• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.41-46
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• 2012

The flash point the lowest temperature at which the concentration of vapor of the substance in the air reaches the lower flammability limit(LFL), and is one of the most important physical properties used to determine the potential for fire and explosion hazards of industrial materials. The most published flash point data was for pure components and the flash points of the binary solutions that have flammable components, appear to be scarce in the literature. In the present study, the flash points of tert-pentanol+n-decane system were measured by Tag open-cup tester. The measured data were compared with the values calculated by the Raoult's law and the optimization methods based on the Wilson and NRTL equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.56-66
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• 2013

The gas production plants supply the inert gas to production plants for maintaining safe operation and also supply combustible, flammable, explosive and toxic gases as functions of basic materials needed for producing chemical goods. In addition, gas plants need to be safe and reliable operation because they are operated under high temperature, high pressure, cryogenic and catalytic reactions. As these plants have a complex process in operation, there has been a risk that major industrial accidents such as a fire, explosion and toxic gas released, also risks of asphyxiations by inert gases and burns caused by high temperature and cryogenic substances. This study is to carry out the semi quantitative risk assesment method which is the generic risk analysis (GRA). This method is applied to air separation unit(ASU) to identify its initial risk, safety barriers, residual risk and elements important for safety(EIS). The result of this study, suggested the management tools and procedures of implementation for EIS management.

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.46-51
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• 2018

A basic sprinkler system is a fire extinguishing system that can be easily installed in a fire-vulnerable place such as a publicly used establishments. However, the publicly used establishments are not only complicated in structure, but also have a large amount of flammable interior materials, and the users are not normally in a normal state, which is a very dangerous fire-fighting object. Therefore, due to the low fire extinguishing performance of the basic sprinkler system installed in the publicly used establishments, the fire suppression control can not be performed quickly in case of fire, which may increase the life and property damage. In this study, the cases of quantitative changes of extinguishing water used in basic sprinkler system and the cases of addition of additives such as wetting agents, reinforced agents to improve extinguishing performance were compared. Experimental results showed that the extinguishing performance was improved as the quantity of extinguishing water increase and the reinforced agents showed similar performance to that of 60% increase in the amount of extinguishing water. The cooling time to $200^{\circ}C$ and oxygen concentration were improved up to 14.3% and 34.5%, respectively. In the case of using the wetting agent, the cooling time to $200^{\circ}C$ and oxygen concentration did not show any significant improvement, but showed the effect of preventing deep seated fire. In order to prevent loss of life and property, it is necessary to improve the performance of the basic sprinkler system by increasing amount of extinguishing water or using additives like reinforced agents.

• Fire Science and Engineering
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• v.33 no.4
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• pp.9-15
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• 2019

The flash points of DMF based organic solvent mixtures used in the synthetic leather manufacturing process were measured. The test group was composed of seven types of solvent mixtures, which included DMF, toluene, and MEK. Each flash point was tested according to the international standard test methods of KS M 2010. The flash points were then predicted using some prediction models and compared with the measured data. From the analysis results, the binary mixtures with a mole ratio of less than approximately 0.7 showed that the measured values were under 25 ℃. This showed that the expectation for the flammable risk lowering effects due to the mixing of high flash point materials was reduced. In addition, the predicted values were evaluated using the average absolute deviation (A.A.D). The results showed that the Le Chatelier's models had an "A.A.D" of 1.95 ℃ and were the closest to the measured values.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.255-259
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• 1990

To investigate relative flammability in flaming combustion among 10 softwoods and 10 hardwoods, oxygen indices were determined for flat-grained sapwoods through Up and Down method following oxygen index test of ASTM D 2863-77. Oxygen index ranged from 21.0 for Pinus strobus to 28.2 for Larix gmelinii var. principis-ruprechtii in softwoods and from 20.7 for Populus davidiana to 27.6 for Quercus acntissima in hardwoods, which indicates Larix gmelinii var. principis-ruprechtii and Quercus acutissima being ranked first in inflammability and Pinus strobus and Populus davidiana being the least in fire resistance by softwood and hardwood because highly flammable materials are likely to have a low oxygen index.

• Journal of the Korean Society of Safety
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• v.33 no.4
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• pp.8-14
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• 2018

In the industrial chemical process involving combustible materials, reliable safety data are required for design prevention, protection and mitigation measures. The accurate combustion properties are necessary to safely treatment, transportation and handling of flammable substances. The combustion parameters necessary for process safety are lower flash point, upper flash point, fire point, lower explosion limit(LEL), upper explosion limit(UEL)and autoignition temperature(AIT) etc.. However, the combustion properties suggested in the Material Safety Data Sheet (MSDS) are presented differently according to the literatures. In the chemical industries, tetralin which is widely used as a raw material of intermediate products, coating substances and rubber chemicals was selected. For safe handling of tetralin, the lower and flash point, the fire point, and the AIT were measured. The LEL and UEL of tetralin were calculated using the lower and upper flash point obtained in the experiment. The flash points of tetralin by using the Setaflash and Pensky-Martens closed-cup testers measured $70^{\circ}C$ and $76^{\circ}C$, respectively. The flash points of tetralin using the Tag and Cleveland open cup testers are measured $78^{\circ}C$ and $81^{\circ}C$, respectively. The AIT of the measured tetralin by the ASTM E659 apparatus was measured at $380^{\circ}C$. The LEL and UEL of tetralin measured by Setaflash closed-cup tester at $70^{\circ}C$ and $109^{\circ}C$ were calculated to be 1.02 vol% and 5.03 vol%, respectively. In this study, it was possible to predict the LEL and the UEL by using the lower and upper flash point of tetralin measured by Setasflash closed-cup tester. A new prediction method for the ignition delay time by the ignition temperature has been developed. It is possible to predict the ignition delay time at different ignition temperatures by the proposed model.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.28-33
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• 2009

