BS4142: Method for Rating Industrial Noise Affecting Mixed Residential and Industrial Areas

In general, the expected amount of community complaints rises as a function of increasing noise, if the noise level goes up, the volume of complaints will increase.

BS4142:1997 enables an assessment of the potential noise nuisance and likelihood of complaints by comparing a specific noise level due to the industrial plant or equipment with assessed or measured daytime and/or night-time background noise levels at sensitive positions. Whilst it is allied to planning requirements it is also a useful tool for assessing existing plant or equipment that may be the subject of noise nuisance complaint.

Note that BS4142 is not suitable for assessing the noise measured inside buildings or when background and rating noise level are very low, a rating level below about 35dB(A) and a background level below about 30dB(A) are considered very low.

Rating Method

The difference between a specific noise level and the background level (re BS4142 definitions for daytime or night-time assessments) corrected for tonal, intermittent, irregular or impact effects is referred to as the assessment level, and BS4142:1997 gives the following guidelines on assessing the likely hood of noise nuisance complaints.

An assessment level greater than +5dB(A) begins to make it very likely that complaints will occur

An assessment level of +5dB (A) is of marginal significance.

An assessment level below 5dB(A) is positive, the lower the value the less likelihood there is that complaints will occur

An assessment level of -10dB or less is a positive indication that complaints are unlikely.

Note that the day is usually divided between day time 0700-2300(16hrs) and night 2300-0700. (8hrs), this can vary dependant on social and environmental conditions.

What requires a BS4142 Survey/Assessment?

In most cases BS4142 is commonly used for planning purposes during the installation of ACCU’s. However it can and is also used for the following:

As a noise nuisance indicator for industrial and commercial sites near residential property.

To assess entertainment noise and its effects on surrounding residential premises. This can be to satisfy a noise abatement notice or as a license extension measure.

As a protection measure for local residents when nearby restaurants install kitchen extraction systems.

Or as a helpful tool to ensure new kitchen extraction systems do not cause a noise nuisance.

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