Acoustics

When selecting cladding materials it is important to consider acoustic performance criteria, such as resultant ambient or background noise levels, reverberation time, sound absorption and transmission, and sound insulation.

When sounds are produced in an enclosed space, the reflection of those sounds from the surrounding surfaces until the sound waves eventually dissipate is referred to as reverberation. Texlon® ETFE is an acoustically transparent material with a mass of less than 1kg/m2. This means that sound generated by building occupants passes through the ETFE foil and is not reflected back into the space below, unlike less acoustically transparent materials such as glass.

The time it takes for any individual sound generated in an enclosed space to effectively dissipate is referred to as the ‘reverberation time’. The desired reverberation time for any particular space depends on its proposed function and activities that may take place in that space. Texlon® ETFE cladding in combination with both harder and more absorbent materials which are typically employed to form internal building surfaces can assist in ensuring that the correct reverberation time for intended usage can be achieved.

Like other cladding materials, rainfall on the outer surface of the ETFE panels will generate some noise. Rain noise can be intrusive in spaces where there is a requirement for minimal background noise, such as certain offices, call centres and libraries.

If rain noise is found to be problematic noise intensity can be easily minimised by installing a patented Texlon® RS rain suppression mesh. The mesh is made from fluoropolymer monofilament fibres or fabrics with a weave diameter typically measuring 20mm to 40mm. It is held under tension across the external surface of each panel and traps a buffering layer of incident rain thereby increasing surface mass and consequently reducing both sound generation and transmission.  Tests have demonstrated that the mesh decreases noise levels by 9.7 dB which equates to a 50% noise reduction to the human ear.

The rain suppression mesh will result in a small reduction in light transmission by 5%-10%.

Rain noise has only been found to be a problem requiring remedy in a very small number of buildings for which Texlon® ETFE cladding forms part of the building envelope. As rain suppressors mesh can be easily retrofitted to any installation we would not recommend its inclusion in standard cladding specifications.

Texlon® ETFE is an acoustically transparent material with a mass of less than 1kg/m2