• Fire Science and Engineering
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• v.30 no.4
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• pp.111-120
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• 2016

This is an experimental study to analyze the explosion and fire hazards of mobile phone batteries. Using the lithium-ion batteries currently used on smart phone as the experiment samples, the experiments were conducted by overcharging, internal and external short circuit, and thermal shock with the potential of explosion and fire caused by careless use or abnormal conditions. The experiment results showed that, in the case of overcharging and external short circuit, there was no explosion and fire hazard in the normal operation of the protection circuit module (PCM), but there were big risks when the PCM faulted conditions were assumed. In the case of the experiments by internal short circuit and thermal shock, such risks varied depending on a battery charge state. In other words, it could be verified that there were low risks of explosion and fire in a full discharge state, but there were high risks in a full charge state. These experiment results suggest that to minimize the explosion and fire hazards of mobile phone batteries, an alarm device is necessary when the PCM fault occurs. In addition, a solid battery case should be made and safety equipment, such as a cooling device to avoid high temperature, is needed.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.67-73
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• 2010

Relatively high density of population and buildings exists in urban area mainly because of broad job opportunities and conveniences available. In other words, if happened, there might be high possibility of disaster which can not be easily recovered. The purpose of this study is to show evaluation approach of the risk degree resulted from the disaster, which considers the attributes of urban area. Cheongju-city in Chungcheongbuk-do is selected as sample district to be estimated. The degree of overall risk including fire risk, building collapse risk, evacuation risk and gas explosion risk etc. is analyzed in the designated area. The analysis suggests the highest risk degree in Bukmun-ro district which also shows CBD decline phenomenon. Therefore, it can be not only predicted that this area as old downtown has not been provided with disaster prevention operation and urban renewal project, but also judged that administrative assistances for the disaster are required possibly soon.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.22-31
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• 2019

The flammable liquid conductivity is an important factor in determining the generation of electrostatic in fire and explosion hazardous areas, so it is necessary to study the physical properties of flammable liquids. In particular, the relevant liquid conductivity in the process of handling flammable liquids in relation to the risk assessment and risk control in fire and explosion hazard areas, such as chemical plants, is classified as a main evaluation item according to the IEC standard, and it is necessary to have flammable liquid conductivity measuring devices and related data are required depending on the handling conditions of the material, such as temperature and mixing ratio for preventing the fire and explosion related to electrostatic. In addition, IEC 60079-32-2 [Explosive Atmospheres-Part 32-2 (Electrostatic hazards-Tests)] refers to the measuring device standard and the conductivity of a single substance. It was concluded that there is no measurement data according to the handling conditions such as mixing ratio of flammable liquid and temperature together with the use and measurement examples. We have developed the measurement reliability by improving the structure, material and measurement method of measuring device by referring to the IEC standard. We have developed a measurement device that is developed and manufactured by itself. The test results of flammable liquid conductivity measurement and the data of the NFPA 77 (Recommended Practice on Static Electricity) Annex B Table B.2 Static Electric Characteristic of Liquids were compared and verified by conducting the conductivity measurement of the flammable liquid handled in the fire and explosion hazardous place by using Measuring / Data Acquisition / Processing / PC Communication. It will contribute to the prevention of static electricity related disaster by taking preliminary measures for fire and explosion prevention by providing technical guidance for static electricity risk assessment and risk control through flammable liquid conductivity measurement experiment. In addition, based on the experimental results, it is possible to create a big data base by constructing electrostatic physical characteristic data of flammable liquids by process and material. Also, it is analyzed that it will contribute to the foundation composition for adding the specific information of conductivity of flammable liquid to the physical and chemical characteristics of MSDS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.385-393
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• 2019

Potential fire, explosion and safety hazards exist in medium- or small-scale chemical plants using radical batch reaction processes due to the various conditions of materials, works or products. To minimize the potential damage, a study was conducted on qualitative hazard analysis using the HAZOP technique, which is a typical method for a qualitative risk assessment and analysis of the potential risks encountered in these chemical plants. For this purpose, a domestic chemical plant, which produces the acrylic resin by a radical batch reaction process, was selected and a risk assessment and analysis according to the procedure of HAZOP method was performed for the process. As the result of the study, to prevent the hazard, the input of inert gas and the installation of a pressure gauge were indispensable. In addition, the initiator and monomer should also be separated, and inhibiting substances and equipment are also necessary to prevent a runaway reaction.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.22-28
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• 2012

