Can you actually contain a distribution system in a building?

[Moult]

In the diagram here https://github.com/buildingSMART/IDS/blob/master/Documentation/UserManual/partof-facet.md it shows a distribution system contained in a building.

I didn't know this was possible. I searched the IFC docs but could not find any mention of this being legal.

Can somebody clarify?

[NickNisbet]

A distribution system ‘serves’ a building (or other spatial element), so 1. Either IfcRelServicesBuildings and IfcRelReferencedInSpatialStructure should be added to the documentation and implementations (preferred) 2. Or the diagram and documentation could be correcte.d

[Moult]

Cheers. Ping @LeeGregory12d I saw this bug in 12D but I wasn't sure who to contact.

[atomczak]

(1.) IfcRelServicesBuildings is deprecated, so shouldn't be used. Let's discuss in the IDS group if IfcRelReferencedInSpatialStructure should be added to PartOf facet. If not, we should update the IDS docs (2.).

[aothms]

Not an expert on building services, but it is my understanding that the PartOf facet is supposed to only cover the hierarchical relationships. A distribution can serve multiple buildings or spatial elems so in that case the system is not "part of" the building (unless it is also contained in it). That also brings me to a second question, if we're not supposed to "contain" systems, how are we then connecting the system to the project decomposition/containment tree?

[NickNisbet]

IfcRelSevicesBuilding (SpatialStructure) was the means to do this. It is now (sadly) deprecated in favour of Use IfcRelReferencedInSpatialStructure<https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcRelReferencedInSpatialStructure.htm> instead. This relationship is a secondary relationship creating a ‘directed net’ , since IfcRelContainsInSpatialStructure is a strict ‘tree’ hierarchy. Other uses of IfcrelreferencedInSpatialStructure include linking upper floors to a lift shaft that is linked to the lowest floor. Adding this to the ‘part of’ facet seems like a good idea. Regards, Nick.