Like many other premises in the tertiary sector, school restaurants (canteens) are spaces of everyday life in which the reverberation should be limited to control ambient sound levels, for the well being of occupants that are both children and supervisory staff. It is often necessary to use in such cases special equipment in terms of architectural acoustics to ensure the habitability requirements for those spaces to which are applicable regulatory provisions related to noise limitation in schools .
ITS will participate in the improvement of the acoustic comfort of a school restaurant (canteen) near Lyon (France, Rhône-Alpes region), in a context where on-site measurements have shown that the values of reverberation time were compliant as a narrow margin to limiting values to be met for such a premise with respect to its use and to its volume.
Given the annoyance felt by the occupants that led the municipal crew to consider soundproofing works, a reduction of the reverberation time will necessitate the installation of products and construction systems having acoustic performance namely for medium and treble frequencies, covering a sufficient portion of the partitions which are currently reflecting (for some: partially) the sound and do not absorb it (for some: not enough).
A particular sensitivity of the Contracting autority team with respect to environmental issues has led it to assert its commitment to investing exclusively in 100% recyclable and free of mineral fiber materials.
Were therefore considered when sizing soundproofing equipment:
- firstly, a wallcovering made of a polyester wool and of a suitable surfacing - with rear plenum - protected (in front) with perforated plasterboard, which in combination with other components of this acoustic multilayer coating under the conditions provided installation had hitherto led to any characterization of acoustic performance that can be brought to the attention of ITS in useful time
- secondly, a suspended ceiling - to replace the existing one - based on a polyester wool and on an appropriate surfacing
Consequently, the simulation of sound absorption coefficient of envisaged construction systems for which a lack of input data was faced for the considered installation conditions was performed using the software SILDIS (cf. acoustics simulation software).
The results of this simulation were used as input data for the prediction by ITS (computer calculation) of the characteristics of the cafeteria after acoustical works founding the commitment to results taken by ITS in-situ (reverberation time guaranteed) on the basis of a quantity of materials to implement (area of surfaces treated obviously impacting the cost of the works) to the liability of ITS.
In addition, the course of this project shows - once again - the possibilities for design and optimization of the software SILDIS, whose computing power and reliability, as well as whose versatility made of it a choice tool for the selection of products and construction systems for many projects of sound insulation.