4.1.5.13 Spatial Structure
Spatial structures, such as site, building, storey, or spaces, may contain physical elements, including building elements, distribution elements, and furnishing elements. The containment relationship between the physical elements and the spatial structures is hierarchical, i.e. a physical element shall only be contained within a single spatial structure.
An IfcBeam is placed within the spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\IfcElement.ContainedInStructure. Subtypes of IfcSpatialStructureElement are valid spatial containers, with IfcBuildingStorey being the default container.The spatial containment relationship, together with the Spatial decomposition relationship, being hierarchical as well, establishes the hierarchical project tree structure in a building information model.
The IfcBuildingStorey that logically contains the IfcBeam decomposes the IfcBuilding using the IfcRelAggregates relationship. Therefore the IfcBeam is also indirectly contained in the building.