Linear Flow Index (LFI)

The Linear Flow Index (LFI) calculates the circular performance of a product or material by analyzing the share of reused, recycled, or sustainable biological feedstock as input and the recycled, reused, energy recovered or composted share at end-of-life as output. This helps understand how much unrecoverable waste the product creates in its lifetime in relation to its weight. The LFI ranges from 0 to 1, with 0 representing complete circularity and 1 representing complete linearity.

In recycling purposes, the calculation applies the "50:50 approach", meaning that it considers both the waste generated for the use of recycled materials (recycled feedstock) and the waste produced during the recycling process at the end-of-life stage. This is best explained using an example. Let's take two products (P1 and P2) with 50% recycled material. At the end of its life, P1 is recycled and has a recycling efficiency of 50%. This recycled material is used as the recycled feedstock for P2. If we were to take 100% of the waste generated from the use of recycled material into account, we would count the waste from the recycled material in P1 twice, because P2 is partly made of the materials of P1. One solution for this problem would be only taking into account recycling at end-of-life. As this would place unequal penalties at end of life stage in comparison to recycled feedstock, the 50:50 approach is applied. This provides equal emphasis on both recycling processes and a holistic perspective of the circular performance of a product.