Hi,
In carbon assessments, materials which absorb CO2 from the atmosphere during the manufacturing process or growth phase and temporarily store it during the lifecycle of the building (such as wood and products engineered from wood) will have a negative GWP (global warming potential).
I think Speckle’s calculation algorithm in the carbon assessment tool already honors that fact (assigning materials with a negative GDP will lower the total embodied carbon), but the graphics in the widget do not. So currently, you can’t see the negative (or positive?) impact of sustainable materials on your construction.
Of course, this creates a headache for anyone concerned with visual data presentation… because pie charts aren’t really made to display such information, unlike let’s say bar charts. I think this thread makes a good point.
Anyways, just another complication to keep in mind… I’m excited to see the solution you guys come up with 
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Thanks @hwollersheim — we’ve got a ticket open to handle this scenario in the visualisations, since materials with negative carbon values don’t fit at all into the current charting approach.
That said, we’re also interested in seeing documented examples of materials that end up with negative kgCO₂/m³ values in practice. Our tool is ultimately working from carbon intensity values rather than full lifecycle GWP assessments, so we’re keen to better understand the datasets and EPDs where these cases appear.
If you have any examples or research-backed EPDs that produce negative values, we’d love to take a look. Real-world data is always useful for validating both the calculations and how we choose to represent them visually.
Here in germany, the most commonly used database for LCA datasets is the aptly named ÖKOBAUDAT, which is maintained by the federal government.
Most wooden building products - solid wood as well as engineered timber products and wooden flooring - have a negative GWP.
Examples -
Structural timber
Cross-laminated timber
Multi layer parquet flooring
(The number to look out for is the “Global Warming Potential - total (GWP-total”, sometimes also called “Climate change”, Phases A1-A3, which represents the production phase of the lifecycle)
Other renewable materials like hemp, cork and straw which are sometimes used as insulation materials can also have a negative GWP:
Straw insulation
Hempflax Thermo Hemp Combi Jute
Additionally, we sometimes use manufacturer EPDs where crucial information is not available on ÖKOBAUDAT. For example, interestingly, even wooden doors sometimes have a manufacturer-declared negative GWP:
Zimmertür ProLine Lack, Color, Normtür | Hörmann Portal
Let me know if you need more examples.
The examples are very helpful. Some of these datasets expose a much richer carbon model than the current dashboard expects, including lifecycle stages and biogenic carbon accounting. While that may be beyond the scope of the current carbon widget, it’s exactly the sort of interoperability problem we’re interested in tackling more broadly as Intelligence evolves. One of the goals there is to be able to work with different standards and schemas without requiring bespoke support for each one.
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