# 4 Fundamental concepts and assumptions

This specification consists of a schema defining data types, along with common concepts indicating use of data types for particular scenarios. This chapter defines such common concepts, which are applied at entities having specific use. Such concepts also form the basis of Model View Definitions, which are supplementary specifications that adapt the scope and rules of this schema for targeted domains within the building industry.

Each concept template defines a graph of entities and attributes, with constraints and parameters set for particular attributes and instance types. Various entities within this schema reference such concept templates and adapt them for particular use according to parameters.

> EXAMPLE The 'Ports' concept template defines distribution system connectivity for mechanical, electrical, and plumbing systems; a pipe segment defines an application of the 'Ports' concept, having one port as an inlet and another as an outlet.