The question of means of limiting the spread (propagation) of noise (in relation to various issues) is important for anyone concerned with the acoustic comfort of buildings, the protection of workers or the preservation of the environment.
What means of limiting the spread (propagation) of noise are used specifically inside buildings ?
There is, basically, only one category of means of limiting the spread (propagation) of noise used specifically inside buildings:
that having to do with reverberation control: it comes to the implementation of absorbent materials (according to the possibilities: in the form of a wall lining, and/or in the form of a suspended ceiling or suspended baffles or/and in the form of a floor covering) which make it possible to increase spatial sound decay and therefore, for example, in work premises, to limit the propagation of noise from machines or production lines towards distant workstations (and, what is not nothing: with limiting the amplification of sound levels due to the effects of reverberation, which can also be important in technical rooms). The main characteristic sought is sound absorption (the sound absorption coefficient, which varies according to the frequency, is expressed in %); the performance, in terms of limiting the spread (propagation) of noise, increases with this indicator (provided that a sufficient proportion of the total surface of the walls of a room is treated, and that the distribution of the absorbing surfaces is fairly homogeneous ). In an anechoic room (used for R&D work in acoustics, in industry as well as in universities or engineering schools), the goal is to overcome the physical limits constituted by the walls of a room. tests or a laboratory.
What means of limiting the spread (propagation) of noise are used indifferently inside or outside buildings?
The means of limiting the spread (propagation) of noise used indifferently inside or outside buildings can be classified into different categories:
- those that have to do with acoustic insulation: it is a question of opposing the propagation of sounds by the implementation of acoustic structures such as elements of the envelope of buildings or constructions inside buildings (consisting of fully enveloping structures: enclosures for noisy equipment, acoustic cabins [1] [2] [3]) e.g. floors, roofs, walls and partitions - which may include doors and windows -. For constructions (housing, tertiary premises, industrial building) the airborne noise insulation illustrates the limitation of the propagation of noise from noisy spaces to the spaces to be protected (interior or exterior). The main characteristic sought is the sound reduction (the sound reduction index, variable depnding to the frequency, is expressed in dB); performance, in terms of noise propagation limitation, increases with this indicator
- those that have to do with the sound barrier effect: these are constructions (noise barriers walls) that oppose the propagation of noise at specified locations. The main characteristics sought are sound reduction and sound absorption as mentioned above; the on-site performance depends on the positioning, with respect to the device for limiting the spread of noise, of the sound source and the location that one wishes to protect, the difference in the path of the sound waves path induced by the presence of the noise-cancelling wall (e.g. depending on its height, if it is unlimited in length) and the properties, in terms of sound absorption, of the adjacent surfaces (e.g. the suspended ceiling of an open space, the under-roof of a industrial building)
- those that have to do with limiting the transmission of structure-borne noise. The main characteristic sought is vibration filtering (the vibration filtering rate, variable according to the frequency, is expressed in %); performance, in terms of noise propagation limitation, increases with this indicator. Decoupling devices (springs when it comes to obtaining low frequency performance e.g. when considering a concept like the "box in the box" type, studs and elastomer supports are useful for the anti-vibration suspension of equipment in technical rooms, boiler rooms as well as for the separation of pipes and ducts)
- those having to do with noise reduction for aeraulic networks or facilities with pressurized fluids e.g. for openings or vents. The main characteristic sought is the insertion loss (variable according to the frequency, expressed in dB) inseparable from the aeraulic performance (i.e. the total pressure loss) which must not reduce the efficiency of the facility. Silencers are devices for limiting the spred of noise with very variable design, shape, dimensions and construction depending on the context (there are big differences between a silencer in a Heating Ventilation Air Conditioning - HVAC - network, involving low-flow air with near-atmospheric thermodynamic conditions and a gas turbine exhaust muffler involving combustion gas with very high-temperature, high-velocity)
What does ITS offer with regard to means of limiting the spread (propagation) of noise ?
What ITS offers with respect to the means of limiting noise spred (propagation) (depending on the context):
- audit and advice: on-site sound measurements for diagnosis, acoustic simulations, impact study, sizing calculations for soundproofing equipment
- marketing of all means of limiting the spread (propagation) of noise: for acoustic insulation (products and constructive systems for all types of construction - building and industry -), for the implementation of acoustic screens (anti-noise walls in all cases, soundproof screens for catering rooms and collective offices), anti-vibration devices, silencers of all kinds (all these materials: developed and built with a view to sustainable performance)
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[1] the cabins for musicians allow the practice of a musical instrument while being freed from the surrounding noise, and without disturbing the neighbors (a certain degree of anechoicity is required inside)
[2] in some workplaces, booths are specially designed constructions to protect people (e.g. machine operators) from ambient noise
[3] audiometric booths are constructions specially designed to allow examinations and tests related to hearing