{
  "url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-8",
  "json_url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-8.json",
  "legislation": "eudr/2015/996",
  "legislation_title": "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)",
  "legislation_url": "https://openlegislation.uk/eu-directive-2015-996",
  "path": "annex/division/ASSESSMENT/division/2/division/2.5/division/2.5.6/division/8",
  "kind": "division",
  "number": null,
  "heading": "General principles",
  "text": "Figure 2.5.c illustrates the general method of calculation of the attenuation due to diffraction. This method is based on breaking down the propagation path into two parts: the ‘source side’ path, located between the source and the diffraction point, and the ‘receiver side’ path, located between the diffraction point and the receiver.\nThe following are calculated:\na ground effect, source side, Δ ground(S,O)\na ground effect, receiver side, Δ ground(O,R)\nand three diffractions:\nbetween the source S and the receiver R: Δ dif(S,R)\nbetween the image source S′ and R: Δ dif(S′,R)\nbetween S and the image receiver R′: Δ dif(S,R′) .\nFigure 2.5.c\nGeometry of a calculation of the attenuation due to diffraction\n1 Source side\n2 Receiver side\nwhere\nS is the source;\nR is the receiver;\nS′ is the image source in relation to the mean ground plane source side;\nR′ is the image receiver in relation to the mean ground plane receiver side;\nO is the diffraction point;\nz s is the equivalent height of the source S in relation to the mean plane source side;\nz o,s is the equivalent height of the diffraction point O in relation to the mean ground plane source side;\nz r is the equivalent height of the receiver R in relation to the mean plane receiver side;\nz o,r is the equivalent height of the diffraction point O in relation to the mean ground plane receiver side.\nThe irregularity of the ground between the source and the diffraction point, and between the diffraction point and the receiver, is taken into account by means of equivalent heights calculated in relation to the mean ground plane, source side first and receiver side second (two mean ground planes), according to the method described in the subsection on significant heights above the ground.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eudr/2015/996/annex/division/ASSESSMENT/division/2/division/2.5/division/2.5.6/division/8",
    "retrieved_at": "2026-11-01T15:21:38.862218+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}