Acoustic wave propagation through panels that are made of used tea bags

These days more than ever, society habits raise the necessity to consider the future of the environment. This presentation will tackle the aspect of more eco-friendly sound absorbing materials, more specifically analyzing the properties of consumed tea bags, starting from the collection up to the application and measurement of the final product. Many good options are often avoided, or not implemented for the lack of reliable properties analysis, encouraging existing materials to be chosen instead. The more information could be found about new materials, the more these could have a chance to be used, compared, or eventually improved. Sound absorbing panels that are made of tea bags were designed and developed to investigate sound transmission through tea-bag panels. Measurements were carried out on tea-bag panels in an impedance tube using a transfer function method to determine their sound absorption and transmission loss. Furthermore, the impedance gun system was used to determine acoustical properties of larger panels. Results show that 70 mm thick panels give an absorption coefficient higher than 0.8 between 500 Hz and 1600 Hz while 17 mm thick panels give an absorption coefficient that is mostly effective at higher frequencies. Up to 9 dB sound transmission loss is obtained at some frequencies.