Groz-Beckert KG, Albstadt/Germany
What is noise? Nonwovens for acoustic applications
In offices, for example, and in open plan offices in particular, there is often a high level of noise, which impacts health, wellbeing and performance significantly. Modern architecture, with its sound-reflecting surfaces, such as stone floors, floor-to-ceiling glass surfaces and spacious rooms, does not help here. These hard surfaces create reflections and result in a long reverberation time of the noise, which is often perceived as extremely unpleasant and tiring. This is why it is particularly important and beneficial to health to combat noise nuisance with sound insulation measures.
How does sound insulation work?
Sound insulation can be achieved with different measures.
One measure is “trapping noise in or out”. Loud machines can be shut off from the surroundings with a special enclosure, such as a sound-insulating cabin, thus reducing the noise in a production environment.
The sound level can also be reduced both by damping and insulation.
One of the older technically produced insulating materials – made from renewable resources – is mineral bonded wood wool board. These boards were standardized in 1938 and replaced by the European standard EN 13168 in 2007.
© Foto: Groz-Beckert
Perforated acoustic elements
However, this is not the only use of nonwovens in the field of sound insulation. Thanks to their special properties, they can be used for a whole host of damping and insulation solutions.
Sound insulation with nonwovens
Due to their wide range of properties, different acoustic effects can be achieved with nonwovens. Depending on the surface quality, nonwovens can have a sound scattering effect or be used as “sound absorbing materials”. The porous structure of nonwovens means that vibrating air molecules can permeate the nonwoven structure. The air molecules rub against each other there and against the fibers of the structure, which converts the kinetic energy of the molecules into heat through friction losses. This reduces the occurring sound field or, to put it another way, the noise level drops.
Nonwovens are being used more and more frequently for sound insulation and damping. In the automotive construction field, for example, they are used to dampen engine noise and ambient noise such as traffic noise in the direction of the passenger compartment. Their sound insulation properties are also used. Absorbers are fitted behind the carpet or dashboard, for example, to reduce the sound field in the passenger compartment.
© Foto: Groz-Beckert
Nonwovens improve room acoustics
In the field of room acoustics, nonwovens are increasingly being used as absorbing “design objects”. This can take place in the form of individual panels on the wall and/or ceiling, as complete wall and ceiling coverings, in the form of acoustic partitions – for example in open-plan offices – or as complete furniture made from felt.
For insulation and damping, single-origin absorbers are used as far as possible, made from recycled fibers or natural fibers, such as wool, mixed with synthetic fibers.