3.7 Use property sets

Fixed positions

IFC describes the use of the property sets with the associated Properties. Because we use an international standard, all properties included have a fixed position and it is possible to find properties in the same place in all aspect models.

Predefined

IFC provides predefined properties in property sets belonging to specific entities: the Common PropertySets. When entities are further qualified by the use of TypeEnumerations, additional property sets sometimes become available.

Properties in property sets (Pset)

An Entity has several Properties that are brought together in a set. Each entity has a collection of properties that are specific to the entity. The most recognisable are Common property sets such as: PsetWallCommon, which contains properties such as FireRating, LoadBearing, IsExternal.

  • If, according to buildingSMART, entered properties belong in a specific Pset, they should at least be found there too.
  • Additional properties that are not provided for by buildingSMART may be placed under their own property set. Name these own sets in the project-specific agreements under 4.8, so that everyone in the project team knows where the properties you have validated can be found.
  • Please note: the name of an optional property set may not, according to BuildingSMART start with ‘Pset’.

Examples

Pset_CoveringCommon (also applies to IfcCovering.FLOORING) contains the following Properties:

  • FireRating
  • IsExternal
  • LoadBearing
  • FlammabilityRating
  • AcousticRating
  • FragilityRating
  • SurfaceSpreadOfFlame
  • Combustible

Pset_Covering.Ceiling (only applies to ceilings) contains the following Properties:

  • FragilityRating
  • Permeability
  • TileLength
  • TileWidth

Differences in IFC2x3Tcl and IFC4

Note that there are differences in Properties and property sets between the different IFC versions. For example, in the case of IfcPile: this entity has in IFC2x3Tc1 no LoadBearing property in the Pset_PileCommon. If you want to indicate that this foundation pile is or is not structurally bearing, you must indicate this in a separate property set in IFC2x3Tc1.

From IFC4.0.2 onward, LoadBearing is included in the Pset_PileCommon.

Figure 3.7: Example Pset_WallCommon

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