Synergy between DyPASI and well-known safety indicator methodologies in the prevention of atypical accident scenarios

DyPASI (Dynamic Procedure for Atypical Scenarios Identification) is a methodology built for the definition and identification of atypical accident scenarios. It is based on the systematization of information from early warnings, represented by past incident events, near misses and in-depth studies related to the industrial process considered. The development of DyPASI was based on the lessons learned from the study of well-known atypical major accidents, such as the Vapour Cloud Explosion at Buncefield in 2005. Moreover, its application to the emerging technology of LNG regasification, whose accident scenarios may not be properly defined due to lack of relevant experience, demonstrated its effectiveness on specific cases. This first phase of creation and validation of the DyPASI methodology was carried out within the framework of the EC project iNTeg-Risk, whose goal was also to develop systems of Key Performance Indicators (KPIs) for emerging risk management, applied to the different case-studies analyzed. The case of Buncefield itself was considered for the assessment of two different safety indicator methodologies aimed at the challenging goal of preventing atypical scenarios: the REWI (Resilience-based Early Warning Indicator) method by SINTEF (research institute in Norway) and the Dual Assurance method by HSE (Health and Safety Executive in UK). In the present study the synergies between DyPASI and the safety indicator methods used are illustrated, also considering the different kinds of application carried out. Complementarities and contrasts are outlined and described in the perspective of prevention of atypical accidents. Moreover, for each safety indicator technique, a generic assessment of the approach to the technical and organizational aspects of the problem was carried out, in order to define a more holistic prevention of a complex phenomenon as the atypical accident scenarios.