10 Discussions and perspectives

In this chapter some of the findings of the project are discussed, connections to other research projects are made, and possible future developments of the EeBGuide guidance document are addressed.

The original aim of the EeBGuide project was not to develop new provisions or even standards for LCA, but to summarize existing provisions from the European standards and the ILCD Handbook, and give guidance on important LCA topics. This guidance is based on the latest LCA practitioners’ experience, and on findings from the EeBGuide project partners’ research and development activities, as well as from other European research projects. LCA practitioners now have a document that gives provisions for and guidance on the critical and most relevant aspects of conducting an LCA study for buildings and building products.

The EeBGuide project’s methodological approach was to combine both the CEN TC 350 and ILCD provisions. In this context, the guidance document remains as transparent as possible by linking to original rules from these reference documents and the chosen provision and guidance. The reference documents sometimes conflict. As far as possible, provisions from CEN TC 350 were applied, but if no provisions were given there, then the ILCD Handbook provisions were also considered (e.g. for consequential modelling). In some cases, both provisions (from CEN and ILCD) were considered, as they provide complementary rules that fulfil different goals and scopes for product or building LCAs (e.g. for the choice of environmental indicators). However, more work will be needed to analyse in greater detail the implications of ILCD provisions when applied to product and building LCA studies. The need for growing consistency between standards and ILCD documentation, however, was obvious throughout the project.

The EeBGuide guidance document is a new contribution to an existing set of documents providing operational guidance for building LCA studies. For example, two previous European research projects (LoRe-LCA and ENSLIC Building) can be also considered relevant sources of information for the LCA practitioner. They provide complementary guidance for some of the aspects covered in the EeBGuide. As far as possible, existing guidance from these projects was reported in the EeBGuide, e.g. by referring to online documentation or deliverables. However, not all of the aspects addressed in the EeBGuide guidance document were covered in these two previous European projects.

Indeed, the main innovation of the EeBGuide guidance document, compared with these previous projects, is to bring together  in a structured document some of the latest findings from the LCA and construction community. More than 150 aspects have been identified to be taken into account for a product or a building LCA. They are structured according to the LCA framework: i.e. goal and scope definition, inventory analysis, impact assessment, interpretation and reporting. This allows any LCA practitioner not necessarily aware of the specific wording of the CEN TC 350 standards to easily go through the document and identify the appropriate rules to follow. At the same time, the aspects are classified according to the life cycle stages of the EN 15804 and EN 15978 standards (Modules A, B, C and D). The provisions and guidance are broken down according to the study types (screening, simplified and complete LCA) so as to allow the practitioner to easily identify the main recommendations according to the stage of a project. The EeBGuide guidance document makes a distinction between stand-alone LCA and comparative assertions. This difference is very important, as comparative studies require more consistency to ensure that the results are not biased. The EeBGuide guidance document also distinguishes provisions for new buildings from those for existing buildings, as the LCA studies will not refer to the same goal and system boundaries. Reporting and review templates for case studies are also part of the guidance.

It is notable that some outcomes of the discussions of the EeBGuide project – within the consortium, with LCA experts, within the public consultation and with the review panel – proved relevant for the value of this document. Among the most important contributions to the general discussion of LCA in construction, the separation of operational guidance between product LCAs and building LCAs – and at the same time the assurance of consistency of these provisions – is one of the most relevant findings. In addition, the formulation of the concept of different study types – screening LCA, simplified LCA and complete LCA – in line with rules on when to apply which study type for what purpose, and how and what to include and exclude, reflects a common need of practitioners. The value of these concepts is given with the fact that the LCA community may now refer to uniform rules on how to conduct studies of the different types.

To summarise, the EeBGuide guidance document takes into account not only the latest findings of recent European projects and research and development works conducted at, for example CSTB (Environment department), Fraunhofer (IBP-GaBi department), PE International, the UNESCO Chair in Life Cycle and Climate Change at the University of Barcelona, and BRE Global, but also current provisions from the standards of CEN TC 350 and the ILCD Handbook. Finally, the EeBGuide guidance document is one of the first contributions at the European level towards a merging of relevant provisions from ILCD and CEN TC 350 in a consistent way. The EeBGuide partners believe that such a consistent guidance document provides a highly operational yet scientifically sound document for the building sector. The EeBGuide guidance document can now be used by the primary audience (LCA practitioners within E2B EI projects) and the secondary audience (building LCA tool developers and certification schemes).

As it is the first comprehensive contribution with the goal of merging diverging reference documents for different study types, the partners remain aware that many research topics still have to be conducted in the near future to support and more precisely specify the different definitions and guidance given as a first step in this guide. If there are any follow-on research projects in this direction, the results could be included in a new version of the EeBGuide. Also if there are new developments or outcomes from the standardization work or the ECO platform, these results will have to be incorporated in the guidance document as well. The EeBGuide guidance document has also identified issues that are not completely resolved when applying the CEN TC 350 standards. It may be a useful document for the standardization committee when revising the EN 15804/EN 15978 standards.

Further outcomes of more operational projects, such as the SBA Common Metrics project, have to be considered as very important contributions next to the EeBGuide guidance document to ensure comparability within different LCA studies. Future research projects should also focus on a common European reference building as a baseline scenario. Here, the most important parameters should be investigated (e.g. reference study periods, main EoL scenarios for materials, etc.) in order to define a European baseline scenario, providing average European values for its parameters, which will facilitate comparisons between research projects, and support the evolution of building labelling schemes.

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