Definition from buildingSMART: The element type (IfcBuildingElementType) defines a list of commonly shared property set definitions of a building element and an optional set of product representations. It is used to define an element specification (i.e. the specific product information, that is common to all occurrences of that product type).
NOTE: The product representations are defined as representation maps (at the level of the supertype IfcTypeProduct, which gets assigned by an element occurrence instance through the IfcShapeRepresentation.Item being an IfcMappedItem.
A building element type is used to define the common properties of a certain type of a building element that may be applied to many instances of that feature type to assign a specific style. Building element types (or the instantiable subtypes) may be exchanged without being already assigned to occurrences.
The occurrences of the IfcBuildingElementType are represented by instances of IfcBuildingElement (or its subtypes).
HISTORY: New entity in Release IFC2x Edition 2.