IfcDistributionSystem

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 or utilities for built facilities.
Important functionalities for the description of a distribution system are derived from existing IFC entities:

From IfcSystem it inherits the ability to couple the built system via IfcRelReferencedInSpatialStructure to one or more IfcSpatialElement subtypes as necessary.
From IfcGroup it inherits the inverse attribute IsGroupedBy, pointing to the relationship class IfcRelAssignsToGroup . This allows the grouping of distribution elements (instances of IfcDistributionElement subtypes).
From IfcObjectDefinition it inherits the inverse attribute IsDecomposedBy pointing to the relationship class 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.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
6	LongName	IfcLabel	?	Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute.\X\0D 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	?		X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRoot
1	GlobalId	IfcGloballyUniqueId		Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	?	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. IFC4 CHANGE The attribute has been changed to be OPTIONAL.	X
3	Name	IfcLabel	?	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	?	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). IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.	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). IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.	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. IFC4 CHANGE The inverse attribute datatype has been added.	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). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	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). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	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	?	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. IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange.	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. IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange.	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. IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange.	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. IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.	X
IfcGroup
	IsGroupedBy	IfcRelAssignsToGroup @RelatingGroup	S[0:?]	Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object. IFC4 CHANGE The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of IfcRelAssignsToGroup to assign the group members. The change has been done with upward compatibility for file based exchange.	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
	ServicesFacilities	IfcRelReferencedInSpatialStructure @RelatedElements	S[0:?]		X
IfcDistributionSystem
6	LongName	IfcLabel	?	Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute.\X\0D 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	?		X

Definitions applying to General Usage

Instance diagram

Concept usage

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 232.

PsetName

Properties

Pset_DistributionSystemCommon

Template	PropertyName	Value
Single Value	Reference	IfcIdentifier

Table 232 — IfcDistributionSystem Property Sets for Objects

Aggregation

The Aggregation concept template applies to this entity as shown in Table 233.

Table 233 — IfcDistributionSystem Aggregation

Group Assignment

The Group Assignment concept template applies to this entity as shown in Table 234.

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

Table 234 — 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 269 illustrates a distribution system for an electrical circuit.

"Instance diagram for electrical circuit"

Figure 269 — Distribution system assignment

mvdXML Specification


<?xml version="1.0" encoding="utf-8"?>

<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="afe1b96a-7618-4ce7-8b0f-fb6d9546f3d0" name="IfcDistributionSystem" applicableRootEntity="IfcDistributionSystem">

 <Applicability>

  <Template ref="49e4352b-1839-4446-82ec-24d742768f1e" />

  <TemplateRules operator="and">

  </TemplateRules>

 </Applicability>

 <Concepts>

  <Concept uuid="11816ae1-f077-4e15-997b-5bac26230c79" name="Property Sets for Objects">

   <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="PsetName[Value]=&apos;Pset_DistributionSystemCommon&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="283ea9eb-dbd3-448c-afad-3303fd84c942" name="Aggregation">

   <Template ref="02eefcc6-b26c-4f20-9c7c-c30ae74eb9a9" />

   <TemplateRules operator="and">

    <TemplateRule Description="Indicates electrical subsystems within the system." />

    <TemplateRule Description="Indicates electrical circuits within the system." />

   </TemplateRules>

  </Concept>

  <Concept uuid="d7d0722e-99d6-45dc-b2b9-78948910f1d7" name="Group Assignment">

   <Template ref="f567967f-5493-44d9-ac51-937c09ac2583" />

   <TemplateRules operator="and">

    <TemplateRule Description="Indicates devices that are part of the system, where any ports of the same PredefinedType are considered part of the system implicitly." />

    <TemplateRule Description="Indicates port that is explicitly part of the system, which overrides any system assignment of the containing device." />

   </TemplateRules>

  </Concept>

 </Concepts>

</ConceptRoot>

Concept inheritance

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General Usage
IfcObjectDefinition
	Classification Association	Classification Association	General Usage
IfcObject
	Object User Identity	Object User Identity	General Usage
	Object Predefined Type	Object Predefined Type	General Usage
	Object Typing	Object Typing	General Usage
	Property Sets with Override	Property Sets with Override	General Usage
IfcDistributionSystem
	Property Sets for Objects	Property Sets for Objects	General Usage
	Aggregation	Aggregation	General Usage
	Group Assignment	Group Assignment	General Usage

Item	SPF	XML	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcDistributionSystem			ADDED
IFC2x3 to IFC4 4.0.0.0
IfcDistributionSystem			ADDED
IFC4x2 to IFC4x3_RC1
IfcDistributionSystem
ServicesFacilities			ADDED

	haustechnische Anlage
	Distribution System
	Système de distribution

IfcDistributionSystem

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations