• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.102-109
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• 2021

Recently, an interest in risk calculation methods has been increasing in Korea due to the establishment of classification code for explosive hazardous area on gas facility (KGS CODE GC101), which is based on the international standard of classification of areas - explosive gas atmospheres (IEC 60079-10-1). However, experiments to check for leaks of combustible or toxic gases are very difficult. These experiments can lead to fire, explosion, and toxic poisoning. Therefore, even if someone tries to provide a laboratory for this experiment, it is difficult to install a gas leakage equipment. In this study we find out differences among actual experiments, CFD by using FLACS and calculation based on classification code for explosive hazardous area on gas facility (KGS CODE GC101) by comparing to each other. We develpoed KGS HAC (hazardous area classification) program which based on KGS GC101 for convenience and popularization. As a result, actual gas leak, CFD and KGS HAC are showing slightly different results. The results of dispersion of 1.8 to 2.7 m were shown in the actual experiment, and the CFD and KGS HAC showed a linear increase of about 0.4 to 1 m depending on the increase in a flow rate. In the actual experiment, the application of 3/8" tubes and orifice to take into account the momentum drop resulted in an increase in the hazardous distance of about 1.95 m. Comparing three methods was able to identify similarities between real and CFD, and also similarities and limitations of CFD and KGS HAC. We hope these results will provide a good basis for future experiments and risk calculations.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.89-95
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• 2016

Keeping the gas pipelines in the common utility tunnel is useful because it has a lower risk of corrosion than conventional burial, and can prevent from excavating construction. But, explosions in common utility tunnels can cause greater damage from the blast overpressure compared to outdoor explosions, due to nature of the confined environment. Despite this fact, however, research on common utility tunnels has been limited to fire hazard and little has been studied on the dangers of explosions. This study developed scenarios of methane gas explosion caused by gas leak from gas piping within the common utility tunnel followed by unknown ignition; the study then calculated the extent of the impact of the explosion on the facilities above, and suggested the needs for designing additional safety measures. Two scenarios were selected per operating condition of safety devices and the consequence analysis was carried out with FLACS, one of the CFD tools for explosion simulation. The overpressures for all scenarios are substantial enough to completely destroy most of the buildings. In addition, we have provided additional measures to secure safety especially reducing incident frequency.

• Fire Science and Engineering
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• v.34 no.2
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• pp.49-53
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• 2020

This study aimed to identify the characteristics of 40 chemical accidents that occurred in Jeollabuk-do from 2004 to 2019. During this time, there were 2.5 accidents per year on average in the province; their types were classified as spill/leak, fire, explosion, adverse reaction, and complex. There were 34 leaks and six explosions, and they are categorized as follows: 12 by worker error, 16 from facility defects, and 12 by transport vehicle accidents. The substances involved in these accidents were ammonia (15%), sulfuric acid (12.5%), and silicon tetrachloride (7.5%). Notably, the rate of chemical accidents (75%) is the highest during spring and summer. In order to reduce chemical accidents, first, there should be compliance with the relevant laws. Second, the quality of safety education and training of workers should be improved. Finally, valuable government support is also necessary to improve facilities.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.497-508
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• 2013

This paper introduces a numerical model which can evaluate the fire-resistant capacity of reinforced concrete members. On the basis of the transient heat transfer considering the heat conduction, convection and radiation, time-dependent temperature distribution across a section is determined. A layered fiber section method is adopted to consider non-linear material properties depending on the temperature and varying with the position of a fiber. Furthermore, effects of non-mechanical strains of each fiber like thermal expansion, transient strain and creep strain are reflected on the non-linear structural analysis to take into account the extreme temperature variation induced by the fire. Analysis results by the numerical model are compared with experimental data from the standard fire tests to validate an exactness of the introduced numerical model. Also, time-dependent changes in the resisting capacities of reinforced concrete members exposed to fire are investigated through the analyses and, the resisting capacities evaluated are compared with those determined by the design code.

