{
  "url": "https://openlegislation.uk/eu-regulation-2014-517/annex-IV",
  "json_url": "https://openlegislation.uk/eu-regulation-2014-517/annex-IV.json",
  "legislation": "eur/2014/517",
  "legislation_title": "Regulation (EU) No 517/2014 of the European Parliament and of the Council of 16 April 2014 on fluorinated greenhouse gases and repealing Regulation (EC) No 842/2006 (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2014-517",
  "path": "annex/IV",
  "kind": "annex",
  "number": "IV",
  "heading": "METHOD OF CALCULATING THE TOTAL GWP OF A MIXTURE",
  "text": "The GWP of a mixture is calculated as a weighted average, derived from the sum of the weight fractions of the individual substances multiplied by their GWP, unless otherwise specified, including substances that are not fluorinated greenhouse gases.\nΣ Substance X % × GWP + Substance Y % × GWP + … Substance N % × GWP ,\nwhere % is the contribution by weight with a weight tolerance of +/– 1 %.\nFor example: applying the formula to a blend of gases consisting of 60 % dimethyl ether, 10 % HFC-152a and 30 % isobutane:\nΣ 60 % × 1 + 10 % × 124 + 30 % × 3\n→ Total GWP = 13,9\nThe GWP of the following non-fluorinated substances are used to calculate the GWP of mixtures. For other substances not listed in this annex a default value of 0 applies.\nBased on the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, unless otherwise indicated.\nSubstance not listed in the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, default value on the basis of the GWPs of other hydrocarbons.\nSubstance\nGWP\nCommon name\nIndustrial designation\nChemical Formula\nmethane\nCH4\n25\nnitrous oxide\nN2O\n298\ndimethyl ether\nCH3OCH3\n1\nmethylene chloride\nCH2Cl2\n9\nmethyl chloride\nCH3Cl\n13\nchloroform\nCHCl3\n31\nethane\nR-170\nCH3CH3\n6\npropane\nR-290\nCH3CH2CH3\n3\nbutane\nR-600\nCH3CH2CH2CH3\n4\nisobutane\nR-600a\nCH(CH3)2CH3\n3\npentane\nR-601\nCH3CH2CH2CH2CH3\n5\nisopentane\nR-601a\n(CH3)2CHCH2CH3\n5\nethoxyethane (diethyl ether)\nR-610\nCH3CH2OCH2CH3\n4\nmethyl formate\nR-611\nHCOOCH3\n25\nhydrogen\nR-702\nH2\n6\nammonia\nR-717\nNH3\n0\nethylene\nR-1150\nC2H4\n4\npropylene\nR-1270\nC3H6\n2\ncyclopentane\nC5H10\n5",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "footnote",
      "label": "f1",
      "text": "Based on the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, unless otherwise indicated."
    },
    {
      "type": "footnote",
      "label": "f2",
      "text": "Substance not listed in the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, default value on the basis of the GWPs of other hydrocarbons."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2014/517/annex/IV",
    "retrieved_at": "2026-11-01T14:47:40.283176+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."
}