Transportable anechoic room ITS

A transportable anechoic room is a mean for acoustic testing used for Research and Development (R & D), marketed by ITS.

Whether it is to quantify the sound emissions of a machine or of an equipment, or to develop and qualify the acoustic performance of electroacoustic or telecommunication equipment, an anechoic room allows the conduct of measurements in conditions close to the free field i.e. by avoiding unwanted sound reflections on the partitions  and with a low background noise level of i.e. by isolating from the surrounding noise, even if the anechoic room is installed in a workshop with significant noise levels related to industrial productions.

Thus, the walls, the roof (and, when it is not a semi-anechoic room: the floor), must be built in such a way as to allow obtaining these two essential functionalities, which require the implementation of specific construction systems, both of great thickness (with regard to the technical requirement related to the obtaining of a strong acoustic absorption) and massive (with regard to the objective of limiting the sound transmission between inside and outside).

Very often, an anechoic room must be transportable, when it comes to coping with the mobility challenges of modern industrial organizations that are characterized by changes in the allocation of premises in relation to relocations of units or of complete facilities, as the strategy changes.

ITS took part in dismantling, transporting and reassembling a transportable anechoic room in Paris area (Ile de France region - France).

This anechoic room had been marketed by ITS just over a year ago, but organizational changes at this client, an industrialist specializing in high-end electroacoustic equipment, have led to his move already being considered.

Fortunately, this anechoic room had been designed in such a way as to make possible such works, considered since a long time to have a fairly high probability of occurrence, things being what they are in our modern world.

This is why the relocation of this transportable anechoic room was carried out without any particular difficulty and without modifying its exceptional acoustic characteristics, since it is based on the use of compact broadband absorbers, the compactness of which has precisely facilitated the process which consisted in finding a new location to accommodate this testing mean (because its footprint was less than that which would have been made necessary by the use of conventional absorbent wedges, all things being equal with respect to the lower cutoff frequency of the anechoic room).

Noise diminution

Noise diminution is a necessity in the context of many industrial projects involving very powerful machines whose operation is accompanied by very large noise emissions, likely to cause an auditory risk for workers.

Even though Directive 2003/10 / EC – that the Decree No. 2006-892 of 19 July 2006 on the safety and health requirements applicable in the event of exposure of workers to the risks arising from noise and amending the Labor Code is a transposition into French law, which specifies that a daily noise exposure level exceeding 80 dB (A) and / or a peak sound pressure level above 135 dB (C), is above the action limit – is not universally enforced, equivalent continuous noise levels below 85 dB (A) are often specified at 1 m from machines or installations with noise levels that exceed such limits, if they are not soundproof, by several tens of decibels.

This is the case of gas power plants, based on the operation of combustion turbines.

ITS participated in the construction of noise diminution devices for a combustion turbine (power output above 40MW) and its gas module as part of the construction of a power generation plant in East Asia.

The noise diminution of these equipments necessitated the construction of metallic soundproof buildings, based on modular soundproofing pannels, integrating particular functionalities in terms of dismountability of the partitions for the maintenance and in terms of ventilation (with silencers), the structural dimensioning having integrated the site constraints (seismic and meteorological risks).

The design has, as often, required the consideration of limited spaces for the installation of soundproofing equipment implemented on a 3D model of the plant before anything else.

The requirements for quality, for respect of short delivery time and for documentation in connection with the construction of these noise diminution devices at a major chemical site required particularly rigorous project management.

Improvement of acoustics in early childhood education center

An early childhood education center is a building for which issues related to acoustic are important, both for the children who carry out different types of learning and for the supervisory staff who practice their professional activity there.

This includes: premises such as atrium, play rooms of different the sections, sleeping rooms, offices, medical rooms, staff rooms, halls and stairwells that can be crossed regularly by children.

A fairly common imperfection encountered in terms of acoustics of an early childhood center lies in the insufficiency, in quality and / or in quantity, of materials that absorb sound properly at the medium and high frequencies, which results in a level of acoustic comfort that leaves something to be desired.

Because if the reverberation time, characterizing the temporal sound decay, reaches values ​​that are too important, then the considered spaces have an insufficient speech intelligibility and favor an increase in the ambient sound levels which is the consequence of the wish. of each one (child or adult) to be better heard by raising the voice, such an increase in sound levels being very undesirable and even counterproductive.

ITS has participated in improving the acoustics of an early childhood eduction center in the region of Bourg-en-Bresse, in the county of Ain (Auvergne Rhône Alpes region, France).

The acoustic situation of this early childhood education center was characterized, for several rooms, on the one hand by an equivalent absorption area lower than what is required to limit the reverberation sufficiently (despite the presence of a sub-roof of which it was expected that it provides) and, secondly by an insufficient acoustic insulation between rooms, due to the gap (up to 1 m) left between the top of the dividing walls and the under-roof.

The arrangements made consisted of installing absorbent wall panels, suspended absorbent elements, and extending the dividing walls with dedicated construction systems, to ensure the necessary airborne sound isolation functionality while permitting the introduction, in the rooms of the early childhood education center, with an additional equivalent acoustic absorption area helping to limit the reverberation in rooms being on both sides.

The satisfaction of the Client and the users (those sufficiently old to speak about it) was measured, being according to the information which was gathered: entire for the improvement in terms of acoustics and for the visual aspect as well (the absorbing materials used, chosen among from a wide range of colors, each one being more attractive than others, often allow to brighten such premises of a early childhood education center).