• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.87-101
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• 2012

In gas industries, the potential risks of serious accidents have been increased due to high technology application and process complexities. Especially, in case of gas-related accidents, the extent of demage is out of control since gas plants handle and produce combustible, flammable, explosive and toxic materials in large amounts. The characteristics of this kind of disaster is that accident frequency is low, while the impact of damage is high, extending to the neighboring residents, environment and related industries as well as employees involved. The hydrogen gases treated important things and it used the basic material of chemical plants and industries. Since 2000, this gas stood in the spotlight the substitution energy for reduction of the global warming in particular however it need to compress high pressure(more than 150 bar.g) and store by using the special cylinders due to their low molecular weight. And this gas led to many times the fire and explosion due to leak of it. To reduce these kinds of risks and accidents, it is necessary to improve the new safety management system through a risk management after technically evaluating potential hazards in this process. This study is to carry out the quantitative risk assesment for hydrogen filling plant which are very dangerous(fire and explosive) and using a basic materials of general industries. As a results of this risk assessment, identified the elements important for safety(EIS) and suggested the practical management tools and verified the reliability of this risk assessment model through case study of accident.

• Fire Science and Engineering
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• v.27 no.1
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• pp.39-45
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• 2013

This study analyzes the explosion hazard of dry cleaning solvent recovery machine in laundry shop in two aspects, i.e. combustible and ignition source, and determines the explosive conditions of this machine by conducting mockup explosion tests repeatedly, varying conditions and using real dry cleaning solvent recovery machines. As to combustibles, two kinds of combustibles used widely in Korea have been selected and tested. The flash points, LEL's, and saturation vapor pressures of those combustibles have been measured, and their explosion specific curves have been drawn, based on the results of the measurements, so that the explosion risks of those materials may be determined, depending on the temperatures. Potential voltages generated from materials for laundry and foreign materials of metals have been assumed to be the ignition sources in this application, and their potential voltages have been measured, depending on temperature, humidity, and antistatic agent, by using real materials for laundry and a potential voltage measuring device. Tests have been conducted, varying the quantities, concentrations, and operating temperatures of materials for laundry. As a result, explosions have not been generated with potential voltages of materials for laundry, but explosions have been observed when applying artificial spark energy of 2.0 mJ.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.35-42
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• 2010

The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of considerable method to solve the social requirements of noise problem. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block. There are specimens which is fixed hall-size, space, depth as the condition of this research, and these are analysed of noise decrease effect using different condition of the first noise of each vehicle. As a result of analysis data according to vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base showed a good alternative solution for decreasing traffic noise level, from 4 dB to 9 dB.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.73-79
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• 2009

Hazardous materials (HazMats) are substances that are flammable, explosive, toxic, or harmful, if released into the environment. Since the transportation of HazMats increases in many developed countries, HazMat transportation has the key function in the process of HazMat usage to trace information of production, storage, shipment, usage, and waste disposal. The Korean Ministry of Environment (KMOE) and the National Emergency Management Agency (NEMA) have developed many laws, regulations, and standards for hazardous materials. However, the Korean HazMat laws, regulations, and standards do not guarantee accurate information of HazMat origin-destination (O-D) shipments, though the HazMat O-D movement is the critical information in safety and security of HazMat transportation. The objectives of this research are: (1) to investigate emerging and recurrent issues in Korean HazMat transportation, and (2) to develop the estimation method of O-D matrices for hazardous materials under limited data sets. The sodium hydroxide waste shipment among forty candidate HazMats is selected as the sample research case. The growth-factor method is applied to estimate the 2005 O-D matrix of sodium-hydroxide waste shipment. The column-and-row factoring process is used to calibrate the estimated sodium-hydroxide O-D matrix. The result shows the applicability of the O-D estimation process for hazardous materials. The Sodium Hydroxide Waste Origin-Destination Matrix is obtained to trace routes and paths of the Sodium Hydroxide transportation.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.47-59
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• 2024

Purpose: This study aims to propose measures for the prevention of fire and explosion accidents within manufacturing facilities by improving the existing classification criteria for hazardous locations based on the leakage patterns of flammable liquids. The objective is to suggest ways to safely manage ignition sources and combustible materials. Method: The hazardous locations were calculated using "KS C IEC 60079-10-1," and the calculated explosion hazard distances were visualized in 3D. Additionally, the formula for the atmospheric dispersion of flammable vapors, as outlined in "P-91-2023," was utilized to calculate the dispersion rates within the hazardous locations represented in 3D. Result: Visualization of hazardous locations in 3D enabled the identification of blind spots in the floor plan, facilitating immediate recognition of ignition sources within these areas. Furthermore, when calculating the time taken for the Lower Explosive Limit (LEL) to reach within the volumetric space of the hazardous locations represented in 3D, it was found that the risk level did not correspond identically with the explosion hazard distances. Conclusion: Considering the atmospheric dispersion of flammable liquids, it was concluded that safety management should be conducted. Therefore, a method for calculating the concentration values requiring detection and alert based on realistically achievable ventilation rates within the facility is proposed.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.13-26
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• 2018

Currently, local regulations, such as KS Code, do not clearly specify how to calculate the range of hazardous area, so the dispersion modeling program should be used to select dispersion. The purpose of this study is to present a methodology of determining the range of hazardous area which is simpler and more reasonable than modelling by using representative materials and process conditions. Based on domestic and overseas regulations that are currently in effect, variables affecting distance to LFL(Lower Flammable Limit) were selected. A total of 16 flammable substances were modelled for substance variables, process conditions variables, and weather conditions variables, and the statistical analysis selected the variables that affect them. Using the selected variables, a three-step classification method was prepared to select the range of locations subject to explosion hazard.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.55-63
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• 2016

