## 3 Obstacles to the Implementation of LCA in the Procurement Process of Buildings
### Methodological Obstacles
\begin{table}
\begin{tabular}{l c} \hline \hline
**Methodological Obstacles** & **Reference** \\ \hline _Review of PEF guide and EPDs_ & \\ _Comparison between the PEF guide and the EPD requirements_ & \\ \(\rightarrow\) PEF and EPDs are not comparable in terms of results & [56] \\ \(\rightarrow\) PEF and EPDs in their current form cannot be alternatively used as tools supporting GPP tender requirement_ & \\ \hline _Review of to-date EPD programs for pavement materials_ & \\ _Discussion about stakeholders' perspectives on the current EPD program with_ & \\ _material manufacturers, public government agencies, and LCA consultants_ & \\ _Use of EPDs in GPP to ensure the environmental improvement of_ & [57] \\ _materials and pavements_ & \\ \(\rightarrow\) EPDs aggregate a LCI into a handful of mid-point indicators, which & \\ _can undermine the details of the supply chain_ & \\ \hline _Discussion with stakeholders (owner/client, designer, and contractor) about_ & \\ _EPD implementation_ & \\ _Application of EPDs during the design and construction stage using an office_ & [58] \\ _building as case study_ & \\ \(\rightarrow\) Lack of result comparability of different LCA tools & \\ \hline _LCA/TOPSIS method is applied to public procurement of urban furniture_ & \\ _Simplified LCA methodology combined with TOPSIS method for_ & \\ _assessing award criteria_ & [59] \\ \(\rightarrow\) Lack of guidelines/handbooks for LCA implementation & \\ \(\rightarrow\) No monetization of LCA results & \\ \hline _LCA is applied to road bridges to push LCA implementation in procurement_ & \\ _Comprehensive LCA framework for road bridge procurement_ & [60] \\ \(\rightarrow\) Different ranking results for different indicators & [60] \\ \(\rightarrow\) Uncertainties in data & \\ _Content analysis of the documents obtained from calls for tenders_ & \\ _Comparison of environmental criteria in tenders_ & \\ \(\rightarrow\) Complex LCA process & \\ \(\rightarrow\) Missing guidelines or toolkits & [61] \\ \(\rightarrow\) Distinct use of tender processes or criteria & \\ \(\rightarrow\) Use of environmental criteria with higher project budgets & \\ \hline _Semi-structured interviews about current practices and obstacles to_ & \\ _environmental requirements in construction_ & \\ _Survey about the existence of municipal policies dealing with_ & \\ _environmental issues_ & [62] \\ \(\rightarrow\) Lack of data quality about material inventories & \\ \(\rightarrow\) Environmental performance requirements are too complex & \\ \(\rightarrow\) Lack of guidance and standardization at national level & \\ \hline _LCA for design selection and decision-making during material procurement_ & \\ _of asphalt mixtures_ & \\ _Analytical approach to identify equivalence intervals that are applicable_ & \\ _during material procurement decision-making_ & \\ \(\rightarrow\) High complexity of the LCA process & \\ \(\rightarrow\) Lack of uncertainty analysis within LCA & \\ \hline _Structured interviews on the assessment of environmental aspects and the_ & \\ _review of environmental requirements_ & \\ _Survey about including environmental requirements in_ & \\ _procument documents_ & \\ \(\rightarrow\) Complexity of LCA analysis & [64] \\ \(\rightarrow\) Lack of evaluation of operating energy & \\ \(\rightarrow\) Lack of LCCA integration & \\ \(\rightarrow\) Lack of assessment models & \\ \hline _Assessment of the determinants and drawbacks of green procurement adoption_ & [65] \\ \(\rightarrow\) Lack of guidelines and tools to support GPP & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Methodological obstacles to the LCA implementation in the procurement process of buildings. Within the methodological obstacles, the lack of standardization at a national level was mentioned as an implementation obstacle. However, as far as the LCA method is concerned, the international standards ISO 14040 and ISO 14044 define the calculation principles of LCA [23; 24].