Trends in Sustainable Building Materials - Part 1
Initiatives that are driving the industry to focus on reduction of embodied carbon
14 March 2023
According to the United Nations, buildings are responsible for 36% of global energy use and more than 39% of greenhouse gas (GHG) emissions (11% from building materials). The construction and operation of buildings negatively impact the environment and are an important place to seek sustainable solutions. While there are no truly sustainable building materials, we can look at the impacts of various materials used in building and construction and how we can make improvements.
When we talk about sustainable building materials, we look at:
- Reducing embodied carbon – emissions associated with making materials and buildings
- Limiting other environmental impacts – controlling emissions to air, water and soil where the materials are produced and used
- Increasing recycled content and circularity – Moving from the established approach of reducing the use of virgin materials to a newer concept, circularity, which is focused on closing the loop (cradle-to-cradle material use) and avoiding downcycling materials into lower quality products at the end of their life
- Reducing human health impacts – Increasing awareness of how the built environment affects health and wellbeing and increasing transparency of material constituents.
Today we're going to focus some of the trends that are driving attention toward embodied carbon in the design and construction of buildings and infrastructure.
The first is the introduction of government purchasing requirements for embodied carbon. For instance, the State of California's Buy Clean California requirements just went into effect, setting embodied carbon limits for a handful of materials used in state-funded projects, including steel, glass, and insulation. A similar act was recently signed into law in Colorado.
A total of seven other states have pending legislation for similar requirements and five municipalities have "buy clean" policies. We can anticipate that more will follow including at the Federal level. The U.S. General Services Administration (GSA) recently released its Recommendations for Procurement of Low Embodied Carbon Materials and last year the House Committee on Energy and Commerce introduced the CLEAN Future Act.
Collectively, this trend will encourage manufacturers to account for the embodied carbon in their products, and to innovate strategies to reduce it.
Whole Building Life Cycle Assessment
Industry-leading sustainable building rating systems, like Leadership in Energy and Environmental Design (LEED) and the Living Building Challenge, are now recognizing whole-building life cycle assessment (LCA) as an important metric for green building certification. Embodied carbon in building materials is a primary parameter measured in a whole-building LCA and tools are available to support this analysis during building design and construction. Similar to government purchasing policies, evolving requirements in rating systems are elevating the importance of embodied carbon.
Sustainable and healthy building rating systems are also recognizing material transparency frameworks like Environmental Product Declarations (EPDs), Health Product Declarations (HPDs), and the International Living Future Institute's Declare Label, all of which are important in procurement process.
There are a number of sustainable building frameworks and green building certification programs globally that employ ratings systems that focus on materials transparency as it relates to operational sustainability, energy consumption, and carbon in buildings. Some of the more well-known programs are LEED, the Building Research Establishment Environmental Assessment Method (BREEAM), the Living Building Challenge, and the International WELL Building Institute.
- LEED is the most well-know of sustainable building frameworks. It was started in U.S. and has been adopted globally. LEED grants materials and resources credits in the following categories: building life cycle impact reduction, environmental product declarations, sourcing of raw materials, and material ingredient reporting. The program also includes an environmental quality credit for the use of low-emitting materials.
- The British Research Establishment's Environmental Assessment Method (BREEAM) is a UK-based, global sustainable building framework that awards materials credits based on life cycle impacts and responsible sourcing of construction products. The program also has health & wellbeing credits for indoor air quality that establishes low-emissions criteria for building products.
- The Living Building Challenge, a leading-edge certification from the International Living Building Institute, has seven performance categories, or petals, as part of its certification. The Materials petal focuses on responsible materials, the red list (prohibited chemical constituents), responsible sourcing, and the living local economy. The program's health and happiness petal focuses on creating healthy interior environments.
- The WELL Building rating system is focused on human health and wellbeing, and including requirements for healthier, low-emitting materials such as enhanced materials restrictions, VOC restrictions, materials transparency, and materials optimization.
Quantifying and disclosing the environmental and health effects of building products and materials is the first step toward reducing the impacts of embodied carbon. Stay tuned for part 2 of this blog, where we'll dive into the process of defining, declaring, and documenting the sustainability of building materials. Until then, watch our on-demand webinar, Declaring and Use of Sustainable Materials, to learn more about what's driving sustainable building trends.
Alan Scott, FAIA, LEED Fellow, LEED AP BD+C, O+M, WELL AP, CEM, is an architect with more than 30 years of experience in sustainable building design. He is Discipline Leader, Sustainability, with Intertek Building Science Solutions in Portland, OR.