Acoustic

The Acoustic absorbents

Acoustic absorbents are designed to prevent propagation.

In a compressible environment, usually in the air, sound spreads in the form of a pressure variation created by the sound source. Only the compression moves along, not the air molecules.

Sound does not travel in a vacuum as there is no matter to carry the waves produced.

Generally, the heavier the material, the greater its sound insulation properties (mass law).

As they work as absorbers or shock absorbers.

Insulating

The Mineral wools are a type of thermal insulation which naturally absorb noise.

They provide effective acoustic comfort by reducing the transmission of airborne noises and their reverberations.

Acoustic:

Acoustic absorption (or acoustic connection), different from sound insulation, is a sound reverberation factor specific to a given place.

It is expressed as a Sabin sound absorption coefficient (or α_w). The closer the value to 1, the better the absorption.

By reducing the reverberation time (Tr per s) to different frequencies varying from 100 to 5000 Hz, depending on the frequency, our products achieve an α_w coefficient ranging from 0.08 to 1.00 (measurements performed in accordance with norm NF EN ISO 354, supplemented by norm NF EN ISO 11654).

Using materials with an open and elastic structure (ISOTHERM or ISOFLAM), it is possible to trap sound waves in ceilings or in vertical walls thanks to their porosity.

This application makes it possible to increase the acoustic performance of construction systems.

By levering the mass-spring law, our products offer a high acoustical performance using structures that are lighter than with other materials.

Designing acoustics that address thermal and fire safety fire safety regulations prevents exceeding of budgets. Our ISOTHERM and ISOFLAM, products meet these three requirements.

The new French acoustics regulation (NRA) governs buildings whose planning applications were submitted after 1st January 2000.

The new regulation modified air noise and shock noise indexes but did not modify acoustic absorption denomination, index, or unit.

Thus the equivalent absorption area (A) corresponds to the relationship:

For example:

• For a hypothetical floor surface area of 200m² (room measuring 10m x 20m )
• For a hypothetical value α_w = 0.80

The calculation is as follows:

The reverberation time (Tr per sec) is calculated using the relationship :

Where :

• 0,16 = constant
• V = volume of the room to insulate
• S = surface area to insulate
• α_w = value indicated in our test reports

In the event that “Tr per s” is imposed, “S” remains to be determined:

The surface area to insulate “S” can correspond to the surface area of the ceiling. If the latter is insufficient the surface area is increased by insulating the vertical walls.