The limitation of reverberation and noise by means of acoustic screens is suitable for obtaining sound comfort for a wide variety of enclosed spaces:
- in the canteens of educational establishments[1], and in other collective catering rooms (medico-social i.e. in hospitals[2], retirement homes, for administrations and companies[3],[4] and also for holiday centres) without forgetting commercial catering (e.g. restaurants, brasseries, cafeterias, snack bars, fast food establishments.
- in open office workspaces[3],[5]
- in the reception areas of Public Access Buildings (PAB) e.g. counters of banking establishments (and of some of some supermarkets) or hospitals and clinics
Of course, in these different contexts, the objectives are variable in terms of acoustics - due to the elements of auditory comfort which may differ - but the concerns have this in common that it is always:
- to limit the reflection of sound waves (often: emitted by people communicating, and, in some cases: by moving furniture and/or moving kitchen utensils in the case of restaurants) on hard surfaces that usually constitute the physical limits of such premises (floors, walls, ceilings or under-roofs if they do not include specific soundproofing materials) at the origin of the reverberation phenomenon (i.e. in closed spaces, the persistence in the sound time after a sound source stops)
- to limit the propagation of noise in space
Otherwise ?
Well, otherwise the qualitative determinants of the acoustic environment of the considered space (which are reverberation and noise) are not optimal, and may even prove to be insufficient; in some cases: may be bad with the risk (for the person responsible for the space in question) of being in contravention of laws and regulations, and also with the risk of causing (on the part of users or customers) recriminations (possibly accompanied, e.g. in the case of a private restaurant, by an undesirable loss of reputation) or even the flight of those who can spare themselves the frequentation of a place with poor acoustics:
- when an abnormal increase in ambient sound levels is observable (everyone raising their voice to try to be heard better[6] which is counter-productive)
- when there is neither desirable discretion[7] nor confidentiality[8] (what is mentioned in the notes to which reference is made and can easily be transposed to universes other than that of the work being considered[3] : the same applies in the case of restaurant tables instead of workplaces)
Reverberation time (duration)[9] and sound pressure level[10] are practical indicators of the comfort level of premises, which can be measured (e.g. by ITS[11]) before[12] or after[13] soundproofing work. Whereas considering the frequency range consisting of the 1/1 octave bands centered at 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz (which is common in the construction industry) in an explicitly distinct form is possible without particular difficulty, the average of the interval 500-2000 Hz (taking into account the characteristics of the ordinary human voice) - for what concerns the central frequencies of octave bands - for the reverberation time and the overall weighted value - (dB(A)), for the noise level - are usual when it comes to comparing measurement results with regulatory or normative reference values.
ITS participated in the limitation of reverberation and noise by means of acoustic screens in a restaurant room in a collective catering unit in Rennes, in the department of Ille-et-Vilaine (France - Brittany region) by means of acoustic screens (see attached brochure)
Entirely pre-assembled in the workshop, on legs (they could have been, if necessary e.g. for larger dimensions and with a greater probability of mobility, with wheels), opaque (they could have been, if necessary e.g. in the event of usefulness of parts allowing vision, translucent) the sixty acoustic screens marketed by ITS will make it possible to create separations between groups of tables (possibly: by being aligned or installed at right angles) not only in the current configuration of the dining room, but also in the case of future changes to its layout or even in the case of its relocation.
For what concerns acoustics of the considered collective catering room, such soundproofing equipment allows both:
- contribute to limiting the reverberation of the room; the relevant intrinsic performance indicator of the screens is the acoustic absorption coefficient (reaching 100% for the 1/1 octave bands of central frequency 500 Hz, 1 kHz and 2 kHz)
- contribute to limiting the propagation of noise from one table to another; the relevant intrinsic performance indicator for screens is the sound reduction index (reaching or exceeding 30 dB at high frequencies)
It is therefore a good way to improve the sound comfort of such spaces, and many others in very different sectors, when there is utility in combining the properties of sound absorption and the ability to obstruct to noise propagation offered by acoustic screens (all the more so when one does not consider - whatever the reason - the implementation of sound-absorbing materials at room physical limits, e.g. covering portions of the walls or hanging from the ceiling or under- roof).
And this also contributes to the decoration of the considered space, since the acoustic screens are available with, for the resistant fabric covering, a wide choice of colors (there is something for everyone, see color chart here)
In addition, this contributes to the strengthening of the social dimension associated with collective catering (when it is not a question of gastronomy, catering consists - of course - of replenishing energy through food, but also - except when having infrequent table neighbors in a canteen - to be able to have conversations in an acoustic environment that must be sufficiently conducive to this).
The acoustic screens marketed by ITS only have advantages.
Spread the word !
[1] in France, an Order of April 25, 2003 relating to noise limitation in educational institutions stipulates reverberation time values to be respected for the dining rooms of nursery schools, elementary schools, colleges, high schools, regional establishments of adapted education, universities and higher education establishments, general, technical or professional, public or private
[2] in France, an Order of April 25, 2003 relating to noise limitation in health facilities stipulates reverberation time values to be respected for catering rooms in healthcare establishments
[3] standard NF S 31-080 Acoustics - Offices and associated spaces - Acoustic performance levels and criteria is a reference document
[4] for premises such as internal restaurants, inter-company restaurants (ICR), cafeterias, "kitchen areas" and private management restaurants
[5] i.e. open plan offices, open spaces, large open offices
[6] sometimes referred to as cocktail effect, or Lombard effect
[7] situation obtained when an effort is required to understand the content of a conversation emitted by a neighboring workstation; in these conditions, the conversation is not a source of distraction
[8] situation obtained when even with an effort to understand a conversation emitted by a neighboring workstation, it remains incomprehensible
[9] time duration (usually in seconds) required for the existing sound level in a room to decrease by 60 dB when the noise source is abruptly interrupted; its determination can be carried out (e.g according to standard NF EN ISO 3382 Acoustics - Measurement of room acoustic parameters - Part 2: Reverberation time of ordinary rooms) using a noise generator and a sound level meter
[10] measurable with a sound level meter
[11] cf. Means of acoustic measurement
[12] to carry out a diagnosis prior to the definition of an action plan with recommendations or even definition of technical solutions to improve the situation in terms of acoustics
[13] to assess the acoustic quality of premises at the end of soundproofing work, to check compliance with a contractual result commitment (e.g. based on specifications) and/or compliance with regulations