• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.2
• /
• pp.74-81
• /
• 2017

An off-site consequence analysis is used to calculate the risks when hazardous chemicals that is being used on-site has been exposed off-site; the biggest factor that impacts the risk is the risks of accident scenarios. This study seeks to calculate risks according to accident scenarios by applying OGP/LOPA risk calculating methods for similar facilities, calculate risk reduction ratio by inspecting applicable IPL for incidents, and propose an appropriate risk standard for different risk calculating methods. Considering all applicable IPL when estimating the safety improvement of accident scenarios, the risk of OGP is 8.05E-04 and the risk of LOPA is 1.00E-04, According to the case of IPL, the risk is 1.34E-02. The optimal risk level for accident scenarios using LOPA was $10^{-2}$, but the appropriate risk criteria for accident scenarios in foreign similar studies were $10^{-3}{\sim}10^{-4}$, the risk of a scenario can be determined at an unacceptable level. When OGP is applied, it is analyzed as acceptable level, but in case of applying LOPA, all applicable IPL should be applied in order to satisfy the acceptable risk level. Compared to OGP, the risk is high when LOPA is applied. Therefore, the acceptable risk level should be set differently for each risk method.

• Fire Science and Engineering
• /
• v.15 no.1
• /
• pp.84-92
• /
• 2001

In today's world, rise in the establishment of social infrastructure resulting from population saturation in large cities has led to more extensive and frequent use of chemical materials on facilities. A result, unexpected and serious accidents, hazards, contingencies and disasters are more prevalent than ever. Such phenomenon calls for more devoted and concerted efforts towards finding ways to reduce the safety hazards that are seen to take place more often than before with the increase in the number of facilities that are prone to bring disaster and hazard coupled with the conventional safety problems that continue to exist even today. In developed countries, such challenge is addressed by various appropriate countermeasures drawn up by local professional committees on industrial facilities, whose members conduct offsite and onsite evaluation un the potential industrial disasters and its seriousness and provide their advice thereof. Against this backdrop, this study aims at identifying a comprehensive safety allowance level (safety acceptable level) when imposing limitation on the development of conventional or new facilities, for the fur pose of establishing a safety allowance level of disastrous and dangerous facilities in Korea. This is done by assessing and applying the level of danger each individual is exposed to in a randomly selected region (disastrous and dangerous areas in Seoul) based on probability of quantitative hazards, as well as simulation and calculation methods which include: i) social disaster evaluation method applying Quantified Risk Assessment of Health & Safety Executive of UK and Matrix of Risk of Evaluated Sources of Hazard; ii) Fault Tree or Event Tree Analysis and etc.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.599-607
• /
• 2017

Since 2015, small and medium domestic enterprises that treat more than a certain quantity of chemical substances in accordance with the Chemical Substance Control Act are obliged to submit an off-site impact assessment and risk management plan. In order to reduce the administrative and economic burden of the risk assessment, its impact was determined. Toxic leaks of nitric acid, methanol, and acetic acid were estimated and the correlations (between them?) were calculated. In addition, the correlations of this study were used to compare the KORA results according to the accident scenarios of the actual workplace and the extent of the damage as a function of distance in the case of toxic leaks. In this study, the correlation formula of the materials can be used to quickly determine the damage distance in the event of the accidental leakage of materials in the road or workplace, and to prepare emergency plans and respond to emergencies more quickly.

• Journal of the Korean Institute of Gas
• /
• v.20 no.2
• /
• pp.49-57
• /
• 2016

Aqueous ammonia is widely used in household cleaners, fertilizers and denitrification process. It is usually treated in concentrations from 10 % to 30 %, and release accidents have occurred frequently. In this study, we developed a simplified estimating method and equation to calculate threat zone easily in case of emergency due to release accident of aqueous ammonia. We calculated the consequence distance for toxic endpoints of aqueous ammonia(concentration 10 % ~ 30 %) at different puddle areas($1m^2{\sim}500m^2$) using the ALOHA program. Based on the result, we analyzed the relationship between concentration and puddle area with the threat zone and created the equation.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.44 no.3
• /
• pp.277-282
• /
• 2024

Recently, the intensity and frequency of typhoons have been increasing due to climate change, and typhoons can cause a loss of offsite power (LOOP) at nuclear power plants (NPPs). Therefore, it is necessary to prepare for typhoon-induced high winds through the probabilistic safety assessment (PSA) of offsite power systems. However, research on PSA for offsite power system in NPPs under typhoon-induced high winds is still lacking. In this study, PSA was performed for offsite power systems subjected to typhoon-induced high winds at the Kori NPP site, which has experienced frequent damages to its offsite power system among NPP sites in Korea. In order to perform PSA for typhoon-induced high winds in offsite power systems, the typhoon hazard at Kori NPP site was derived using logic tree and Monte Carlo simulation. Utilizing the fragility of components constituting the power system, performed a fragility analysis of the power system. Lastly, the probability that offsite power system will not be able to supply power to the NPP was derived.

