Noise reduction in workplace is one of the actions that should be considered in the case of a daily noise exposure level above 85 dB (A) and / or a peak sound pressure level beyond 137 dB (C) pursuant to Decree No. 2006-892 of 19 July 2006 (in France).
However, many machines are, without / before soundproofing, likely to cause such noise levels, which then expose employees to auditory risks: in the case of sufficiently powerful noise sources, impacted workplaces can be located not only nearby, but also (sometimes: in large numbers) at great distances from the considered machines, especially in a building whose acoustic quality is not sufficient to allow significant spatial noise decay (which is subject - in France – to special regulatory provisions through the Decree of 30 August 1990), in relation to the reverberation of work premises.
In such cases, it is appropriate to implement specific technical measures to reduce noise in the concerned workplaces, while maintaining production and machinery maintenance conditions compatible with the other technical requirements and with productivity.
This is the case, in particular, in industrial premises such as those in the corrugated cardboard industry, in which it is not uncommon to measure sound pressure levels above 100 dB (A) near production lines: hear (all day long) whistling related to complex manufacturing processes involving high speed paper (150 m/min or more), high pressure steam for corrugation creation is particularly unpleasant, in addition to being dangerous for the ears of personnel assigned to conduct, supervision, control or maintenance work.
Fortunately, solutions exist, in this case, for the reduction of noise in the workplace, based in particular on the implementation of an enclosure for the corrugator (i.e. the machine whose operation is particularly noisy).
ITS will participate in the noise reduction in workplace in a corrugated cardboard production plant near Paris (France): it will come to the design and construction of an envelope to limit the spread of noise emissions from a production machine.
The enclosure will be realized by means of metal acoustic insulation panels which will be dismountable.
Visibility will be possible, at locations for which operator control is required (from the outside) to monitor the machine, by means of glazed frames equipped with laminated safety glazing (it will ensure, in case of breakage, a protection before replacement, having for this a central layer constituting an armature, between two thicknesses of glass).
The accesses (some pivoting, others sliding) will be provided as needed with respect to the constraints related to the production and replacement of faulty or worn mechanical parts and subassemblies of the machine: the roof ( whose periphery will be equipped with a guardrail) will be accessible by means of a crinoline ladder.
This equipment for noise reduction in workplace will also require a sophisticated ventilation system, to allow the necessary evacuation of hot and humid air which is a by-product (sometimes: recycled) of the manufacture of corrugated cardboard.
The development of the design details, based on a thorough study of the site constraints and on a good understanding of the needs of the on-site staff in relation to the accomplishment of their tasks, and allowing the development of a 3D model making it possible to verify the absence of undesirable interference between the construction and existing equipment (frame elements, piping) will be a key factor for the success of this operation of noise reduction in workplace