BS4142: a major revision
We reported back in December that BSI had recently revised BS4142: ‘Methods for rating and assessing industrial and commercial sound’. This standard can be used for assessing how nearby residents and communities are affected by sound of a commercial or industrial nature. Here, we revisit our last blog and highlight the main points to consider about the revision. The previous 1997 version of the standard rated how complaints were likely to be whereas the 2014 edition determines sound levels for the purpose of investigating complaints.
The 1997 version of BS4142 allowed a +5dB correction to be made to the noise if it contained distinguishable content such as a whine, screech or bang. In the 2014 edition, this simple one-off correction has been replaced by a three pronged approach which takes into account tonal, impulsive and intermittent noise. In the worse case scenario, this could mean a correction of +18dB.
BS4142 revision: an improvement but not without costs
From the noise consultant’s point of view:
- The “reference time period” for night time noise measurements has gone up to 15 minutes from 5 minutes
- Weather data now needs to be considered for each measurement location. Essentially this means that all noise measurements should either be attended or that a logging meteorological station should be used at each unattended measurement location.
- The uncertainty of measurements and of calculations has to be considered and reported upon accordingly
Annex A of the 2014 edition gives examples of how to use the standard to obtain ratings and Annex B ‘discusses’ the consideration of uncertainty and good practice for reducing uncertainty.
All in all, the 2014 version of BS4142 is a major revision. This is best summed up by the Committee Chairman, Phil Dunbavin who said on publication “It has been fifteen years since the last BS4142 revision, in which time, the accumulated research from around the world that has been taken into account in this revision is vast, and that, together with the input of some eighty users of the standard at a workshop in Birmingham, UK has produced a significantly improved BS4142. This revised standard should enable more consistent and better decision-making by appropriately experienced users.”
It remains to be seen as to how the new standard will be received by end-users, particularly in light of the fact that at a ‘BS4142 revision meeting’ that I attended, it was felt that the cost to the client for such an assessment could double and, in many cases, the resulting implications will be more costly as well!
However, it should be noted that noise problems generated by industry are not confined to upsetting the neighbours. In cases such as this, there is also the likelihood that there could be noise at work issues as well which would need identifying and attending to. These could include noise-induced hearing loss and high stress levels amongst the workforce employed in this industry.
For essential advice on controlling workplace noise, download Pulsar’s FREE 5 Steps Guide for Employers to Controlling Workplace Noise.
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