# Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance), Division: Calculation of the attenuation Adif

Extent: E+W+S+N.I.

The attenuation due to diffraction, taking the ground effects on the source side and receiver side into account, is calculated according to the following general equations:
A dif = Δ dif S,R + Δ ground S,O + Δ ground O n , R
(2.5.30)
where
Δ dif (S,R) is the attenuation due to the diffraction between the source S and the receiver R
Δ ground(S,O) is the attenuation due to the ground effect on the source side, weighted by the diffraction on the source side; where it is understood that O = O1 in case of multiple diffractions as in Figure 2.5.f
Δ ground(O,R) is the attenuation due to the ground effect on the receiver side, weighted by the diffraction on the receiver side (see the following subsection on calculation of the term Δ ground(O,R) ).

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Source: https://www.legislation.gov.uk/eudr/2015/996/annex/division/ASSESSMENT/division/2/division/2.5/division/2.5.6/division/13 (the official version)
Page: https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-13
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.