IfcDistributionSystem

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcDistributionSystem			ADDED

Semantic definitions at the entity

Entity definition

A distribution system is a network designed to receive, store, maintain, distribute, or control the flow of a distribution media. A common example is a heating hot water system that consists of a pump, a tank, and an interconnected piping system for distributing hot water to terminals.

The group IfcDistributionSystem defines the occurrence of a specialized system for use within the context of building services.

Important functionalities for the description of a distribution system are derived from existing IFC entities:

From IfcSystem it inherits the ability to couple the distribution system via IfcRelServicesBuildings to one or more IfcSpatialElement subtypes as necessary.

From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship entity IfcRelAssignsToGroup. This allows to group distribution elements (instances of IfcDistributionElement subtypes), and in special cases ports directly (instances of IfcDistributionPort).

From IfcObject it inherits the inverse attribute IsDecomposedBy pointing to the relationship entity IfcRelAggregates. It provides the hierarchy between the separate (partial) distribution systems. For example, an electrical main circuit may be aggregated into branch circuits.

HISTORY New entity in IFC4.

IFC4 CHANGE For electrical power systems, IfcElectricalCircuit has been used for low-voltage (12-1000 V) power circuits and has been replaced by IfcDistributionCircuit in IFC4; IfcDistributionSystem with PredefinedType 'ELECTRICAL' should be used for overall power systems, and IfcDistributionCircuit with PredefinedType 'ELECTRICAL' should be used for each switched circuit.

Attribute definitions

#	Attribute	Type	Cardinality	Description	C
6	LongName	IfcLabel	[0:1]	Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute. NOTE In many scenarios the Name attribute refers to the short name or number of a distribution system or branch circuit, and the LongName refers to a descriptive name.	X
7	PredefinedType	IfcDistributionSystemEnum	[0:1]	Predefined types of distribution systems.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification.	X
3	Name	IfcLabel	[0:1]	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.	X
4	Description	IfcText	[0:1]	Optional description, provided for exchanging informative comments.	X
IfcObjectDefinition
	HasAssignments	IfcRelAssigns @RelatedObjects	S[0:?]	Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.	X
	Nests	IfcRelNests @RelatedObjects	S[0:1]	References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).	X
	IsNestedBy	IfcRelNests @RelatingObject	S[0:?]	References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).	X
	HasContext	IfcRelDeclares @RelatedDefinitions	S[0:1]	References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.	X
	IsDecomposedBy	IfcRelAggregates @RelatingObject	S[0:?]	References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).	X
	Decomposes	IfcRelAggregates @RelatedObjects	S[0:1]	References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).	X
	HasAssociations	IfcRelAssociates @RelatedObjects	S[0:?]	Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.	X
IfcObject
5	ObjectType	IfcLabel	[0:1]	The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.	X
	IsDeclaredBy	IfcRelDefinesByObject @RelatedObjects	S[0:1]	Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.	X
	Declares	IfcRelDefinesByObject @RelatingObject	S[0:?]	Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.	X
	IsTypedBy	IfcRelDefinesByType @RelatedObjects	S[0:1]	Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.	X
	IsDefinedBy	IfcRelDefinesByProperties @RelatedObjects	S[0:?]	Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.	X
IfcGroup
	IsGroupedBy	IfcRelAssignsToGroup @RelatingGroup	S[0:?]	Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.	X
IfcSystem
	ServicesBuildings	IfcRelServicesBuildings @RelatingSystem	S[0:1]	Reference to the ~~building~~ spatial structure via the objectified relationship IfcRelServicesBuildings, which is serviced by the system.	X
IfcDistributionSystem
6	LongName	IfcLabel	[0:1]	Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute. NOTE In many scenarios the Name attribute refers to the short name or number of a distribution system or branch circuit, and the LongName refers to a descriptive name.	X
7	PredefinedType	IfcDistributionSystemEnum	[0:1]	Predefined types of distribution systems.	X

Definitions applying to Common Use Definitions

Instance diagram

Concept usage

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 219.

PredefinedType

Name

Properties

Pset_DistributionSystemCommon

Single Value

Name	Value
Reference	IfcIdentifier

Pset_ServiceLifeFactors

Bounded Value

Name	Value	Value
QualityOfComponents	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
DesignLevel	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
WorkExecutionLevel	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
IndoorEnvironment	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
OutdoorEnvironment	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
InUseConditions	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure
MaintenanceLevel	IfcPositiveRatioMeasure	IfcPositiveRatioMeasure

Table 219 — IfcDistributionSystem Property Sets for Objects

Aggregation

The Aggregation concept applies to this entity as shown in Table 220.

PredefinedType	RelatedObjects	Description
ELECTRICAL	IfcDistributionSystem	Indicates electrical subsystems within the system.
ELECTRICAL	IfcDistributionCircuit	Indicates electrical circuits within the system.

Table 220 — IfcDistributionSystem Aggregation

Group Assignment

The Group Assignment concept applies to this entity as shown in Table 221.

RelatedType	Description
	Indicates devices that are part of the system, where any ports of the same PredefinedType are considered part of the system implicitly.

Table 221 — IfcDistributionSystem Group Assignment

For the most common case of an IfcDistributionElement subtype containing ports of a particular PredefinedType that all belong to the same distribution system, the IfcDistributionElement is assigned to the IfcDistributionSystem via the IfcRelAssignsToGroup relationship, where IfcDistributionPort's are implied as part of the corresponding system based on their PredefinedType. An IfcDistributionElement may belong to multiple systems, however only one IfcDistributionSystem of a particular PredefinedType.

For rare cases where an IfcDistributionElement subtype contains ports of the same PredefinedType yet different ports belong to different systems, alternatively each IfcDistributionPort may be directly assigned to a single IfcDistributionSystem via the IfcRelAssignsToGroup relationship, where the PredefinedType must match. Such assignment indicates that the IfcDistributionSystem assigned from the IfcDistributionPort overrides any such system of the same PredefinedType assigned from the containing IfcDistributionElement, if any.

Additionally, an IfcDistributionSystem may in turn be assigned to an IfcDistributionPort indicating the host or origination of the system using IfcRelAssignsToProduct.

EXAMPLE A gas-powered hot water heater may have three ports: GAS, DOMESTICCOLDWATER, and DOMESTICHOTWATER. The heater is a member of two systems (GAS and DOMESTICCOLDWATER), and hosts one system (DOMESTICHOTWATER) at the corresponding port.

Figure 262 illustrates a distribution system for an electrical circuit.

Figure 262 — Distribution system assignment

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Common Use Definitions
	Revision Control	Common Use Definitions
IfcObject
	Object Occurrence Predefined Type	Common Use Definitions
IfcGroup
IfcSystem
IfcDistributionSystem
	Property Sets for Objects	Common Use Definitions
	Aggregation	Common Use Definitions
	Group Assignment	Common Use Definitions

Formal representations

XSD Specification

 <xs:element name="IfcDistributionSystem" type="ifc:IfcDistributionSystem" substitutionGroup="ifc:IfcSystem" nillable="true"/>

 <xs:complexType name="IfcDistributionSystem">

  <xs:complexContent>

   <xs:extension base="ifc:IfcSystem">

    <xs:attribute name="LongName" type="ifc:IfcLabel" use="optional"/>

    <xs:attribute name="PredefinedType" type="ifc:IfcDistributionSystemEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcDistributionSystem

 SUPERTYPE OF(IfcDistributionCircuit)

 SUBTYPE OF (IfcSystem);

  LongName : OPTIONAL IfcLabel;

  PredefinedType : OPTIONAL IfcDistributionSystemEnum;

END_ENTITY;

 EXPRESS-G diagram

Link to this page

	haustechnische Anlage
	Distribution System
	Système de distribution