• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.65-75
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• 2022

Recently, the possibility of fire and explosion due to hydrogen leakage and the resulting risk are increasing since the operating pressure of the electrolysis increases. This study performed the hazardous area classification in accordance with KS C IEC 60079-10-1 and KGS GC101 in consideration of the general operating conditions of the electrolysis. In addition, in order to achieve a To Non-hazardous, an appropriate ventilation rate was estimated to maintain a concentration of less than 25 % of the lower explosive limit. As a result, it was reviewed that the electrolysis is classified as an hazardous area when only natural ventilation is applied, and a huge amount of ventilation is required to classify it as a non-hazardous area.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.29-34
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• 2019

Safety of hydrogen handling facilities is needed as supply of hydrogen cars has been expanded recently. In this study, the adequacy of safety regulations of hydrogen handling facilities and the risk of damage with hydrogen leakage were studied. The range of explosion hazard location of the hydrogen filling plant was investigated using the computational fluid dynamics (CFD) method, Explosive hazardous area is influenced by leakage type, hole size and sectional area. When the conditions of KS standard are applied, range explosive hazardous area is expanded 7.05 m, maximum. It is about 7 times larger than exceptional standard of hydrogen station. Meanwhile, distance from leakage point to 25% LEL of hydrogen is investigated 1.6 m. Considering the shape of charging hose, regulation of hydrogen station is appropriate.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.19-26
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• 2024

In workplaces handling flammable gas such as hydrogen, hazardous area is determined through KS C IEC 60079-10-1 standard. Because this standard determines the hazardous distance based on the release characteristic regardless of the type of gas, indoor/outdoor conditions, and atmospheric conditions, concerns are being raised about the effectiveness. In this study, simulations (PHAST, HyRAM) were performed to calculate the hazardous distance for hydrogen under various release characteristics and atmospheric conditions, and compared these results to IEC standard log-log graph. Also, we performed regression analysis according to each result. we found that the simulation results were 0.6 to 3.8 times less than the IEC standard, presented convenient linear regression equations. In addition, We confirmed that the results of hazardous distance varied based on wind velocity and atmospheric stability at the same release characteristic. In addition, we derived linear regression equations for release characteristics and hazardous distance that can be conveniently utilized. So, when classifying hazardous area in workplaces where they handle the hydrogen, the integrated graph and linear regression equation are helpful for confirming the hazardous area. Moreover, it is expected that the economic burden will be minimized by being able to classify reasonable hazardous area and to greatly reduce the risk of hydrogen explosion.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.14-23
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• 2010

A considerable number of construction disasters occurs on pathway. A safety management in construction sites is usually performed to prevent accidents in activity areas. This means that safety management level of hazards on pathway is relatively minified. Many researchers have introduced that a hazard identification is fundamental of safety management. Thus, algorithms for helping safety managers' hazardous area identification is developed using automated data collection technology. These algorithms primarily search potential hazardous area by comparing workers' location logs based on real-time locating system and optimal routes based on BIM. And potential hazardous areas is filtered by identified hazardous areas and activity areas. After that, safety managers are provided with information about potential hazardous areas and can establish proper safety countermeasures. This can help improving safety in construction sites.

• 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.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1119-1126
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• 2002

In this paper, we propose two predictive spatial data mining based on spatial statistics and apply for predicting the forest fire hazardous area. These are conditional probability and likelihood ratio methods. In these approaches, the prediction models and estimation procedures are depending un the basic quantitative relationships of spatial data sets relevant forest fire with respect to selected the past forest fire ignition areas. To make forest fire hazardous area prediction map using the two proposed methods and evaluate the performance of prediction power, we applied a FHR (Forest Fire Hazard Rate) and a PRC (Prediction Rate Curve) respectively. In comparison of the prediction power of the two proposed prediction model, the likelihood ratio method is mort powerful than conditional probability method. The proposed model for prediction of forest fire hazardous area would be helpful to increase the efficiency of forest fire management such as prevention of forest fire occurrence and effective placement of forest fire monitoring equipment and manpower.

• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.454-465
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• 1998

This study was to investigate the recognition level of food contamination with residual pesticides and hazardous heavy metals from 365 male and female adults in Taejon area using questionnaires. Among the recognizing level of residual pesticides in overall foods, 69.1% were 'serious', 25.6% were 'average' and 5.3% were 'not serious'. Over 94.7% of the subjects recognized residual pesticides pollution infoods. for hazardous heavy metals in food, 47.8% responsed as 'serious', 40.5% as 'average' and 11.8 as ' not serious' . Over 88.3% of the subjects recognized contaminated pesticides seriously in fruits, 72.1% in vegetables and 51.7% in cereals, whereas 55.7% of the subjects recognized hazardous heavy metal contamination seriously in fruits, 53.4% in vegetables, 40.8% in fishes and shellfishes and 35.0% in seaweeds. The subjects recognized residual pesticides contamination more seriously in overall foods, cereal, potatoes and starches, bean, vegetables and fruits, whereas hazardous heavy metal contamination was recognized more seriously in fishes and shellfishes, and seaweeds food groups. Comparisons were shown based on individuial's occupation. Farmer, forester, iner and fisher showed the lowest recognizing level of food contamination in most food groups. The mean score of the dietary effect by mass media's information on food contamination from residual pesticides and hazardous heavy metals were 3.51±0.96 out of 5 points. By Duncan's multiple range test, sex, age, marriage, food cost per month, concerns about health and nutrition knowledge showed significant differences in the mean effect score at p<0.05. According to a pesticides contamination in several food groups were affected by food cost per month, mass media's information on food contamination, health status, and concerns about health, But a recognition level of hazardous heavy metals in food were affected by income and, food cost per month mass media's information on food contamination, health status, concern about health and nutrition knowledge. People who need to take extreme precautions of food contamination were in order of producers, government officials, homemakers, the consumer's association and consumers.

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.65-70
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• 2018

Terrain data for disaster analysis in hazardous or disaster areas is not only important but also needs to be built quickly. In particular, the introduction of drones is in the early stages of research using drones in a variety of fields such as shooting, analyzing and managing hazardous areas. It is expected that drone will be faster, safer and more effective than existing data collection method in case of small scale disaster hazard area and disaster area where equipment or manpower input is difficult. Therefore, in this study, drone shooting was performed for hazardous areas in mountainous roads located in Samcheok city, Gangwon province, and ground reference points were measured by RTK-GPS. The measured data were converted into DSM (Digital Surface Model) data by coordinate correction using Pix4D postprocessing program and then applied to the analysis of the hazard area of mountainous area. As a result, it was shown that it is effective to identify the risk by using the basic terrain data obtained from the drones.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.1-9
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• 2017

In the industrial field, various type of fuel have been used for product processing facilities. Recent for 10 years, the usage of natural gas (NG) was gradually increased. Because it has many merits; clean fuel, no transportation, storage facility and so on. There are common safety concept that strict explosion protection approaches are needed for facilities where explosive materials such as flammable liquid, vapor and gases exist. But some has an optimistic point of view that the lighter than air gases such as NG disperse rapidly, hence do not form explosion environment upon release into the atmosphere, many parts has a conventional safety point of view that those gases are also inflammable gases, hence can form explosion environment although the extent is limited and present. In this paper, the heating equipments (Hot Oil Heater) was reviewed and some risk management measures were proposed. These measures include hazardous area classification and explosion-proof provisions of electric apparatus, an early gas leak detection and isolation, ventilation system reliability, emergency response plan and training and so on. This study calculates Hazardous Area Classification using the hypothetical volume in the KS C IEC code.

• Journal of the Korean Society of Safety
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• v.33 no.4
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• pp.21-29
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• 2018

In many companies handling flammable liquids, explosion-proof electrical equipment have been installed according to the Korean Industrial Standards (KS C IEC 60079-10-1). In these standards, hazardous area for explosive gas atmospheres has to be classified by the evaluation of the evaporation rate of flammable liquid leakage. The evaporation rate is an important factor to determine the zones classification and hazardous area distance. However, there is no systematic method or rule for the estimation of evaporation rate in these standards and the first principle equations of a evaporation rate are very difficult. Thus, it is really hard for industrial workplaces to employ these equations. Thus, this problem can trigger inaccurate results for evaluating evaporation range. In this study, empirical models for estimating an evaporation rate of flammable liquid have been developed to tackle this problem. Throughout the sensitivity analysis of the first principle equations, it can be found that main factors for the evaporation rate are wind speed and temperature and empirical models have to be nonlinear. Polynomial regression is employed to build empirical models. Methanol, benzene, para-xylene and toluene are selected as case studies to verify the accuracy of empirical models.