This study examined the mounting status of cigar lighter receptacles for vehicles and analyzed the tracking phenomenon that occurs when foreign material entered a cigar lighter receptacle to obtain data for the analysis of accident investigation. Regardless of the vehicle's output, cigar lighter receptacles are mounted in a vehicle horizontally, vertically, or at tilting or inclined angle. The tilting type cigar lighter receptacle is much easier to use but current leakage resulting from foreign materials (coffee, beverages, water, etc.) falling into the cigar lighter receptacle may cause a fire to start. This study used a vehicle battery (DC 12V) as a power supply for the tracking test and configured its circuit in the same way as that of an electrical device in a vehicle. The tracking phenomenon that occurred in the standby mode of the vehicle exhibited a fine flame and an irregular occurrence of smoke. While this tracking phenomenon was occurring, the leakage current and the reaching distance of the flame were measured to be approximately 930mA and $20{\sim}50cm$, respectively. It is thought that the resultant flame may ignite toluene, dust, cigarettes, etc. It was observed that as the tracking progressed, the internal metal socket melted and a hole was created, the surface of which was also severely carbonized. In addition, the electrical resistance of the carbonized conductive path was measured to be approximately $30{\Omega}$. It is thought that this much resistance may cause local heating when leakage current flows and could ignite any nearby flammable material.

• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.419-424
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• 1989

To obtain relative effectiveness in fire resistance among fire retardant chemicals, oxygen indices were determined for 3.5 mm thick, three-ply, meranti plywoods, treated with 5 commercial chemicals and water and then press-dried, through Up and Down method following oxygen index test of ASTM D 2863-77. The oxygen indices obtained were 28.4 for ammonium sulfate, 26.9 for monoammonium phosphate, 43.4 for diammonium phosphate, 30.1 for borax-boric acid, 32.4 for minalith, and 25.5 for water. Therefore, diammonium phosphate was found to rank first in fire-retardant effectiveness, followed by minalith, borax-boric acid, ammonium sulfate, and monoammonium phosphate in turn, judging from the fact that highly flammable materials are likely to have a low oxygen index.

• Current Photovoltaic Research
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• v.7 no.1
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• pp.9-14
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• 2019

Carrier selective solar cell structure has allured curiosity of photovoltaic researchers due to the use of wide band gap transition metal oxide (TMO). Distinctive p/n-type character, broad range of work functions (2 to 7 eV) and risk free fabrication of TMO has evolved new concept of heterojunction intrinsic thin layer (HIT) solar cell employing carrier selective layers such as $MoO_x$, $WO_x$, $V_2O_5$ and $TiO_2$ replacing the doped a-Si layers on either front side or back side. The p/n-doped hydrogenated amorphous silicon (a-Si:H) layers are deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD), which includes the flammable and toxic boron/phosphorous gas precursors. Due to this, carrier selective TMO is gaining popularity as analternative risk-free material in place of conventional a-Si:H. In this work hole selective materials such as $MoO_x$, $WO_x$ and $V_2O_5$has been investigated. Recently $MoO_x$, $WO_x$ & $V_2O_5$ hetero-structures showed conversion efficiency of 22.5%, 12.6% & 15.7% respectively at temperature below $200^{\circ}C$. In this work a concise review on few important aspects of the hole selective material solar cell such as historical developments, device structure, fabrication, factors effecting cell performance and dependency on temperature has been reported.

• Safety and Health at Work
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• v.11 no.4
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• pp.509-516
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• 2020

Background: Meta-analyses have shown firefighters to be at an increased risk of several cancer types. Occupational carcinogen exposure may explain these increased risks. This study aims to describe Norwegian fire departments' work conditions from 1950 until today, focusing on factors relevant for potential occupational carcinogen exposure. Methods: With the help of a reference group, we developed a questionnaire on topics related to occupational exposure to carcinogens for the period 1950-2018. Selected Norwegian fire departments provided department-specific responses. Results: Sixteen departments, providing fire services for 48% of the Norwegian population as of 2019 and mainly consisting of professional firefighters, responded to our questionnaire. The introduction of synthetic firefighting foams, more regular live fire training, the introduction of chemical diving, and a higher number of diesel-driven fire service vehicles were identified as changes thought to increase exposure to occupational carcinogens. Changes thought to decrease exposure included the switch from negative to positive pressure self-contained breathing apparatuses, the use of self-contained breathing apparatuses during all phases of firefighting, the use of ventilating fans during firefighting, increased attention to flammable materials used during live fire training, increased attention to handling and cleaning of turnout gear and other equipment, and installment of exhaust removal systems in apparatus bays. Conclusion: Norwegian fire departments' work conditions have seen several changes since 1950, and this could influence firefighters' occupational carcinogen exposure. A peak of carcinogen exposure may have occurred in the 1970s and 1980s before recent changes have reduced exposure.