In Europe, after the Directive 2012/18/UE entered into force, the operators of establishments at major hazard accident are required to evaluate and manage equipment ageing through a detailed planning with the aim to control the integrity and prevent unwanted losses of hazardous materials as well as occupational risk. It is essential to estimate the equipment health and predict its remaining useful lifetime. Reliable estimates make possible to achieve a safe and efficient conduction of normal operations. To contribute to the achievement of these aims, a system is being developed, which is based on prognostic modelling and augmented reality for the prediction of the equipment degradation and the remaining useful lifetime. The system consists of hardware and software, in which the forecasting models draw information from a network of sensors installed on the equipment and from a database containing the history of inspections. The model integrates also information about deterioration mechanisms. This paper presents a preliminary study carried out for the derivation of the degradation model with respect to the mechanisms affecting atmospheric storage tanks, namely the internal corrosion of metal structures exposed hydrocarbons and the backside corrosion of the bottom floors. A comparison between the proposed method and the EEMUA standard is also given.