Q: After having Environmental Product Declarations (EPDs) done for each one of your Concrete Masonry Unit mix designs, is there anything in particular that you learned?
-Environmentally Lowering Impacts
Dear ELI:
Having EPDs for each of our mix designs has really helped us see what factors affect the environmental impacts of our products. One interesting thing we uncovered was that previously valued sustainable attributes, such as recycled content and regional materials, didn’t matter as much as we thought for environmental impacts. What mattered the most was the amount of cement in a mix. Cement content affected most of the impact indicators; global warming potential (GWP), acidification, eutrophication, smog creation and ozone depletion. The less cement we use, the less impact we have. One way to reduce the cement content is to use Supplementary Cementitious Materials (SCMs) such as slag (a by-product of the steel industry, unfortunately not usually a regional material anymore). For easy numbers, let’s take a CMU mix design that uses 10% cement. If we replace 40% of the cement with slag, and we were looking at recycled content, the overall weight of pre-consumer recycled content is only around 4%. But, if we look at the GWP, comparing these 2 mix designs, it is lowered by more than 1/3. There were many other things like this that we uncovered by having EPDs for every mix design. Now, not only do we have our EPDs for the rating systems, we also have an environmental impact baseline and solid direction of how to improve our sustainability moving forward.
Heidi Jandris grew up immersed in all things concrete block. As a kid she helped her dad build block walls and as an adult worked by his side as a welder. She received a Bachelor of Architecture degree from Pratt Institute and a Masters of Sustainable Building Systems degree from Northeastern University’s College of Engineering. She is part of the 3rd generation of her family’s business. She provides technical services to the design community while researching and implementing ways to improve the efficiency and lower the environmental impacts of their products.
