{
  "url": "https://openlegislation.uk/eu-regulation-2009-761/annex-I/division-1/division-1.2",
  "json_url": "https://openlegislation.uk/eu-regulation-2009-761/annex-I/division-1/division-1.2.json",
  "legislation": "eur/2009/761",
  "legislation_title": "Commission Regulation (EC) No 761/2009 of 23 July 2009 amending, for the purpose of its adaptation to technical progress, Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2009-761",
  "path": "annex/I/division/1/division/1.2",
  "kind": "division",
  "number": "1.2",
  "heading": "DEFINITIONS AND UNITS",
  "text": "The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance.\nThe SI unit of pressure, which is the pascal (Pa), should be used. Other units which have been employed historically are given hereafter, together with their conversion factors:\n1 Torr\n=\n1 mm Hg\n=\n1,333 × 102 Pa\n1 atmosphere\n=\n1,013 × 105 Pa\n1 bar\n=\n105 Pa\nThe SI unit of temperature is the kelvin (K). The conversion of degrees Celsius to kelvin is according to the formula:\nT = t + 273,15\nwhere, T is the kelvin or thermodynamic temperature and t is the Celsius temperature.\nTable 1\nWhen using a capacitance manometer\nMeasuring method\nSubstances\nEstimated repeatability\nEstimated reproducibility\nRecommended range\nSolid\nLiquid\nDynamic method\nLow melting\nYes\nup to 25 %\n1 to 5 %\nup to 25 %\n1 to 5 %\n103 Pa to 2 × 103 Pa\n2 × 103 Pa to 105 Pa\nStatic method\nYes\nYes\n5 to 10 %\n5 to 10 %\n10 Pa to 105 Pa\n10–2 Pa to 105 Pa\nIsoteniscope method\nYes\nYes\n5 to 10 %\n5 to 10 %\n102 Pa to 105 Pa\nEffusion method: vapour pressure balance\nYes\nYes\n5 to 20 %\nup to 50 %\n10–3 to 1 Pa\nEffusion method: Knudsen cell\nYes\nYes\n10 to 30 %\n—\n10–10 to 1 P\nEffusion method: isothermal thermogravimetry\nYes\nYes\n5 to 30 %\nup to 50 %\n10–10 to 1 Pa\nGas saturation method\nYes\nYes\n10 to 30 %\nup to 50 %\n10–10 to 103 Pa\nSpinning rotor method\nYes\nYes\n10 to 20 %\n—\n10–4 to 0,5 Pa",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "footnote",
      "label": "f1",
      "text": "When using a capacitance manometer"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2009/761/annex/I/division/1/division/1.2",
    "retrieved_at": "2026-11-01T14:51:19.625001+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."
}