How to reduce noise in a restaurant ?

How to reduce noise in a restaurant ?

This question frequently arises for collective catering spaces ; not only in school, university or business canteens or in fast food restaurants (they are then mainly frequented for food), but also in other places where we go to combine business (eat and drink) with pleasure: i.e. by having a good time e.g. with family, or with friends, even alone (if the circumstances impose it or else if you have made this choice) in a brasserie, cafe or pub, or in a restaurant: with or without distinction in the specialized guides, about which it is clear that they do not always inform enough than desirable on the soundscape of the places they list.

Because there are many culinary establishments in which the acoustic comfort leaves a lot to be desired, which is often the source of an increase in noise, in particular due to the difficulties experienced by the occupants (guests or employees e.g. those assigned to room service) to be heard.

In addition, the noises linked to the handling (even delicate, but how to avoid shocks ?) of cutlery, glasses, plates, dishes, decanters and bottles and those linked to traffic (of staff and users e.g. when they require the movement of chairs or armchairs - the problem also arises for stools -) are sometimes unduly amplified, to the point of being perceived as very unpleasant or even aggressive (and it is not only those who have good hearing to complain about, then).

Not to mention the unbearable presence of music (a fortiori: if amplified) when the dining room is unsuitable for such use, due to the lack of a fitting design or layout.

From all this it can result in a restaurant hubbub not conducive to discussions (even less: to listening to musical recordings or to the performance of an orchestra) and, in the more or less long term, unfavorable to attendance (you sometimes have only one desire: to get out as quickly as possible and never come back), mouth then often doing its job, through the grapevine.

  • in such situations, a deficit in materials that absorb sound sufficiently at the mid and high frequencies (i.e. in the frequency bands centered on 500, 1000 and 2000 Hz where the noise emissions in relation to speech are countered) is often involved.

How to reduce noise in a restaurant in this case ?

It is then necessary to clad walls and ceiling (not necessarily entirely: in the case of vertical walls, the presence of large bay windows, if they often provide visual comfort - a fortiori if the exterior is suitable - is sometimes a problem anyway) soundproofing devices, which are generally in the form of plates or panels, which can be installed vertically or horizontally (or even: following the slope of a roof, if necessary), or even: which can be suspended, with more or less sophisticated forms.

It may be noted that the installation of a carpet (having, generally, a sound absorption coefficient at best equal to 0.1) can also constitute a remedy, when it comes to limiting the reverberation of a catering premises with a view to limiting noise.

  • moreover, the absence of separations between tables (a fortiori if they are brought together, sometimes to the point of leading to an overpopulation of space which, then, limits improvements in terms of acoustics) can constitute an aggravating circumstance for the the noise discomfort, when nothing prevents (sufficiently) the propagation of noise from a table to the neighboring tables.

How to reduce noise in a restaurant in this case ?

The implementation of screens (dividers) having a functionality in terms of soundproofing (they must not be openwork and they must have a sufficient mass density) makes it possible to compensate for this lack, the choice of products (also) with performance in terms of sound absorption (i.e. for their capacity not to reflect sound waves) being of course more than recommended.

When it comes to how to reduce noise in a restaurant, you can consult Isolation Technologie Services (ITS) to obtain, after a contextual study, optimized solutions.

How to reduce fan noise - study and solutions

How to reduce the noise of a fan?

This question is frequently asked in relation to the limitation of noise exposure of employees in factories, and in some cases also, in relation to the protection of residents, against noise pollution due to equipment or facilities.

This is why, depending on the context, the architect, the designer, the engineer working for a Technical Studies Office (TOS) or the builder of a construction, but also the installer of an equipment, the Hygiene Safety Environment (HSE) manager of an industrial site is at the origin of the questioning, when it is not the trustee of a condominium.

Indeed, the noise emissions of a fan (aka extractor, blower), noisy equipment by nature, are often able to create disorders when it is installed in an aeraulic network (e.g. ventilation system, various processes) or when it is integrated into an equipment used to transport air (pure, or mixed with other gases, or even containing particles) or for a cooling process (e.g. air condenser, cooling tower).

How to reduce fan noise depends on the location of the noise source in question.

Because when the noise emissions of a fan are problematic, it is generally illustrated by exceeding noise limits (sometimes: not only because of high values of the sound pressure level at a specified location, but also because of a marked tone, the consequence of which is the perception of an undesirable whistling sound):

