Why do I get negative impact results in the resource depletion impact category?

Question

I am doing an LCA on wood plastic composite boards. I am using the ELCD database and the ILCD 2011 midpoint+ impact assessment method. Here is my product system:

The material is made of PVC and wood flour, however I am comparing different plastics materials as well. When using PVC as an input in the blender process I get negative results in the resource depletion impact category. This makes no sense to me, as PVC is not environmentally friendly at all.

Does anyone know why I get negative results in this impact category only? If i use PE or PP input I get positive results for this impact category.

Answer 1

Hi, the picture is a bit pixelated (and you could uncheck "route" in the context menu, this makes it easier to see the connections)

PVC alone does not have negative impacts with the ILCD method, with which flow do you connect? Maybe the "-waste" in the output?

Best wishes,

Andreas

Comments

I checked the contribution tree and turns out that the PVC process in the ELCD database has a negative sulfur input flow which translates to a negative resource depletion [kg Sb eq] that outweighs the other negative impact contributions.

I only connected the PVC process as an input to the blender process. I did not connect any inputs to the PVC process.

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I am also facing this type of problem. Can you please elaborate the process to deal with negative impact results?