California is taking a proactive approach to tackling embodied carbon in building construction, as the California Building Standards Commission (CBSC) recently voted unanimously to implement two building code changes aimed at limiting embodied carbon emissions.
The modifications will apply for the building, renovation, or repurposing of commercial structures that exceed 100,000 square feet in size, as well as school projects that go beyond 50,000 square feet in area.
Embodied carbon refers to the carbon emissions associated with the production, transportation, and assembly of building materials and the CO2 footprint they leave behind during their whole lifecycle.
In the state of California, construction activity is credited with about 40% of the state’s greenhouse gas pollution. By reducing embodied carbon, California aims to mitigate its contribution to climate change and promote sustainable building practices.
The fresh changes to the building code were developed via the CALGreen Carbon Reduction Collaborative. This collective,established by the Division of the State Architect (DSA) and CBSC following a 2019 request for code modification from the American Institute of Architects (AIA) California, consists of individuals representing non-governmental organizations and California State agencies.
The code additions refer to changes made to CALGreen, Part 11, Title 24, which is the 2022 California Green Building Standards Code.
These additions offer three different ways for design professionals to comply with the new standards, and they are an extension of the carbon reduction efforts introduced by the BCCA in 2017, as they expand the range of monitored projects and add concrete to the list of covered materials.
The compliance options include reusing at least 45% of an existing structure, using materials that meet specific emission limits, and using a performance-based approach that involves analyzing the entire lifecycle of a building.
Starting July 1, 2024, California will take the lead as the first state to implement customized measures aimed at reducing embodied carbon emissions in accordance with the newly established rules, which will be valid across the entire state.