NOISEFREETEX (LIFE+09 ENV/ES/461) began on the 1st January 2011 to find demonstrative solutions to reduce noise pollution in industrial areas by using finishing technologies on textile materials. The project is coordinated by AITEX and the consortium is formed by PIEL, S.A. (Spain), NTT Tecnotessile (Italy), The Valencia Polytechnic University (Gandía campus) (Spain) and the Association of Valencian Textile Manufacturers ATEVAL (Spain).
Textile finishing technologies are applied to sound absorption material. These textile-based solutions can then be used as construction elements in industrial plants, walls, floors, ceilings and noise barriers on public roads to minimize the impact of noise pollution.
The lighter materials obtained by the project will be more effective compared to the mineral wool typically used for industrial acoustic insulation, which will lead indirectly to reduced traffic pollution by reducing the use of heavier materials and the transport costs associated with their use.
As most significant results we could point out:
- Application and optimization electrospinning process to coat selected textile materials with nanofiber webs. Also, we have applied and optimized plasma surface treatments to functionalise and improve previous selected textile materials. Nonwoven materials seems the most suitable one because they have small specific gravity induced by the open structure, high thickness and also a high amount of fine fibres can be used. We have used PA6 nanofibres and Recycled PET nanofibres (from food industry), Nylon 6/PEO nanofibres (virgin nylon and PVA).
- During the validation phase, one semi-industrial reverberant chamber was built in order to validate the samples obtained before doing so in real instalation. We have observed that:
- The influence (%) of the drilling in the sound absorption coefficient depends on the frequency. Within medium and low range of frequencies, the sound absorption values are slightly greater in the case of lower percentage of drilled area. Within medium and high range of frequencies, the sound absorption increases according to an increase of the percentage of drilled area.
- The distribution of hole diameters has higher sound absorption values in broader frequency spectrum is the combination of diameter 3mm, 4mm, 5mm, and 6mm.
Moreover, the effect that produces on the category and on the sound reduction index has been also studied. :
- We are going to obtain a higher category when we increase the percentage of drilled area.
- Distribution and diameters of the holes don’t produce any influence on the category of the barrier.
- Finally a Simulation Software was developed. With this software we could predict the results in Kundt tube and in reverberant chamber and also we are able to classify the barrier with the absorption coefficient.