Life Cycle Assessment and Circularity Assessment as Complementary Methods for the Circular and Sustainable Redesign of Multi-Material Products: A Case Study on Safety Industrial Footwear

The transition toward circular and sustainable products is critical for addressing environmental and resource concerns. Complex, multi-material products pose challenges due to their diverse material compositions, lifetimes, and end-of-life pathways. This study integrates Life Cycle Assessment (LCA) and the Material Circularity Indicator (MCI) to assess the sustainable and circular redesign of complex products using safety industrial footwear as a case of a multi-component product with strict safety standards. Results indicate that redesign improves both circularity and environmental performance. The circular model achieves a 51% reduction in environmental impact (normalized through environmental prices) versus the linear model, mainly through material substitution, design for recyclability, and reduced complexity. While circularity and sustainability align at the product level, they do not at the component level, making LCA and MCI complementary. Two decision-support tools were developed: (1) a product-level transition ladder and (2) a prioritization matrix for component-level redesign. This research contributes to the development of integrated assessments and informs policy discussions and design practice related to circular and sustainable products.