BS 4142:2014 – Methods for rating and assessing industrial and commercial sound

Noise can be a big problem for many people – it can be the reason for stress and unproductive operations. It might even be the cause of financial penalties to some businesses.

BS 4142 assesses the potential impact of industrial/commercial noise on residential (noise-sensitive) dwellings. It is established to assess several sources of noise – from a single AC unit to large installations like an oil refinery; it also evaluates the effects to the people nearby, along with the associated risks that can be minimised.

Acoustic instruments have changed a lot since the last 1997 revision. The latest editions consider the advances in technology, which can help to improve the accuracy of final assessments.

According to the BSI (British Standards Institution) group, many sections of the standard have also been revised to improve clarity:

  • Helps assess sound levels at proposed new residential premises
  • Enables the investigation of complaints by determining sound levels
  • Reduces the likelihood of financial penalties
  • Supports the current UK planning guidance and Environment Agency guidance

Guidelines for commercial or industrial noise with no distinguishable features

  • A significant adverse impact is said to occur if the commercial/industrial noise reaches up to 10 dB or if it is much higher than the background noise level. 10 dB above background is not acceptable – a cause for “severe annoyance”, in accordance with BS 4142. 5 dB above background is “moderate annoyance”.
  • Commercial/industrial noise should be avoided if it reaches 5 dB or much higher than the background noise level
  • Normally, it is acceptable if commercial/industrial noise is lower than the background noise level


Our acoustic engineers carry out noise impact assessments in accordance with the requirements of BS 4142 to include:

  • Background noise assessments
  • Noise calculations
  • Evaluations against noise impact criteria

Acoustic Report

BS 4142 noise measurements and evaluations are all written up in an acoustic report along with the noise mitigation strategies; this will be issued to the Local Planning Authority (LPA).

Where necessary, our acoustic consultants communicate directly with the LPA Environmental Health Team to ensure the successful resolution of noise related problems.

The typical noise mitigation measures also include Acoustic Enclosures, Acoustic Louvres or Attenuators.


Sources of noise that require this type of assessment include:

  • External air conditioning (AC) units
  • Compressors
  • Chillers
  • Generators
  • Plant rooms
  • Kitchen extraction systems
  • Air handling units (AHU)
  • Fans
  • Generators
  • Various industrial or commercial activities

Sound Planning offers noise and vibration consultancy and engineering services in the United Kingdom. For enquiries, please call us on 01252 711972 or email us at

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