{
  "url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-6",
  "json_url": "https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-6.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/6",
  "kind": "division",
  "number": null,
  "heading": "Calculation in favourable conditions",
  "text": "The ground effect in favourable conditions is calculated with the equation of Aground,H , provided that the following modifications are made:\nIf Gpath ≠ 0\n(a) In the equation of Aground,H , the heights zs and zr are replaced by zs + δ zs + δ zT and zr + δ zr + δ zT respectively where\nδz s = a 0 z s z s + z r 2 d 2 p 2\n(2.5.19)\nδz r = a 0 z r z s + z r 2 d 2 p 2\nao =2 × 10–4 m–1 is the reverse of the radius of curvature\nδz T = 6 × 10 − 3 d p z s + z r\n(b) The lower bound of Aground,F depends on the geometry of the path:\n(2.5.20)\nIf Gpath = 0\nAground,F = Aground,F,min\nThe height corrections δ zs and δ zr convey the effect of the sound ray bending. δ zT accounts for the effect of the turbulence.\nḠm may also be equal to either Gpath or G′path depending on whether the ground effect is calculated with or without diffraction, and according to the nature of the ground under the source (real source or diffracted). This is specified in the following subsections.\nFor a path (Si,R) in favourable conditions without diffraction:\nḠw = Gpath in equation (2.5.17);\nḠm = G′path .\nWith diffraction, refer to the next section for the definitions of Ḡw and Ḡm .",
  "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/6",
    "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."
}