In a metal-forming workshop, a press is a very powerful noise source potentially causing sound nuisance for the personnel operating in the vicinity (in production halls) and sometimes also for the neighborhood. It is often necessary to use in such cases a high-tech soundproofing equipment (noise hood) to ensure the conformity of the facility with respect to the legislation on noise in workplaces and sometimes also with respect to the regulations in terms of fight against domestic noise.
This is moreover true in many other industrial contexts, which necessitates the implementation hardware for noise protection against noise in work places.
ITS will participate in the construction of a noise hood for soundproofing a press near Paris in the county of Yvelines in the region Ile-de-France (France).
This industrial soundproofing device will have a sound reduction particularly important at medium and high frequency where the maximum of the noise emission of the enclosed noisy equipments is, requiring a specific design and a specific construction of the partitions of the noise hood, which will be carried out by means of multilayer metal industrial soundproofing panels:
- a sound-absorbing layer, on the side of the noise source - formed by the press - i.e. avoiding the reflection of acoustic waves on the walls of the noise hood (the omission of such a layer would be counterproductive, since then causing an increase in the sound pressure level inside the soundproofing device; with a performance of the walls in terms of sound transmission limitation beig constant, the sound level outside the noise hood would be increased accordingly); the choice of a mineral wool (surfaced by a glass veil and with a perforated sheet for the necessary mechanical protection) of a sufficiently high density (not too much so as not to harm the sound absorption) will contribute to the sound reduction
- an external layer, made of a steel sheet (this one: non-perforated) which will attenuate the noise, to obtain sound levels outside the noise hood compatible with the regulations, i.e. Directive 2003/10 / CE of European Parliament and of the Council of 6 February 2003 concerning the minimum health and safety requirements relating to the exposure of workers to the risks due to physical agents (noise) [1] with regard to:
- the peak sound pressure (ρpeak): maximum value of the instantaneous sound pressure measured with the frequency weighting C
- the daily noise exposure level (L EX, 8h) (dB (A) ref. 20 µPa): time-weighted average of noise exposure levels for a nominal eight-hour working day
Related features such as visibility for the operation of the machines, access for maintenance work, disassembly of some subsets of the soundproofing equipments ... will be integrated according to the needs for this noise hood for a press.
[1] exposure limit values: LEX, 8h = 87 dB (A) and ρpeak = 200 Pa respectively; higher exposure values triggering the action: LEX, 8h = 85 dB (A) and ρpeak = 140 Pa respectively; lower exposure values triggering the action: LEX, 8h = 80 dB (A) and ρpeak = 112 Pa respectively