Sound absorbing and insulating low-cost panels from end-of-life household materials for the development of vulnerable contexts in circular economy perspective

From a construction point of view, neighborhoods with residents living at or below
the poverty threshold are characterized by low energy efficiency buildings, in which people live
in acoustic discomfort with no viable options for home improvements, as they usually can not afford
the materials and labor costs associated. An alternative to this is to use low-cost insulating elements
made of non-conventional materials with acceptable acoustic properties. Given that household
materials at their end-of-life (EoLHM) are free of costs and available also to the more disadvantaged
population, they can be used to build acoustic panels for such contexts. This approach embraces several benefits since it reduces the amount of waste produced, the footprint deriving from the extraction
of new raw materials and, by highlighting the potential of the EoLHM, discourages the abandonment
of waste. In this paper, the acoustic properties of EoLHM, such as cardboard, egg-cartons, clothes,
metal elements and combinations of them, are investigated by means of the impedance tube technique. The measured sound absorption coefficient and transmission loss have shown that EoLHM
can be used for the realization of acoustic panels. However, since none of the analyzed materials
shows absorbing and insulating properties at the same time, EoLHM must be wisely selected. This
innovative approach supports the circular economy and the improvement for the living condition of
low-income households.