Evaluation of the sound insulation performance of coconut coir fiber panels

Coconut coir, an abundant agricultural by-product in Vietnam, has received increasing attention as a sustainable building material. Although previous studies have demonstrated its excellent sound absorption performance, its sound insulation properties remain insufficiently explored. This study experimentally evaluates the transmission loss (TL) of coconut coir panels with thicknesses ranging from 2.5 to 15 mm over a frequency range of 200 - 4500 Hz. The results indicate that the TL values were generally low, ranging from 0 to 2 dB, with several localized resonance peaks observed at mid frequencies. Increasing panel thickness resulted in more stable TL responses but produced only a marginal improvement in sound insulation, primarily due to the material’s porous structure and low surface density. While coconut coir panels are therefore unsuitable as standalone sound-insulating barriers, they show considerable potential as sound-absorbing layers or porous cores in multilayer acoustic systems. This study extends existing research on the acoustic performance of coconut coir and contributes to the development of sustainable bio-based building materials.