Asking for insight on the eutrophication impacts of wood when documenting WBLCA for LEED. Often times wood products show a DECREASE in global warming potential but an INCREASE in eutrophication. We suspect this is mostly due to fertilizers, and would vary significantly based on forestry practices (eg. sustainable vs. less sustainable). Since eutrophication rates would then be highly dependent on forestry practices, the ongoing lack of forestry data makes it nearly impossible for us to address this impact category. Do we still submit the increase to USGBC and argue this lack of data?
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Emily Purcell
Sustainable Design LeadCannonDesign
LEEDuser Expert
319 thumbs up
April 2, 2021 - 11:32 am
I don't have any insight on how USGBC would address this, but this recent discussion on the CLF forum looks relevant: https://community.carbonleadershipforum.org/t/what-the-heck-is-a-kg-of-n...
Dirk Kestner
PrincipalWalter P Moore
26 thumbs up
April 3, 2021 - 1:17 pm
We have seen similar results in our WBLCAs when comparing buildings that primarily use timber to those framed with other materials. We have seen this across multiple WBLCA programs, though to varying degrees. We have also seen increases in some of the other impacts. The total % increase, and if it becomes problematic to the language of the LEED credit, tends to depend on the specifics of the entire building and other assemblies.
I agree that the lack of specific data complicates this issue, but I’d also be surprised if reviewers saw it as reason to exclude an increase in a certain impact category. Similar issues exist with other materials related to industry average data vs “best performers”, as well as with comparisons between assemblies. If exceptions are granted based on general trends but without specific data, then the question becomes where to draw the line.
Perhaps this issue can be used to help illustrate the need for more supply chain specific data that quantifies the benefit of specific forestry and manufacturing practices? I know that this may not help for the specific LEED points for a specific project, but with the 4.1 revisions the WBLCA would at least provide 1 point.
Kate Sector
Design Performance ManagerLake|Flato Architects
January 28, 2022 - 11:25 am
I am doing a WBLCA using Tally for a project that is primarily glulam and CLT. When compared to our baseline building that is concrete and steel, we are also seeing a large increase in eutrophication and acidification way above the 5% threshold limit for LEED. It mainly looks like this is due to the CLT during the end-of-life stages. Has anyone stumbled upon best practices for addressing how to lower eutrophication and acidification whether that is through changing our baseline model, or substituting in more accurate CLT data that reflects the specific EPD's we are using? So far, we have found the only way to meet the credit is to include CLT in our baseline model, or other materials that are high in eutrophication and acidification. In addition, has anyone found ways when specifying products to not only lower GWP impact but eutrophication and acidification as well if the results due conclude that timber products are much worse than concrete in these impact categories? Thanks,
Bipin Karki
Project Manager - Sustainability Division84 thumbs up
January 25, 2023 - 2:21 pm
Hello Kate, Did you submit your WBLCA project for LEED Review? I am also working on projects that is using CLT and Glulam. When comparing proposed wood based building with baseline concrete and steel, I am seeing a large incerase in eutrophication. As you said, this is coming mainly from end of life scenario. Can you share your learning from the project?