Australian Life Cycle Assessment Society conference
The use of timber construction products and their environmental impacts is growing in Europe. This paper examines the LCA approach adopted in the European CEN/TC350 standards, which are expected to improve the comparability and availability of Environmental Product Declarations (EPDs). The embodied energy and carbon (EE and EC) of timber products is discussed quantitatively, with a case study of the Forte building illustrating the significance of End-of-Life (EoL) impacts. The relative importance of timber in the context of all construction materials is analysed using a new LCA tool, Butterfly. The tool calculates EE and EC at each life cycle stage, and results show that timber products are likely to account for the bulk of the EoL impacts for a typical UK domestic building.
International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
August 4–7, 2013, Portland, Oregon, USA
As sustainable building design practices become more prevalent in today’s construction market, designers are looking to alternative materials for novel design strategies. This paper presents a case study comparing the sustainability performance of cross laminated timber (CLT) and reinforced concrete. A comparative sustainability assessment of cross laminated timber and concrete, considering economic, environmental, and social aspects was performed. Environmental impact is measured in terms of CO2 equivalent, economic impact is measured with total sector cost (including sector interdependencies), and qualitative metrics were considered for social impact. In order to conduct an accurate performance comparison, a functional unit of building facade volume was chosen for each product. For this paper, several end-of-life strategies were modeled for CLT and concrete facades. To understand environmental, economic, and social impact, three different scenarios were analyzed to compare performance of both CLT and concrete, including cradle to gate product manufacturing, manufacturing with landfill end-of-life, and manufacturing with recycling end-of-life. Environmental LCA was modeled using GaBi 5.0 Education Edition, which includes its own database for elements including materials, processes, and transportation. To compare the economic impact, Carnegie Mellon’s EIO-LCA online tool is used. Finally, social life cycle impact was considered by identifying process attributes of both products that affect the social domain. Based on this analysis, the use of CLT has a significantly lower environmental impact than concrete, however there are additional costs.
The study investigates the environmental benefits of reusing Cross Laminated Timber (CLT) panels. The Global Warming Potential (GWP) of a single-stored Coffee shop built in 2016 in Kobe city was calculated, considering different CLT reuse ratios, forest land-use and material substitution possibilities. The results showed that as the rate of reused CLT panel increases the total GWP decreases. Moreover, in all cases, the option with smallest GWP is when the surplus wood is used for carbon storage in the forest, revealing the importance of a growing forest for increasing the environmental benefits of timber utilisation. The results suggest the systematic reuse of CLT panels offers a possibility to increase the carbon stock of Japanese Cedar plantation forests and further mitigate the environmental impact of construction.
The purpose of this research is to evaluate the environmental performance of various timber constructions that have been realised within intensively utilised area in recent years. The appraisal is carried out by means of life cycle assessment (LCA) and covers different timber constructions, mainly the multi-storey building. The ultimate goal is to compare their environmental performance to the outcomes of other constructions like reinforced concrete (RC) and steel construction (SC).
The environmental burdens caused by constructions are evaluated based on the framework of LCA. First, the material inventory of selected building projects is established. The scope is emphasised on the primary structural elements such as columns, beams, deck, load-bearing wall and roof. Secondary components, facility and decoration are eliminated out of the research boundary. Based on the material inventory, the impact assessment is carried out to preliminarily calculate the embodied outcome of the timber constructions. The environmental implications of structural elements during early life cycle stages are evaluated. Then, the effect of both disposal and material recycling is integrated in the LCA, including reuse or recovery of the structural wooden components. The LCA takes into account different disposal scenarios associated with construction and demolition waste (C&DW). By doing so, the LCA is the so-called ‘from cradle to gate’ and ‘gate to cradle’, without consideration upon the using phase. Among numerous environmental indictors, this research quantifies and discusses the energy consumption and global warming potential (GWP) of the timber buildings only.
The five-storey timber building located in urban context is a pioneer project in Taiwan. This building applies crosslaminated-timber (CLT) as the primary structural elements and takes over tremendous loading circumstances. It demonstrates not only the engineering feasibility of CLT for architectural design but also the utilising compatibility of wooden house in urban context.
The environmental evaluation proofs the ecological efficiency of timber buildings. In addition, this study compares the environmental performance of timber constructions and other materials. Alternative building models made of RC and steel are developed and intended for further LCA. The LCA results demonstrate that timber constructions cause significantly less impacts than RC and SC do. Timber constructions exhibit carbon sequestration effect, which is unique among three materials. Meanwhile, timber constructions consume only about 20% energy of the RC and SC. While possessing similar form and functionality, timber constructions exhibit better eco-efficiency compared to other generally used materials. When the material recycling is taken into account, the life-cycle eco-efficiency of timber structures is further significant. Wooden constructions can be energy-neutral or even energy-productive, depending on the recycling strategies.
Consuming over 40% of total primary energy, the built environment is in the centre of worldwide strategies and measures towards a more sustainable future. To provide resilient solutions, a simple optimisation of individual technologies will not be sufficient. In contrast, whole system thinking reveals and exploits connections between parts. Each system interacts with others on different scales (materials, components, buildings, cities) and domains (ecology, economy and social). Whole-system designers optimize the performance of such systems by understanding interconnections and identifying synergies. The more complete the design integration, the better the result.
In this book, the reader will find the proceedings of the 2016 Sustainable Built Environment (SBE) Regional Conference in Zurich. Papers have been written by academics and practitioners from all continents to bring forth the latest understanding on systems thinking in the built environment.