The BS 4142 standard is currently used in planning and public enquiries and is invaluable to environmental health officers, acoustics consultants, and anyone involved in planning, training or legal matters where noise levels may be a problem. Above all, this standard is used to assess the likelihood of complaints from local residents should a new industrial or commercial noise source be introduced to the vicinity.
What does it all mean?
To put it context, if the noise source is 5dB (decibels) above the background noise then it is of marginal significance. If the noise source is 10dB (decibels) or more above the background noise then complaints are likely, whereas if the noise source is 10dB (decibels) or more below the background noise then this is a positive indication that complaints are unlikely.
- An increase in scope to bring in assessment of new sensitive receivers, including new homes, close to existing industrial operations
- Separate tonal and impulsive characteristic penalties of up to 6dB and 9dB respectively. These could be applied in combination to give a new maximum correction of up to 15dB
- Detailed methods to determine whether noise emissions have tonal or impulsive elements
The changes to the proposed methods to assess tonal or impulsive elements are technically difficult and will mean more noise measurements onsite. In addition, new industrial developments could be hit with the 15dB penalty as it’s likely that, at the planning stage, much of the required information will not be available.
In summary, the new proposed BS 4142 noise assessment method will be more complex than its predecessor and thus more costly both to carry out (at a ‘BS 4142 update meeting’ that I attended it was felt that the cost to the client for the assessment could double!) and, in many cases, the resulting implications will be more costly as well.
Of course when BSI publishes the ‘new’ BS 4142 it is possible that not all of the proposed changes will be incorporated – we shall have to wait and see!
Examples of acoustic instruments commonly used to assist with BS 4142 assessments can be found on the Pulsar Instruments website.
Since posting this blog early this week, BSI have issued the new BS 4142 standard! We are looking into this and will follow up on this story as it develops… keep checking our blog.
About our author: Graham Ellicott is a professional member of The Institute of Acoustics since 1999. In 2004, he became a Chartered Scientist and this status was renewed in 2009. In 1995 Graham was awarded an M.Sc. in Acoustics, Vibration and Noise Control by Heriot-Watt University in Edinburgh.
Dakat Limited was formed by Graham in 1999. It is an acoustic consultancy based in the Thames Valley that offers a wide range of services to solve noise problems. To find out more, visit: www.dakat.co.uk