Environmental Noise Monitoring to BS4142

There is often a need for Environmental Noise Monitoring to BS4142 when a factory is next to housing. It can affect the quality of life of the people subjected to it.

Environmental noise from industry can also be a problem for Business. Noise Monitoring can be useful for many reasons. For Business, it can be:

  • In response to complaints.
  • Where there is a need to predict future noise. This prediction allows us to estimate the steps that will be required to reduce the problem.
  • When a site’s licensing hours are under review.
  • Or when otherwise required by planning conditions.

What does Monitoring to BS4142 involve?

Our Environmental Noise Monitoring Assessments follow BS4142 – Methods for rating and assessing industrial and commercial sound. So, the process involves taking measurements and working out several different figures. Such as:

The Ambient sound is the total sound coming from many sources at the test point. Because of this, the ambient sound includes the sound produced by the process of concern, known as the specific sound.

Following this, we measure the Residual sound. The residual sound is the sound that’s left at the assessment location when the specific sound is not active. As a result, it does not add to the ambient sound.

Graph shpwing the variation of noise with time in an Environmental Noise Monitoring Survey to BS4142

Background sound level, LA90, T is the sound pressure level, at the test point, that the residual sound is above for 90% of the time.

Specific Sound Level – Ls is the term for the continuous A-weighted sound pressure level that the sound source produces at the test point. Sometimes it is not possible to work out the specific sound level by measurement of the ambient and residual sound level alone. For example, because the difference between them is too low. In this case, we work out the specific sound level from each of the separate sources.

Acoustic Feature Correction is the correction to the specific sound level because of its nature. It usually increases the impact of the noise over the direct comparison between the specific sound and the background sound.

Rating Level is the Acoustic Feature Correction added to the Specific Sound gives the Rating Level.

Excess of Rating over Background Sound Level. The Rating Level minus the Background Sound Level gives the amount of rating over background Sound Level.

Results of Environmental Noise Monitoring to BS4142 

The result of the exercise gives a figure called the Excess of Rating over Background Sound Level (dB). BS4142 states that the larger this is, the larger the problem is likely to be. The standard rates the results as below:

  • A difference of greater than 10 dB is an indicator to expect a significant adverse impact. 
  • A difference of about 5 dB is an indicator to presume an adverse effect.
  • The lower the rating level is, the less likely it is that it will be an adverse impact.

Environmental Noise Monitoring Report

The BS4142 Environmental Noise Monitoring report will consider the impact on people in the nearby area. We assess the effects using the guidance given in BS 8233:2014 – Guidance on sound insulation and noise reduction for buildings. This document allows us to work out what the indoor ambient noise levels will be. We look at these results for both daytime and night time and with the windows closed or open. Since environmental noise can also be a problem outdoors, we also work out the impact of noise in areas such as gardens.

Further information is available below
Noise nuisances: how councils deal with complaints
Regulations 2006
UK Government noise emission from outdoor equipment

Did you know that Synergy also provides workplace noise monitoring and air quality assessments for nitrogen dioxide?

Call or email us today about Environmental Noise Monitoring to BS4142. We are here to help!

01782 614236 or info@synergy-environmental.co.uk