26. Noise generated by construction activities which do not exceed these lower cut off levels (for example 65dB(A) for daytime construction activities) are considered to be of negligible significance.
27.
It is important to note that noise levels considered significant under BS5228-1 are viewed in the context of construction noise. As a result are considered to be temporary, intermittent and of comparatively short duration within the construction phase of the proposed works.
28.
As the impact is anticipated to be temporary and intermittent during the construction phase these significance levels are higher than those proposed for long term, continuous noise resulting from the operation of industrial processes (Industrial noise assessment: Method for Rating Industrial Noise Affecting Mixed Residential and Industrial Areas (BS 4142: 1997) and World Health Organisation (WHO) Night Noise Guidelines for Europe).
29.
The method within BS 5228-1 has been used to assess noise from construction works associated with offshore trenching, landfall HDD, onshore cable trenching and HDD, Construction Consolidation Sites (CCS) and the converter station.
Calculation of Road Traffic Noise (CRTN) & Design Manual for Roads and Bridges (DMRB) 30.
The ‘Calculation of Road Traffic Noise’ (CRTN) produced by the Department of Transport / Welsh Office provides a method for the prediction of noise from road traffic. The Highways Agency Design Manual for Roads and Bridges (DMRB), Volume 11, Section 3, Part 7 Had 213/11 Noise and Vibration, provides guidance on the assessment of noise impacts from roads and contains guidance for assessing the likely impact of noise generated by road traffic. The criteria from DMRB for short term effects are presented in Table 26.5.
Table 26.5 DMRB criteria for determining magnitude of impact in the short-term Increase in traffic noise level
(dB LAeq,11h)
0.0 – 0.9dB 1.0 – 2.9dB 3.0 – 4.9dB >= 5.0dB
31.
Very Low Low
Medium High
The DMRB criteria have been used in the assessment of changes to traffic noise as a result of proposed construction HGV traffic.
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 26 Noise and Vibration Page 11
Impact magnitude
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