Whether the weight in the inputs have to add up to the outputs in a process?

Question

We have been using openLCA for performing LCA for a garments manufacturer. One of the processes in the entire lifecycle is the testing of the fabric. In this process a small piece of fabric is taken for testing. However all the environmental impacts of testing the fabric is allocated to the entire roll of fabric that gets approved once the piece of that entire roll gets tested. So in this case, the material inputs for fabric testing process is for only a small piece of fabric. I just added the weight of the entire roll as output, the weights don't add up. But the software still runs it without any error. Will this affect my analysis?

Answer 1

Hi, I am not sure I understand, it sounds quite straightforward, if you have a small piece (1cm²) for testing and the entire role is 100m², then you can say you need 100.01 m² e.g. for the final product of 100m² (or you can make it a bit more sophisticated, you can define 1 piece of testing and the effort for cutting and testing it, and maybe a percentage of failures of the product), and add this to the 100m² role. openLCA does not necessarily "shout" if something does not make sense from a content point of view, unless the system can be calculated (which e.g. happens if you model that a process produces 2 kg of garments with input of 1 kg of garment and nothing else).

If you want, you can post a picture of the process you model (edit your question to be able to add images).

Thank you!

Andreas