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Semiconductor manufacturing is performed through unit processes that use various chemicals and facilities. In particular, flammable gases, such as H2, NH3, and CH4, are used, and there is a risk of explosion when such gases leak. In this study, computational fluid dynamics (CFD) simulation and a "tracer gas test" according to the SEMI (Semiconductor Equipment and Materials International) S6 Environmental, Health, and Safety Guideline for Exhaust Ventilation of Semiconductor Manufacturing Equipment specification were performed during the leakage of hydrogen, a highly flammable gas used in the etching process of a gas box in the semiconductor industry. The CFD simulation was conducted to investigate the safety of semiconductor production facilities in relation to the explosion risk. Flow analysis was performed for the interior of a gas box used in the etching process. A steady-state analysis was performed to predict the concentration range of the explosion limit in the case of continuous hydrogen gas leakage. The interior of the gas box used in the simulation was modeled, and the ventilation flow rate, which has a significant impact on the leakage gas concentration distribution, obtained from experiments was used. The lower flammability limit (LFL) value of the leaked gas was 4% based on H2, and LFL/4 (25% of the LFL) was analyzed as the explosion limit concentration according to the acceptance criteria of the SEMI S6 tracer gas test. To validate the CFD simulation, a tracer gas test was performed according to SEMI S6. A mixture of hydrogen (5%) and nitrogen (95%) was used as the tracer gas. The flow rate was controlled by a gas regulator valve and measured using an Aalborg mass flow meter. The measured concentration of the tracer gas was calculated using the equivalent release concentration, which was calculated when 100% of the hydrogen was released, and the risk was assessed by comparing it with the LFL/4 of H2. [ABSTRACT FROM AUTHOR]

This paper describes and reports an analysis of an explosion accident at a wastewater storage pond in South Korea, which resulted in six fatalities and one injury. This study was aimed at analyzing and determining the possibility of fracture of concrete structure by vapor cloud explosion (VCE) and ignition point of explosion, using computational fluid dynamics (CFD) for the explosion simulation. The result obtained via CFD analysis was connected with finite element analysis (FEA) to accurately review the structural damages resulting from the explosion. As a result, the mechanism of the accident was determined, and preventive solutions against such accidents are recommended. This study was aimed at analyzing and determining the possibility of fracture of concrete structure by vapor cloud explosion (VCE) and ignition point of explosion, using computational fluid dynamics (CFD) for the explosion simulation. [ABSTRACT FROM AUTHOR]

Due to numerous hazardous chemicals to handle, the process plant industry has a higher risk of fire, explosion, and toxic release than other industries. Reviewing the accidents at process plants in the past, it is clear that fire accidents occur with the highest frequency, leading this study to consider accidental fire scenarios at process plants. For the scenario of an incident, a jet fire involving a massive amount of hydrogen gas to be processed or delivered at the process plant has been selected. The analysis of incident outcome resulting from the hydrogen jet fire has been implemented through the computational fluid dynamics simulation methodology Kameleon FireEx. Based on the outcome of this simulation, the consequences of a jet fire with high temperature and heat radiation are analyzed and evaluated. In addition, the results from Phast ver. 7.11 simulation for the same scenario are presented for comparison and further validation. [ABSTRACT FROM AUTHOR]

There has been an increase in environmental degradation associated with the use of fossil fuels in an attempt to meet the ever-increasing demand for electricity. Therefore, alterative renewable energy sources have garnered the attention of many researchers globally; hydrogen is an important example due to its eco-friendly nature. For hydrogen to be used as an energy source, it has to first be compressed. The explosion of high-pressure hydrogen vessels has been the driver of most accidents associated with its use. To prevent explosions, thermally activated pressure relief devices (TPRDs) are used to release hydrogen. The TPRD release orientations in a tunnel, which is a confined space, were investigated in this study based on a high-pressure release of hydrogen. In addition, we also propose an evacuation and safety protocol in the event of such an accident. In addition, the dynamics associated with the release of hydrogen were analyzed based on vehicle type. We found that in passenger cars and buses, hydrogen is released from the bottom and top, respectively. The dispersion range in this study was simulated based on a hydrogen concentration of 4%, in which air currents, including those from jet fans in the tunnel, are considered. The results confirm that passenger cars are barely affected by the jet fan airflow, and backward release facilitates evacuation and secures a safety zone more effectively compared with vertical emission. Meanwhile, upward releases were significantly affected by the jet fan. Overall, release in the airflow direction, regardless of the tunnel location, was confirmed to be effective in the context of evacuation and securing safety zones for buses. • Consequence analysis for Thermally-activated Pressure Relief Devices of HFCVs. • Thorough CFD simulations to help the decision-making for emergency responders. • Open space and confined space hazards comparison for different vehicle types. • Open space and confined space hazards comparison for different TPRD release angles. [ABSTRACT FROM AUTHOR]