Urbanistic
Noisemap
Sound
level criteria applied to town planning
©
Tisseyre & Associés
PATENT NR 99 08039
Application
domain - Technical core - Aid
to the interpretation of punctual sound level recordings
Aid
in the allocation of land - Examples
Town
center of Montauban
Map of maximum admissible night noise levels criteria
APPLICATION DOMAIN
This tool is a system of identification and characterization of the soundscape (i.e. the "acoustic landscape") of a site as a function of urban types. From the following urban characteristics: urban fabric, type of way and distance, and at a given point on the site, the major components of the soundscape by day and by night are calculated, as well as the maximum acceptable expected sound level value. This tool helps defining the frontier beyond which the exposed population expresses disturbance. These criteria meet the requirements of standards NFS 31010 and NFS 31110.
A compilation of more than 500 urban configurations and 1000 days of acoustic measurements made it possible to establish correlations between urban types and sound level criteria. The correlations lead to the calculation of the criteria for maximum admissible sound level by day or by night, in accordance with applicable standards in this field.
On
the basis of 1000 days of measurements dealing with over 500 urban configurations,
the correlation was established between the various acoustic components
typical of the 1000 soundscape measurement days and the classification
urban fabrics / transportation ways described below .
In brief, the main sound level indicators used in Urbanistic Noise Map are :
- Maximum admissible sound levels by day and by night
- Leq day and night, and related L1, L10, L50 and L95
AID TO THE INTERPRETATION OF PUNCTUAL SOUND LEVEL RECORDINGS
It is totally irrelevant and above all extremely dangerous to characterise ambient sound level by a punctual measure, possibly by night from 2:00 to 3:00 a.m., as is often the case. In fact, characterising the ambient sound level in this manner does not take the entirety of the components of the soundscape into account, and therefore leads to confuse the ambient sound level with the sound level of the background noise. The next figure displays the offset between the night sound level criterion and the background noise (L95).
The
danger is obvious of classifying the zones based on the sole background
noise: this would overestimate from 5 to 20 dB(A) the potential emergence,
with respect to such a criterion, of the noise emitted when exploiting
the installation, and lead to a negative judgment of non-feasibility on
the exploitation or the soundproofing of the installation, thus leading
to the erroneous conclusion that functioning and exploitation of the installation
are impossible.
Operations
classified according to urban types
The comparison of the sound level criteria provided by Urbanistic Noise Map with the punctual measurements shows the validity of the observations.
The acoustic components typical of urban and suburban soundscapes come from the summation of the land and air transportation noise and of noise emitted by human activities. Sources are numerous and varied. It is difficult to determine their components, all the more for any day of the year. However, knowing the acoustic components of our urban soundscapes makes it possible to predict if implanting a transportation way, some industry, an industrial estate or an amusement park, will induce modifications of these components and consequently, possibly generate a disturbance in the vicinity (in the sense of the 1992 noise law).
Faced with the complexity of soundscapes, and considering the impossibility to make predictive noise maps accounting for all the urban sound sources, transportation ways and human activities, it appeared necessary to have a global and statistical approach of the subject: this is the purpose of Urbanistic Noise Map (UNM).
The maximum acceptable sound levels criteria, by day and by night, in the observer's environment, are deduced from the classification of the urbanism.
This information, connected to a Geographical Information System makes it now possible to map the maximum acceptable sound levels criteria in the environment: see examples below
Creation of en amusement park (naturascope) in Loudun
Using UNM, a map of maximum acceptable sound levels criteria in the environment was established, all over the zone encompassing the neighbouring villages.
It is possible to superimpose the predicted noise emission (Leq) map of the park in activity over the map of maximum acceptable sound levels criteria :
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Implanting the EADS plant in Toulouse
Sound level criteria by day and by night
The application of UNM made it possible to :
- Map the criteria and hence extend the display of punctual criteria coming from measurements, which are always punctual.
- Check the validity of punctual observations in space and in time coming from measurement campaigns and consequently, sort the data.
- See
the evolution of these criteria as a function of the changes in urbanism,
in the present case an upgrading of the road from small street to national
road.
Main maps achieved to this day :
City areas : Toulouse, Bordeaux, Nantes, Paris, Lyon, Villeneuve-St. Georges, Cannes-Mandelieu, Brussels, Kiev, Chongqing, Beijing, Shanghai.