Linked Data Working Group (LDWG)

The buildingSMART Linked Data Working Group (LDWG) is responsible for building and maintaining a recommended version of an ifcOWL ontology as an equivalent to the IFC EXPRESS schema. The ifcOWL ontology is to be used in linked data and semantic web applications that consume IFC data. The group meets at regular intervals, both virtual and live, to keep track of and discuss possible enhancements to the ifcOWL ontology. The LDWG is part of the Technical Room and closely interacts with the other working groups, such as the MSG and the bsDD-WG.

The LDWG operates within the auspices of the Technical Room for the purpose of helping provide guidance in the development of technical advancements that allow the implementation of robust open BIM solutions to end users. This also allows the group to propose developments and enhancements for the existing bSI standards, so that they are more easily accessible via linked data technologies.


The role and purpose of the LDWG includes:

  • Responsibility for developing and maintaining a recommended ifcOWL ontology;
  • Proposing technical enhancements and developments to the existing bSI standards in the Technical Room;
  • Aligning semantic web activities with ongoing efforts in buildingSMART, such as the bSDD;
  • Providing support in the usage of an ifcOWL ontology.

Membership / Participation

Participation in the Linked Data Working Group is open to all Technical Room Steering Committee members, Technical Room Sponsors with active projects, SACs, and International members of bSI.

The LDWG meets via an online conference call at least once each month

The group is chaired by Pieter Pauwels ( and Jakob Beetz ( If you want to join the group, please send a message to the chairs.

The buildingSMART Forums also have a Category for the discussion of Linked Data topics for developers at: