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Corgan Unveils CO2e Emission Calculator for Mass Timber

via Business Wire

New research and tool help architects identify unaccounted emissions

Global architecture and design firm Corgan has released new research addressing mass timber biogenic carbon emissions. Mass timber is lauded for its renewable nature compared to traditional building materials, but there are carbon emissions from wood harvesting and material transport that should be considered. Corgan’s sustainability practice, Echo, and research group, Hugo, conducted a study to identify the biogenic carbon emissions that are often unaccounted for in industry standard life-cycle assessment (LCA) studies for mass timber buildings. Further, to educate and empower the industry, the firm developed the Corgan Mass Timber Carbon Calculator — a free tool that will help architects and designers to estimate biogenic carbon emissions in mass timber projects and better manage a project’s overall embodied carbon calculations.

By 2050, global demand for wood as a building material is expected to quadruple, driven in part by the rising popularity of mass timber, which has become increasingly common as designers seek more sustainable, low carbon alternatives to construction materials like steel and concrete. However, a 2023 World Resources Institute report explored mass timber’s broader environmental impact, questioning a standard assumption in the AEC industry that mass-timber is carbon neutral owing to carbon capture during the life of the tree. The report points to carbon emissions associated with decomposition of parts of the tree left behind in the forest, also referred to as ‘slash.’

Corgan’s research identified that during mass timber harvesting, ‘slash’ which includes parts of the tree like branches, twigs, roots, and bark are left behind. While 35% of materials that are cut down make it to the building stage, the remaining 65% of materials re-release biogenic carbon — though this is often unaccounted for in mass timber emission counts. Corgan’s resulting report, Understanding Real CO2e Emissions in Mass Timber Production, considers factors that impact CO2e emissions associated with mass timber including:

  • Tree harvest residue or “slash” management: The study explores three common slash management scenarios, including site composting; pile burning; and mastication.
  • Tree species: CO2e emissions from tree slash vary by tree species. The study analyzed seven species commonly used in mass timber projects in the U.S.: Alaska Yellow Cedar, Douglas Fir, Hemlock Fir, Ponderosa Pine, Southern Yellow Pine, Spruce Pine Fir, Western Red Cedar.
  • Raw material transport: The transportation of mass timber from manufacturing site to building site is considered, as it has a significant impact on embodied carbon, which refers to greenhouse gases released during extraction, production, and transportation of materials.

To illustrate the practical application, a case study of a theoretical 216,000-square-foot, six-story office building with mass timber structural elements was conducted. This study found that even with the worst-case scenario for slash management, mass timber accounts for lower embodied carbon values than concrete or steel structures.

A carbon calculator for mass timber

Inspired by the research findings, Corgan developed a new dynamic tool to help architects and designers better understand the biogenic carbon emissions of different tree species and slash management scenarios. The Corgan Mass Timber Carbon Calculator allows designers to compare the impact of different tree species within their building scope and consider lower carbon-intensive timber species at every project phase, leading to more sustainable project outcomes.

“Approximately 20% of a building’s total energy usage over its lifetime is determined long before it is even built and occupied,” said Varun Kohli, director of Corgan—Echo. “Our mass timber carbon calculation tool provides a methodology to help provide the industry with additional data for a more informed decision for Mass Timber projects, especially as the global demand for wood products continues to multiply.”

Available to all and free to access, the Corgan Mass Timber Carbon Calculator was created with the intent of empowering, educating and engaging professionals in the architecture, engineering, and construction industries. Architects and designers can use the tool to make decisions and facilitate discussions with contractors and engineers, promoting transparency and positive changes throughout the project cycle.

“Our tool empowers firms to confidently utilize and present the biogenic carbon value of mass timber, enhancing accuracy and credibility in their sustainability efforts,” said Mahdi Afkhami, Ph.D., design researcher within Corgan—Hugo. “Our research is the next step in fostering industry collaboration. We hope this collective effort will improve carbon accounting practices and promote more sustainable construction processes.”

ABOUT CORGAN

Corgan is an employee-owned architecture and design firm with 19 locations and more than 1,200 team members globally. The firm, ranked as the No. 4 architecture firm by Building Design + Construction, works with clients in a variety of sectors including aviation & transportation, data centers, education, government, health, mixed-use, multifamily, office, and workplace. Founded in 1938, Corgan has developed a strong reputation for agility in design by anticipating marketplace changes and leading clients to thoughtful, data-driven design solutions. Its research insights and design expertise empower the organization to foresee emerging changes and develop solutions that minimize risk, create flexibility, and maximize longevity. To learn more about Corgan, visit www.corgan.com.

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