{
  "url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-12",
  "json_url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-12.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/12",
  "kind": "division",
  "number": null,
  "heading": "Favourable conditions",
  "text": "Figure 2.5.e\nCalculation of the path difference in favourable conditions (single diffraction)\nIn favourable conditions, it is considered that the three curved sound rays SO, OR, and SR have an identical radius of curvature Γ defined by:\nΓ = max(1 000,8d)\n(2.5.24)\nThe length of a sound ray curve MN is noted M̂N in favourable conditions. This length is equal to:\n(2.5.25)\nIn principle, three scenarios should be considered in the calculation of the path difference in favourable conditions δF (see Figure 2.5.e). In practice, two equations are sufficient:\nif the straight sound ray SR is masked by the obstacle (1st and 2nd case in Figure 2.5.e):\n(2.5.26)\nif the straight sound ray SR is not masked by the obstacle (3rd case in Figure 2.5.e):\n(2.5.27)\nwhere A is the intersection of the straight sound ray SR and the extension of the diffracting obstacle.\nFor the multiple diffractions in favourable conditions:\ndetermine the convex hull defined by the various potential diffraction edges;\neliminate the diffraction edges which are not on the boundary of the convex hull;\ncalculate δF based on the lengths of the curved sound ray, by breaking down the diffracted path into as many curved segments as necessary (see Figure 2.5.f)\n(2.5.28)\nFigure 2.5.f\nExample of calculation of the path difference in favourable conditions, in the case of multiple diffractions\nIn the scenario presented in Figure 2.5.f, the path difference is:\n(2.5.29)",
  "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/12",
    "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."
}