This study was commissioned to perform environmental life cycle assessment (LCA) of two new buildings being constructed on the Canadian Nuclear Laboratories Chalk River campus: the B703 Business Hub and B750 Support Facility. The buildings feature prominent use of mass timber and are participating in the Green Construction with Wood (GC Wood) program operated by Natural Resources Canada (NRCan), which requires an LCA to evaluate the carbon implications of the project. To this end, the environmental performance of the two buildings is compared to baseline designs with functionally equivalent structural steel framing.
The assessments have been performed according to the Committee for European Standardization (CEN) standard EN 159781, which stipulates an LCA-based calculation method and reporting requirements for whole-buildings or building parts. While European in scope, EN 15978 is the standard for whole-building LCA worldwide. We therefore applied our North American interpretation of EN 15978 as a suitable methodological choice to meet the purpose of the assessment.
The scope of the LCA is a cradle-to-grave analysis of the material effects of structure and envelope over a 60-year period. Seven metrics were calculated using the Athena Sustainable Materials Institute's ISO 14040/44 conforming Impact Estimator for Buildings (IE4B) software database, including the net biogenic carbon sequestered by wood products.