Sources: Sierra Club California; CP staff
The Marin County (Calif.) Board of Supervisors unanimously adopted an ordinance that adds a low-carbon concrete specification to the county’s building code, effective January 1, 2020. The new code applies to concrete mix designs for all private and public construction projects, and includes pathways for compliance with either reduced cement levels or lower-emission supplementary cementitious materials.
The ordinance is the result of the county’s ongoing “Bay Area Low-Carbon Concrete Codes Project,” which aims to reduce embodied emissions in the built environment by creating local specifications and model policies for low embodied-carbon concrete. Funded through the Bay Area Air Quality Management District’s Climate Protection Grant Program, project lead Marin County works in close partnership with Alameda County’s StopWaste; structural engineer Bruce King, PE; design firm Arup; and, the Carbon Leadership Forum. Future target outcomes are a) four pilot projects receiving technical assistance to apply the low embodied-carbon concrete specifications by 2022; and, b) formation of a Bay Area Concrete Working Group as an extension of the Embodied Carbon Network.
In response to the ordinance passage, Molly Culton, conservation organizer for Sierra Club California, issued the following statement: “While a lot of work has been done to reduce operational emissions in buildings, addressing embodied emissions is the next frontier. With this concrete ordinance, Marin County has established itself as a leader in addressing greenhouse gas emissions in the built environment. We anticipate other local governments in the Bay Area and beyond will pass similar policies.”
The low-carbon concrete ordinance is part of a larger wave of policies that aim to address embodied carbon emissions in building materials. Earlier this year, Portland, Ore., adopted a program that requires all concrete used in city projects to disclose emissions through a product-specific, third-party verified environmental product declaration.