Rapid-N - rapid natech risk assessment tool : user manual version 1.0

Major accidents at chemical process industries, which are triggered by natural hazards, can have serious consequences on the population, the natural and built environment, and the economy. Termed natechs, the risk of such accidents is expected to increase in the future due to the growing number of industries, the occurrence of larger-scale natural hazards due to climate change, and the vulnerability of the society that is becoming gradually more interconnected. Adequate preparedness and proper emergency planning are needed for the prevention of natechs and the mitigation of their consequences. For this purpose, natech-prone areas should be identified and natech risk must be assessed in a methodical way. A recent survey has shown that hardly any natech risk maps exist within the EU or OECD. Where existing, natech risk maps simply overlay natural and technological hazards without considering site-specific features or interaction of hazards. The need for a proper and systematic natech risk-mapping methodology is therefore evident. In order to fill this gap a probabilistic natech risk-mapping methodology was developed. The methodology is based on the calculation of damage probabilities at process and storage units of industrial facilities for different damage states, and the estimation of the nature and extent of the consequences that can be caused by the natural hazard damage. For damage assessment, on-site hazard parameters are calculated from hazard scenarios and fragility curves are used to determine damage states and corresponding probabilities. For natech risk assessment, damage states are converted into risk states that define probable consequence scenarios, and the distance to endpoints of the consequences are calculated by using a simplified modeling approach used by US EPA. The methodology is implemented as a web-based software application, RAPID-N, which allows easy and user-friendly data entry, complementary data estimation, and rapid risk assessment. The results are presented as summary reports and natech risk maps.