Reducing Embodied Carbon in the Early-Design Phase

Under the Architecture 2030 Challenge, many designers and builders are focusing on constructing high-performance or net-zero-energy (NZE) building projects, helping to reduce as much operational carbon as possible while the building is in use. However, embodied carbon (EC) must also be evaluated to effectively achieve these sustainability goals.

Embodied carbon (kgCO2e) refers to the Greenhouse Gases (GHGs) emitted during the extraction, manufacture, transportation, construction, replacement, and deconstruction of building materials, together with the end-of-life emissions. Between 39%-80% of a building’s total carbon footprint is a result of the embodied carbon from building materials. If evaluated early in the design phase, 80% of a building’s embodied carbon can be reduced.

In this article, we share how to start integrating embodied carbon studies in your projects during the early stages of design to reduce the amount of embodied carbon emitted throughout the full lifecycle of the building.

Finding Embodied Carbon Values

All of the building materials and products used in the construction of a project significantly contribute to the climate crisis. To design for embodied carbon early in the process, it is important to select the right values for each product and understand the full impact this has on the project. Here are three data types you can use to obtain the most accurate data for your embodied carbon study:

  1. From the EC3 database (or similar)
    The Embodied Carbon in Construction Calculator (EC3) tool is an open-source industry-leading sustainability platform that helps professionals find, assess, compare, benchmark, and reduce the amount of embodied carbon used in construction.
  2. Environmental Product Declaration (EPD)
    Environmental Product Declaration
     (EPDs) are a standardized assessment of a product or building system's effect on the environment.
  3. The median kgC02e value for the product type based on known industry values

Understanding Which Values to Prioritize

Traditionally an embodied carbon analysis can be one of the most time-intensive studies to undertake. The challenge of an Inventory analysis (ex. below) is the number one deterrent for running an embodied carbon study. If there is not time to look at everything, the best approach is to start with the largest contributors of embodied carbon by building component category and move down from the biggest to smallest impact.

The relationship between capital cost and embodied CO2e emissions are influenced by the characteristics of each building making optimization essential for each project.

  • For low-rise buildings, embodied CO2e emissions are dominated by external walls, slabs, and foundations (Oldfield, 2012; Sansom and Pope, 2012).

  • For medium to high-rise buildings, embodied CO2-e emissions are dominated by floors and building frames (Sansom and Pope, 2012).

Getting Started

With this information, a good rule of thumb approach is to start collecting embodied carbon data for structural framing and support structure. Having just these categories can be a significant boost in knowing your embodied carbon footprint and being able to significantly reduce your building’s total. Another useful tip for getting started is creating internal documents with commonly used structural products in your area and their embodied carbon values, so whenever a similar study is conducted by your team, it can be quickly repeated.

To find typical values and which items have the biggest impact on your building’s embodied carbon total, download our e-Book, “How to Approach Embodied Carbon Reduction On Your Project.”


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