Buy Clean Colorado presentation with Colorado Office of the State Architect

Concrete is the most impactful construction material

On May 21, I had the opportunity to present about the recent Buy Clean Colorado legislation (HB21-1303).  Having testified at the state capitol on behalf of this legislation a few years ago, I was particularly keen to participate in this event, held at the Association of General Contractors of Colorado (AGC)  office.   The meeting included professionals from three different organizations - the AGC, The American Council of Consulting Engineers (ACEC), and the American Institute of Architects (AIA).   I was there representing a new group called the Colorado Embodied Carbon Collaborative, founded by my good friend and longtime collaborator, Bob Redwine.  We were joined by three members of the Office of the State Architect - Tana Lane, Rod Vanderwall, and Bailey Vigil.  

Our purpose was to review the recent legislation and its implementation, which began Jan. 1, 2024.  The bill will have an impact on all state funded projects in Colorado, imposing maximum greenhouse  gas warming potential (GWP) for five product categories.  Those are asphalt, concrete and cement, structural steel, plate glass, and structural wood.   My portion of the presentation focused on what the design professions are doing to reduce the embodied carbon of commonly used construction materials.  I find this an interesting topic because the typical design approach is not aligned with the typical regulatory approach.  

Designers have focused on developing tools and modeling techniques to calculate a project’s total embodied carbon, usually measured as kg CO2e/sq. meter.  We designers look for ways to reduce that as much as possible.  Buy Clean legislation in various states and cities has focused instead on typical product categories and required that such products, when used in a project, meet maximum carbon emissions per unit.  These regulations ignore the total CO2e emissions of the project per square meter.

In summary, designers are focused on the total embodied carbon of a design whereas government policy fixates on a small set of individual materials.  It is entirely possible that a project could meet the regulatory criteria and still exceed the average kg CO2e/sq. meter.  Ideally building codes would require meeting a maximum GWP per square meter of project and that would be submitted at time of building permit application.  This would conform to how we’ve been handling energy efficiency for more than a decade.  Unfortunately, embodied carbon modeling is still a young field and there is not yet enough agreement or certainty about specifics so that building departments could use it as a regulatory benchmark.  That day may be coming, but in the meantime improving the most carbon intensive materials is a great start.  

For a link to the Office of the State Architect’s website on the Buy Clean Colorado rollout, look at this website:  Buy Clean Colorado Act | OSA