IfcDistributionFlowElement

Definition from IAI: The distribution element IfcDistributionFlowElement defines occurrence elements of a distribution system that facilitate the distribution of energy or matter, such as air, water or power.

EXAMPLEs of distribution flow elements are ducts, pipes, wires, fittings, equipment, etc.

The IfcDistributionFlowElement utilizes the following capabilities mainly through inverse references to objectified relationships:

• Grouping - being part of a logical group of objects
• Classification - assigned reference to an external classification
• Documentation - assigned reference to an external documentation
• Type - reference to the product type information for the element occurrence
• Properties - reference to all attached properties, including quantities
• Cost control - reference to cost elements associated with this distribution element
• Work processes - reference to work tasks, in which this distribution element participates
• Aggregation - aggregated together with other elements to form an aggregate
• Connection - connectivity to other elements, including the definition of the connection or joint

The IfcDistributionFlowElement defines the occurrence of a distribution element within the spatial context of a project. The parameters that define the type of the distribution element and/or its shape are defined by the IfcDistributionFlowElementType subtypes, which is related by the inverse relationship IsDefinedBy pointing to IfcRelDefinesByType.

Property Set Use Definition:

The property sets relating to this entity 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 this entity are part of this IFC release:

• Pset_DistributionFlowElementCommon: common property set for distribution flow element occurrences

HISTORY: New entity in IFC R2.0.

Containment Use Definition

The IfcDistributionFlowElement, like any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierachical spatial containment, the second (optional) relationship is the aggregation within an element assembly.

• The IfcDistributionFlowElement is placed within the project 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 IfcDistributionFlowElement may be aggregated into an element assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype.

  In this case it should not be additionally contained in the project spatial hierarchy, i.e. SELF\IfcElement.ContainedInStructure should be NIL.

Geometry Use Definitions

The geometric representation of IfcDistributionFlowElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. If an IfcRepresentationMap is defined for the IfcFlowElementType or one of its subtypes, then the IfcDistributionFlowELement utilizes it through the IfcMappedItem. Included geometric representations are:

Local Placement

The local placement is defined in the supertype IfcProduct. It is defined by the IfcLocalPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. If given, the PlacementRelTo relationship of IfcLocalPlacement, shall point to the referenced IfcProduct. If the relative placement is not used, the absolute placement is defined within the world coordinate system.

Informal propositions for local placement:

1. If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement.

Geometric Representations

Currently, the use of 'SweptSolid', 'Clipping', 'Brep' and 'MappedRepresentation' representations are supported. In addition, the general representation types 'SurfaceModel' and 'BoundingBox' are allowed. The geometry use definitions for 'BoundingBox', 'SurfaceModel' and 'Brep' are explained at IfcBuildingElement. The geometry use definitions for 'SweptSolid' and 'Clipping' are identical to those explained in detail at IfcBeam.

MappedRepresentation

In addition to the standard and advanced geometric representation of IfcFlowDistributionElement that is defined using the SweptSolid or Clipping geometry, the MappedRepresentation shall be supported as it allows for reusing the geometry definition of the flow distribution element type at all occurrences of the same type. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

• RepresentationIdentifier: 'Body'
• RepresentationType: 'MappedRepresentation'

The same constraints as those given for the standard SweptSolid and the advanced SweptSolid and Clipping geometric representations shall apply to the MappedRepresentation of the IfcRepresentationMap.

EXPRESS specification:

Attribute definitions:

Inheritance graph