## 3 BIM and DTs--Latest Development Trends and Challenges
### Standards, Requirements, and Approaches
#### 4.1.2 BACS and Smartness of Buildings  
Based on experience from the implementation of the EN 15232 and EN ISO 52120 standards, the Smart Readiness Indicator (SRI) was launched in 2018. Initially, the SRI was incorporated into the Directive of the European Parliament and the Council of the European EPBD 2018. Since then, further work has been conducted, which concluded in 2020, resulting in a detailed methodology for evaluating the readiness of buildings for intelligent solutions, discussed in detail in the technical report [19]. Voluntary implementation by EU countries is currently underway. Importantly, the SRI assesses the readiness of buildings to be \"smart\" rather than their current performance or energy efficiency [109; 110; 111; 16; 22]. However, the aforementioned report contains a crucial element: two lists of functions and services of building automation systems, dedicated to various building infrastructure subsystems (domains). For each individual function, several functional levels are defined and described, relating to the level of advancement of the automation functions--smart services. The lists of functions are based on the lists of control functions described in the EN 15232 and EN ISO 52120 standards but have been extended to include functions and services dedicated to the operation of energy management systems. These include, for example, the charging of electric vehicles, the monitoring of energy consumption and power quality, the integration of renewable energy sources and energy storage, and the support for demand-side management and demand-side response mechanisms. Consequently, these lists can be employed as a framework for the design of BACS and BMS systems in accordance with the principles of BIM and DT tools. Furthermore, in a manner analogous to the EN ISO 52120 standard, the report delineates three methodologies for calculating the SRI value, presented in Figure 7. The initial two methodologies are based directly on the functional analysis and selection of automation functions/services, while the third methodology is the most precise and necessitates the measurement and analysis of the system already operating within the facility. In this context, it is possible to utilize DT tools as a source of data feedback for the calibration and verification of BACS control parameters. Figure 7: Three assessment methods for SRI with potential applications for BIM and DT. The accurate and precise evaluation of the SRI allows one to identify buildings that may contribute to energy production. This is important in the context of urban management. Furthermore, the SRI would be beneficial in the management of power networks in terms of generation, transmission, and distribution. In this context, it is particularly important to consider the role of public buildings, such as educational institutions. Bearing in mind the results of the study presented by [PERSON] et al. [109], and combining them with the guidelines for BACS systems and their effects of improving the energy efficiency and smartness of buildings, the energy efficiency of buildings is inextricably linked to the level of building automation and control systems for the technical systems of a building. The aforementioned study demonstrates the need for parallel and simultaneous consideration of both assessments in order to obtain a more comprehensive assessment of the overall energy performance of the building. Furthermore, the study [113] proposes that the SRI level of a building should be considered in the EPC (Energy Performance Certificate) evaluation. In the future, energy audits could also encompass \"smart\" buildings, and activities related to the modernization of energy systems could be adapted to take account of the modernization of smart systems. Further integration of the SRI into the energy efficiency assessment of buildings is necessary [114]. As illustrated in Figures 6 and 7, the joint application of DTs and BIM can significantly accelerate data collection and analysis, thereby increasing the accuracy of computational methods.