Industry Foundation Classes (IFC), an object data model of buildings, are being developed by the International Alliance for Interoperability (IAI) to support data sharing and exchange in the building and construction industry. The IAI, founded in 1995, has published four releases of IFC so far. Several prototype implementations by leading software companies show that commercial IFC software is beginning to meet end user expectations of interoperability in the industry. BS-8 is an LBNL project that started last summer. It is developing the IFC HVAC extension schemata that will extend the IFC object data model and support the exchange of HVAC information between software currently used by the AEC/FM community (e.g., CAD) and various building services simulation tools, such as EnergyPlus. Supporting the exchange of HVAC information will make the use of such tools more efficient and cost-effective, and will therefore remove the primary barriers to their more widespread use. The new extension schemata will provide access to these data not only during design, but also during the operation of the constructed building. In order to assure the HVAC data can be exchanged across the life cycle of a building, the project defines models for connectivity, time series, electrical systems, HVAC equipment and systems and controls. These models will all be incorporated in the next IFC release. Several organizations and institutions from around the world are cooperating on this project.  --This seminar will review the background of the project and its initial structure. It will also examine the ways in which the project is developing the underlying models, and will discuss the next steps in planned work.