• Korean Journal of Hazardous Materials
• /
• v.6 no.2
• /
• pp.7-12
• /
• 2018

Hydrochloric acid is a highly corrosive toxic substance and requires proper safety to minimize damage in case of leakage. Among the various risk-reduction facilities, the dike is a typical safety facility installed to protect the surrounding buildings and facilities by preventing the external spread of hazardous materials from the storage tank. In this study, the KORA program was used to assume leakage accident of hydrochloric acid storage tank. At this time, the extent of the damage effects of ERPG-2 were assessed for each of the three separation distance between the storage tank and the dike. The study found that the smaller the separation distance between the dike and the storage tank, the smaller the extent of damage caused by hydrochloric acid leakage, and the greater the impact of indoor conditions under the same conditions. Through this process, we are going to assist in selecting locations and installing facilities for new and existing businesses.

• International Journal of Advanced Culture Technology
• /
• v.11 no.3
• /
• pp.346-357
• /
• 2023

The purpose of this study is to suggest improvement plans for prevention regulations by reflecting the toxicity, fire and explosion effects of hazardous materials factories and surrounding areas using an off-site consequence assessment program. Regarding the effects of the hydrogen cyanide leak accident, which is the 1st petroleum of the 4th class flammable liquid, Areal Locations of Hazardous Atmospheres (ALOHA) program was used to compare and analyze the extent of damage effects for toxicity, overpressure, and radiation. As a result, the toxicity was analyzed to exceed 5km in the area with Acute exposure guideline level (AEGL)-2 concentration or higher, the overpressure was 103m in the range of 1 psi or more, and the radiant heat was analyzed to be 724m in the range of 2kw/m² or more. Toxicity and radiation affected the area outside the hazardous material storage area, but the overpressure was limited to the inside of the hazardous material storage area. Therefore, we propose to improve the safety management of hazardous materials by conducting a risk assessment for hazardous materials and reflecting the results in internal and external emergency response plans to prepare prevention regulations.

• Journal of the Korean Institute of Gas
• /
• v.22 no.5
• /
• pp.31-37
• /
• 2018

The distrust about chemical plant safety have been increased by occurring the major industrial accidents. Chemical plants have become more and more enlarged and sophisticated to increase production amount and decrease cost. So hazard of industrial accidents also have been increased. In this situation, quantitative risk assessment is activated by introducing OCA(Off-site Consequence Analysis). So it is possible to analyze the objective hazard of chemical plant. Currently OCA focus on the end point of hazardous area by fire/explosion/dispersion. But in this case, it is possible to analyze the industrial accident effect to near the chemical plant but hard to consider the actual hazard by frequency and population density. This study analyzes the validity about application of F-N curve to OCA by compare end point with F-N curve about accident.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.12
• /
• pp.685-688
• /
• 2017

Using ALOHA and PHAST Program, it was modeled assuming the leakage accident scenarios of chlorine which is designated as accident preparation chemical in chemical control act. End-point distances corresponding to ERPG-2 concentrations were calculated while varying annual mean temperature, wind speed, humidity, and atmospheric stability. The calculated endpoint distance values were compared and the correlation with each meteorological factor was analyzed. And we also investigated strengths and weaknesses of ALOHA and PHAST. The results show that ALOHA has little or no correlation with annual average temperature, humidity and it has a large correlation with wind speed and atmospheric stability. In the case of PHAST, the end-point distances were correlated with all the meteorological factors such as average annual temperature, wind speed, humidity, and atmospheric stability, Among them, the effect of atmospheric stability were the largest.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.11
• /
• pp.650-654
• /
• 2017

As the amount of chemicals increases, there is a global movement to reorganize the chemical management system. Korea has also reorganized its chemical management system to enact the act on Chemical Control and Registration and Evaluation etc. of chemical substance. However, it is true that there are not enough explanations in domestic workplaces. Therefore, deepening understanding of chemical control act and searched for a complementary point and future development direction. Through the proposed method, chemical control act should be widely adopted and studied both inside and outside the country as a safe chemical management system.