Indoor Walkability Index: BIM-enabled approach to Quantifying building circulation

Building circulation is one of the crucial design factors associated with spatial planning, especially in the early phases of building design and has a significant impact on the overall design quality. In this paper, we describe the development of an evaluation framework for design analysis that focuses on the Walkability of building circulation in a Building Information Modeling (BIM) environment as a consideration for simplifying complex design problems. The evaluation framework emphasizes a quantitative, explicit approach utilizing the Indoor Walkability Index (IWI), which is a measure of indoor circulation performance that includes criteria such as distance, simplicity, accessibility, and pedestrian-friendly circulation. Contrary to explicitly defined building standards such as ‘shorter than 20 meters walking distances’, other aspects of building circulation are frequently illustrated as implicit factors, such as ‘convenient access’, which seem to require domain-specific knowledge, rather than a simple calculation. The IWI defined in this paper has an open objective to address these types of circulation issues by using computational and quantitative data derived from given BIM models. In the long method of handling design knowledge issues by computation, the IWI employs rich building information to analyze and find better design alternatives as a decision-support tool. This paper illustrates an overall approach to such building circulation issues with a software demonstration and open-ended sub-algorithms, along with a growing number of BIM applications. To demonstrate the utility of the IWI, an actual building remodeling project was used as a test model, and IWI analysis was performed for various design alternatives. Directions for further improvement of the framework are also discussed.