Is the acoustic cabin really soundproof?The solution for a calm working environment
What is sound insulation?
To understand how a acoustic cabin it is
important to distinguish between acoustic insulation and insulation
phonic.
Acoustic insulation aims to prevent the propagation of all the
noises while sound insulation is intended for the absorption of
voice sounds.
It is therefore important to look at the total reduction in the level of
speech in decibels of your soundproof cabin . The reduction is interesting from 25 decibels. Beware of phonebooth manufacturers who promise you insulation greater than 40 decibels, this is surely the performance of a wall and not the cabin.
Composition of the acoustic cabin
Sound has a series of different frequencies and amplitudes. Each material,
depending on its properties, absorbs a certain type of wave. Below you can
discover the different phenomena when sound comes into contact with a surface.
As can be seen in the diagram on the left, four phenomena can occur depending on the material of the surface. For example, if the medium is a very strong, hard material like wood or glass, most of the sound will reflect off it. Rubber, on the other hand, absorbs most of the sound. Regarding the foam, most sounds will be absorbed, although some will penetrate it to reach the other side. These events can sometimes occur at the same time depending on the material. However, to be able to guarantee perfect acoustic insulation of the phonebooths, it is essential to superimpose several types of materials.
Note: it is thanks to absorption that an echo effect is avoided. Good absorption will allow your interlocutor on the phone to hear you clearly.
What materials are used for
make the Island cabins?
As we have seen previously, the materials used are very important because they have a direct impact on the acoustics. These vary from one manufacturer to another, so we will focus on those used by the Work With Island teams.
The walls
To form the walls of our Island cabins, we sandwiched three different materials to absorb all the noise. Let's take a closer look at the materials we have chosen. We use a so-called asymmetrical wall structure. Placed between the wood and the felt, the Métisse®, an acoustic insulator made from recycled textiles, will play the role of a spring and will contribute to the attenuation of noise.
The diagram on the left illustrates the principle of operation. The first rigid wall reflects part of the noise. Partly absorbed by the insulation, the residual noise will be reflected by the second facing plate. In the end, only a small residual part of the sound emission will cross the 3 layers.
The door
The door is a very important element of the acoustic cabin because once closed it must guarantee the absorption of noise. Our team of engineers opted for an 8mm thick tempered glass door, which is denser and therefore more insulating than Plexiglas. Also, its transparency allows light to penetrate inside and not suffer from the cramped conditions of the cabin.
What is ISO 23351-1?
Published in 2020, the ISO 23351-1 standard is specific to partition elements such as office telephone booths and other sets of semi-partitioned furniture (conventional workstations, groups of partially closed sofas, etc.). Its purpose is to measure the ability of cabins to reduce the user's speech level. The ISO 23351-1 score evaluates the product's speech privacy and noise reduction. It calculates a number called “speech level reduction”. This indicates the degree of conversation privacy that the product provides. And the higher the score, the better the privacy.
Why should ISO 23351-1 be taken into account?
The main criterion when a company invests in an acoustic cabin is the reduction of noise pollution. While acoustics is the primary selling point, it can also be a source of confusion for the customer because some manufacturers who are not certified decide to measure the performance of their cabins themselves.
What is the problem in this practice?
These companies tend to embellish the acoustic level by only measuring the performance of the acoustic panels rather than the overall performance of the cabin. Therefore, it will communicate only on the sound reduction index (Rw). This index characterizes the ability of a material or a partition to attenuate the direct transmission of noise. And unsurprisingly, the Rw has better performance than the index communicated by the ISO 23351-1 standard.
The concern in this process is that it does not take into account the glass doors or even the ventilation channels which contribute to the drop in the overall level of insulation.
How is the test carried out
ISO 23351-1:2020?
The test is quite simple. We measure speech level with and without the booth. (see diagram on the right) The measurements are then compared to calculate the total reduction in speech level in decibels made by the acoustic booth.
For information, the ISO 23351-1 standard classifies booths into several categories: A+, A, B, C or D depending on the reduction in speech level. Those classified in categories A+, A and B guarantee the best soundproofing.
Please note: all Island cabins are classified in category B, which offers you considerable comfort and allows you to chat in complete confidentiality.
Would you like more information or would you like to test the acoustics of our cabins?
We invite you to contact us by email at contact@workwithisland.com .
