Designers must investigate solutions that represent the best trade-off between the results of different design options. This entails a quantitative assessment of safety levels. Key Performance Indicators (KPIs) facilitate this assessment by providing a clear and concise visualization of safety levels in buildings. This paper concerns fire safety design of buildings, focusing on the structural components’ fire resistance. Technically, we developed a framework, integrated in a BIM environment, to implement performance-based assessments of structural elements, ensuring that fire safety objectives are met. Fire safety performances are tracked by means of a KPI identified for its representativeness. The visualization of the KPI in BIM models highlights critical elements and enables a quick refinement of design solutions. The outcome is a BIM information-rich model handed over to facility managers, to track the performances of structural components and timely implement renovation actions in the use phase of buildings.