• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.114-119
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• 1993

The explosion characteristics of nonhomogeneous LPG-Air mixtures was measured in a cylindrical vessel and a pipe. The maximum explosion pressure, the maximum rate of explosion pressure rise, and the flame propagation velocity were measured and compared with that of homogeneous explosion by changing the effective factors on the explosion of nonhomogeneous mixtures such as pressure difference, effusion time and delay time. Explosion was occured even in the lower concentration than the lean flammability limit of mixture. The maximum explosion pressure was increased with increase of LPG concentration, however, the maximum explosion pressure rise was not in the nonhomogeneous explosion. An d the flame propagation velocity was decreased with nonhomogeneity, however, the maximum explosion pressure was always above 0.7kg/$\textrm{cm}^2$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1317-1326
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• 2003

The maximum temperature limit at which liquid boils explosively is called the superheat limit of liquids. The superheat limits of hydrocarbon liquids and their mixtures were measured by the droplet explosion technique. Also the fully evaporated droplet at the superheat limit and subsequent bubble evolution from the fully evaporated droplet were visualized. The pressure wave emanating from the evaporating droplet and subsequent bubble evolution process were measured by a piezoelectric transducer.

• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.84-89
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• 2007

The lower explosion limit(LEL) is one of the major combustion properties used to determine the fire and explosion hazards of the combustible substances. In this study, the lower explosion limits of the ester compounds were predicted by using the normal boiling points and the flash points based on the liquid thermodynamic theory. As a results, the A.A.P.E.(average absolute percent error) and the A.A.D.(average absolute deviation) of the reported and the calculated the LEL for the ester are 8.80 vol% and 0.18 vol%, respectively and the coefficient of correlation was 0.965. From a given results, by the use of the proposed methodology, it is possible to predict the lower explosion limits of the other flammable materials.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.75-81
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• 2011

For the safe handling of cyclohexane, the explosion limit at $25^{\circ}C$ and the temperature dependence of the explosion limits were investigated. Flash point and AIT(autoignition temperature) for cyclohexane were experimented. By using the literatures data, the lower and upper explosion limits of cyclohexane recommended 1.0 Vol% and 9.0 Vol%, respectively. Moreover lower flash points of cyclohexane recommended $-20^{\circ}C$. It was measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for cyclohexane, and the experimental AIT was $255^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of cyclohexane is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.8-14
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• 2015

For the safe handling of 2-methyl-1-butanol being used in various ways in the chemical industry, the flash point and the autoignition temperature(AIT) of 2-methyl-1-butanol was experimented. And, the lower explosion limit of 2-methyl-1-butanol was calculated by using the lower flash point obtained in the experiment. The flash points of 2-methyl-1-butanol by using the Setaflash and Pensky-Martens closed-cup testers measured $40^{\circ}C$ and $44^{\circ}C$, respectively. The flash points of 2-methyl-1-butanol by using the Tag and Cleveland open cup testers are measured $49^{\circ}C$ and $47^{\circ}C$. The AIT of 2-methyl-1-butanol by ASTM 659E tester was measured as $335^{\circ}C$. The lower explosion limit by the measured flash point $40^{\circ}C$ was calculated as 1.30 Vol.%. It was possible to predict lower explosion limit by using the experimental flash point or flash point in the literature.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.59-63
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• 2007

The purpose of this paper is to find optimum vent port of the booth for gas explosion experiment. Also, it is to understand the safety of the booth for explosion experiment which is installed to let the trainees for legal education which is managed by IGTT(Institute of gas technology training) blow the riskiness of explosion. Since the booth for gas explosion experiment is a confined space, we used the exhaust model for indoor explosion. As the result, it was safety calculated when the amount of leaking gas was close to the maximum of explosion limit on the explosion experiment.

• Fire Science and Engineering
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• v.28 no.2
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• pp.64-68
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• 2014

For the safe handling of cyclohexanol, this study was investigated the explosion limits of cyclohexanol in the reference data. The flash points and auto-ignition temperatures (AITs) by ignition delay time were experimented. The lower flash points of cyclohexanol by using closed-cup tester were experimented in$60^{\circ}C{\sim}64^{\circ}C$. The lower flash points of cyclohexanol by using open cup tester were experimented in $66^{\circ}C{\sim}68^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for cyclohexanol. The AIT of cyclohexanol was experimented as $297^{\circ}C$. The lower explosion limit (LEL) and the upper explosion limit UEL) by the measured the lower flash point and the upper flash point of cyclohexanol were calculated as 0.95 Vol% and 10.7 Vol%, respectively.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.21-26
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• 2014

In this study, the explosion characteristic of aluminium powders have been investigated as a function of particle size using by a 20 L dust explosion apparatus (K$\ddot{u}$hner). The tested aluminium particle sizes were the volume mean diameter of 16, 33 and $88{\mu}m$. The lower explosion limit increases gradually with the increasing of dust particle diameter, respectively 40, 60, $125g/m^3$ in mean diameter of 16, 33 and $88{\mu}m$. Also the increase in particle size for each aluminum dusts was found to cause an decrease in explosion pressure and Kst of dust explosion index, and a increase in the lower explosion concentration. Research results may have important implications for aluminum powders utilization and safety operation.

• Corrosion Science and Technology
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• v.3 no.6
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• pp.257-261
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• 2004

Leaking of fuel gas in a building creates flammable atmosphere and gives rise to explosion. Observations from accidents suggest that some explosions are caused by quantity of gas significantly less than the lower explosion limit amount required to fill the whole confined space, which might be attributed to inhomogeneous mixing of the leaked gas. The minimum amount of leaked gas for explosion is highly dependent on the degree of mixing in the building. This paper proposes a method for estimating minimum amount of flammable gas for explosion assuming Gaussian distribution of flammable gas.

• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.38-43
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• 2024

Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.