The ISO 15926 standard was developed to facilitate the integration of data in support of the life-cycle activities and processes of process plants. It is currently used for the handover of design documents between those companies that design and engineer engineering equipment to those organisations responsible for their operation and maintenance within the oil & gas industry. Part 2 of the standard contains a generic data model which represents the core of the standard. In this paper we applied well established software modelling principles on this part to overcome some previously identified problems such as inconsistent terminology and complexity. The two main outcomes are: (1) a multi-level view on Part 2 that formalises some aspects of the current data model and (2) the simplification of the data model, lowering the barriers to the adoption of ISO 15926 in industry.