Utilizing natural fibre as a sustainable acoustic absorber

Abstract

The availability of agricultural waste as sound absorptive materials can be used in indoor and outdoor application. This study aims the potential of natural fibre from agricultural waste as materials for measurement of sound absorption coefficient (SAC). The fibre selected in this study are oil palm, coconut and banana. The natural fibre samples were treated by alkaline treatment during processing stage. The mixture proportion with 95% of natural fibre and 5% of sodium hydroxide (NaOH) as a binder and all the samples follow the fixed ratio of 95:5 for every weight of selected natural fibre. Then, the treated and mixed natural fibre were put into a mould for compaction process to produce diameter of 100 mm and 30 mm with thickness of 20 mm and 30 mm, respectively. All natural fibre samples were tested using Impendence Tube Method (ITM) based on ASTM E1050-09. The tests were conducted according to standard ISO10534-2 with high frequency range and low frequency. As a result, samples of coconut fibre with 20 mm thickness showed a good SAC value at low frequency which is 0.31, meanwhile oil palm fibre with 30 mm thickness attained 0.41. For high frequency testing, coconut fibre sample of 20 mm thickness resulted the highest SAC value at 0.41 and oil palm fibre sample of 30 mm thickness had the highest SAC value which is 0.81. Therefore, natural fibre showed respectable potential as an absorption material for sound reduction.