Sharing fire engineering simulation data using the IFC building information model
Fire engineers use computer-based fire simulation models to determine the spread of fire and smoke; the response of a structure to high temperatures and the movement of people exiting from a building. The standardised Industry Foundation Classes (IFC) Building Product Model can be used to begin to achieve interoperability between electronic building descriptions created in commercially available Building Information Modelling (BIM) applications and fire simulation models. Two mainstream BIM applications, ArchiCAD and Revit, have been used to generate IFC compliant files that are translated by a parsing software tool into input files for two fire simulation models widely used by fire engineers, BRANZFIRE and FDS. The specific needs of fire simulation software means that a software tool has been developed to parse the IFC Model from the STEP physical file format to generate a subset of fire simulation related entities. This intermediate data is used by dedicated software interfaces developed to create specific input data for different fire simulation models (Figure 1). The two fire simulation models employ distinctive conceptual representations of a building and differ in the way in which they carry out their computations. These differences significantly determine the requirements of the translation process from the IFC Model. The translation of geometrical and topological building information requires the identification of spaces, boundaries (walls and slabs) and openings (windows and doors) and their relationship to one another. Trial buildings have been used to test the ability to correctly interpret the IFC files and to determine where difficulties occur. A specific trial building is described here as an illustration of the capability of the current parsing tool. There are a number of challenges when using this approach for data sharing. There are limitations inherent in the IFC Model in describing buildings and fire engineering specific information where the structure of entities may not be compatible with the requirements of a particular fire simulation model. The representation of building spaces and elements can differ significantly with the various categories of models. This requires an ability to interpret and translate IFC Model entities to these alternate representations which adds to the complexity of the exchange process. Finally there are issues with the implementation of the IFC schema in commercial BIM applications and the capacity for users to populate IFC Model entities. The ability to quickly and accurately share building information created in BIM applications with fire simulation models has the potential to assist fire engineers during their design process. The IFC Model can be used to fulfil this role but there are a considerable number of obstacles that need to be tackled before then.