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IfcZone

Definition from IAI: A zone (IfcZone) is an aggregation 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 aggregated 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.
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.
RECOMMENDATION  In case of a zone denoting a (fire) compartment, the following types should be used, if applicable, as values of the ObjectType attribute:

Additional classifications of the IfcZone, as provided by a national classification system, can be assigned by using the IfcRelAssociatesClassification relationship.

HISTORY New entity in IFC Release 1.0

Property Set Use Definition:

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

EXPRESS specification:

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

Formal Propositions:

WR1  :  A Zone is grouped by the objectified relationship IfcRelAssignsToGroup. Only objects of type IfcSpace or IfcZone are allowed as RelatedObjects.

Inheritance graph

ENTITY IfcZone;
ENTITY IfcRoot;
GlobalId  :  IfcGloballyUniqueId;
OwnerHistory  :  IfcOwnerHistory;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ENTITY IfcObjectDefinition;
INVERSE
HasAssignments  :  SET OF IfcRelAssigns FOR RelatedObjects;
IsDecomposedBy  :  SET OF IfcRelDecomposes FOR RelatingObject;
Decomposes  :  SET [0:1] OF IfcRelDecomposes FOR RelatedObjects;
HasAssociations  :  SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject;
ObjectType  :  OPTIONAL IfcLabel;
INVERSE
IsDefinedBy  :  SET OF IfcRelDefines FOR RelatedObjects;
ENTITY IfcGroup;
INVERSE
IsGroupedBy  :  IfcRelAssignsToGroup FOR RelatingGroup;
ENTITY IfcZone;
END_ENTITY;