Directed Representative Graph Modeling of MEP Systems Using BIM Data

Abstract

Mechanical, electrical, and plumbing (MEP) systems are crucial to a building, which directly affect the building safety, energy saving, and operational efficiency. Building information models (BIMs) help engineers to view the connection structure of MEP elements, reducing the time for reading drawings and training costs. However, existing MEP systems bring a tremendous challenge to monitoring due to issues with the complicated spatial structure, large scale, and intuitiveness. In addition, there is still a lack of feasible methods to model a representative graph in MEP systems. To address this problem, this study proposes an approach to model a directed representative graph of MEP systems using BIM data. The proposed approach contains two parts, the representative edge extraction and the direction identification. Firstly, MEP elements are converted into triangular meshes on which boundary points are extracted. Secondly, representative sets are developed to extract the representative points. Thirdly, representative points are connected to generate representative edges. Meanwhile, there are topological connection relationships among MEP elements and the flow directions of MEP ports, all of which are extracted to obtain the graph direction based on Industry Foundation Classes (IFC). Subsequently, representative edges and directions are combined to obtain the directed representative graph. Finally, experiments of directed representative graph extraction are evaluated on six BIM models. The experimental results show that directed representative graphs are extracted successfully. Furthermore, a simulated system is developed to integrate the directed representative graph and the Internet of Things (IoT) to realize the intelligent monitoring of MEP systems. The proposed directed representative graph model lays a solid foundation for the development of MEP systems monitoring management in smart buildings.