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The number of pressure vessel bursts (PVBs) has reduced since the 1990s due to the introduction of many rules and regulations. However, accidents frequently occur during pressure resistance tests (pneumatics) and there are scant safety guidelines for examining pressure vessels. Thus, this study proposes a safe distance to prevent accidents during a test, based on the explosion energy and vessel shape. First, the maximum explosion energy was computed using Brode's equation and the distance and overpressure were nondimensionalized via Sachs' scaling. Next, the overpressure ratio of the spherical tank (opsphere) was calculated based on the overpressure ratio of the cylindrical tank (opcylinder), considering the length to diameter ratio of the cylindrical vessel. Finally, the function of the safety distance was obtained. The result was validated by comparing it with data from the catastrophic failure that occurred at D. D. Williamson & Co. Inc. in 2003. This study could help establish safety guidelines and the prevention of PVB damage. [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]