Australian Life Cycle Assessment Society conference
Research Status
Complete
Summary
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.
Project contact is André Potvin at Université Laval
Summary
The biomimetic approach in architecture explores the genius of organic natural forms resulting from a long process of environmental adaptation. These forms often have a high compactness and an optimal material / volume ratio in line with the importance of reducing the material in the building to limit its environmental impact in terms of energy and resources. What are the natural forms and processes of growth of the form most appropriate to the physical properties of wood? What design process promotes the integration of a biomimetic approach from the earliest stages of design? Based on a review of the main achievements claiming this approach, this project will develop a taxonomy of the different biomimetic typologies and identify the most promising in the context of a wood realization. A digital manufacturing process will be developed to reflect the complexity of natural shapes and flows in an organic architecture that optimizes environmental performance and aesthetics.
As the population continues to grow in China’s urban settings, the building sector contributes to increasing levels of greenhouse gas (GHG) emissions. Concrete and steel are the two most common construction materials used in China and account for 60% of the carbon emissions among all building components. Mass timber is recognized as an alternative building material to concrete and steel, characterized by better environmental performance and unique structural features. Nonetheless, research associated with mass timber buildings is still lacking in China. Quantifying the emission mitigation potentials of using mass timber in new buildings can help accelerate associated policy development and provide valuable references for developing more sustainable constructions in China. This study used a life cycle assessment (LCA) approach to compare the environmental impacts of a baseline concrete building and a functionally equivalent timber building that uses cross-laminated timber as the primary material. A cradle-to-gate LCA model was developed based on onsite interviews and surveys collected in China, existing publications, and geography-specific life cycle inventory data. The results show that the timber building achieved a 25% reduction in global warming potential compared to its concrete counterpart. The environmental performance of timber buildings can be further improved through local sourcing, enhanced logistics, and manufacturing optimizations.
Cross Laminated Timber (CLT), which is made by laminating dimension lumber at right
angles, is an innovative high-performance building material that offers many positive attributes
including renewability, high structural stability, storage of carbon during the building life, good
fire resistance, possibility of material recycling and reuse. It is conceptually a sustainable and
cost effective structural timber solution that can compete with concrete in non-residential and
multi-family mid-rise building market. Therefore, there is a need to understand and quantify the
environmental attribute of this building system in the context of North American resources,
manufacturing technology, energy constraints, building types, and construction practice. This
study is to compare energy consumption of two building designs using different materials, i.e.
CLT and concrete.
Our built environment is constantly adapting to changing factors: technology, the state of the economy, material resource availability, and, in turn, environmental conditions. The latter has gained notable importance in popular discourse, and especially in the architecture and construction professions. However, as much as we see terms such as “sustainability” and “green” in our everyday lives, government and industry are slow to take action investing in our future environment. Material resources in the building industry are worth investigating. Timber, used as a structural material to compete with concrete and steel, brings more energy efficient and natural renewable resources to our growing cities. In order to provide a broader perspective of how we as a society use concrete, steel, and timber, I will compare the three building materials in a four part guideline: Environmental Performance, Ease of Manufacture, Organized Assembly, and Design Flexibility.
IOP Conference Series: Earth and Environmental Science
Summary
Cross laminated timber (CLT) has recently increased in use as a building material for low carbon design and is often applied in small and multi-story buildings. Several studies have shown lower fossil related greenhouse gas emission than alternatives, but the life cycle emissions vary substantially between different CLT producers. These emissions are mainly indirect and thus climate change mitigation could reduce these emissions. Previous research shows that that biofuels and carbon capture and storage (CCS) are technologies that have the potential to reduce the climate impacts of the CLT life cycle. This study assesses the impacts on climate change from CLT with these technologies within the framework of environmental product declarations (EPD). In the short run, switching to fossil free fuels provides a reduction in the carbon footprint of CLT. In the long run, CCS at the end-of-life of CLT buildings can provide a net negative carbon footprint over the life cycle. This assessment on the use of CLT is mainly related to the Sustainable Development Goal SDG9 Industries, innovation and infrastructure and the indicator for CO2 emissions per value added, so the assessment in this paper is mainly focused on this goal. SDG7 on affordable and clean energy and SDG15 Life on land are also relevant.