A dust explosion is a phenomenon of strong blast wave propagation involving destruction which results from dust pyrolysis and rapid oxidation in a confined space. There has been some research done to find individual explosion characteristics and common physical laws for various dust types. However, there has been insufficient number of studies related to the heat of combustion of materials and the oxygen consumption energy about materials in respect of dust explosion characteristics. The present study focuses on the relationship between dust explosion characteristics of wood dust samples and oxygen consumption energy. Since it is difficult to estimate the weight of suspended dust participating in explosions in dust explosion and mixtures are in fuel-rich conditions concentrations with equivalent ratios exceeding 1, methods for estimating explosion overpressure by applying oxygen consumption energy based on unit volume air at standard atmospheric pressure and temperature are proposed. In this study an oxygen consumption energy model for dust explosion is developed, and by applying this model to TNT equivalent model, initial explosion efficiency was calculated by comparing the results of standardized dust explosion experiments.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.265-275
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• 1993

A vapor explosion has been a concern in nuclear reactor safety due to its potential for a destructive mechanical energy release. In order to properly assess the hazard of a vapor explosion, it is necessary to accurately estimate the conversion efficiency of the thermal energy to mechanical energy. In the absence of a complete model to determine the explosive energy yield, one may have to rely on a simpler upper bound estimate such as a thermodynamic model. This paper discusses various thermodynamic models and presents a clarification of each model in their mathematical formulation and the thermodynamic work conversion. It is shown that the work release in the shock adiabatic model of Board and Hall is essentially equal to that of Hicks-Menzies thermodynamic model. The effect of coolant void fraction on the explosion efficiency is also predicted based on these thermodynamic models. Finally, the Hicks-Menzies model is modified to account for the chemical reaction between a metallic fuel and water and the resultant effects on the explosion expansion work are discussed.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.154-154
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• 2011

최근 세계 각지에서 발생하는 대규모 터널 화재사고는 많은 사상자를 동반하고 이에 따른 경제적, 사회적 손실 또한 방대하게 진행되는 실정이다. 터널 구조물의 화재 특성상 외부에 쉽게 노출되지 않기 때문에 화재 발생 시 화재에 노출된 표층이 박리되거나 비산해서 단면결손이 생기는 폭렬 현상(explosive spalling)이 발생하게 된다. 이러한 폭렬 현상은 붕괴와 같은 대형 참사로 이어질 가능성이 크다. 따라서 본 연구에서는 터널 내 화재 발생 시 콘크리트 구조물의 폭렬에 의한 붕괴를 예방하기 위하여 이액형 상온경화 실리콘 고무와 인체에 무해한 친환경 첨가제인 펄라이트를 일정한 혼합비(5wt%, 10wt%, 15wt%, 20wt%)로 혼합하여 고성능 난연 복합체를 제조하고, 열적 특성과 난연 특성을 연구를 진행하였다. 열적 특성에 관한 시험으로 TGA를 측정하였으며, 난연 특성에 관한 시험으로는 화염 시험, 내화로 시험, 탄화로 시험을 진행하였다. 우선 TGA 시험은 $20^{\circ}C/min$ 승온 속도로 $800^{\circ}C$까지 실험을 하였고, 화염 시험은 제작한 시편과 gas torch($1200^{\circ}C$)의 화염 거리를 약 10cm로 하여 약 1시간 동안 시험을 하였다. 내화로 시험은 내화로 장치를 이용하여 RABT curve(5분만에 $1200^{\circ}C$도달 후 한 시간 동안 유지 후 냉각, 총 시험 시간 180분) 조건을 만족하는 환경에서 제작한 시편을 콘크리트에 부착하여 콘크리트의 내부온도를 측정하였다. 탄화로 시험은 탄화로 장치를 이용하여 $2^{\circ}C/min$ 승온속도로 $900^{\circ}C$까지 실험을 하여 외부 형태 변화를 관찰하였다. 각각의 시험 결과 TGA 열분해 결과 순수한 실리콘 고무보다 난연제인 펄라이트를 첨가했을 때 더 높은 온도에서 초기 분해 거동을 보였으며, 최종 잔류량은 80%를 보였고, 5 wt%의 펄라이트가 혼합된 시편의 최종 잔류량이 높은 것으로 보아 열분해에 가장 강한 조성임을 알 수 있었다. 화염 시험 결과 펄라이트가 혼합된 모든 시편에서 $300^{\circ}C$가 넘지 않은 결과를 보였다. 이는 제조된 복합체가 화염에 직접적으로 장시간 노출이 되어도 안전하다는 것을 알 수 있다. 내화로 및 탄화로 시험 결과 펄라이트가 15wt%와 20wt%가 첨가된 시편들보다 5wt%와 10wt% 첨가된 시편들이 고온에서 안정하다는 것을 보였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.477-484
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• 2014

Caldera is a large depression commonly formed by collapse of the ground following explosive eruption of a large body of stored magma. On earth, calderas and caldera complexes range in size from kilometers to tens of kilometers. Historical eruptions associated with caldera collapse have led to huge fatalities in Indonesia as well as left global impacts. This study presents case study on calderas in Indonesia which resembles to Mount Baekdu located at the border of China and North Korea; in the perspectives of similar characteristics, principal hazard, recent symptom of volcanic activity and the threat if eruption occurs in the near future. Calculation by using weighted evaluation matrix for Mount Krakatau, Mount Tambora, Mount Ijen, Tengger Caldera, Mount Rinjani and Ranau Caldera were taken for the selection of a site for future case study.