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Hydrogen, an advanced energy source, is growing quickly in its infrastructure and technological development. Urban areas are constructing convergence-type hydrogen refilling stations utilizing existing gas stations to ensure economic viability. However, it is essential to conduct a risk analysis as hydrogen has a broad range for combustion and possesses significant explosive capabilities, potentially leading to a domino explosion in the most severe circumstances. This study employed quantitative risk assessment to evaluate the range of damage effects of single and domino explosions. The PHAST program was utilized to generate quantitative data on the impacts of fires and explosions in the event of a single explosion, with notable effects from explosions. Monte Carlo simulations were utilized to forecast a domino explosion, aiming to predict uncertain events by reflecting the outcome of a single explosion. Monte Carlo simulations indicate a 69% chance of a domino explosion happening at a hydrogen refueling station if multi-layer safety devices fail, resulting in damage estimated to be three times greater than a single explosion. [ABSTRACT FROM AUTHOR]

The commercialization of eco-friendly hydrogen vehicles has elicited attempts to expand hydrogen refueling stations in urban areas; however, safety measures to reduce the risk of jet fires have not been established. The RISKCURVES software was used to evaluate the individual and societal risks of hydrogen refueling stations in urban areas, and the F–N (Frequency–Number of fatalities) curve was used to compare whether the safety measures satisfied international standards. From the results of the analysis, it was found that there is a risk of explosion in the expansion of hydrogen refueling stations in urban areas, and safety measures should be considered. To lower the risk of hydrogen refueling stations, this study applied the passive and active independent protection layers (IPLs) of LOPA (Layer of Protection Analysis) and confirmed that these measures significantly reduced societal risk as well as individual risk and met international standards. In particular, such measures could effectively reduce the impact of jet fire in dispensers and tube trailers that had a high risk. Measures employing both IPL types were efficient in meeting international standard criteria; however, passive IPLs were found to have a greater risk reduction effect than active IPLs. The combination of RISKCURVES and LOPA is an appropriate risk assessment method that can reduce work time and mitigate risks through protective measures compared to existing risk assessment methods. This method can be applied to risk assessment and risk mitigation not only for hydrogen facilities, but also for hazardous materials with high fire or explosion risk. [ABSTRACT FROM AUTHOR]

The advent of eco-friendly hydrogen vehicles has prompted attempts to increase the installation of hydrogen refueling stations in urban areas; however, sufficient safety measures have yet to be established. Gas plume dispersion, jet flame, and heat flux were investigated using HyRAM software by considering accidents at hydrogen refueling stations in reports published by Sandia National Laboratories. Hydrogen release and jet flame length were measured using the Schlieren imaging system and a thermal imaging camera. The HyRAM simulation analysis results were more conservative than the experimental results. These showed that the pressure and leak diameter greatly influenced the safety of hydrogen facilities. Individual and societal risks were analyzed through RISKCURVES, and the risks were found to be highest in the sidewalk and dispenser. An F-N (Frequency- Number of fatalities) curve to verify the risk of installing a hydrogen refueling station in urban areas was derived, and the safety distance from residents was proposed. [Display omitted] [ABSTRACT FROM AUTHOR]