This comprehensive guide explains the design standards, code provisions, and safety requirements engineers need to know to use cross-laminated timber as a structural building material. The book covers all applicable design considerations, including the relevant structural load requirements and fire safety requirements.
Written by a collection of experts in the field, Cross-Laminated Timber Design: Structural Properties, Standards, and Safety introduces the material properties of CLT and goes on to cover the recommended lateral and vertical design standards. Design examples and case studies are featured throughout. You will get design recommendations for connections, building envelopes, acoustics for CLT projects, and much more. Sustainability and environmental issues are discussed in full detail.
- Covers the latest methods and design techniques being used for CLT
- Explains the code provisions in the NDS, ASCE 7, and IBC that apply to CLT
- Include contributions from some of the leading experts in the field
Environmental Life-Cycle Assessment and Life-Cycle Cost Analysis of a High-Rise Mass Timber Building: A Case Study in Pacific Northwestern United States
Global construction industry has a huge influence on world primary energy consumption, spending, and greenhouse gas (GHGs) emissions. To better understand these factors for mass timber construction, this work quantified the life cycle environmental and economic performances of a high-rise mass timber building in U.S. Pacific Northwest region through the use of life-cycle assessment (LCA) and life-cycle cost analysis (LCCA). Using the TRACI impact category method, the cradle-to-grave LCA results showed better environmental performances for the mass timber building relative to conventional concrete building, with 3153 kg CO2-eq per m2 floor area compared to 3203 CO2-eq per m2 floor area, respectively. Over 90% of GHGs emissions occur at the operational stage with a 60-year study period. The end-of-life recycling of mass timber could provide carbon offset of 364 kg CO2-eq per m2 floor that lowers the GHG emissions of the mass timber building to a total 12% lower GHGs emissions than concrete building. The LCCA results showed that mass timber building had total life cycle cost of $3976 per m2 floor area that was 9.6% higher than concrete building, driven mainly by upfront construction costs related to the mass timber material. Uncertainty analysis of mass timber product pricing provided a pathway for builders to make mass timber buildings cost competitive. The integration of LCA and LCCA on mass timber building study can contribute more information to the decision makers such as building developers and policymakers.
The use of wood and timber products in the construction of buildings is repeatedly pointed towards as a mean for lowering the environmental footprint. With several countries preparing regulation for life cycle assessment of buildings, practitioners from industry will presumably look to the pool of data on wood products found in environmental product declarations (EPDs). However, the EPDs may vary broadly in terms of reporting and results. This study provides a comprehensive review of 81 third-party verified EN 15804 EPDs of cross laminated timber (CLT), glulam, laminated veneer lumber (LVL) and timber. The 81 EPDs represent 86 different products and 152 different product scenarios. The EPDs mainly represent European production, but also North America and Australia/New Zealand productions are represented. Reported global warming potential (GWP) from the EPDs vary within each of the investigated product categories, due to density of the products and the end-of-life scenarios applied. Median results per kg of product, excluding the biogenic CO2, are found at 0.26, 0.24, and 0.17 kg CO2e for CLT, glulam, and timber, respectively. Results further showed that the correlation between GWP and other impact categories is limited. Analysis of the inherent data uncertainty showed to add up to ±41% to reported impacts when assessed with an uncertainty method from the literature. However, in some of the average EPDs, even larger uncertainties of up to 90% for GWP are reported. Life cycle assessment practitioners can use the median values from this study as generic data in their assessments of buildings. To make the EPDs easier to use for practitioners, a more detailed coordination between EPD programs and their product category rules is recommended, as well as digitalization of EPD data.
