I am pleased to see embodied carbon being addressed in LEED v5's Materials and Resources (MR) category. However, both the Assess Embodied Carbon prerequisite and the Reduce Embodied Carbon credit present too high a benchmark GWP for CMUs.
At 290 kg CO2e/m3, the LEED benchmark GWP for CMUs is well above the EC3's average GWP for CMUs (around 260), as well as what the EC3 considers "achievable" (around 217). The benchmark should be adjusted so that real changes to specifications and corresponding GWP reductions are rewarded-- as it stands, using a standard CMU would qualify as a reduction, and there is no incentive to take further steps to reduce embodied carbon, such as using improved mix designs or innovative processes and solutions.
Additionally, there are crucial regional differences to standard GWP of CMUs that would make it very difficult to achieve even the baseline GWP in some states, while others would have advantages due to the standard production processes in their region. If local (regional or state-wide) benchmark GWPs were used as the assessment rather than an average, it would provide a more even playing field. For example, according to EC3 the California average GWP of a CMU is 246, while in Colorado the average is 357-- a major difference.
Although I am more familiar with the industry benchmarks for CMUs, perhaps this system accounting for regional differences in baseline GWP would be helpful in addressing the embodied carbon levels of other products.
Paul Sambanis
May 16, 2024 - 5:00 am
My name is Paul Sambanis, and I am the Vice President of Sustainability at Sloan, a manufacturer of commerical restroom solutions. Sloan supports the Embodied Carbon in LEED v5, however we recommend that LEED consider the following: Including plumbing products in Table 1. Most plumbing manufacturer have determined the GWP of flushometer, faucets etc.