Release of hazardous substances in flood events: Damage model for horizontal cylindrical vessels

Severe accidents may be triggered by the impact of floods on process and storage equipment containing hazardous substances. The present study analyses the possible damage of horizontal cylindrical equipment, either operating at atmospheric or at higher pressures. A mechanical damage model was developed and validated by available literature data on past accidents. Simplified correlations were then obtained to calculate the critical flooding conditions leading to vessel failure. A fragility model was proposed for the straightforward assessment of equipment damage probability in the framework of the quantitative risk assessment of NaTech scenarios triggered by floods. A case-study was discussed to test the potentialities of the method.