California has become the first state to set general code standards requiring the reduction of embodied carbon emissions in the design and building process, applicable to both commercial buildings and schools.
In a recent meeting, the California Building Standards Commission (CBSC) voted unanimously for two building code changes to limit embodied carbon emissions in the construction, remodel, or adaptive reuse of commercial buildings larger than 9,290 m2 (100,000 sf) and school projects with more than 4,645 m2 (50,000 sf). These statewide changes will be in effect as of July 1, 2024.
Embodied carbon refers to greenhouse gas (GHG) emissions arising from building materials over their life cycles, which includes manufacturing, transportation, installation, maintenance, decommissioning, and disposal.
The code additions are amendments to the 2022 California Green Building Standards Code (CALGreen), Part 11, Title 24. They provide three alternative compliance paths that can be elected by design professionals to meet the new standards. The carbon reductions build on California’s Buy Clean California Act (BCCA) of 2017, extending the scope of the projects covered significantly, and adding to the list of covered materials to include concrete. The compliance paths include one based on reuse of at least 45 percent of an existing structure; one based on the specification of materials that meet specified emission limits, and a third performance-based path that allows the use of a whole building lifecycle assessment (LCA) analysis.
A 2019 Code Change Petition submitted by AIA California was instrumental in leading to the foundation of the CALGreen Carbon Reduction Collaborative (CCRC) by the Division of the State Architect (DSA) and the CBSC. The collaborative is comprised of representatives from several California State agencies and non-governmental groups.
In the coming months, AIA California will be developing and hosting programs to expand awareness and the implementation of the code changes for design professionals, collaterals, and partners in the building industry and beyond.
“It can take up to 80 years to overcome embodied carbon’s impact through strategies that reduce energy usage or operational carbon; the planet doesn’t have that time,” says AIA California president Scott Gaudineer. “Today’s actions by the DSA, led by the California State Architect Ida Clair, AIA, and the CBSC led, until very recently by executive director Mia Marvelli, AIA, codify a cultural shift: to meet decarbonization timelines set by California law, embodied carbon must be reduced in addition to operational carbon.”
