Research in focus

Small is beautiful – Minimizing the ecological footprint of buildings

How many litres of water does it take to produce a window, until the finished product comes off the line, is transported to the building site, installed on site and, after the building has been demolished, is at best recycled and thus returned to the production cycle? Which construction material is more sustainable - a material that is capable of storing a particularly high degree of heat, or a material that requires the least use of energy for its production, and that is manufactured in close vicinity to the building site? It is not easy for builders who have ambitious objectives regarding the sustainability of their project to find construction materials that comply with the manifold requirements on sustainability. Builders who want to observe eco-friendly criteria need to weigh various requirements – like recyclability, low-emission options or durability – against each other. It is true that some years ago several European countries established certification procedures or quality labels for sustainable buildings. In practice, however, these systems do not ensure reliable comparability, since previous standards for the life cycle assessment of buildings and construction products give room to a wide range of diverging interpretations. According to data provided by the European Commission, the construction and maintenance of buildings (including heating, air conditioning, lighting, and electrical equipment) accounts for 40 percent of the energy consumption. The European Union is responsible for one third of CO2 emissions. However, the converse conclusion may be drawn that Europe still has a huge potential for more efficiency and sustainability regarding construction products and buildings.

"In the scope of the EeBGuide project we have developed uniform calculation rules for preparing life cycle assessments (LCA) in the European construction industry, which we issued in a guideline", declares Johannes Gantner, a scientist with the Fraunhofer Institute for Building Physics IBP. While he was still at university, the architect specialized in the field of sustainability in the building sector. Now he played a leading role in this groundbreaking project. "Up to now, EU countries used different measurement categories, which resulted in inconsistent standards and guidelines. Hence it was not possible to compare construction products, construction systems or buildings with regard to their sustainability. To put it casually, each country has a different approach", he describes the previous practice. "The French approach, for example, tries to quantify the phases of a building's life cycle, including the building-site processes and the transports. As a lot of information is lacking, however, unspecific default values are used in many cases. In 1990, the BREEAM label (BRE Environmental Assessment Method) was developed in Great Britain. In this system, the LCA for construction products is based on a qualitative assessment system and it is not necessary to determine comparable, quantitative figures". The assessment system for Sustainable Government Buildings (Bewertungssystem Nachhaltiges Bauen für Bundesgebäude, BNB), which was established by the German Federal Ministry of Transport, Building and Urban Affairs (BMVBS), supplements the Guideline on Sustainable Building (Leitfaden Nachhaltiges Bauen) as a holistic, quantitative assessment method for offices and administrative buildings. In 2009, the German Seal of Approval for Sustainable Building was introduced, which was developed by the German Sustainable Building Council (Deutsche Gesellschaft für Nachhaltiges Bauen e. V., DGNB) to provide a comprehensive assessment system for commercial buildings. In this system, the LCA is attributed key importance regarding the sustainability of buildings. To provide a common basis for dealing with LCAs on a European level, the EeBGuide project examined and defined uniform and binding rules.


Along with Fraunhofer IBP, several other European institutions were involved in the project: Building Research Establishment (BRE) from the UK, Centre Scientifique et Technique du Bâtiment (CSTB) from France, from Spain the UNESCO Chair in Life Cycle and Climate Change at Escola Superior de Comerc International (ESCI), 'thinkstep' company from Germany, and from Sweden Prof. Ch. Sjöström Consultancy. This body joined members from industry and research who intensively discussed the requirements on calculation rules that are to be applied in future when conducting comprehensive LCA analyses and studies on the environmental impact of energy efficient buildings and construction products in Europe. "We document any material and energy flows in connection with the product, and we evaluate the related environmental impacts", Gantner explains the methodology.


One core item of this project was given special priority, namely the practical applicability of the guidelines. "To ensure practical application, we have done many case studies of real buildings", Gantner explains. "And we have provided an opportunity for users to give feedback. The expertise of building professionals and LCA experts should not remain unexploited." This scientific method is known as Public Consulting, targeting relevant interested parties to get them involved in specified processes. A specially provided online platform supplied templates and forms for current updates, thus enabling every user of life cycle analyses to actively contribute, without having to overcome excessive barriers or bureaucratic obstacles.


The result of these efforts is an interactive guidance document that promotes transparency and consistency. Two manuals entitled " EeBGuide Guidance Document – Part A: Products" and " EeBGuide Guidance Document – Part B: Buildings" were recently published, both of which were compiled with significant participation by Johannes Gantner. The guidance document was split up into two separate documents – one relating to products, one to buildings – to provide better support to users. In many European research projects, life cycle analyses were not seen as a central part of the project, which is why they were not included right at the beginning. When integrating LCAs at a later stage, it becomes difficult to optimally use the ecological optimisation potential, as it is no longer possible to integrate the results of the analysis in the technological process. The guidance document EeBGuide is designed to address this problem. It works as a kind of adviser that enables the user to quickly access profound analyses, which are based on definitions, calculation rules, assumptions and comparable results.
The Fraunhofer IBP scientist also thinks it is important to enhance the aspect of communication in the building sector and to improve the exchange of information among all parties involved. He has a clear vision concerning the future of Europe: "I imagine there will be a transformation towards a sustainable society, paving the way for environmental innovations and efficiency" he declares and continues "Disclosing and improving the environmental efficiency of products and technologies in the building sector provides the framework for separating economic and urban growth from the use of resources. However, we must continue our efforts to find solutions. This system could be extended to other product systems, for instance in aviation or in the food sector." And he would welcome improvements in product information, i.e. to get precise information about the environmental impact of each individual construction product. Harmonizing and interlinking EPDs (Environmental Product Declarations) on a European level (as currently promoted by merging the "ECO Platform") would have the advantage that manufacturers need no longer cope with different requirements in various European markets.
"To be able to assess the sustainability of a certain product with sufficient precision, the LCA needs to consider additional data like transportation to the building site, the use of water during the entire life cycle or the disposal of waste water. Likewise, emerging fundamental societal changes like the turnaround in energy policy should be integrated. In the scope of this project it was not possible to consider all the criteria", Gantner explains. This is why he still sees potential for improvement regarding the certification of buildings. In his opinion, however, this was a balancing act, the Fraunhofer IBP researcher says: On the one hand, regulations are often the only way to promote changes, on the other hand this would affect the flexibility of European markets. Too high barriers are liable to prevent further impetus to the market and creative entrepreneurship. In the final analysis, it's all about reaching compromises that will be beneficial to all parties involved – but most of all to our environment and our climate.