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IfcBuildingStorey

Definition from buildingSMART: The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound.

A storey is (if specified) associated to a building. A storey may span over several connected storeys. Therefore storey complex provides for a collection of storeys included in a building. A storey can also be decomposed in (horizontal) parts, where each part defines a partial storey. This is defined by the composition type attribute of the supertype IfcSpatialStructureElements which is interpreted as follow:

EXAMPLE: In split level houses, a storey is split into two or more partial storeys, each with a different elevation. It can be handled by defining a storey, which includes two or more partial storeys with the individual elevations.
HISTORY New entity in IFC Release 1.0

Property Set Use Definition

The property sets relating to the IfcBuildingStorey are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcBuildingStorey are part of this IFC release:

Quantity Use Definition

The quantities relating to the building storey are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement:

Name Description Value Type
NominalHeight Standard height of this storey, from the bottom surface of the floor, to the bottom surface of the floor or roof above. The exact definition and calculation rules depend on the method of measurement used. IfcQuantityLength
GrossFloorArea Calculated sum of all areas covered by the building storey (as horizontal projections and normally including the area of construction elements. The exact definition and calculation rules depend on the method of measurement used. IfcQuantityArea
NetFloorArea Calculated sum of all usable areas covered by the building storey (normally excluding the area of construction elements). The exact definition and calculation rules depend on the method of measurement used. IfcQuantityArea
GrossVolume Calculated gross volume of all areas enclosed by the building storey (normally including the area of construction elements). The exact definition and calculation rules depend on the method of measurement used. IfcQuantityVolume
NetVolume Calculated net volume of all areas enclosed by the building storey (normally excluding the area of construction elements). The exact definition and calculation rules depend on the method of measurement used. IfcQuantityVolume

Spatial Structure Use Definition

The IfcBuildingStorey is used to build the spatial structure of a building (that serves as the primary project breakdown and is required to be hierarchical). The spatial structure elements are linked together by using the objectified relationship IfcRelAggregates. The IfcBuildingStoreyreferences them by its inverse relationships:

If there are building elements and/or other elements directly related to the IfcBuildingStorey (like most building elements, such as walls, columns, etc.), they are associated with the IfcBuildingStorey by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcBuildingStorey references them by its inverse relationship:
IfcBuildingStorey as part of a spatial structure

Figure shows the IfcBuildingStorey as part of the spatial structure. It also serves as the spatial container for building and other elements.

Geometry Use Definitions

The geometric representation of IfcBuildingStorey is given by the IfcProductDefinitionShape and IfcLocalPlacement, allowing multiple geometric representation.

Local Placement

The local placement for IfcBuildingStorey is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.

Geometric Representations

Currently, the use of a 2D 'FootPrint' representation of type 'GeometricCurveSet' and a 3D 'Body' representation of type 'Brep' is supported.

NOTE The independent geometric representation of IfcBuildingStorey may not be required or allowed in certain view definitions. In those cases only the contained elements and spaces have an independent geometric representation.

Foot Print Representation

The foot print representation of IfcBuildingStorey is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries), if the building storey has an independent geometric representation.

The representation identifier and type of this geometric representation of IfcBuildingStorey is:

Body Representation

The body (or solid model) geometric representation (if the building storey has an independent geometric representation) of IfcBuildingStorey is defined using faceted B-Rep capabilities (with or without voids), based on the IfcFacetedBrep or on the IfcFacetedBrepWithVoids.

The representation identifier and type of this representation of IfcBuildingStorey is:

Since the building storey shape is usually described by the exterior building elements, an independent shape representation shall only be given, if the building storey is exposed independently from its constituting elements.

EXPRESS specification:

ENTITY IfcBuildingStorey
SUBTYPE OF ( IfcSpatialStructureElement);
Elevation  :  OPTIONAL IfcLengthMeasure;
END_ENTITY;

Attribute definitions:

Elevation  :  Elevation of the base of this storey, relative to the 0,00 internal reference height of the building. The 0.00 level is given by the absolute above sea level height by the ElevationOfRefHeight attribute given at IfcBuilding.

Inheritance graph

ENTITY IfcBuildingStorey;
ENTITY IfcRoot;
GlobalId  :  IfcGloballyUniqueId;
OwnerHistory  :  IfcOwnerHistory;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ENTITY IfcObjectDefinition;
INVERSE
HasAssignments  :  SET OF IfcRelAssigns FOR RelatedObjects;
IsDecomposedBy  :  SET OF IfcRelDecomposes FOR RelatingObject;
Decomposes  :  SET [0:1] OF IfcRelDecomposes FOR RelatedObjects;
HasAssociations  :  SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject;
ObjectType  :  OPTIONAL IfcLabel;
INVERSE
IsDefinedBy  :  SET OF IfcRelDefines FOR RelatedObjects;
ENTITY IfcProduct;
ObjectPlacement  :  OPTIONAL IfcObjectPlacement;
Representation  :  OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy  :  SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcSpatialStructureElement;
LongName  :  OPTIONAL IfcLabel;
CompositionType  :  IfcElementCompositionEnum;
INVERSE
ReferencesElements  :  SET OF IfcRelReferencedInSpatialStructure FOR RelatingStructure;
ServicedBySystems  :  SET OF IfcRelServicesBuildings FOR RelatedBuildings;
ContainsElements  :  SET OF IfcRelContainedInSpatialStructure FOR RelatingStructure;
ENTITY IfcBuildingStorey;
Elevation  :  OPTIONAL IfcLengthMeasure;
END_ENTITY;