French Public Health Code
In forceOverall emergence in a given location is defined as the difference between the ambient noise level, including the particular noise in question, and the residual noise level, made up of all the usual outdoor and indoor noises corresponding to normal occupation of the premises and normal operation of the equipment, in the absence of the particular noise in question.
The limit values for emergence are 5 A-weighted decibels during the day (from 7 a.m. to 10 p.m.) and 3 A-weighted decibels during the night (from 10 p.m. to 7 a.m.), to which is added a corrective term in A-weighted decibels, depending on the cumulative duration of the particular noise:
1° Six for a duration of less than or equal to 1 minute, the duration of measurement of the ambient noise level being extended to 10 seconds when the cumulative duration of appearance of the particular noise is less than 10 seconds;
2° Five for a duration of more than 1 minute and less than or equal to 5 minutes;
3° Four for a duration of more than 5 minutes and less than or equal to 20 minutes;
4° Three for a duration of more than 20 minutes and less than or equal to 2 hours;
5° Two for a duration of more than 2 hours and less than or equal to 4 hours;
6° One for a period of more than 4 hours and less than or equal to 8 hours;
7° Zero for a period of more than 8 hours.