For a methanol separation column of the BPA (Bisphenol A) plant, HAZOP (hazard and operability) assessment was performed and damage ranges were predicted from the accident scenarios for the fire and the explosion. As a result, the damage range of the jet fire was 20 m in the case of rupture of the discharge pipe (50 mm diameter) of safety valve, and that of the flash fire was 267 m in the case of catastrophic rupture. Also, the damage ranges of the unconfined vapor cloud explosion (UVCE) for the rupture of the discharge pipe and for the catastrophic rupture were 22 m and 542 m, respectively. For the worst case of release scenarios, safety measures were suggested as follows: the pressure instruments, which can detect abnormal rise of the internal pressure in the methanol separation column, should be installed by the 2 out of 3 voting method in the top section of the column. Through the detection, the instruments should simultaneously shut down the control and the emergency shut-off valves.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.205-216
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• 2024

Recently, seismic Probabilistic Safety Assessment (PSA) methods have been developed for process plants, such as gas plants, oil refineries, and chemical plants. The framework originated from the PSA of nuclear power plants, which aims to assess the risk of reactor core damage. The original PSA method was modified to adopt the characteristics of a process plant whose purpose is continuous operation without shutdown. Therefore, a fault tree, whose top event is shut down, was constructed and transformed into a Bayesian Network (BN), a probabilistic graph model, for efficient risk-informed decision-making. In this research, the fault tree-based BN from the previous research is further developed to consider the multi-hazard of earthquake-induced fire and explosion (EQ-induced F&E). For this purpose, an event tree describing the occurrence of fire and explosion from a release is first constructed and transformed into a BN. And then, this BN is connected to the previous BN model developed for seismic PSA. A virtual plot plan of a gas plant is introduced as a basis for the construction of the specific EQ-induced F&E BN to test the proposed BN framework. The paper demonstrates the method through two examples of risk-informed decision-making. In particular, the second example verifies how the proposed method can establish a repair and retrofit strategy when a shutdown occurs in a process plant.

• 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 Ocean Engineering and Technology
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• v.32 no.2
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• pp.95-105
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• 2018

An FLNG (floating liquefied natural gas) or LNG FPSO (floating production, storage and offloading) unit is a notable offshore unit with the increasing demand for LNG. The liquefaction process on an FLNG unit is the most important process because it determines the economic feasibility, but would be a hazard source because of the large quantity of hydrocarbons. While a high efficiency process such as C3MR has been preferred for onshore liquefaction processes, a relatively simple process such as the SMR (single mixed refrigerant) or DMR (dual mixed refrigerant) liquefaction process has been selected for offshore units because they require a more compact size, lighter weight, and higher safety due to their space limitation for facilities and long distance from shore. It is known that an SMR has the advantages of a simple configuration, small footprint, and lower risk. However, with an increased production rate, the inherent safety of SMR needs to be evaluated because of its small train capacity. In this study, the potential explosion risks of the SMR and DMR liquefaction processes were evaluated at the conceptual design stage. The results showed that an SMR has a lower overpressure than a DMR at the same frequency, only with a small production capacity of 0.9 MTPA. With increased capacity, the overpressure of the SMR was higher than that of the DMR. The increased number of trains increased the frequency in spite of the small amount of equipment per train. This showed that the inherent risk of an SMR is not always lower than that of a DMR, and an additional risk management strategy is recommended when an SMR is selected as the concept for an FLNG liquefaction process compared to the DMR liquefaction process.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.52-60
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• 2014

This study aims to suggest risk management plan including safety measures through hazard identification followed by consequence analysis in petrochemical plants. Consequence analysis was performed through practical release scenario by using PHAST RISK(ver. 6.7) software in the propylene recovery process(PRP). As results, consequences by fire or explosion accidents in the depropanizer zone, deethanizer zone and heat pump zone were relatively larger than other else zones among six process zones in the PRP. In the case of jet fire, it is recommendable not to install residence building within 200 m of the process zone. Additionally, process zones having large inventory or high pressure must be prevented from accidents and required to establish quick response against accidents.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.76-83
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• 2024

In the semiconductor manufacturing process, the Diffusion process generates various reactive by-products. These by-products are deposited inside the pipes of post-processing and exhaust treatment systems, posing a potential risk of substantial dust explosions. In this study, three methods material verification, selection of analysis samples, and risk analysis were employed to address the substances produced during the Diffusion process. Among the materials handled in the Diffusion process, ZrO₂, TEOD, and E-DEOS were identified as raw material capable of generating by-product dust. Test for Minimum Ignition Energy and dust explosion were conducted on the by-products collected from each processing facility. The results indicated that, in the case of MIE, none of the by-products ignited. However, the dust explosion test revealed that ZrO₂ exhibited a maximum pressure of 7.6 bar and K_st value of 73.3 bar·m/s, its explosive hazard. Consequently, to mitigate such risks in semiconductor processes, it is excessive buildup.