  • near the casing (i.e. the enveloppe) of the fan: it is then necessary to consider, depending on the context, the lagging of the fan wheel (if it is centrifugal) or else (in particular: if it is an axial fan) an enclosure (which must then itself be equipped with a ventilation system to avoid overheating) by means of industrial soundproofing panels whose constitution and thickness must be selected according to the targeted acoustic objective (in general, steel panels, 60 to 120 mm thick, with rock wool or sufficiently dense polyester wool insulation are appropriate); sealing around the suction and discharge ducts (to limit the propagation of sound) requires special constructive arrangements, just like the other openings (cable and duct penetrations), and also around the easily removable panels or else doors that maintenance constraints may make necessary
  • suction or discharge: it is then useful to consider silencers whose noise attenuation principle (by dissipation, by reaction, by resonance), dimensions, internal parts (e.g. airways, lining sound absorbing system) must be defined not only according to the targeted acoustic objective, but also according to other technical imperatives: frequency distribution of the acoustic pressure level of the fan, total admissible pressure loss, sensitivity to physico-chemical aggressions for the different possible materials, constraints linked to the size (it is not uncommon for a silencer to be installed in an existing chimney, the casing of which then serves as an envelope for the internal parts of the silencers e.g. the absorbing splitters), the weight, the wind resistance (it is common for silencers to be installed on building roofs with limited support possibilities (sometimes with glass or fiber cement roof)

On-site measurements, acoustic and aeraulic performance simulations, impact calculations, definition and marketing, with or without on-site installation: ITS knows how to reduce fan noise, whatever the context.

The applications are varied, and depending on the case, the diameters of the fans are counted in decimeters or meters: ventilation and air conditioning systems, but also: paint booths, suction networks, draft fans, air condensers and air coolers, not forgetting the fans coupled to the engines of the generator sets, and the larger fans: those of the wind tunnels (aeroacoustic or not) and of cooling towers.

How to reduce fan noise, by endeavoring to offer technically efficient, guaranteed and affordable solutions: this is the problem that ITS human resources succesfully faces since decades, in all activity sectors with Orginal Equipment Manufacturers (OEM), integrators (and installers), and also with final users.

Improving office acoustics

Improving office acoustics is necessary when its occupants complain about the lack of noise comfort in their workplace, possible symptoms that may be the sensation of too high ambient noise - sometimes related to telephone ringings and calls, or caused by equipment such as a Heating Ventilation Air Conditioning (HVAC) system, the lack of discretion or of confidentiality during conversations, the difficulty for concentrating to accomplish tasks e.g. due to distraction caused by work, the impossibility of having a discussion with other people.

It may be appropriate to improve the acoustics of an individual office (partitioned, assigned to a staff member) wit respect to external noise if it is troublesome, e.g. in connection with insufficient airborne noise insulationwith respect to neighboring offices: the door and the connection between partitions and ceiling are often weak points in terms of construction, thus constituting privileged paths for the sound transmission (in certain cases the noise of the ventilation openings can pose a problem, if the the noise of the fan is not sufficiently attenuated by a silencer, or if the air speed in the diffuser section is too high and generates a self noise that no soundproofing device can then attenuate, the intercom i.e. the transmission noise from one office to another through the HVAC network is not impossible if nothing has been planned to prevent it).

This same problem is also found in a collective office (partitioned, assigned to 2 to 5 people) with, in addition, the need to take into account their co-activity i.e. the accomplishment by each one of tasks (administrative work, telephone calls, engineering, design and calculations) that can be more or less noisy or require relative calm.

By definition, the aspects of the problem related to airborne sound insulation are only relevant with respect to external noise in the case of open spaces (open plan offices) since there is then no complete separation between workstations; however, the issue of noise propagation is further increased if nothing is planned to limit it.

Improving office acoustics often involves reducing its reverberation; this requires increasing the amount of sound absorbing materials at medium and high frequencies, corresponding to the human voice: their absorption coefficient must be as close as possible to 100%.

For the floor, a carpet can contribute to improve the acoustics of an office (even if its absorption coefficient will be far from reaching 100% because of its small thickness) by increasing the equivalent absorption area of considered space and in addition by limiting the impact noise related to traffic and chairs moving.

The walls themselves (when they are not glazed) can be covered with absorbent panels sometimes called acoustic items.

The ceiling or sub-roof can be treated with acoustic tiles, and / or with suspended absorbent elements called baffles.

In addition, acoustic screens (on legs or on wheels), also made up of panels absorbing the sounds, can partition the space (generally: at height of man when they are not fixed on the desks) and thus limit the noise propagation.

ITS can intervene to improve office acoustics by carrying out measurements on site and by marketing soundproofing equipment optimized for each context (industry, tertiary).

The accompaniment of the client (owner, lessor) is personalized, the results can be guaranteed. . Airborne sound insulation, reverberation time and rate of spatial sound decay of sound pressure levels per distance doubling are common performance indicators for office sound quality.

Which acoustic office screens?

Which acoustic office screens ? This is a question that are asking all those who work in a collective office i.e. a partitioned volume usually hosting from 2 to 5 people or, a fortiori, in an open space (open plan office) i.e. a space in which it is planned to host a large number of people without complete separation between workstations and are hindered by noise emissions related to the professional activity of their colleagues: telephone ringing, telephone conversations, even small-group discussions (and even when efforts are made to do not raise one’s voice too much).

