• 한국안전학회지
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• 제33권3호
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• pp.39-45
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• 2018

The occupational safety and health act defines how to evaluate the explosion hazardous areas according to KS (Korean Industrial Standards). Current KS have to follow IEC (International Electrotechnical Commission) 60079-10-1 1st edition and there has been no change since 2008. And its 2nd edition has been revised in 2015. In this study, IEC 1st Ed. (IEC 60079-10-1 1st edition) is compared with IEC 2nd edition. Total 112 case studies including four materials (methane, propane, benzene, methanol) are selected to test and explosion hazardous ranges evaluated by IEC 1st and 2nd Ed. are analyzed according to various leakage pressures and hole sizes. In order to verify the results calculated by them, PHAST, which is one of the most representative consequence analysis programs, is employed. As a result, it can be concluded that there are many differences between IEC 1st and 2nd Ed. due to the discharge and the ventilation parameters. As comparing with PHAST, it is confirmed that IEC 1st provides more conservative values than PHAST. Even if IEC 2nd Ed. provides more conservative for gases, this fails to provide more conservative values for liquids. Therefore, it is worth to note that a large value between the explosion hazardous ranges value calculated by the IEC 1st Ed. and 2nd Ed. should be selected until further investigation and analysis is made. Morevover, the full consideration for IEC 2nd Ed. have to be needed.

• 한국식품영양학회지
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• 제34권1호
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• pp.132-136
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• 2021

The purpose of this study is to measure the levels of eluted and dissolved CO2, and CO, volatile organic substances and radiation composition of Cheongsong mineral water which were collected from November 2019 to July 2020 during the autumn, spring, and summer seasons at collection points located in the upper, middle and lower spring waters. Data of the upper, middle and lower spring waters include the following: the amount of eluted water (average value±standard deviation, mL/min) was 30.07±0.52, 15.03±0.16, 23.73±0.42, and the amount of CO2 gas was 1,000 ppm or more. In addition, there was no detection of CO or total volatile organic substances (TVOC) and the radiation dose was 0.08 to 0.13. μSv/h. A blank test value of 0.08 to 0.10 μSv/h, when compared with the median value, showed a high value of 0.02 μSv/h, and the uranium test results provided by the Cheongsong-gun Office were 0.0118 mg/L (date 2019.06.18) and 0.0091 mg/L (date 2020.06.04.) respectively, which was less than the permission limit of 0.03 mg/L. However, it is believed that further research using more precise devices is needed in order to guarantee the safety and health of the water.

• Journal of Radiation Protection and Research
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• 제25권2호
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• pp.99-107
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• 2000

플라즈마 아크 용융방식 유리화 시험설비의 계통내 기체 및 최종배출구 전단의 배기체를 분석함으로써 배기체중에 포함된 분석용 첨가물의 거동 및 배기가스 처리장치의 제염성능을 평가하였다. 중금속 물질(Pb, Cd, Hg), 방사성 모의물질(Co, Cs) 그리고 방사성핵종($^{60}Co,\;^{137}Cs$)을 분석용 첨가물로 사용한 실험결과로부터 첨가물질의 거동에 따른 유리화 설비 배기체처리시스템의 제염특성 및 제염제수를 구하였다.

• 한국안전학회지
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• 제15권4호
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• pp.150-156
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• 2000

In this paper, the human error contributions to the system unavailability are calculated and compared to the mechanical failure contributions. The system unavailability is a probability that a system is in the failed state at time t, given that it was the normal state at time zero. It is a function of human errors committed during maintenance and tests, component failure rates, surveillance test intervals, and allowed outage time. The THERP (Technique for Human Error Rate Prediction), generally called "HRA handbook", is used here for evaluating human error rates. This method treats the operator as one of the system components, and human reliability is assessed in the same manner as that of components. Based on the calculation results, the human error contribution to the system unavailability is shown to be more important than the mechanical failure contribution in the example system. It is also demonstrated that this method is very flexible in that it can be applied to any hazardous facilities, such as gas valve stations and chemical process plants.ss plants.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2011년도 춘계학술논문발표회 논문집
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• pp.155-159
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• 2011

건축법에서 건축마감재료의 연소독성은 설치류(마우스)를 사용한 가스유해성시험으로 평가되고 있다. 최근 동물시험에 대한 최소화 및 대체시험개발의 필요성으로 인해 연소가스의 정량분석을 통한 독성지수연구가 요구되고 있다. 본 연구에서는 이미 철도차량에서 적용되고 있는 BS6853의 연소독성평가를 통해 기존 가스유해성시험결과의 상대적인 비교분석을 수행하여, 건축재료의 연소독성평가에 대한 다양한 가능성을 제시하고자 하였다.

• 수산해양교육연구
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• 제9권1호
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• pp.83-97
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• 1997

Diesel engine is widely used for ship and industry source of power because of its high thermal efficiency and reliability and durability. However it lead to air pollution due to exhaust gas, and it is important to develop diesel engine of lower air-pollution to decrease the hazardous exhaust gas emissions. As one of the ways, the study for practically using the high pressure of fuel injection and variable injection timing system is being processing. The high pressure injection, which is said to be an effective means for reducing both NOx and particulate emissions, and great improvements in combustion characteristics have been reported by many researchers. In this study, electronic-hydraulic fuel injection system and hydraulic fuel injector system have been applied to the D.I. test engine for high pressure injection and variable injection timing. The injection pressure and injection rate depending upon accumulator pressure were measured with strain gage and Bosch injection rate measuring system before fitting the system into test engine, and analyzed the characteristics of the injection system. The combustion characteristics with this injection system has been analyzed with data concerning heat release rate, pressure rising rate, ignition point, ignition delay and maximum pressure value.

