Polypropylene as an absorbent layer for acoustic ceilings: Sound absorption and life cycle assessment

The substantial volume of polypropylene fabric waste generated because of its use in protective elements in hospital environments calls for the exploration of environmentally friendly solutions. This study characterises the acoustic absorption coefficient of surgical mask waste (polypropylene) to be used as absorbent layers in acoustic ceilings. Additionally, a life cycle assessment (LCA) has been carried out. Although values of absorption coefficients for polypropylene have been published, none include life cycle studies. This research is in keeping with the principles of circular economy, contributing to waste reduction while also exploring innovative applications for recycled materials. The starting point of this study is the replacement of the most common material layer on the market, mineral wool, with a polypropylene layer that has the same or better acoustic performance based on single number absorption indexes and ratings following international standards for the calculation of sound absorption coefficients and life cycles. Various waste processing methods and different densities and thicknesses have been evaluated. The results show that recycled polypropylene material exhibits suitable behaviour as an acoustic absorbent layer, particularly in acoustic ceilings. The LCA considered transport, shredding, washing, disinfection, and drying and confirms the eco-efficiency of this absorbent layer.