5.4.3.57 IfcZone

Zone
Zone

A zone is a group of spaces, partial spaces or other zones. Zone structures may not be hierarchical (in contrary to the spatial structure of a project - see IfcSpatialStructureElement), i.e. one individual IfcSpace may be associated with zero, one, or several IfcZone's. IfcSpace's are grouped into an IfcZone by using the objectified relationship IfcRelAssignsToGroup as specified at the supertype IfcGroup.

NOTE  Certain use cases may restrict the freedom of non hierarchical relationships. In some building service use cases the zone denotes a view based delimited volume for the purpose of analysis and calculation. This type of zone cannot overlap with respect to that analysis, but may overlap otherwise.
HISTORY  New entity in IFC1.0
IFC4 CHANGE  The entity is now subtyped from IfcSystem (not its supertype IfcGroup) with upward compatibility for file based exchange.

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Object Classification

The Object Classification concept applies to this entity.

Additional classifications of the IfcZone, as provided by a national classification system, can be assigned by using the IfcRelAssociatesClassification relationship, accessible via the inverse attribute HasAssociations. The IfcZone can be assigned to a spatial structure element, it refers to, e.g. to a particular IfcBuildingStorey by using the IfcRelServicesBuildings relationship, accessible via the inverse attribute ServicesBuilding.



Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 78.
PredefinedTypeName
 Pset_ZoneCommon
 Pset_ServiceLifeFactors

Table 78 — IfcZone Property Sets for Objects



Group Assignment

The Group Assignment concept applies to this entity as shown in Table 79.
Type
IfcSpatialStructureElement

Table 79 — IfcZone Group Assignment

An IfcZone is a spatial system under which individual IfcSpace's (and other IfcZone's) are grouped. In contrary to the IfcSpatialZone entity, IfcZone is a mere grouping, it can not define an own geometric representation and placement. Therefore it cannot be used for spatial zones having a different shape and size compared to the shape and size of aggregated spaces.

NOTE  The IfcZone is regarded as the spatial system (as compared to the building service, electrical, or analytical system), the name remains IfcZone for compatibility reasons, instead of using a proper naming convention, like IfcSpatialSystem.
NOTE  One of the purposes of a zone is to define a fire compartmentation. In this case it defines the geometric information about the fire compartment (through the contained spaces) and information, whether this compartment is ventilated or sprinkler protected. In addition the fire risk code and the hazard type can be added, the coding is normally defined within a national fire regulation. All that information is available within the relevant property sets. Again, if an independent shape has to be provided to the fire compartment, then the entity IfcSpatialZone shall be used.

In case of a zone denoting a (fire) compartment, the following types should be used, if applicable, as values of the ObjectType attribute:




XSD Specification:

 <xs:element name="IfcZone" type="ifc:IfcZone" substitutionGroup="ifc:IfcSystem" nillable="true"/>
 <xs:complexType name="IfcZone">
  <xs:complexContent>
   <xs:extension base="ifc:IfcSystem">
    <xs:attribute name="LongName" type="ifc:IfcLabel" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification:

ENTITY IfcZone
SUBTYPE OF IfcSystem;
LongName : OPTIONAL IfcLabel;
WHERE
WR1 : (SIZEOF(SELF\IfcGroup.IsGroupedBy) = 0) OR (SIZEOF (QUERY (temp <* SELF\IfcGroup.IsGroupedBy[1].RelatedObjects | NOT(('IFCPRODUCTEXTENSION.IFCZONE' IN TYPEOF(temp)) OR ('IFCPRODUCTEXTENSION.IFCSPACE' IN TYPEOF(temp)) OR ('IFCPRODUCTEXTENSION.IFCSPATIALZONE' IN TYPEOF(temp)) ))) = 0);
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

LongName : Long name for a zone, 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 zone, and the LongName refers to the full name.

IFC4 CHANGE The attribute has been added at the end of the entity definition.

Formal Propositions:

WR1 : An IfcZone is grouped by the objectified relationship IfcRelAssignsToGroup. Only objects of type IfcSpace, IfcZone and IfcSpatialZone are allowed as RelatedObjects.

Inheritance Graph:

ENTITY IfcZone
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 IfcZone
LongName : OPTIONAL IfcLabel;
END_ENTITY;

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