6.2.3.9 IfcDistributionSystem

Système de distribution
haustechnische Anlage

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:

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 For electrical power systems, IfcElectricalCircuit has been used for low-voltage (12-1000 V) power circuits and has been replaced by IfcDistributionCircuit in IFC4; IfcDistributionSystem with PredefinedType 'ELECTRICAL' should be used for overall power systems, and IfcDistributionCircuit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

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 221.
PredefinedTypeName
 Pset_DistributionSystemCommon
ELECTRICALPset_DistributionSystemTypeElectrical
VENTILATIONPset_DistributionSystemTypeVentilation
 Pset_ServiceLifeFactors

Table 221 — IfcDistributionSystem Property Sets for Objects



Object Aggregation

The Object Aggregation concept applies to this entity as shown in Table 222.
PredefinedTypeRelatedObjectsDescription
ELECTRICALIfcDistributionSystemIndicates electrical subsystems within the system.
ELECTRICALIfcDistributionCircuitIndicates electrical circuits within the system.

Table 222 — IfcDistributionSystem Object Aggregation



Group Assignment

The Group Assignment concept applies to this entity as shown in Table 223.
TypeDescription
IfcDistributionElementIndicates devices that are part of the system, where any ports of the same PredefinedType are considered part of the system implicitly.
IfcDistributionPortIndicates port that is explicitly part of the system, which overrides any system assignment of the containing device.

Table 223 — 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 237 illustrates a distribution system for an electrical circuit.

Instance diagram for electrical circuit

Figure 237 — Distribution system assignment




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;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

LongName : Long name for a 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.
PredefinedType : Predefined types of distribution systems.

Inheritance Graph:

ENTITY IfcDistributionSystem
ENTITY IfcRoot
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
INVERSE
HasAssignments : SET OF IfcRelAssigns FOR RelatedObjects;
Nests : SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy : SET OF IfcRelNests FOR RelatingObject;
HasContext : SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy : SET OF IfcRelAggregates FOR RelatingObject;
Decomposes : SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations : SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject
ObjectType : OPTIONAL IfcLabel;
INVERSE
IsDeclaredBy : SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares : SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy : SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy : SET OF IfcRelDefinesByProperties FOR RelatedObjects;
ENTITY IfcGroup
INVERSE
IsGroupedBy : SET OF IfcRelAssignsToGroup FOR RelatingGroup;
ENTITY IfcSystem
INVERSE
ServicesBuildings : SET [0:1] OF IfcRelServicesBuildings FOR RelatingSystem;
ENTITY IfcDistributionSystem
LongName : OPTIONAL IfcLabel;
PredefinedType : OPTIONAL IfcDistributionSystemEnum;
END_ENTITY;

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