Because what concentration is possible then for tasks (administrative, call center, design office or design) that require a sound environment being sufficiently quiet when what is said in the near desk interferes with a conversation that one is trying to establish at one’s workstation or compromises a crucial moment of reflection that may be necessary even if only to re-read an email before sending it or checking a mathematical operation ?

And what discretion / confidentiality or even intelligibility is there then in the exchanges with other people (being part of the staff of the company or not, eg when it comes to customers or suppliers) ?

In many situations where nothing is done to limit the spread of noise, the quality of the work done in an office suffers from this, and of course the employees' appreciation of their working conditions, despite their efforts to do well.

First, acoustic office screens must oppose the transmission of noise through the physical separation they allow. To do this, their packing must have a sufficient density (10 kg/m2 is appropriate in many cases): it is necessary to consider a high density product when it comes to glass wool (what is usual).

Then, acoustic office screens shall allow to absorb sounds at frequencies corresponding to human speech (especially 500-2000 Hz to mention central frequencies of octave bands), what is illustrated by a sound absorption coefficient of the lining as close to 1 (i.e. 100%) as possible (the absorption class is evaluated from the practical absorption coefficient αp, which is a usual indicator); they then participate in controlling the reverberation of the workspace, what is a fundamental aspect of any soundproofing project in a building. This property should be considered with cover (a durable, easy-to-clean fabric, whose shade can be chosen from a color chart to match the rest of the decoration is often what customers are looking for in such a case).

Finally, acoustic office screens must be in a form compatible with their implementation on a desk (to which they can be easily attached) or allowing their installation on the floor (on legs or on wheels); glass parts (not too much !) can be provided when needed.

ITS sells acoustic office screens being high performing and decorative; modular, they can accompany lay-out changes often in vogue in modern workspaces.

In addition to reducing the reverberation of sounds and limiting the spread of noise between workstations, acoustic office screens can be used to confine a noisy photocopier, a plotter or any other source of unwanted noise.

These same soundproofing equipment can be used to create a discussion area, a relaxation area, or to separate tables in a company restaurant.

Improving restaurant acoustics

Improving restaurant acoustics is a necessity when noise is a subject of recrimination:

  • from the clientele, if it is led to consider that the sound environment is not sufficiently conducive to discussions (whatever the context: business meals, with family, friends ...) for which intelligibility and confidentiality are often desired or even not calm enough to fully enjoy a moment of relaxation (possibly: with music, amplified or not), and sometimes fun (if the table is intended to accommodate gastronomy fans)
  • from the staff, if they are subject to excessive fatigue, in relation to what the quality of their service may be felt

Starred according the rating of a prestigious guidebook or not, a restaurant for which it is desired appropriate reception conditions for its customers (sometimes: with the desire to retain them) must have a minimum acoustic quality (even if it is a canteen - a refectory - where users are often captives).

Because otherwise, each one raising his voice to be heard, the resulting sound atmosphere can be appreciated very negatively, especially if the reverberation of the considered restauration space leads to an excessive amplification of traffic noise (passing, chairs movements) and those related to the accessories of the Art of the table (e.g. plates, glasses, cutlery).

It must be said that some architectural biases in vogue e.g. large windows, walls and floors made of concrete do not help (if nothing else is specifically planned) to obtain the acoustic comfort desirable for a place with this destination when they focus on hard surfaces, to which one can associate an aesthetic charm, but which reflect the sounds.

Improving restaurant acoustics generally requires the installation of sound-absorbing materials, especially at frequencies corresponding to human speech e.g. for which the absorption coefficient must be as close as possible to 1 (i.e. 100%) in the frequency band corresponding to the central frequency octave bands 500, 1000 and 2000 Hz.

These can be suspended ceilings (which can in some cases significantly reduce the ceiling height, which is generally favorable - all other things being equal - to the lowering of the reverberation time (what is a major indicator of the acoustical quality of a restaurant room) or wall-absorbing linings (e.g. with fabric surfacing, or with perforated wood protection) with regard to the existing limits of the catering space which is considered.

Elsewhere, additional absorbing elements of various shapes and designations (on the ground: totems, noise shields, sound screens, partition walls, for ceiling: suspended baffles, on the walls: acoustic items) can also contribute effectively to improving restaurant acoustics, also participating in its decoration.

As regards acoustic screens, their effect is not limited to allowing the introduction into the room of an additional surface of sound-absorbing materials: dividing the space, they contribute to limiting the propagation of noise, e.g. from a noisy table to the adjacent tables, in relation to the diffraction effect which is all the more beneficial for the limitation of the ambient noise (in terms of the reduction of the sound level and in terms of the spatial extent of its decrease) that the local is not very reverberant.

Improving restaurant acoustics is a problem for which ITS intervenes to carry out an on-site diagnosis and propose customized soundproofing solutions: the work carried out can be covered by a contracted result guarantee.

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