Automated 3D compliance checking in pipe spool fabrication

In pipe spool assemblies used in construction, pre-fabrication errors inevitably occur due to the complexity of the tasks involved in the pipe spool fabrication process, the inaccuracy of the tools employed for performing these tasks, human error, and inadequate inspection and monitoring during the process. Permanent deflections may also occur during shipment and transportation. After delivery at construction sites, defective spools must be detected and further consideration given to the erection of the spools to tolerance levels specified; otherwise, the repair and realignment associated with rework can cause schedule delays and consequent substantial costs increases. This paper presents an automated approach for monitoring and assessing fabricated pipe spools using automated scan-to-BIM registration. Defects are detected through a neighborhood-based Iterative Closest Point (ICP) approach for the registration process. While this technique can be broadly employed, this paper focuses on industrial construction facilities with particular emphasis on pipe spool assemblies. Experiments show that the proposed approach can be employed for the automatic and continual monitoring of such assemblies throughout fabrication, assembly and erection to enable timely detection and characterization of deviations. The main contribution of the work presented in this paper is an automated 3D inspection framework and algorithms for construction assemblies in general and pipe spools in particular. Fabrication imperfections in construction assemblies are often unavoidable due to the intensive level of manual work involved. Such imperfections and errors can add significant costs to construction projects, especially when they are not detected early. According to Akinci et al. [1], Burati et al. [2], Hwang et al. [3], Josephson and Hammarlund [4], Patterson and Ledbetter [5], up to 10% of construction costs are attributable to rework due to the late and untimely identification of defects, and 5% are the result of rework during maintenance [1,5]. A major risk associated with construction projects is thus the cost of rework due to defects that occur as a result of human error or material flaws. It has been noted that more than 50% of rework cases arise from human errors due to an insufficient level of inspection or lack of regard for the importance of quality assessment in the construction phase [1]. Approximately 10% of the cost of construction rework is attributable to material defects [1,6]. Continual inspection and assessment to detect human error and the quality of construction materials can therefore prevent rework and save substantial associated costs. Even minor errors in the fabrication …