The subject of this paper is an information technology framework based on the use of an ontology that can be used for explicit and consistent specification, design, engineering, production and maintenance of complex facilities, e.g. ships and infrastructure. The framework supports the needs of Systems Engineering for unambiguous and explicit communication about such a facility between project participants, companies, disciplines etc. It further facilitates interoperability, increases efficiency and reduces failure costs. To show the complexity of realizing complex facilities nowadays, the first part of the paper gives the basics of a system as a capital facility and the corresponding Systems Engineering process which results in such capital facilities. Subsequently in the second part this is used to explore the need for an ontology-based framework.