By Adam Shoemaker, CSI, CDT, LEED AP BD+C
In December 2021, the United States placed a federal emphasis on climate-friendly construction materials by implementing the Buy Clean initiative. This initiative leverages the U.S. government’s purchasing power to help spur “a large and stable demand signal to the marketplace” for American-made products with lower embodied emissions in the manufacturing sector, which accounts for nearly one-third of the nation’s total greenhouse gas (GHG).1
In 2022, the effort was strengthened by the Inflation Reduction Act (IRA), which provided more than $4 billion to federal agencies, including the General Services Administration (GSA), to source climate-friendly materials on federally funded construction projects. As of writing, much of the funding related to low-embodied carbon projects has already been disbursed, but it is unclear how future funding may be impacted.
The U.S. is not the only country cracking down on embodied emissions. France, Switzerland, and the Nordic countries have led the charge with similar programs that require mandatory embodied carbon calculations.2 Canada also took action in 2022 with its “Standard on Embodied Carbon in Construction,” which requires disclosing and reducing the carbon footprint of structural materials in major construction projects.3
Since the onset of these efforts, terms such as “low embodied carbon” have grown more commonplace in the construction sector. According to the Environmental Protection Agency (EPA), low embodied carbon steel products “have less climate impact associated with mining, manufacturing, and transportation.” Essentially, this term correlates to a product’s greenhouse gas emissions, measured across its entire supply chain.
Steel production has historically been a significant source of carbon emissions.4 However, growing awareness of the lower embodied carbon in steel from electric arc furnaces drives a shift towards this more sustainable production method.
How production differs for low embodied carbon steel
Steelmaking is a multi-step process with varying methods and production routes. Each choice along the way, from raw materials to manufacturing processes, influences the sustainability of the final product. Ultimately, how the steel is sourced and produced determines whether it will qualify as low embodied carbon steel framing. The World Steel Association has a comprehensive breakdown of the steelmaking process,5 categorizing it into seven basic steps: raw materials, raw materials preparation, ironmaking, steelmaking, semi-finished products, hot-rolled products, and finishing operations.
Raw materials
The journey toward a sustainable steel product begins at the raw materials stage. Using recycled steel at this early juncture sets a benchmark for low embodied carbon by effectively bypassing several energy-intensive processes. New steel is conventionally made via the basic oxygen furnace (BOF). This relies on iron ore, which necessitates mining, transportation, raw material preparation, and ironmaking—each step contributing significantly to embodied carbon emissions. In contrast, recycled steel, predominantly used in an electric arc furnace (EAF), enters the steelmaking phase after being sorted, generally circumventing the raw materials preparation and ironmaking steps. This fundamental shift in raw material sourcing underscores the pivotal role recycling plays in decarbonizing the steel industry and establishes a greener foundation from the outset.
Raw materials preparation
The raw materials are then processed to optimize suitability for subsequent ironmaking or steelmaking processes. Iron ore headed to a BOF mill must undergo extensive preparation, including processes to enhance the iron content and remove impurities, as well as crushing and grinding the ore into smaller, uniform pieces. By contrast, EAF mills using recycled steel typically demand less extensive sorting and sizing preparation before the material is charged into the furnace.
Ironmaking
In this step, iron ore is transformed into molten iron using a blast furnace. Iron ore, coke (derived from coal), and limestone are heated, with coke acting as fuel and reducing agent. Limestone removes impurities such as slag. Notably, this step applies only to the BOF route; the EAF route completely bypasses this energy-intensive stage.
Steelmaking
In the steelmaking process, molten iron, derived from ironmaking or recycled steel, is transformed into steel. In BOF mills, oxygen is blown into the BOF to reduce the carbon content of the molten iron and remove impurities, resulting in steel. EAF mills, on the other hand, use electrical energy, sometimes supplemented with oxygen injection, to melt scrap steel and adjust its chemical composition by adding alloys.
