Comparative Life-Cycle Assessment of a High-Rise Mass Timber Building with an Equivalent Reinforced Concrete Alternative Using the Athena Impact Estimator for Buildings
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.
EBD was first developed by the Athena Sustainable Materials Institute. An EBD is a summary report of the comprehensive environmental footprint data for a building and declares life-cycle impacts according to a standardized format. It is a statement of performance and is publicly disclosed, similar to a nutrition label on a food package. The intent of the document is to present results as transparently and concisely as possible.
Athena’s EBDs are compliant with the European standard EN 15978, a whole-building LCA standard that is intended to support decision-making and documentation around the assessment of environmental performance of buildings. The Design Building would be the fourth building to be assessed as part of Athena’s EBD initiative and the first located in the United States.
