Noise emissions are often undesirable by-products of many activities, regardless of their level of industrialization.
Noise diminution is a necessity in the context of many industrial projects involving very powerful machines whose operation is accompanied by very large noise emissions, likely to cause an auditory risk for workers.
Even though Directive 2003/10 / EC – that the Decree No. 2006-892 of 19 July 2006 on the safety and health requirements applicable in the event of exposure of workers to the risks arising from noise and amending the Labor Code is a transposition into French law, which specifies that a daily noise exposure level exceeding 80 dB (A) and / or a peak sound pressure level above 135 dB (C), is above the action limit – is not universally enforced, equivalent continuous noise levels below 85 dB (A) are often specified at 1 m from machines or installations with noise levels that exceed such limits, if they are not soundproof, by several tens of decibels.
This is the case of gas power plants, based on the operation of combustion turbines.
ITS participated in the construction of noise diminution devices for a combustion turbine (power output above 40MW) and its gas module as part of the construction of a power generation plant in East Asia.
The noise diminution of these equipments necessitated the construction of metallic soundproof buildings, based on modular soundproofing pannels, integrating particular functionalities in terms of dismountability of the partitions for the maintenance and in terms of ventilation (with silencers), the structural dimensioning having integrated the site constraints (seismic and meteorological risks).
Of course, the selection of appropriate construction systems for the partitions (walls and roof) was a highlight of the project, when it came to reconciling two fundamental functionalities in terms of soundproofing:
- acoustic absorption i.e. the capacity of the walls not to reflect acoustic waves (which makes it possible to avoid the phenomenon of amplification of sound levels resulting from the implementation of limits to acoustic propagation); this induces the implementation, on the side of the noise source, of a layer of material having a sufficiently low resistance to the passage of air - in practice, often: a mineral wool, surfaced by an anti-defibration glass cloth, with mechanical protection consisting of a perforated sheet -
- sound reduction i.e. limitation of sound transmission; it is useful to use a metal plate, generally made of steel, constituting the outer casing of acoustic insulation panels, the assembly system of which (with or without seal) must be sufficiently waterproof (not only to provide protection against bad weather, but also to limit the propagation of noise)
The design has, as often, required the consideration of limited spaces for the installation of industrial soundproofing equipment implemented on a 3D model of the plant before anything else.
The requirements for quality, for respect of short delivery time and for documentation in connection with the construction of these noise diminution devices at a major chemical site required particularly rigorous project management in a noise emissions limitation context particularly ambitious.