Control of Plant Ageing at Seveso Sites: Achievements in Research and Transfer to Current Practice

This paper addresses the issue of "ageing", which for over a decade has been recognised as one the most relevant causes of accidents in chemical and oil industries. The EU Legislation explicitly mentions to manage ageing in the Directive Seveso III. Following the implementation of the Directive in national legislations, regulators had a few initiatives, including the publication of guidelines and recommended practices. Yet ageing is a very complex issue involving both technical and organizational factors. The greatest concern is the integrity of static containment systems, including pipes and vessels, where rupture may cause major losses of hazardous materials. Dynamic containment systems, including rotating machinery, are also important. The paper discusses a few practical solutions adopted by regulators in Europe, focusing on Italy and the Netherlands. Since 2018, Italian Authorities require the inspectors in charge to evaluate the adequateness of the ageing control programs of upper-tier Seveso sites by means of a codified protocol. The method has been developed with the collaboration of Regulators, Academia, and Industry. In three and more years of application, essential data about plant ageing of hundreds of Seveso sites were collected. This allowed a first statistical balance of ageing of Italian sites, as well as an assessment of the effectiveness of the Italian method. In order to place it in a broader context, these results are compared with related methods and findings about ageing in the Netherlands, obtained from investigated accidents 2004-2018.