## 1 Introduction  
Buildings accounted in 2023 for 34% of global energy demand and 37% of energy- and process-related CO\({}_{2}\) emissions according to UNEP [1]. The construction sector is also a major generator of waste and, just in the EU-27 in 2018, the total construction and demolition waste accounted for nearly 8.5\(\cdot\)10\({}^{8}\) tons according to the EU Science Hub [2]. Digitalization of the construction sector is increasingly recognized as a potential game danger in relation to resource and energy efficiency. The sustainability challenges posed by climate change, resource depletion, waste generation and other environmental aspects can be addressed by integrating a life cycle perspective into decision-making processes related to the design, construction and operational management of built assets. Life cycle assessment (LCA) is a standardized, comprehensive methodology used to calculate the environmental impacts associated with a product, system, process or service considering its entire life cycle. LCA can be used to compare different construction methods or materials, and the results can be the basis for public and private procurement, thereby promoting the selection of environmentally preferable products or services. However, both LCA and green procurement must be based on reliable data calculated according to internationally accepted standards. The international and European standardization organizations ISO and CEN have published a set of standards for the environmental assessment of buildings and civil engineering works based on LCA (see Section 3.1). Manufacturers present the environmental information from their products in environmental product declarations (EPDs) calculated according to ISO 21930 [3] or EN 15804 [4]. The calculation defined in the sustainability assessment standards can be integrated into BIM tools. The use of BIM to design, construct and manage buildings and infrastructures is rapidly growing in Europe, as shown in the analysis from the European Commission [5]. [PERSON], [PERSON] & [PERSON] [6] identified the integration of LCA tools with BIM as an enabler for the implementation of green public procurement (GPP), together with standardization. Nevertheless, the substantial volume of data necessary to perform the LCA of a built asset complicates its utilization for most projects, as it necessitates the consideration of numerous distinct materials. Furthermore, the environmental data is presented in various formats, many of which are non-structured or incompatible with BIM tools. The predominant digital format used to issue EPDs is pdf, which generally lacks an inherent logical data structure, thereby impeding machine interpretation of the information. The provision of EPD data in BIM-compatible formats, such as IFC, can reduce the effort required to use environmental information in digital models. IFC (see Section 3.3) is the main format used in the BIM environment, primarily due to its role as an open, vendor-neutral, and internationally recognized standard developed by buildingSMART and ISO. It represents a universal language for construction information, ensuring seamless data exchange and interoperability between diverse software applications and disciplines throughout the entire building lifecycle. [PERSON] & Gudmundsson [7] provides a comprehensive assessment of digital approaches for the integration of LCA in circular design strategies, addressing interoperability aspects and the link with regulations and standards. The integration of LCA into BIM with plug-ins is analyzed as a promising solution. However, the use of plug-ins presents several limitations, as the data will have limited interoperability across the system. Therefore, this paper proposes the integration of LCA data into the official IFC schema. The current schema (IFC 4.3, see Section 3.3 for more information) is not entirely machine-interpretable for environmental information, requiring significant effort to incorporate LCA data into BIM.