Pierobon, Francesca; Huang, Monica; Simonen, Kathrina; Ganguly, Indroneil. (2019). Environmental Benefits of Using Hybrid CLT Structure in Midrise Non-Residential Construction: An LCA Based Comparative Case Study in the U.S. Pacific Northwest. Journal Of Building Engineering, 26.
Abstract
In this study, the cradle-to-gate environmental impact of a hybrid, mid-rise, cross-laminated timber (CLT) commercial building is evaluated and compared to that of a reinforced concrete building with similar functional characteristics. This study evaluates the embodied emissions and energy associated with building materials, manufacturing, and construction. Two alternative designs are considered for fire protection in the hybrid CLT building: 1) a 'fireproofing design', where gypsum wallboard is applied to the structural wood; and 2) a 'charring design', where two extra layers of CLT are added to the panel. The life cycle environmental impacts are assessed using TRACI 2.1 and the total primary energy is evaluated using the Cumulative Energy Demand impact method. Results show that an average of 26.5% reduction in the global warming potential is achieved in the hybrid CLT building compared to the concrete building, excluding biogenic carbon emissions. Except ozone depletion, where the difference in impact between scenarios is < 1%, replacing fireproofing with charring is beneficial for all impact categories. The embodied energy assessment of the building types reveals that, on average, the total primary energy in the hybrid CLT buildings and concrete building are similar. However, the non-renewable energy (fossil-based) use in the hybrid CLT building is 8% lower compared to that of the concrete building. As compared to the concrete building, additional 1,556 tCO(2)(e) and 2,567 tCO(2e) are stored in the wood components of the building (long-term storage of biogenic carbon) in the scenario with fireproofing and with charring, respectively.
Keywords
Wood; Concrete; Energy; Buildings; Impacts; Cross-laminated Timber; U.s. Pacific Northwest; Life Cycle Assessment; Cumulative Energy Demand; Biogenic Carbon; Carbon Storage