• Fire Science and Engineering
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• v.32 no.4
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• pp.60-68
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• 2018

Due to the complicated plan structure of the apartment units and the improved room-to-room sound insulation performance, it is difficult to communicate and recognize the fire situation by emergency broadcast equipment. In this study, speech intelligibility was measured and analyzed for three types of apartment unit by emergency broadcast equipment on various measurement points. Simulations were also conducted to improve the speech intelligibility. As a result of field measurements 72, 84, and 101 Type were not satisfied with NFSC standard of 90 dBA at the point of 1 m distance from source. In addition, it was evaluated that 75 dBA and CIS 0.7 of NFPA standard was not satisfied at all measurement points except for the 72 Type at living room point with door opened condition. Based on the door opened condition of the bedroom, it satisfied the NFPA of 75 dBA and CIS 0.7 in each bedroom when more than 90 dBA was satisfied at the 1 m separation point provided in NFSC standard.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.110-116
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• 2007

There have been 3E problems of energy, economy and environment since the earth has its history. Especially, as the industrial society is highly developing, human need in daily life has also changed drastically. With the introduction of 40 hour working week system, more households enjoy picnics on weekends. More gas accidents take place on Saturdays and on Sundays than any other days of week. Consequently, this study tries to find out the influence of flame caused by the explosion of butane canister on the adjacent combustibles and people by simulating relevant quantity of TNT. In addition, the damage estimation was conducted by using API regulations. If the scale of the radiation heat is known by calculating the distance of flame influence from the explosion site, the damage from the site can be easily estimated. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the pro bit analyze, the spot which is 50cm away from the flame has 97% of the damage probability by the first-degree burn, 8% of the damage probability by the second-degree burn and 4% of the death probability by the fire.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.7-12
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• 2011

LPG(Liquefied Petroluem Gas) Vehicles in metropolitan area being applied to improve air quality and have been proven effective for the reduction of air pollution. These gas stations are required to safe the storage tank because of possibility of causing huge loss of life and property. While storage tanks above ground have potential risk of explosion if fire breaks out and those under-ground are difficult to inspect due to poor accessibility neither above nor under-ground tank can serve us well. This study used the RPS-TRIZ (Rapidly Problem Solving-Teoriya Resheniya Izobretatelskikh Zadatch) technique and suggested the use of under-ground containment storage tank as a solution for safety issues and safety inspection.

• Journal of the Korean Institute of Gas
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• v.9 no.1 s.26
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• pp.9-15
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• 2005

Hydrogen is considered to be the most important future energy carrier in many applications reducing significantly greenhouse gas emissions, but the safety issues associated with hydrogen applications need to be investigated and fully understood to be applicable as the carrier. Therefore, there is a considerable demand for further research concerning the dispersion of hydrogen/air mixture clouds and the possible consequences of their ignition. In this study, the dispersion of hydrogen gas in atmosphere has been analysed with atmospheric condition by concerning the buoyancy of hydrogen. The hazard ranges to wind direction increase with wind speed and the stability of atmosphere. The concentration of hydrogen at just above ground is nearly zero due to buoyancy of hydrogen gas. Therefore, the ignition probability of hydrogen gas cloud is low and the hazard of explosion or fire associated with hydrogen gas is relatively low comparing with the other fuel gas such as propane or butane.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1184-1191
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• 2013

Probability of ignition due to arc-fault and energy of the arc-fault for the case of applying serial arc-fault interruption time of 120 V defined in UL 1699 to the voltage of 220 V of domestic condition and also for the case of applying it to the HIV wire type are analyzed. It has been confirmed that when the arc-fault occurs under 5 A, 10 A, and 20 A. Probability of ignition for the three different current conditions is 0.74(74%), 0.48(48%), and 0.32(32%) respectively for respective interruption time within 1 sec, 0.4 sec, and 0.2 sec. We discover that when we apply the same arc interruption time for 120 V defined in UL 1699 to the domestic environment of 220 V. The probability of ignition increases from 1.5% for 120 V condition to as much as 74% for 220 V condition. Conclusively, if we apply the standard for the serial arc-fault interruption time defined in UL 1699 for 120 V to the domestic condition of 220 V, the fire prevention effect of electric fire due to arc-fault equal to that of UL standard of 120 V can not be achieved.