Perspectives Meet Embodied Carbon Emissions Reduction Goals with These Steps

Whole Building Life Cycle Assessments (WBLCA) is a method used to quantify GHG emissions associated with building materials and evaluate alternative materials with potentially lower emissions. The first step toward mitigating the environmental impact of each project is to measure current projects. This not only allows companies to promptly relay average emissions data to potential investors for upcoming projects, but also establishes a baseline for enhancing design guidelines and requirements. Companies are establishing protocols for carbon accounting programs, which comprehensively quantify all greenhouse gas emissions linked to a project. Once a baseline is established, it’s time to reduce emissions. This can be achieved by evaluating design guidelines and specifications to make decisions based on the largest impact for carbon reduction.

High-carbon materials are ubiquitous in the built environment, and lower-impact substitutions are increasingly evaluated. Concrete, other cement-based materials and steel are all major contributors to GHG emissions. While embodied carbon in buildings account for at least 11% of global GHG emissions annually, concrete and steel alone account for 11% and 10% of global GHG emissions annually (respectively) due to the ubiquitous use of these materials in other sectors beyond the building sector. As such, chiefly addressing concrete and steel emissions is critical to the global effort to reduce construction impact on climate change. Some of the most common replacement materials, their reduction potential, and their limitations are presented below, with more details available in the study.

Are you ready to take the steps to achieve a lower embodied carbon footprint with your next project? While the steps necessary to lowering the emissions associated with building materials are simple, they are not easy:

1. Establish a baseline by conducting an embodied carbon study.
2. Change design standards and material tracking requirements.
3. Build differently.

Step 1: Establish a baseline by conducting an embodied carbon study

Measuring reduction without fully understanding where you’re starting from is hard. Establishing a baseline allows you to show reduction and celebrate success. If your portfolio stretches across various regions or countries, we recommend selecting a representative project from each region and/or country to review emissions associated with building materials, as it can vary based on the location. For example, colder climates will use more insulation, which increases embodied carbon emissions, yet tremendous savings in operational carbon emissions will occur. To avoid the ground getting too hot, warmer climates may choose concrete for paving instead of asphalt, which also increases embodied carbon emissions. Regional differences are essential to understand when setting a baseline.

Step 2: Change design standards and material tracking requirements

An industry expert like BranchPattern can help assess your current design standards and specifications, and recommend changes requiring lower emissions materials and reducing material quantities. Without realizing it, projects can put more building materials in the project than is necessary, increasing the overall emissions. Engaging the design and construction teams to track material types and quantities and provide submittals is also essential. Some teams may not know how to do this, so training them on what information they need to collect is critical. Ideally, manufacturers are providing product-specific Environmental Product Disclosures (EPDs) or participating in an industry-wide EPD study. Also, encourage team communication with material manufacturers to ensure information flows smoothly across all projects.

Step 3: Build differently

Finally, we need to build differently. Oftentimes, people are quick to embrace new materials or technologies to reduce emissions associated with building materials. It’s exciting to think of the innovation that will likely occur to help building owners reach their goals.

However, several steps exist before jumping to a low-carbon material substitute: 

Step 1 – Consider reusing a building and/or building materials. While ground-up construction can be simpler and easier in many ways, starting with an existing building can represent massive embodied carbon savings – a compelling reason for developers to consider renovating existing building stock before turning to ground-up new construction.

Step 2 – By simply reducing the material quantities in a project, teams can realize huge emissions reduction. Projects can see a huge reduction in emissions and can also save money by reducing the volume of asphalt, pavement, concrete walls, and slabs because the project uses fewer materials. With the help of sustainability consultants, teams can also consider optimizing structural framing systems, which reduces the materials needed to achieve the same result.

Step 3 – Designing for disassembly and future reuse is paramount. Being thoughtful about the full life of a building and how the building will be used in 50 years, 100 years, or 150 years from now can be overwhelming, but is extremely important so that we aren’t continuing to emit generations into the future. Consider ways internal wall systems can be reused or other applications for the building structure in the future. Avoiding demolition is critical to saving future emissions.

After considering these critical steps, we can begin to look at new technologies, systems and materials to help further reduce emissions. This should be the last step when consciously reducing emissions, although teams usually revert to it first.

There are several opportunities to reduce emissions with low-carbon material substitutions:

• Incorporate SCMs (Supplementary Cementitious Materials) in concrete – these materials replace ordinary Portland cement (OPC), which is a major emitter. Traditional SCMs can include fly ash, slag, and pozzolan. More innovative SCMs are entering the market as well.
• Incorporate mass timber along with concrete; the beauty of using trees to build is that we can continue to grow the building material, unlike steel or concrete. Also, while the trees grow, they capture carbon. In an industrial building setting, it can be a challenge to completely remove concrete from the project, but by incorporating some timber in the project, you can see reductions in overall emissions.
• TIPS is a wall panel solution with an EPS insulation at the core of reinforced concrete (a sandwich panel, similar to precast walls but are constructed on site like tilt up walls). TIPS are structural panels and can reduce the amount of concrete typically required. Using TIPS walls in lieu of traditional tilt-up wall construction could reduce the wall’s carbon emissions by about 20%.
• Nexii panels are a wall system with EPS insulation at the core of reinforced cementitious material. Part of the benefit that Nexii brings is that the system can be taken apart at the end of a building’s life and be reused in a future project. This particular material substitution works best in Industrial projects if the project already has a structural framing system supporting the baseline walls, such as with non-structural precast concrete walls.
• DUCTILCRETE engineered slab systems are typically thinner than traditional concrete slabs and therefore require considerably less Ordinary Portland Cement. Using a DUCTILCRETE could reduce the slab’s carbon emissions by 25% as compared to a baseline slab design.*

*The estimated reductions are the result of BranchPattern internal assessments, using current data available from manufacturers and proxy EPDs where applicable. Published EPDs would confirm environmental performance.

When alternative materials have been exhausted, teams can also select materials with higher recycled content as recycled materials generally have less manufacture process, energy and carbon required than virgin material, for example, consider 100% recycled steel.

Final thoughts

Reducing the carbon footprint of buildings isn’t an easy task, but it can be accomplished with the right planning ahead of time. “The whole team is going to have to collaborate and work together, which they do already but inherently it’s going to be more difficult when you’re doing something new like the TIPS panels,” Emrick said. In return, property teams may be able to realize drastically improved building carbon performance, while seeing similar or only slightly higher development costs. The broader sustainability impact of properties is now considered alongside financial metrics, Hullum added.

Next steps

To continue the discussion, contact us at ImprovingLife@BranchPattern.com or to begin a project, submit a request for proposal.

About BranchPattern
BranchPattern is a building consultancy dedicated to creating Better Built Environments®. Our team consists of Professional Engineers, Registered Architects and Building Scientists that focus on implementing programs and solutions to optimize human experience and environmental stewardship.  The firm provides broad expertise to support the sustainability goals of the Commercial Real Estate Industry throughout North America, South America, and Europe.