and activity coefficient models. In this study, the reference values of lower flash points were compared with the calculated values by using Raoult's law and MRSM(modified response surface methodology) model. The lower flash points were in agreement with the predicted by Raoult's law and MRSM model. By means of this methodology, it is possible to evaluate reliability of experimental data of the flash points of the flammable mixtures.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.50-55
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• 2023

Lithium-ion secondary batteries are currently in high demand and supply. The purpose of this study is to secure the safety of the process by studying the combustion characteristics of EC(Ethylene Carbonate), Which is mainly used as an electrolyte organic solvent for lithium ion batteries. The flash points of the EC by using Setaflash and Pensky-Martens closed-cup testers were experimented at 141 ℃ and 143 ℃, respectively. The flash points of the EC by Tag and Cleveland open cup testers were experimented at 152 ℃ and 156 ℃, respectively. The AIT(Auto Ignition Temperature) of the EC was experimented at 420 ℃. The LEL(Lower Explosive Limit) calculated by using lower flash point of Setaflash was calculated at 3.6 Vol.%.

• Journal of the Korean Institute of Gas
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• v.26 no.5
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• pp.35-40
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• 2022

PCVD (Plasma Chemical Vapor Deposition), a solar cell manufacturing facility, is a facility that deposits plasma generated in a chamber (NH₃, SIH₄, O₂ on a wafer. In the PCVD facility, gas movement and injection is performed in the gas cabinet, and there are many leak points inside because MFC, regulator, valve, pipe, etc. are intricately connected. In order to prevent explosion in case of leakage of NH₃ with an upper explosive limit (UEL) of 33.6% and a lower explosive limit (LEL) of 15%, the dilution capacity must be capable of allowing the concentration of NH₃ to be out of the explosive range. This study was analyzed using the CFD analysis technique, which can confirm the dilution ability in 3D and numerical values when NH₃ gas leaks from the existing PCVD gas cabinet. As a result, it was concluded that it corresponds to medium dilution and that testicular ventilation is possible through facility improvement.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.331-332
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• 2014

Underground power plant is required the strict safety management and safety assessment. Because it is the high risk of explosion by characteristic of enclosed space. In case gas leak of enclosed space, the ventilation facilities is very important in order to prevent explosion by the maintain less than the LEL(lower explosive limit). Thus, Through a safety assessment of ventilation volume is to reduce the risk for ventilation facilities in Underground power plant.

• Journal of Radiation Protection and Research
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• v.20 no.4
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• pp.237-243
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• 1995

An estimate is made on the potential generation rate of H: from radiolysis of the Paraffin-wax encapsulant Proposed for the solidified liquid concentrate wasteform. The results show that the radiolytic Production of $H_2$ from paraffin-wax-encapsulated waste is dominated by the radiation energy released from $^{60}Co$. The radiolytic production of $H_2$ will proceed at an initial rate equivalent to aproximately $4.4{\times}10^2cm^3yr^1$ in 200 litre drums that are partly filled with 120 litres of encapsulated waste. The gas production rate will fall to a value of $7.2cm^3yr^1$ after 100 years. The lower flammable limit for $H_2$ in air will be reached in about 25 years and the lower explosive limit for $H_2$ in air would not be reached in 1000years. The timescale in which these safety-related limits are reached is strongly dependent on the level of filling of each waste drum. A reduction of the air space inside each drum would reduce the time required to reach the lower flammable limit.