Semi-finished products, hot-rolled products, and finishing operations
Steel is cast into a semi-finished shape, such as slabs, billets, or blooms. It is then hot-rolled into various products, including rebar, coils, structural shapes, etc. Several finishing procedures can then occur, including painting, galvanizing, and cold rolling, to further reduce the thickness of a hot-rolled plate or coil product. After this final step, the steel is shipped to companies such as steel framing manufacturers, where it is formed into end-use products.
In most cases, LEC steel is made with high percentages of recycled content and processed at an EAF mill, resulting in up to 30 percent less embodied carbon than steels using different raw material inputs. LEC steel framing has the proper data to back this up, including environmental product declarations (EPDs), life cycle assessments (LCAs) and more.6
It is worth noting that while a low embodied carbon perspective would have all steel ideally coming from EAF mills, BOF mills do still have a benefit in today’s market. There is currently not enough steel being recycled to supply the total market demand for new steel products,7 and maintaining a balance between EAF and BOF sources supports a resilient supply chain, help mitigate price volatility, and allow for quick and flexible adaptations to demands.
BOF mills are also exploring many ways to produce more sustainable steel, such as hydrogen-based direct reduced iron (DRI); carbon capture, utilization, and storage (CCUS); electric smelting furnace (ESF); oxygen-enriched blowing; and increased scrap utilization, to name a few.8
Specifying LEC steel
According to the Office of the Federal Chief Sustainability Officer, U.S. manufacturing accounts for nearly one-third of the country’s total greenhouse gas emissions, and half of those emissions come from asphalt, concrete, glass, and steel production.9 In 2023, the GSA launched a pilot program to test new requirements for LEC construction materials in 11 initial IRA-funded projects, focusing on those four key materials. To date, the GSA has seen an increase of more than 17,000 new EPDs in the four material categories (including more than 5,000 during the six-month trial program alone), indicating the industry is following suit with the new push for increased transparency and lower emissions. Following the pilot’s success, the GSA announced $2.51 billion in funding for more than 150 projects across the U.S. that meet its LEC material requirements.10 Projects that use LEC steel verified by a third-party Type III EPD qualify for funding from the GSA.11
The federal government is not the only agency encouraging the use of LEC materials. The initiative has flourished at the state level as well. Through the Federal-State Buy Clean Partnership—which currently includes 13 states: California, Colorado, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New York, Oregon, and Washington12—LEC materials are also being prioritized in state-funded projects.
California is taking things a step further, becoming the first state to mandate a reduction in embodied carbon emissions as part of its building code. Effective July 2024, the code change offers three paths to meet the new standards for commercial buildings of more than 9,290 m2 (100,000 sf) and schools of more than 4,645 m2 (50,000 sf). According to the U.S. Green Building Council, “The first calls for the reuse of at least 45% of an existing structure, the second requires the use of materials (steel, glass, mineral wool, and concrete)13 that fall within specified emission limits, and the third is a performance-based compliance path that allows the use of a whole building life cycle assessment analysis.”14
Accreditation programs such as LEED also support products with environmental transparency and lower embodied carbon. In LEED v4.1, for example, building teams can earn up to two points under the “Material and Resources Credit: EPDs.” To earn these points, teams must achieve one or more of the following options: Option 1—Environmental Product Declaration (1 point), or Option 2—Embodied Carbon/LCA Optimization (1 point). Option 1 requires that a project include at least 20 different products from at least five different manufacturers that meet certain disclosure criteria. Option 2 requires that projects include at least five products from at least three manufacturers that have a compliant embodied carbon optimization report or action plan separate from the LCA or EPD.15
In achieving these LEED credits, it is important to understand the distinction between LEED “points” and “products.” Various environmental disclosures contribute differently toward the required product count. For instance, an LCA, a Product-Specific Type III EPD (not third-party certified), or an Industry-Wide Type III EPD each count as “one whole product.” Meanwhile, a third-party certified Product-Specific Type III EPD counts as “1.5 products” toward the required total. Under Option 2, products with demonstrated reductions in Global Warming Potential (GWP) can be weighted differently. For example, a single product with a 20 percent or greater reduction in GWP and at least a five percent reduction in two additional impact categories may count as two products toward the five-product requirement.
