## 5 Conclusions  
MOC is a new technology for MEP contractors to improve productivity, especially in piping construction. Few MEP contractors have adopted this technology in their pilot project. More and more  
Figure 9: Configuration of a pipe fabrication production line. (**1**) the arrival of standard pipes; (**2**) high-speed pipe cutting machine; (**3**) the beveling machine; (**4**) the piping prefabrication fast fitting-up machine; (**5**) piping automatic welding machine; (**6**) the prefabricated pipe spools. contractors in China want to adopt this new technology in their projects. Based on the information collected from the contractors, interviews with some professors in MEP area, and a comprehensive survey, the levels of the feasibility of piping prefabrication in different piping systems, different connection modes, and different types of project were analyzed. The influences of BIM, the IPD method, and early involvement of manufacturers or distributors were then surveyed. The top five challenges to implement piping prefabrication successfully were identified and summarized. Finally, the suggested pattern and route of piping prefabrication was proposed. To get a comprehensive understanding of the current practices and challenges during piping prefabrication, several data collection methods were used. Ten experts were interviewed then fabrication facilities as well as project site were visited. Two case studies were collected and analyzed carefully. Based on the data collected from these three methods, a comprehensive survey was conducted. According to the results, the levels of the feasibility of piping prefabrication differ in connection modes, type of piping systems and projects. The prefabrication of the piping system with a threaded coupling, flange coupling, or groove coupling modes has a higher level of feasibility, as the pipe component connected by the three methods are detachable. The higher standardization of design in the hotels, offices, and residential projects increases the feasibility of piping prefabrication in these projects. The significant effects of BIM, integrated project delivery, and the early involvement of manufacturers and distributors were verified from the result. The development of a detailed BIM model needs accurate information from the manufacturers and distributors. This BIM model is a basis for piping prefabrication. The IPD method is beneficial to the coordination of the detailed design, installation of the whole piping systems. The integrated plan made by all the participants would decrease the risk from prefabrication. As piping prefabrication is still in its infancy in China, challenges and barriers exist in various aspects. According to the result of survey, the biggest challenge is the low level of standardization of design, followed by the lack of preferential policy, low-skilled workers, the economies of scale, as well as the availability of fittings and valves. Other challenges related to the function of BIM software, the production information provided by manufacturers and distributors are easy to overcome and improve. The present design and construction specifications have little restriction to the piping prefabrication according to the semi-interviews and the result of survey. Finally, a four-phase route of piping prefabrication for MEP contractors was suggested, taking account of the abovementioned results related to the levels of feasibility and challenges. MEP contractors should firstly learn to develop the BIM model above LOD 300 with real size of fittings. Productivity needs to be evaluated when the BIM model is used to provide accurate dimensions of pipes. Then MEP contractors should collaborate with a fabrication facility to adopt piping prefabrication in a pilot project. In this second phase, the management process started from detailed design of BIM model to installation of pipe components to the right place will be learned and analyzed.