IFC 4.3.x development

5.4.3.73 IfcZone

Change log

IFC4

additions attributes LongName
additions where_rulesWR1
deletions where_rulesWR1
modificationssupertype Changed from IfcGroup to IfcSystem

IFC4X1

additionswhere_rulesWR1
deletionswhere_rulesWR1

IFC4X2

additionswhere_rulesWR1
deletionswhere_rulesWR1

IFC4X3_RC3

additionswhere_rulesWR1
deletionswhere_rulesWR1

5.4.3.73.1 Semantic definitions at the entity

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.

5.4.3.73.1 Attributes

# Attribute Type Description
IfcRoot
1 GlobalId IfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world.
2 OwnerHistory OPTIONAL 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.
3 Name OPTIONAL 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.
4 Description OPTIONAL IfcText Optional description, provided for exchanging informative comments.
IfcObjectDefinition
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects 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.
Nests SET [0:1] OF IfcRelNests FOR RelatedObjects 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.
IsNestedBy SET [0:?] OF IfcRelNests FOR RelatingObject 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.
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions 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.
IsDecomposedBy SET [0:?] OF IfcRelAggregates FOR RelatingObject 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.
Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects 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.
HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects 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.
IfcObject
5 ObjectType OPTIONAL 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.
IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects 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.
Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject 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.
IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects 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.
IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects 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.
IfcGroup
IsGroupedBy SET [0:?] OF IfcRelAssignsToGroup FOR RelatingGroup 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.
IfcSystem
ServicesBuildings SET [0:1] OF IfcRelServicesBuildings FOR RelatingSystem Reference to the ~~building~~ spatial structure via the objectified relationship IfcRelServicesBuildings, which is serviced by the system.
ServicesFacilitiesSET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements
IfcZone
6 LongName OPTIONAL IfcLabel 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.

5.4.3.73.2 Entity inheritance

dot_inheritance IfcZone IfcZone IfcSystem IfcSystem IfcZone->IfcSystem IfcSystem_children 4 more... IfcSystem_children->IfcSystem IfcGroup IfcGroup IfcSystem->IfcGroup IfcGroup_children 4 more... IfcGroup_children->IfcGroup IfcObject IfcObject IfcGroup->IfcObject IfcObject_children 5 more... IfcObject_children->IfcObject IfcObjectDefinition IfcObjectDefinition IfcObject->IfcObjectDefinition IfcContext IfcContext IfcContext->IfcObjectDefinition IfcRoot IfcRoot IfcObjectDefinition->IfcRoot IfcTypeObject IfcTypeObject IfcTypeObject->IfcObjectDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertyDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

5.4.3.73.3 Definitions applying to General Usage

5.4.3.73.3.1 Classification Association

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

5.4.3.73.3.2 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:

  • 'FireCompartment': a zone of spaces, collected to represent a single fire compartment.
  • 'ElevatorShaft': a collection of spaces within an elevator, potentially going through many storeys.
  • 'RisingDuct': A collection of vertical airspaces.
  • 'RunningDuct': A collection of horizontal airspaces.

5.4.3.73.3.3 Identity

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

5.4.3.73.3.4 Object Predefined Type

5.4.3.73.3.5 Object Typing

Any object occurrence can be typed by being assigned to a common object type utilizing this concept. A particular rule, restricting the applicable subtypes of IfcTypeObject that can be assigned, is introduced by overriding this concept at the level of subtypes of IfcObject.

5.4.3.73.3.6 Object User Identity

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as ifcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

5.4.3.73.3.7 Property Sets

PsetName
'Pset_ServiceLifeFactors'

5.4.3.73.3.8 Property Sets for Objects

PsetName
'Pset_ZoneCommon'
'Pset_AirSideSystemInformation'

5.4.3.73.3.9 Property Sets with Override

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case, that the same property (within the same property set, is defined both, in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

5.4.3.73.3.10 Revision Control

Ownership, history, and merge state is captured using IfcOwnerHistory.

5.4.3.73.4 Formal representations

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(('IFC4X3_DEV_a1492713.IFCZONE' IN TYPEOF(temp)) OR 
  ('IFC4X3_DEV_a1492713.IFCSPACE' IN TYPEOF(temp)) OR
  ('IFC4X3_DEV_a1492713.IFCSPATIALZONE' IN TYPEOF(temp))
 ))) = 0);
END_ENTITY;