The Seveso III Directive requires plant operators have to monitor and control the ageing of critical equipment in order to prevent losses due to corrosion and other deterioration phenomena. It is essential to verify and demonstrate the adequateness of measures adopted for these purposes, therefore there is a need of methods and tools supporting these duties. A huge amount of data coming from smart sensors and information related to the Safety Management System have to be gathered and managed. They must be presented in an effective way during internal and external audits. To overcome the difficulties in facing such duties, a digital log of primary containment equipment is needed; this is particular important when equipment has the potential to cause major accidents, because it is affected by many concurrent deterioration mechanisms and cannot be easily replaced, thus its lifetime is very long. Based on this register, the actual ageing status can be presented in visual effective form during a safety-walk around the plant. This paper presents a system solving these issues and providing support to operators and Control Authorities; the core of the system is an ageing prognostic model, based on accelerating and slowing down factors.