Ashrae Journal - December 2008 - 46

starting point, the implementation of BIM in North America has been focused on the architect with the result that the 3D aspect of BIM is the primary aspect that you see and hear about. In Europe, the role of the architect and engineer on typical building design projects is not as hierarchical as in North America. The architect is responsible for the aesthetics of the building, but owners do not view the architect as in charge of the design team in the same way as it has evolved in North America. The architect’s expertise is still recognized and valued as architectural design is held in high regard, but the overall team relationship is different. With the starting point for roles different in Europe, implementation of BIM has had the opportunity to take a somewhat different course. Creating a multidisciplinary 3D integrated model of a building is a valuable tool in the design and construction process, but if it does not enable interoperability (such as in the case of data sharing with an energy model), then it is not truly BIM. To go from 3D integrated design to a BIM/Interoperable design, additional effort is required. This effort is focused on the creation of the total BIM database or file so that it can be used in an interoperable way. The effort to create the BIM model hopefully will result in less effort downstream or more value added overall, but it must be recognized that there is a significant effort involved in creating and maintaining the building physical model in a manner in which it can support all of the Space is Drawn to the Inside of the Wall Columns are Excluded from the Net Area Figure 3: GSA model view deἀnition for spatial program validation.2 www.info.hotims.com/16020-5 necessary downstream applications (such as energy modeling). BIM may not always need to be implemented as a single data file, it can be developed as federated data models (separate linked or coordinated data models). However, the same type of effort is required to enable interoperability. There have been some projects completed in Europe where interoperability between the building model and the energy model have been achieved. Through discussions with participants and review of the results, some differences in approach that have led to these successes can be identified. In those more successful projects, the mechanical/electrical/plumbing (MEP) consultant on the project took a central role in terms of interoperability. The architect developed the design of the building using a 3D object-based tool. Then, the MEP engineer took the architect’s building files and did the necessary additional work that allowed the creation of a data view suitable for input into their proprietary middleware tool and energy model. The MEP consultant did not attempt to send the building file back to the architect, instead they retained the responsibility of maintaining that portion of the overall project BIM/IFC file. Updates to the building file were carefully coordinated between the architect and the engineer, and were managed through the MEP engineer. This engineering-centric approach to BIM puts the responsibility of maintaining a significant portion of the overall BIM/ IFC file with the team member that had the best expertise to execute the task. There is more to interoperability than data exchange between the building physical data and the energy model, but this particular aspect of interoperability is an application that is very encompassing. Once the physical data of the building is defined and organized in the manner necessary for the energy model, it is relatively easy to extract other forms of this same data for use in other applications. Examples of this would be space lists, area summaries, window take-offs, etc. The MEP engineer is not attempting to usurp any other team member’s role, but can become a central player in many interoperability aspects of the overall BIM application with this type of approach. In this example, the MEP consultant was able to December 2008 46 ASHRAE Journal

Ashrae Journal - December 2008

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