An investigation into practical values of sound transmission loss across natural luffa fibers

Natural fibers could be used as sound insulation due to their advantageous acoustic properties. The main object of this study is to investigate the sound transmission loss (STL) of natural Luffa fibers (LF) due to their availability and sustainability where they would be a good choice instead of synthetic materials that have some health issues. The study has been done experimentally. The work has included a collection of LF from local gardens in Iraq, manufacturing of the specimens and measuring the STL using an impedance tube for selected samples: 20 mm of 970 kg/m3, 30 mm of 880 kg/m3 as well as 30 mm of 600 kg/m3. The effect of both thickness and density of the samples on the values of STL were studied. The results show that the increase of the thickness by adding 10 mm layer improved the STL value by 15-20 %. Also, the increasing of the density enhanced the sound insulation, where the STL value at 880 kg/m3 has improved by 3040 % comparing to 600 kg/m3 for the same thickness (30 mm).