In addition to understanding how different environmental disclosures contribute toward product counts, the EPD credit specifically aims to promote the use of products with available lifecycle information that demonstrate environmentally, economically, and socially preferable impacts. It rewards project teams for selecting products from manufacturers with verified environmental improvements.
Demand for LEC building materials is higher than ever. Specifiers should be aware of legislative actions and code changes that emphasize such products and which manufacturers are adapting to these new standards. For instance, only a handful of products on the market meet the criteria for the embodied carbon/lifecycle analysis optimization point (“Option 2”) under LEED v4.1’s MR Credit: EPDs. (As of writing, there is only one steel framing manufacturer with the data available to help achieve credit for this option.) Therefore, specifiers may need to source strategically to meet specific accreditations or standards requirements.
Luckily, with the growing demand for LEC steel, it is easier to specify than before. At least one manufacturer offers LEC steel framing products with a nationwide footprint, and others may additionally serve smaller geographic regions. When specifying LEC steel, look for readily available third-party EPDs, LCAs, or EPD optimization reports that compare the LEC product against a baseline product. Some manufacturers even have a dedicated sustainability platform to make finding product environmental data simple and streamlined. The EPA has also announced a new label program for LEC construction materials, which, when in effect, will identify “clean” products and list them in a centralized, public registry to make sourcing and purchasing LEC materials easier.16
Many groups are also dedicated to educating about and advocating for reducing embodied carbon within the construction industry. For years, the Carbon Leadership Forum has worked to transform the building sector by “radically reduc[ing] the greenhouse gas emissions attributed to materials (also known as embodied carbon) used in buildings and infrastructure.”17 In 2019, the group issued a challenge that “all structural engineers shall understand, reduce, and ultimately eliminate embodied carbon in their projects by 2050.” As a result, SE 2050, or Structural Engineers 2050 Commitment Program, formed, “designed to ensure substantive embodied carbon reductions in the design and construction of structural systems by the collective structural engineering profession.”18 Both of these groups are examples of industry professionals collaborating for the mission of reducing embodied carbon in buildings and materials. Closely following groups like these can help specifiers and building teams stay informed on the latest carbon reduction policies, regulations, or updates from manufacturers.
When incorporating low-embodied carbon cold-formed steel framing into construction projects, specifiers might be unsure where to specify it in their documents. This is a common question, and for good reason. While LEC requirements can appear in various sections, it is recommended to focus on these three key areas:
- Sustainable Design Requirements—01 81 13: This section is a natural fit for LEC, as it directly addresses environmentally conscious building practices.
- Cold-Formed Metal Framing—05 40 00: Since this section deals specifically with cold-formed steel, including LEC requirements here ensures they are seen by those directly involved with the framing process.
- Non-Structural Metal Framing—09 22 16: If the LEC steel is primarily for non-structural applications, this section is the most relevant.
Referencing the GSA IRA Limits for Low Embodied Carbon Steel Cold-Formed and Galvanized products19 provides a standardized baseline for everyone involved. This avoids confusion and ensures everyone is on the same page regarding these evolving standards. For ease of use, place LEC requirements directly within sections 05 40 00 or 09 22 16 to ensure project teams sourcing and installing the steel products see the requirements clearly without having to delve into the broader sustainable design section.
Looking forward
The surge of government-supported initiatives, such as Buy Clean, is just the tip of the sustainability revolution iceberg for the building sector. As more programs increase the demand for lower embodied carbon materials, steel mills and manufacturers should strive to continue to evolve their practices to better address the need for less carbon-intensive processes.
