• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.13-18
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• 2010

To investigate electrostatic ignition hazards of commercial gasoline used in the gas station, experiments were conducted dealing with the minimum ignition energy(MIE) of several kinds of gasoline under the various temperature. The conductivity of gasoline that was required for an accurate risk assessment as well as the MIE were also examined. The solvent ignitability apparatus which can heat up the inside of the vessels up to $210^{\circ}C$ was used in this study. Four kinds of premium gasoline and four kinds of regular gasoline, differing with respect to the companies, were used as test specimens. The following results were obtained: (1) all gasoline specimens were so sensitive that even an electrostatic discharge with a very low energy, such as about 0.5mJ, could ignite them. The ignitability of premium gasoline was constant irrespective of the companies. On the other hand, the ignitability of regular gasoline was variable depending on the company. (2) The MIE of all specimens depended markedly on the temperature; in other words, an increase in temperature decreases the ignition energy value. (3) The conductivity values of all specimens were low. Those must be taken into consideration in electrostatic risk assessment.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.48-53
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• 1999

It is widely recognized that Hartmann tube for measuring the minimum ignition energy(MIE) of powder. But It requires long time and operational skills for measuring. As a variety of new fine powders are being produced day by day in industry, Japen has been developing a measurement system which employs a new method to create a dust/air mixture in a miniature combustion box. In this system, by vibration, the powder is successively fed downward through a hopper made up of metal mesh, and then it is formed into a thin, certain-like, dust/air mixture. With this new apparatus, three types of powder-Lycopodium, Anthraquinone, and Polyacry-lonitrile-were tested and the data of MIE were compared with those of a conventional apparatus (the Hartmann tube). Two of them agreed satisfactory, but the other, Anthraquinone, showed quite different values. It is guessed that the agglomerations of the powder particles appear because of particle shapes, static-charge and humidity.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.3
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• pp.99-105
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• 2003

The influence of discharge conditions, including the resistance of the sparking circuit, the shape of the electrodes and the width of the falling dust on the ignitability of lycopodium streams were investigated. Discharge characteristics and the ignition phenomena were also explored. When a 100 ㏀ resistor was connected in series with the sparking circuit, the lowest level of minimum ignition energy (MIE) was attained for lycopodium streams. Simultaneously, the area where flammable gas generated increased and the duration of flammable gas generation decreased. That is, the ignita-bility of lycopodium streams depended strongly on the discharge power and discharge duration. Electrodes with sharp tips gave smaller MIEs than those with round tips in a capacitive-inductive sparking circuit, while shape made no difference in a capacitive-resistive circuit. Streams that were too narrow required a considerable amount of energy for ignition.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.229-233
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• 1999

일반적으로 가연성 분진의 최소착화에너지(Minimum Ignition Energy; MIE)를 측정하는 방법에는 Hartmann식(이하 재래식이라 칭한다)이 주로 이용되고 있다. 그러나, 재래식은 상당히 정확하게 측정할 수 있으나 착화 후 용기류의 청소, 실험장치의 조작성 등 실험에 어려움이 있으며, 또한, 압축공기계통의 필요 등으로 제조 가격이 상당히 고가이다. 따라서, 일본에서는 이러한 재래식의 단점을 보완하면서도 기존의 재래식보다 신뢰성이 크게 뒤떨어지지 않은 장치를 개발하고자, 신 개념의 진동형 분진 최소 착화 에너지 측정장치를 개발중에 있다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.179-182
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• 1998

It is widely recognized that conventional means for determining the minimum ignition energy(MIE) of powder are time-consuming and require operational skill. As a variety of new fine powders are being produced day by day in industry, there is an urgent need to a quicker and more economical means to measure MIE. To meet this requirement, we have developed a measurement system which employs a novel method to create an air/dust mixture in a miniature combustion box. In this system, the powder to be tested input into a hopper made of metal mesh, and successively fed downward to form a thin, curtain-like dust/air mixture by vibration. With this new apparatus, three type of powders -Lycopodium, Anthraquinone, and Polyacrylonitrile-were tested and the MIE data were compared with those taken with a conventional apparatus(the Hartmann tube). Two of them agreed satisfactory, but the other, anthraquinone, showed quite different values supposedly due to the agglomeration of the powder particles by static-charge.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.11a
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• pp.291-296
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• 2002

Flammable compounds are indispensible in domestic as well as in industrial fields as fuel, solvent and raw materials. The fire and explosion properties necessary for safe storage, transport, process design and operation of handling flammable substances are lower explosive limits(LEL), upper explosive limits(UEL), flash point, fire point, AIT(auto ignition temperature), MIE(minimum ignition energy), MOC(minimum oxygen concentration) and heats of combustion.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.19-24
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• 2010

A large amount of electrostatic charges is often generated on polymer powders in fluidized bed and thereby may lead to electrostatic problems. In this study, to evaluate electrostatic hazards of powder in fluidized bed, the electric field(E[v/m]) and the charge amount(q[c/g]) during fluidizing were monitored. We also investigated the Minimum Ignition Energy(MIE [J]) of sample powder used in fluidized bed with the Hartman vertical-tube apparatus. The batch-type fluidized bed system and 2kg as Polypropylene(PP) resin powders were used in the experiments. The following results were obtained: (1) Even when a safe margin of several times was considered, the values of E obtained with PP powder in this paper did not exceed 3 to 5kV/cm, at which an incendiary electrostatic discharge could occur. (2) the ave. q was -0.26${\mu}$C/g during fluidizing. This value was high enough to cause electrostatic agglomeration and adhesion. (3) the entrained PP powder in upper column due to fluidizing could be ignited by electrostatic discharges of 71mJ.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.96-100
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• 2000

과거에는 정전기에 의한 분진 폭발이 사이로 등을 이용해 대량의 분진을 취급하는 기업에서만 발생하는 것으로 인식되어졌다. 그러나, 근래에 와서 정전기에 의한 분진 폭발은 그 취급하는 양에 관계없이 기업의 보편적인 관심의 대상이 되고 있다. 분진 폭발을 방지하기 위한 계획에는 취급 분진의 최소 착화 에너지(Minimum Ignition Energy: 이하 MIE라고 함)측정이 필수적으로 요구되어진다［1］.(중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.64-69
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• 2000

오늘날 분진은 석유 화학공업, 제약공업, 플라스틱공업 등 기능이 점점 다양화되고 있으며 산업분야에서도 광범위하게 이용되고 있다. 그로 인해 분진 폭발사고는 대형 공정에서뿐만 아니라 저장, 취급, 운송하는 일반화된 공정에서도 정전기 방전등의 점화원에 의해 화재 및 폭발의 위험성이 증가하고 있다. 이러한 재해를 미연에 방지하기 위해 안전관리의 일환으로 분진의 최소착화에너지(Minimum Ignition Energy; MIE)를 측정하여 관리하고 있다. (중략)

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.15-22
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• 2011

Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.