|Acoustics applied to industry    |
Concerning, noise emissions, the main preoccupations of industry are the risks of deafness due to work and the inconvenience for the residents.
The regulation defines thresholds for sound limits including noise at workstations, noise emitted in the environment by classified installations, labelling of machines, and processing of the industrial workshops. There are adapted tools which allow measurements, analysis and forecasting for each problem that may arise.
Noise at work place : the French decree n° 2006-892 of July the 19th of 2006 is relative to workers’ protection against noise. It defines limit values. Beyond those, noise abatement actions become compulsory. An analysis of crew exposure to noise levels is done by series of measurements on existing installations or by estimated computing plans. This allows a forecast of the most adapted acoustic process for each situation.
Classified installations : most industrial facilities are subjected to the French decree of January 23rd 1997 which is relative to the limitation of noise emitted in the environment by classified installations for the environmental protection. This decree defines the maximum acceptable emergence from the industrial facility, which is compared to the residual noise level (existing noise, before the industrial facility construction). The emergence varies according to the time of day, night or weekend.
An estimation of the industrial facility equipments and buildings noise emission combined with a propagation calculation (modelling) allow to treat each noise on a hierarchical basis. It is then possible to define the priorities and reduction devices for each noise source.
Processing of industrial workshop : the French decree of August 1990 defines the minimal acoustical performances of workshops by the evaluation of the “decreasing sound value by doubling the distance”. This depends on workshops walls coating (walls - ceilings). It can be forecasted and optimized by the mean of workshops modelling.
Machines : equipments are the principle noise sources in industry. The reduction of sound must be a priority because of it can limit the expensive interventions along the propagation path of noise (buildings, screens, hoods...). The mechanical analysis of machines during construction allows to locate the risks of acoustic emission and to design the necessary noise reduction device. On existing equipment, the vibratory and intensimetric analysis, makes it possible to locate the origin of noise, and constitutes an essential basis for the design of noise reduction devices.
Forecasts - modelling : The acoustic analysis phenomenon is enabled by an adapted data modelling process which matches each situation. This takes into account material and dimensional project characteristics (buildings and area topography). It is then possible to forecast noise level, sound listening quality of the buildings and environment as well as the incidence of noise reduction devices on the installation.
Measurement : acoustic and vibratory measurements constitute an essential means to carry out the situation diagnosis. They make it possible to characterize environment and listening quality of a room, home or work place comfort, embarrassment or machine noise emission... Accord Acoustique is very well equipped with powerful measurement instruments : level of acoustic pressure, intensimetry, vibratory analysis...