In August 2023, California raised the stakes on embodied carbon when it became the first state to mandate reductions in embodied carbon emissions as part of its building code. The update to the California Green Building Standards Code, which was driven by the advocacy of architects and building industry experts in the state, takes effect on July 1, 2024.

The recent embodied carbon regulations under CALGreen applied to non-residential developments over 100,000 square feet that fall under CBSC authority; and school constructions exceeding 50,000 square feet that fall under DSA authority must adhere to one of three compliance routes outlined in the code.

Examples of building types that will be subject to these measures include office, retail, warehouses, K-12 schools, community colleges. Examples of building types not subject to these requirements include housing of all types, and medical facilities regulated by OSHPD.

The first pathway is for projects involving building reuse, which will be required to reuse at least 45 percent of an existing building’s structure and exterior. When reuse projects are combined with new construction, the new building cannot exceed twice the size of the existing structure.

The second pathway allows compliance through a comprehensive assessment of the building’s lifecycle. To meet this criterion, the project must demonstrate a 10-percent reduction in carbon emissions compared to a baseline project design of a similar construction type.

The third pathway, termed prescriptive, centers on the global warming potential of products. Projects must adhere to limits that are based on Buy Clean California, expanded to include concrete. Materials covered include structural steel (including hot-rolled sections, hollow structural sections, and plate), concrete reinforcing steel, flat glass, mineral wool board insulation, and concrete.

CALGreen Embodied Carbon provisions are in Chapter 5 and the compliance forms and worksheets are in Chapter 8.

Compliance Pathway Options:

Section 5.105 – Re-use of Existing Buildings’ Pathway – Page 4
Section 5.409.2 – Lifecycle Assessment Pathway – Page 23
Section 5.409.3 – GWP Compliance Prescriptive Pathway – Page 28

Worksheets: Pages 37-38

Worksheet (Ws-3) 5.105.2 Building Reuse path
Worksheet (Ws-4) Section 5.409.2 Whole Building Life Cycle Assessment path
Worksheet (Ws-5) Section 5.409.3 Product Gwp Compliance – Prescriptive Path

Worksheets for Tiers: Pages 39-42

Worksheet (Ws-6) [BSc-Cg] Section A5.105.2 Building Reuse Tier 1 And Tier 2
Worksheet (Ws-7) [BSc-Cg] Section A5.409.2 Whole Building Life Cycle Assessment
Worksheet (Ws-8) [BSc-Cg] Section A5.409.3 Product GWP Compliance-Prescriptive Path
Worksheet (Ws-9) Section 5.409.2 And Section A5.409.2 Whole Building Life Cycle Assessment