IfcPropertySingleValue

BACnet MVD

#### IfcPropertySingleValue

Natural language names

| Merkmal mit Einzelwert
| Property Single Value
| Propriété à valeur simple

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC4 Addendum 1
IfcPropertySingleValue |  |  |  |
HasConstraints |  |  | ADDED |
HasApprovals |  |  | ADDED |

##### Semantic definitions at the entity

Entity definition

The property with a single value IfcPropertySingleValue defines a property object which has a single (numeric or descriptive) value assigned. It defines a property - single value combination for which the property Name, an optional Description, and an optional NominalValue with measure type is provided. In addition, the default unit as specified within the project unit context can be overriden by assigning an Unit.

The unit is handled by the Unit attribute, see Table 45 for an example of various single value properties:

- If the Unit attribute is not given, then the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext).
- If the Unit attribute is given, then the unit assigned by the Unit attribute overrides the globally assigned unit.

Name | NominalValue | Type (through IfcValue) | Unit
--- | --- | --- | ---
Description | Manufacturer "A" door | IfcLabel | -
PanelThickness | 0.12 | IfcPositiveLengthMeasure | -
ThermalTransmittance | 2.6 | IfcThermalTransmittanceMeasure | W/(m2K)

Table 45 — Single value properties with values, measure types and units

> HISTORY New entity in IFC1.0.

> IFC2x CHANGE Entity has been renamed from IfcSimpleProperty.

> IFC2x3 CHANGE Attribute NominalValue has been made OPTIONAL with upward compatibility for file based exchange.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---

3

NominalValue

IfcValue

?

Value and measure type of this property.

> NOTE By virtue of the defined data type, that is selected from the SELECT IfcValue, the appropriate unit can be found within the IfcUnitAssignment, defined for the project if no value for the unit attribute is given.

> IFC2x3 CHANGE The attribute has been made optional with upward compatibility for file based exchange.

X

X

4 | Unit | IfcUnit | ? | Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject. |  | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcPropertyAbstraction

HasExternalReferences

IfcExternalReferenceRelationship
@RelatedResourceObjects

S[0:?]

Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition.

> IFC4 CHANGE New inverse attribute.

X

IfcProperty
1 | Name | IfcIdentifier |  | Name for this property. This label is the significant name string that defines the semantic meaning for the property. | X | X
2 | Description | IfcText | ? | Informative text to explain the property. | X | X

PartOfPset

IfcPropertySet
@HasProperties

S[0:?]

Reference to the IfcPropertySet by which the IfcProperty is referenced.

> IFC4 CHANGE New inverse attribute to navigate from IfcProperty to IfcPropertySet with upward compatibility for file based exchange.

X

| PropertyForDependance | IfcPropertyDependencyRelationship @DependingProperty | S[0:?] | The property on whose value that of another property depends. |  | X
| PropertyDependsOn | IfcPropertyDependencyRelationship @DependantProperty | S[0:?] | The relating property on which the value of the property depends. |  | X

PartOfComplex

IfcComplexProperty
@HasProperties

S[0:?]

Reference to the IfcComplexProperty in which the IfcProperty is contained.

> IFC4 CHANGE The cardinality has changed to 0..n to allow reuse of instances of IfcProperty in several IfcComplexProperty with upward compatibility for file based exchange.

X

| HasConstraints | IfcResourceConstraintRelationship @RelatedResourceObjects | ? S[0:?] | User-defined constraints for the property. |  | X
| HasApprovals | IfcResourceApprovalRelationship @RelatedResourceObjects | ? S[0:?] | User-defined approvals for the property. |  | X
IfcSimpleProperty
IfcPropertySingleValue

3

NominalValue

IfcValue

?

Value and measure type of this property.

> NOTE By virtue of the defined data type, that is selected from the SELECT IfcValue, the appropriate unit can be found within the IfcUnitAssignment, defined for the project if no value for the unit attribute is given.

> IFC2x3 CHANGE The attribute has been made optional with upward compatibility for file based exchange.

X

X

4 | Unit | IfcUnit | ? | Unit for the nominal value, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcPropertySingleValue" type="ifc:IfcPropertySingleValue" substitutionGroup="ifc:IfcSimpleProperty" nillable="true"/>
<xs:complexType name="IfcPropertySingleValue">
<xs:complexContent>
<xs:extension base="ifc:IfcSimpleProperty">
<xs:sequence>
<xs:element name="NominalValue" nillable="true" minOccurs="0">
<xs:complexType>
<xs:group ref="ifc:IfcValue"/>
</xs:complexType>
</xs:element>
<xs:element name="Unit" nillable="true" minOccurs="0">
<xs:complexType>
<xs:group ref="ifc:IfcUnit"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcPropertySingleValue
SUBTYPE OF (IfcSimpleProperty);
NominalValue : OPTIONAL IfcValue;
Unit : OPTIONAL IfcUnit;
END_ENTITY;

EXPRESS-G diagram

`

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