• 한국분무공학회지
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• 제18권2호
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• pp.106-111
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• 2013

Adulterations fuel have been using in the vehicle in these days. Because gasoline, diesel prices are rising every day. so people find more cheap price fuel. Adulterations fuel caused a serious air pollution problems. Adulteration fuel were made from waste engine oil, waste paint. According to Government regulations permit to be used recycle fuel(adulteration fuel) only in industrial boiler. Unburned fuel pollutants are effected to human health. In this paper, the hazardous air pollutants characteristics in the diesel vehicles according to adulterations of vehicle fuels were carried out in the NEDC test mode in chassis dynamometer. It is revealed that the all of the regulation pollutants (THC, NOx, CO and PM) emission in the adulterations of vehicle fuels was increased also the green house gas, $CO_2$ was increased. In the hazardous air pollutants characteristics, the VOCs(Volitile Organic Compounds) BTEX(Benzene, Toluene, Ethylbenzene, Xylene) emissions in the adulterations of vehicle fuels showed higher level than these in the diesel fuels.

• 한국가스학회지
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• 제24권2호
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• pp.15-21
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• 2020

현재 KS C IEC 60079-10-1 등에서 2차 누출 시 누출 구멍의 반경(hole radius)은 권고로 하여 표현되어 있다. 누출 구멍 크기의 과소평가는 누출률에 대한 계산 값의 과소평가로 이어질 수 있고, 안전상의 이유로 검토되는 누출 구멍 크기의 보수적인 계산은 과대평가로 이루어 질 수 있어 과대한 위험장소 범위로 나타낼 수 있기 때문에 이 또한 피해야 한다. 그러므로 누출 구멍의 크기를 추정할 때에는 신중하게 균형 잡힌 접근이 필요하다. 이러한 논리를 바탕으로 하여 금번 연구에서는 반도체 산업에서 적용되는 국제안전규격인 SEMI S6 기준에 따른 실험결과로 위험물질 누출 시 가스박스 내부 농도를 파악하여 안정성을 검토해보고 SEMI F15 누출률 기준, SEMI S6 누출률 기준에 따라 KS C IEC 60079-10-1의 공식을 적용하여 폭발위험장소의 범위 선정을 실시하였다. 이를 바탕으로 하여 향후 반도체 산업 등 폭발위험장소의 적용이 까다로운 FAB 설비의 대안으로 배기성능 향상이 필요한지 여부를 검토해보고자 한다.

• 한국산업보건학회지
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• 제25권2호
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• pp.156-165
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• 2015

Objectives: The purpose of this study was to investigate the possible effects of a gasoline vapor recovery system on personal exposure levels of gasoline vapor constituents including benzene, toluene, ethyl benzene, xylene(BTEX), and methyl tert-butyl ether(MTBE) among gas station workers in a metropolitan area. Methods: Thirty-one gas station workers at ten gas stations in a metropolitan area were selected as subjects for this study. Test method PV2028 as recommended in the OSHA process was used for sampling and analysis. Results: The personal exposure levels of benzene, toluene, ethyl benzene, xylene, MTBE and gasoline vapor in the gas station workers were $0.0018{\pm}0.0069ppm$, $0.0077{\pm}0.0137ppm$, $0.0002{\pm}0.0008ppm$, $0.0016{\pm}0.0084ppm$, $0.2619{\pm}0.3340ppm$, and $1.4940{\pm}1.7984ppm$, respectively. After adjustment for refueling frequency and volume, personal exposure levelswere higher in the gas stations where gasoline vapor recovery systems(Stage II) were not installed, but the results were not statistically significant. Gasoline vapor concentrations showed a positive correlation to the level of MTBE, a gasoline additive. Conclusions: Vapor recovery systems(Stage II) were effective not only in reducing emissions of air pollutants, but also in reducing exposure to hazardous substances among gas station workers. In addition, acorrelation between gasoline vapors and MTBE concentration was confirmed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.115-121
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• 2008

A core engine for pre-cooled turbojet engines is designed and its component performances are examined both by CFD analyses and experiments. The engine is designed for a flight demonstration of precooled turbojet engine cycle. The engine uses gas hydrogen as fuel. The external boundary including measurement devices is set within $23cm{\times}23cm$ of rectangular cross section, in order to install the engine downstream of the air intake. The rotation speed is 80000 rpm at design point. Mixed flow compressor is selected to attain high pressure ratio and small diameter by single stage. Reverse type main combustor is selected to reduce the engine diameter and the rotating shaft length. The temperature at main combustor is determined by the temperature limit of non-cooled turbine. High loading turbine is designed to attain high pressure ratio by single stage. The firing test of the core engine is conducted using components of small pre-cooled turbojet engine. Gas hydrogen is injected into the main burner and hot gas is generated to drive the turbine. Air flow rate of the compressor can be modulated by a variable geometry exhaust nozzle, which is connected downstream of the core engine. As a result, 75% rotation speed is attained without hazardous vibration and heat damage. Aerodynamic performances of both compressor and turbine are obtained and evaluated independently.