Noise from facilities (e.g. industrial, artisanal, commercial, agricultural) is subject to regulation, particularly in the case of Establishments Classified for Environmental Protection (ECEP) subject to authorization put into service or modified after 1 July 1997 (in France, see the Order of 23 January 1997).
For such installations, the prefectural authorization decree sets, for each period of the day (daytime and nighttime), noise levels (not exceeding 70 dB (A) for the daytime period and 60 dB (A) for the night period, unless the residual noise for the period considered is greater than this limit) not to exceed the establishment's property limits.
But in addition, the facility's compliance in terms of noise emissions is based on the consideration of emergence in Areas with Restrcicted Emergences (AREs).
Emergence is defined as (being) the difference between the A-weighted equivalent continuous pressure levels of the ambient noise (establishment in operation) and the residual noise (in the absence of the noise generated by the facility).
The zones with regulated emergence (ZER) consist on the one hand of the interior of buildings inhabited or occupied by thirds, existing on the date of the decree of authorization of the installation and their nearest possible external parts (courtyard, garden, terrace); on the other hand, building zones defined by planning documents enforceable against third parties and published on the date of the authorization order; and finally by the interior of inhabited or occupied buildings by third parties which were established after the date of the authorization order in the building zones defined above and their nearest possible external parts (courtyard, garden, terrace) , excluding those of buildings located in areas intended to receive craft or industrial activities.
Limitation of facility noise
For the daytime period, i.e. from 7 am to 10 pm, except Sundays and public holidays, the permissible emergence is 6 dB (A) when the ambient noise level is above 35 dB (A) but not greater than 45 dB ( AT) ; it is 5 dB (A) when the ambient noise level is above 45 dB (A).
For the night period i.e. from 10 pm - am and for Sundays and public holidays, the admissible emergence is 4 dB (A) when the ambient noise level is beyond 35 dB (A) but not greater than 45 dB (AT) ; it is 3 dB (A) when the ambient noise level is above 45 dB (A).
In addition, for noise from installations, the marked tone is detected in an unweighted third octave spectrum when the difference in level between the third octave band and the four nearest third octave bands (the two immediately lower bands and the two immediately higher bands) reaches or exceeds the following levels for the considered band: 10 dB from 50 Hz to 315 Hz, 5 dB from 400 Hz to 1250 Hz, 5 dB from 50 Hz to 315 Hz.
ITS can intervene to evaluate the compliance of a facility in terms of noise and, where appropriate, to size and market soundproofing equipment.
In the case of facilities whose noise is (at least partly) related to the transport / discharge of fluids, ITS offers silencers (sometimes called "sound traps") e.g. for ventilation, exhaust, venting of pressurized gases and doublings of pipes and ducts. In other cases, the noise reduction means envisaged are often enclosures (sometimes referred to as "sound-reducing canopies") or acoustic screens (sometimes referred to as "noise barriers").
Any soundproofing equipment offered by ITS to limit the noise of installations is subject to a guarantee of acoustic performance.