Annette Hafner

Life cycle assessment of wood construction according to the normative standards

AbstractThis study demonstrates life cycle assessment (LCA) on a reference wooden building according to the latest normative standards: EN 15978, EN 15804 and EN 16485. Global warming potential and primary energy balance over the reference building were assessed in a case study. Through the assessment, the application of the standards was studied. In addition, possible points for development in the standards, especially concerning wood products and wood construction, were discussed from a practical perspective. The lack of proper data is a critical issue in conducting the assessment in compliance with the standards. Since LCA is a data-intensive method, the preparation of data for the building assessment according to the standard is certainly required. This paper also raises questions about the life cycle modules defined in the standards and the importance of the communication system used for the assessment results. It would be of importance to develop the communication system in such a way as to stimulate environmental consciousness in society. In order to develop a relevant communication system, further discussion and case studies would be important and feedback from such practices should be incorporated into the development of the guideline for the assessment.

Greenhouse gas emission from construction stage of wooden buildings

Abstract This study reports on a detailed investigation into the greenhouse gas emissions associated with the construction process of multistory wooden buildings relative to the other life cycle stages: the material production and operation stages. The results showed that the construction stage accounts for 20–30% of the initial embodied emissions and 6–10% of the total emission of the included life cycle stages. Especially the transport process of building components seems to have higher potential to mitigate the emissions than the actual construction work. In addition, the emissions from different construction systems were studied based on the reference buildings. Although definitive conclusion would be difficult to be drawn from this study alone due to the small sample size and the assumptions made, prefabrication work seems to be a more efficient construction method compared to on-site work for wooden buildings.

Recycling and End-of-Life Scenarios for Timber Structures

In consideration of sustainable buildings, closing life cycle loops becomes more and more important. Up to now reuse and recycling is taken rarely into account in building processes. With rising consumption of wood for energetic use recycling of material becomes more important.

A Case Study for End of Life Reuse and Recycling Survey Methodologies： The Hollentalanger Cottage

Up to now, reuse and recycling of existing buildings have not been examined widely. This paper discusses the theories, methods and practicalities of buildings’ end of life with a main focus on planning and managing reuse and recycling of existing buildings. Our aim is the realistic modelling of theoretical scenarios for end of life based on a case study. The methods of building survey, material classification and documentation for reuse, recycling and disposal of existing constructions are presented. Investigations and calculations were done on an existing cottage in the Alps. The ecologically most beneficial disposal phase of the old wooden hut is our main objective. Critical questions arise from the quality of the material and how it can be extracted, separated and balanced in an appropriate way. A systematic survey of the building by inspection of constructions and materials in iterative steps allows a detailed material balance with condition and property information. This information is crucial for scenarios and material flow analysis of demolished and rebuilt building in environmental system analysis. For future planning, the reuse and recycling of existing buildings should be integrated quite early in the planning process so that we can use the materials in the best way.