Soundproofing involves the implementation of means of protection of workers against noise, and/or of environmental protection against noise, and/or of means for compliance with regulatory in terms of acoustics of buildings (industrial, tertiary, residential ...). Soundproofing can involve different techniques:
- for reverberation control (of a room)
- for acoustic insulation
- for the implementation of noise barriers
- for teh implementation of silencers
What does soundproofing based on reverberation control consist in ?
Soundproofing based on reverberation control consists in limiting the reflections of sound waves on surfaces, often hard, (e.g. the limits of an enclosed space), founding the phenomenon of reverberation. It is therefore a question of covering such surfaces with materials having properties in terms of acoustic absorption (up to 100%) in a frequency range of interest. The main effects of soundproofing based on acoustic correction are:
an increase in the temporal sound decay, quantified by the time - alias the duration - of reverberation (in general: expressed in seconds) which is all the shorter as the soundproofing solution implemented is effective
an increase in spatial sound decay, quantified by the rate of spatial sound decay (generally: expressed in dB(A) per doubling of the distance to the source) which is all the higher as the soundproofing solution implemented work is effective; 6 dB(A) per doubling distance corresponds to a free sound field (as observed outdoors or in an anechoic room)
What dies soundproofing based on acoustic insulation consist in ?
Soundproofing based on acoustic insulation consists of limiting the transmission of sound from one space to another (e.g. from the inside of a building to the outside - or in the opposite direction -, from one premise to another premise - from a room to another room if it comes to a dwelling - or even from a technical room to a living room or to a hospital or hotel room). It is therefore a question of interposing an acoustic structure (often: multilayer) having acoustic attenuation properties (scale in dB without upper limit) in a frequency range of interest (in the building sector: corresponding to the bands of 1/1 octave centered on 125 Hz to 4 kHz).
With regard to acoustic insulation between interior and exterior (of a building, or of a construction similar to it), and with regard to constructions inside a building (e.g. soundproof cabins), the main components of acoustic insulation are walls and partitions (if necessary with doors, windows), roofs, floors. With regard to the acoustic insulation of machines and equipment, of pipe networks, the main components are the walls of casings and cowlings, lagging of the thermal insulation type with materials having properties in terms of noise transmission limitation.
The main effects of soundproofing based on acoustic insulation are:
- a difference in sound pressure level between the two spaces separated by the construction erected with a view to providing acoustic insulation
What does soundproofing based on the implementation of acoustic screens consist in ?
Soundproofing based on the implementation of acoustic screens consists in limiting the propagation of noise (inside a building or outside) by means of constructions (also called: anti-noise walls) having not the continuity of those provided for acoustic insulation: at the very least, an acoustic screen has an upper edge, at the level of which the phenomenon of diffraction of the acoustic waves takes place (in practice, the acoustic screens are not infinite, and this phenomenon concerns often several vertical edges or a single vertical edge - it happens that a screen is installed perpendicular to a wall -, unless it is a construction forming an enclosure without discontinuity (e.g. of rectangular shape, with 4 walls surrounding an air condenser). Acoustic screens must combine the sound absorption and sound reduction functionalities mentioned above in a frequency range of interest (which rarely includes the low frequencies, due to inherent low performance). Regarding the implementation of an acoustic screen:
- the efficiency is characterized by the insertion loss (i.e. the difference in sound pressure levels measurable at a specified location on the one hand with the screen and on the other hand without the screen), unless it is is a sound level at a measurement point
What does soundproofing based on the implementation of silencers consist in ?
Soundproofing based on the implementation of silencers relates to constructions intended to limit the propagation of noise from openings or vents without opposing the passage of a fluid. This concept therefore covers very different operating realities, depending on whether it is air in quasi-ambient conditions (e.g. ventilation, air conditioning) or an industrial fluid (not only a combustion gas), possibly pressurized and/or with an extreme temperature (very low during expansion, or very high in the case of exhaust gases or steam purges). A silencer can be dissipative, i.e. with a sound absorbing lining e.g. with fibrous materials including mineral wool of all kinds and foams - with surfacing - or having to do with the presence of discontinuities causing reflections of sound waves e.g. changes in duct sections, connections between chambers, tube perforations, change in the direction of fluid circulation; these two principles are often combined e.g. for combustion engine exhaust silencers, for pressurized gas venting silencers.
Regarding the implementation of an acoustic screen:
- the efficiency is characterized by the insertion loss (i.e. the difference in sound pressure levels measurable at a specified location on the one hand with the silencer and on the other hand without the silencer), unless it is is a sound level at a measurement point
ITS markets all products and services for soundproofing
ITS markets all products and services for soundproofing (construction, industry):
- components: acoustic panels and building envelope elements of all kinds, silencers for all applications
- systems: for the reverberation control of premises, for the acoustic insulation of buildings, acoustic screens and noise barriers
- acoustical engineering e.g. on-site measurements, solution studies, calculations, sizing
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