## 3 Results Analysis
### Operation and Maintenance Stage
#### 3.9.1 Specific Analysis of the Operation and Maintenance Stage  
The importance of building maintenance is emphasized worldwide, and the proportion of systems in buildings is increasing [100], and the maintenance cost is a higher percentage of the life cycle cost of buildings [101]. A report from the National Institute of Standards and Technology shows that the U.S. construction industry wastes about $15.8 billion annually, of which about $10.6 billion occurs in the O&M stage [102]. Their O&M costs represent a significant percentage of the total project [65]. Effective maintenance of building performance can minimize adverse impacts, and from this perspective, it is essential to establish a proper maintenance plan for O&M [103]. One of the reasons for the low level of intelligence in the management of M&E systems during the O&M stage is that M&E management needs to take full advantage of the new technologies that have emerged with the development of information technology. For example, building information modeling technology [6]. In this regard, researchers should embark on introducing new technologies, and studies have shown that three-dimensional visualization is helpful in property management [104]. The development of BIM models provides an intuitive view of the system's operational status for MEP operations, and the efficiency of maintenance coordination is improved [64], as is the ability to detect possible problems [70]. BIM ensures the sustainability of buildings by managing various information in a unified manner [105]. Researchers have developed a multi-scale BIM-based facility management system for M&E works and applied it intensively in real-world, large-scale airport terminal M&E works [106], where practical examples have proved its feasibility. Regarding algorithms and information recognition in the O&M stage, methods of automatically constructing logical chains, equipment identification, and grouping mechanisms are used. As well as algorithms for generating geographic information system maps based on building information during the delivery of MEP management in the O&M stage [6], the final information generated in the design and construction stages is standardized and delivered to the O&M stage [107]. Two-dimensional barcodes are used to identify and locate specific equipment for routine maintenance of the M&E system and its subsystems to ensure proper equipment operation. Another essential factor to be considered in the O&M stage is the service life [108], which should consider the different usage scenarios of real users [109]. In reality, various parameters, such as quality and user patterns, affect the lifetime of MEP components. This poses a risk to the building maintenance program because the replacement of components occurs at different times [110]. Therefore, life planning of MEP system components can improve the accuracy of maintenance programs [111]. Estimating the lifetime of the electromechanical components of various assembled M&E systems [112] is essential for building maintenance planning of assembled M&E systems [113]. In terms of inspection and maintenance in the operation and maintenance stage, it is difficult to find the failure points and solve the problems because the M&E systems are mostly installed and hidden in the interior of the building. New technologies are needed to adapt to the development, and new methods of monitoring structural health using laser scanning can be used [114]. Subsequent studies have confirmed the usefulness and effectiveness of these techniques for quality control [115] and damage detection [116], as well as for monitoring thermal conditions using wireless sensor networks [117]. Proposing new models for the O&M stage is also a good option. [PERSON] et al. [118] created a set of equipment management classes, essentially a prototype of an O&M information description standard.