Sir, WE READ with great interest the report in which Keith Jefferson criticises BS5228:1997 for over-predicting noise levels (Construction News, July 6).
The problem of variability of noise sources was recognised in the original research in which WS Atkins participated.
This was published in April 1997 by the research group CIRIA, in its Report 64.
The 1984 version of BS5228 gives the average noise level and percentage on-time for a construction activity. The percentage on-time takes the variability of noise level in to account.
The percentage on-time information has been omitted from the 1997 version of BS5228.
As a result, those wanting guidance on the variability of particular construction activities may need to turn to the original CIRIA report for information on the effective percentage on-time of the activity.
Roger Tompsett Head of Acoustics WS Atkins Noise and Vibration Epsom Surrey