8.11.3.2 IfcConversionBasedUnit
RV ⓘ
AbV ⓘ
8.11.3.2.1 Semantic definition
An IfcConversionBasedUnit is used to define a unit that has a conversion rate to a base unit. To identify some commonly used conversion based units, the standard designations (case insensitive) for the Name attribute are indicated in Table 8.11.3.2.R.
| Name | Description |
|---|---|
| 'inch' | Length measure equal to 25.4 mm |
| 'foot' | Length measure equal to 304.8 mm |
| 'US survey foot' | Length measure equal to 304.80060960122 mm (i.e. the approximate value of 1200/3937 meters) |
| 'yard' | Length measure equal to 914 mm |
| 'mile' | Length measure equal to 1609 m |
| 'square inch' | Area measure equal to 0.0006452 square meters |
| 'square foot' | Area measure equal to 0.09290 square meters |
| 'square yard' | Area measure equal to 0.83612736 square meters |
| 'acre' | Area measure equal to 4046.86 square meters |
| 'square mile' | Area measure equal to 2 588 881 square meters |
| 'cubic inch' | Volume measure equal to 0.00001639 cubic meters |
| 'cubic foot' | Volume measure equal to 0.02832 cubic meters |
| 'cubic yard' | Volume measure equal to 0.7636 cubic meters |
| 'litre' | Volume measure equal to 0.001 cubic meters |
| 'fluid ounce UK' | Volume measure equal to 0.0000284130625 cubic meters |
| 'fluid ounce US' | Volume measure equal to 0.00002957353 cubic meters |
| 'pint UK' | Volume measure equal to 0.000568 cubic meters |
| 'pint US' | Volume measure equal to 0.000473 cubic meters |
| 'gallon UK' | Volume measure equal to 0.004546 cubic meters |
| 'gallon US' | Volume measure equal to 0.003785 cubic meters |
| 'degree' | Angle measure equal to π/180 rad |
| 'ounce' | Mass measure equal to 28.35 g |
| 'pound' | Mass measure equal to 0.454 kg |
| 'ton UK' | Mass measure equal to 1016.0469088 kg, also known as long ton, gross ton, shipper's ton |
| 'ton US' | Mass measure equal to 907.18474 kg, also known as short ton, net ton |
| 'lbf' | Force measure equal to 4.4482216153 N, pound-force |
| 'kip' | Force measure equal to 4448.2216153 N, kilopound-force |
| 'psi' | Pressure measure equal to 6894.7572932 Pa, pound-force per square inch |
| 'ksi' | Pressure measure equal to 6894757.2932 Pa, kilopound-force per square inch |
| 'minute' | Time measure equal to 60 s |
| 'hour' | Time measure equal to 3600 s |
| 'day' | Time measure equal to 86400 s |
| 'btu' | Energy measure equal to 1055.056 J, British Thermal Unit |
8.11.3.2.2 Entity inheritance
8.11.3.2.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcNamedUnit (2) | |||
| 1 | Dimensions | IfcDimensionalExponents |
The dimensional exponents of the SI base units by which the named unit is defined. |
| 2 | UnitType | IfcUnitEnum |
The type of the unit. |
| Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes | |||
| IfcConversionBasedUnit (3) | |||
| 3 | Name | IfcLabel |
The word, or group of words, by which the conversion based unit is referred to. |
| 4 | ConversionFactor | IfcMeasureWithUnit |
The physical quantity from which the converted unit is derived. |
| HasExternalReference | SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects |
Reference to external information, e.g. library, classification, or document information, which is associated with the conversion-based unit. New inverse attribute. |
|
8.11.3.2.4 Examples
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Figure 8.11.3.2.A -
Figure 8.11.3.2.B -
Figure 8.11.3.2.C -
Figure 8.11.3.2.D -
Figure 8.11.3.2.E -
Figure 8.11.3.2.F -
Figure 8.11.3.2.G -
Figure 8.11.3.2.H -
Figure 8.11.3.2.I -
Figure 8.11.3.2.J -
Figure 8.11.3.2.K -
Figure 8.11.3.2.L -
Figure 8.11.3.2.M -
Figure 8.11.3.2.N -
Figure 8.11.3.2.O -
Figure 8.11.3.2.P -
Figure 8.11.3.2.Q
8.11.3.2.5 Formal representation
ENTITY IfcConversionBasedUnit
SUPERTYPE OF (ONEOF
(IfcConversionBasedUnitWithOffset))
SUBTYPE OF (IfcNamedUnit);
Name : IfcLabel;
ConversionFactor : IfcMeasureWithUnit;
INVERSE
HasExternalReference : SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects;
END_ENTITY;