Large scale experiment of a roof vented deflagration of high-concentration hydrogen-air mixtures

Countermeasures against hydrogen leaks, fires, and explosions that may occur in hydrogen facilities are currently insufficient to support demonstration of hydrogen infrastructure in Korea. Therefore, to reduce the risk of accidents and ensure safety in hydrogen infrastructures, the underground installation of hydrogen storage tank facilities was studied. To contribute to research on the safe underground installation of hydrogen storage tank facilities, the pressure reduction effect achieved by using different vent sizes, which were installed on roofs of these facilities. The influence of the vent coefficient (KV) on the internal and external overpressure of a 20.33 m3 cuboid concrete structure containing a high -concentration (30-70 vol%) hydrogen-air mixture was investigated with a large scale experiment. It was found that the internal and external overpressure of the structure increased as the vent coefficient (KV = V2/3/AV) increased. Considering the peak overpressure, the maximum internal peak overpressure showed a pressure difference of more than 3.7 times (from 2.21 to 6.62) as the vent coefficient increased, confirming that the maximum overpressure can be significantly reduced in a vented deflagration with increased vent size.