In the late summer of 2023, the California Building Standards Commission adopted new mandatory embodied carbon requirements through the California Green Building Standard Code, colloquially known as CALGreen. These measures will be required for all non-residential buildings greater than 100,000 SF and school buildings greater than 50,000 SF, making California the first State in the nation to implement embodied carbon mandates on new construction. In this month’s OnTrack article, we delve deeper into what that means for the building industry, our clients and how we have evolved our practice to fit the ever-evolving policy landscape.

A Quick Reminder: What is Embodied Carbon and Why Does it Matter?

Embodied Carbon refers to the greenhouse emissions associated with the extraction, manufacturing, transport, use and end of life of building products. The metric with which it quantifies its effects on the environment is referred to as Global Warming Potential (GWP), measured in the units of kgCO2e.

Up until recently, much of the decarbonization discussion has focused on operational carbon – the greenhouse gas emissions emitted from the heating and cooling of a building. Our MEP systems have gotten quite efficient at reducing operational carbon; however, as our MEP systems become more efficient, upfront carbon (embodied carbon) becomes an increasingly large portion of the pie that makes up the carbon problem. Most of a building’s total embodied carbon is released at the beginning of the building’s life cycle – so measuring, tracking, and reducing this embodied carbon at the design phase is incredibly important to holistic building decarbonization.

Carbon Leadership Forum Graphic - Embodied and Operational carbon

What Types of Buildings will be Affected and When and How?

All non-residential building projects greater than 100,000 SF and school building projects greater than 50,000 SF will be mandated to comply with the new CALGreen embodied carbon measures. These types of buildings must start to show compliance if they are issued for permit after July 1, 2024.

The CALGreen mandates provides three pathways to compliance:

1. Building Reuse
2. Whole Building Life Cycle Assessment (WBLCA)
3. Prescriptive Approach

For existing buildings where 45% of the existing structure and exterior is used, the Building Reuse pathway satisfies the mandatory compliance requirement. For new construction, design teams must decide whether they would prefer to show compliance through one of two methods: a WBLCA, which demonstrates a 10% reduction in embodied carbon or through the “Prescriptive Approach”, which requires documentation of environmental product declarations (EPDs) for primary structural and architectural components.

There are more stringent, voluntary, tiers for each pathway that are laid out as framework for local municipalities to adopt now and for CALGreen to implement as mandatory in the future. The Sustainable Design Committee of the Structural Engineering Association of California created a helpful infographic to understand these new measures.

CALGreen 2022 Mid-Cycle Updates - Glotman Simpson

What Does This Mean for the Industry and How Can We Help?

While these embodied carbon measures are the first State-wide code requirement in the U.S., they are far from new in both Canada and the majority of Europe. Two years ago, the City of Vancouver revised their Bylaws to require WBLCA for almost all buildings, with a stated goal of 10-20% reduction from the baseline starting in 2025 – to read more about the code mandates, check out the article we wrote on it at the time. The City of Toronto has already imposed an absolute embodied carbon intensity limit of 350 kgCO2e/m2 for both structural and architectural components for all government-owned buildings.

The earlier code revisions in various cities in Canada have allowed Glotman Simpson to allocate additional resources focusing on building decarbonization to meet embodied carbon reduction goals. We have collaborated with our automation team to create various embodied carbon tracking and visualization tools, one of which we dived deep into for our September OnTrack blog post. We have been working on fine-tuning our LCA practice and using BIM integration with Tally LCA to create a cohesive picture of the embodied carbon associated with each structural element. We have built out our own database of EPDs, closely aligning the data with CLF’s Regional Benchmark Report and have used these numbers to inform our GWP calculators embedded in our design spreadsheets. We have closely collaborated with ready-mix suppliers and know the constraints and various levers we can pull to get significant embodied carbon reduction in concrete mixes based on the local area, whether that be Vancouver, Los Angeles or San Jose.

Glotman Simpson embodied carbon intensity by project status plot

These swift policy pushes seem to be here to stay and will only get more stringent. So, in the face of the ever-changing building industry landscape, we have not only learned how to adapt but created meaningful tools for clients pursuing embodied carbon reductions, whether that be of their own volition or as required by the CALGreen mandates, starting July 1st.

Written by Rachelle Habchi, Director of Sustainability

Glotman Simpson’s On Track series delves into factors we can explore to reduce the environmental impact of building structures. The need to accelerate climate action in the form of innovative solutions that minimize both operational and embodied carbon is imperative and represents a critical part of a low-carbon future.