Geometric quality inspection of prefabricated MEP modules with 3D laser scanning

Abstract

Prefabricated mechanical, electrical and plumbing (MEP) module is one of the off-site construction technologies that can significantly improve productivity. To successfully install MEP modules on-site, performing a geometric quality inspection in prefabrication factories is required to ensure all as-produced MEP elements have accurate positions and correct dimensions. However, the traditional manual inspection process is inaccurate and time-consuming. To address the problem, this study presents an automated geometric quality inspection technique to estimate the geometric properties of MEP modules using 3D laser scanning. The proposed technique firstly extracts the steel frame of the MEP module from the scanned data and registers the scanned data with the as-designed building information modeling (BIM) model of the module. Each MEP element in the module is then detected from the scanned data with the proposed shape fitting algorithm customized for different types of elements. Lastly, the checklist items for geometric quality inspection are computed based on the extracted as-built MEP elements. Experiments on two prefabricated MEP modules were conducted, which demonstrated the accuracy and efficiency of the proposed method.