Improvements in the industry can already be seen. Following the GSA’s six-month LEC pilot program, the agency has published program updates, including that “the steel industry has shown substantial improvement, with average GWPs (emissions per unit of product) dropping in most of GSA’s steel product subcategories, including hot-rolled sections and cold-formed galvanized steel.” Published in June 2024, the update went on to recognize that “two major U.S. manufacturers of steel have also published their first-ever EPDs, or are currently in the process of doing so. Both companies have said their action was motivated by the Federal Buy Clean leadership.” This shows that the market has already evolved tremendously.
Seeing these improvements in the manufacturing processes for materials such as asphalt, concrete, glass, and steel is incredibly encouraging. It is imperative to continue innovating and moving forward. The betterment of the built environment and beyond demands nothing less.
Notes
1 To learn more, visit sustainability.gov/buyclean
2 To learn more about carbon regulations, visit preoptima.com/the-carbon-source/embodied-carbon-regulations
3 Review the standard on embodied carbon at tbs-sct.canada.ca/pol/doc-eng.aspx?id=32742
4 See steel’s environmental impact and next steps
at globalefficiencyintel.com/steel-climate-impact-international-benchmarking-energy-co2-intensities
5 Check out this interactive infographic at worldsteel.org/about-steel/steelmaking-process/
6 Refer to ClarkDietrich’s LEC-EPD LCA Optimization Assessment at clarkdietrich.com/sites/default/files/media/documents/ClarkDietrich%20LEC-EPD%20LCA%20Optimization%20Assessment.pdf
7 Read “What is Steel” by the World Steel Association
at worldsteel.org/about-steel/what-is steel/#:~:text=Most%20steel%20products%20remain%20in,BOF%20and%20EAF%20production%20methods
8 Review “Climate Action: worldsteel member initiatives” from the World Steel Association at worldsteel.org/climate-action/climate-member-initiatives/
9 See note 1.
10 Learn more at www.gsa.gov/real-estate/gsa-properties/inflation-reduction-act/lec-program-details/program-updates/lec-pilot-fact-sheet-archived-version
11 See the requirements for asphalt, concrete, glass, and steel at www.gsa.gov/real-estate/gsa-properties/inflation-reduction-act/lec-program-details/material-requirements
12 Read more about the principles of the partnership at www.sustainability.gov/pdfs/federal-state-partnership-principles.pdf
13 Review the document Revision Record for the State Of California—Supplement, July 1, 2024 at iccsafe.org/wp-content/uploads/errata_central/2022-CA_Green_July24-Supp_COMPLETE.pdf
14 See California’s code update at www.usgbc.org/articles/california-code-update-aims-reduce-embodied-carbon
15 Review the full LEEDv4.1 criteria guide at build.usgbc.org/bd+c_guide
16 Refer to the Environmental Protection Agency’s (EPA’s) label program at www.epa.gov/greenerproducts/label-program-low-embodied-carbon-construction-materials
17 To learn more, see the Carbon Leadership Forum at carbonleadershipforum.org/
18 Learn more about SE 2050 by visiting se2050.org/
19 Refer to the following document at www.gsa.gov/system/files/Steel%20-%20GSA%20IRA%20Low%20Embodied%20Carbon%20Requirements%20%28Dec.%202023%29_508.pdf
Author
Adam Shoemaker is the director of corporate sustainability for ClarkDietrich, North America’s largest manufacturer of cold-formed steel framing. He is a LEED AP BD+C and CDT-certified professional with expertise in navigating the complexities of sustainability, building codes, and green building programs for the construction industry. He can be reached at adam.
Key Takeaways
The push for sustainable construction materials is accelerating worldwide, driven by initiatives such as the Buy Clean program, strengthened by the Inflation Reduction Act (IRA), which promotes low-embodied carbon (LEC) materials. Steel, a major contributor to embodied emissions, is undergoing a transformation through the adoption of electric arc furnaces (EAF) and the use of recycled materials. Countries such as Canada, France, and the Nordic nations are enforcing stricter embodied carbon standards, while California leads the U.S. with building code updates. As demand for LEC materials grows, specifiers and manufacturers must adapt, leveraging environmental product declarations (EPDs) and evolving production methods to meet sustainability goals.
