Hello,
I am conducting a LCA in accordance with the EN 15804 standard for construction products, and I have some questions regarding how to correctly model the end-of-life stage, specifically modules C3 and D (please see attached screenshots).
The product consists of several materials: steel, aluminium, plastics, zinc, and glass. In module C3, I have included the energy consumption associated with product disassembly. Some amount of the materials are recycled, all plastics are incinerated, and the rest are landfilled. For the modelling, I applied the “double negative” approach in module C3 and selected the “avoided product” option in module D.
The issue is that I’m getting negative impact values in module C3, which I understand should not be happening. I am unsure what I might be doing wrong or how to correct it.
Could anyone advise on how to correctly model this end-of-life scenario?
Additional assumptions I have used include a 90% recycling efficiency and 60% energy recovery efficiency for plastics.
I have checked the OpenLCA manual and reviewed related forum posts, but I haven’t found a clear answer.
Thank you for your support.
