BS4142 Noise Assessment (2014)
BS4142 noise assessment – The rating of industrial noise is required to investigate the impact of a noise source that is located or is proposed to be located close to any residential dwellings. You may be required to carry out a day time or a night time BS4142 noise assessment.
The standard details a procedure whereby noise from the source in question is corrected for character and occurrence and then compared with the prevailing background sound level in the absence of the source noise. In general terms, the likelihood of complaints can be expected to increase as source noise exceeds the background level.
Since background noise levels vary throughout a 24 hour period it is usually necessary to assess the acceptability of noise levels for separate periods (e.g. day and night). The recommended time periods for day and night assessments are 0700-2300 and 2300-0700 hours respectively. The night period covers “the times when the general adult population are preparing for sleep or are actually sleeping”.