## 4 Results and Discussion
### Proposed Actions  
This study identifies 20 limitations for the incorporation of LCA data in IFC, enumerated in Tables 1-3 and 7. Future revisions of IFC should consider these gaps to improve the machine interpretability of EPD data, allowing its direct incorporation in BIM models. This incorporation will reduce the resources required for the environmental assessments of buildings, therefore promoting its widespread use. The study has analyzed four options for the delivery of tabular-based EPD data using the IFC 4.3.2.0 schema in a use case (see Section 4.3). Each option has its own limitations and constraints. The use of the _IfcTable_ entity, standardized within the current IFC schema, is an interesting solution, as it aligns well with the tabular structure commonly used to represent EPD data. However, it should be noted that this option does not guarantee interoperability across systems unless a revised IFC schema defines a common structure for LCA data. Current BIM authoring software does not support the transfer of EPD data across systems or organizations using different tools. The reason is that each software relies on proprietary/native data structures that have been developed over time. Switching to a single standard brings significant technical and resource-related challenges, in addition to the efforts needed to enhance IFC standards in relation to LCA data. The approaches described in 4.3 require further research to assess the impact of its implementation. The main topics for consideration in the next versions of IFC are outlined in Table 11.  
\begin{table}
\begin{tabular}{p{14.2 pt} p{142.3 pt} p{142.3 pt}} \hline \hline
**Action** & **Headline** & **Description** \\ \hline \multirow{8}{*}{1} & Improve & Improve the structure of _Pset_EnvironmentalImpactIndicators_ to cover all EPD indicators and impact categories. In particular, for EN 15804+A2: & \multirow{8}{*}{1} \\  & & a. _ClimateChangePerUnit_ should be structured into four elements: _GWPtotal_, _GWPfossil_, _GWPbiogenic_ and _GWPluluc_. The report [48] from buildingSMART proposed this structure, but the terminology used in EPD standards should be applied (i.e., _GWP_ instead of _ClimateChange_). & \multirow{8}{*}{1} \\  & Improve & & \\  & _Pset_EnvironmentalImpactIndicators_. Gaps 12, 15, 16, 18 and 19 & & \\  & & a. _ClimateChangePerUnit_ should be structured into four elements: _GWPtotal_, _GWPfossil_, _GWPbiogenic_ and _GWPluluc_. The report [48] from buildingSMART proposed this structure, but the terminology used in EPD standards should be applied (i.e., _GWP_ instead of _ClimateChange_). & \multirow{8}{*}{1} \\  & Improve & & \\  & _Pset_EnvironmentalImpactIndicators_. Interoperability should not be equated with the automatic transfer of data between systems (or formats). The relevant data should be filtered based on the level of detail required at asset level, to avoid excessive computation loads. Ensuring the maintainability and quality of the model is contingent upon selecting the relevant data in an efficient manner. Therefore, each addition to the IFC schema should be carefully considered and the mapping between dEPDs and BIM should be based on efficiency. The IFC standard itself is evolving as it expands its application across a broader range of domains within the built environment, such as infrastructure. Although the IFC schema has certain shortcomings, it is the most widely recognized and implemented open standard