{
  "url": "https://openlegislation.uk/eu-regulation-2017-1151/annex-Sub/5/division/division-4./division-4.2./division-4.2.2./division-4.2.2.4.",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-1151/annex-Sub/5/division/division-4./division-4.2./division-4.2.2./division-4.2.2.4..json",
  "legislation": "eur/2017/1151",
  "legislation_title": "Commission Regulation (EU) 2017/1151 of 1 June 2017 supplementing Regulation (EC) No 715/2007 of the European Parliament and of the Council on type-approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) and on access to vehicle repair and maintenance information, amending Directive 2007/46/EC of the European Parliament and of the Council, Commission Regulation (EC) No 692/2008 and Commission Regulation (EU) No 1230/2012 and repealing Commission Regulation (EC) No 692/2008 (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-1151",
  "path": "annex/Sub/5/division/division/4./division/4.2./division/4.2.2./division/4.2.2.4.",
  "kind": "division",
  "number": "4.2.2.4",
  "heading": "Buoyancy correction",
  "text": "The sample and reference filter weights shall be corrected for their buoyancy in air. The buoyancy correction is a function of sampling filter density, air density and the density of the balance calibration weight, and does not account for the buoyancy of the particulate matter itself.\nIf the density of the filter material is not known, the following densities shall be used:\n(a)PTFE coated glass fibre filter: 2 300 kg/m3;\n(b)PTFE membrane filter: 2 144 kg/m3;\n(c)PTFE membrane filter with polymethylpentene support ring: 920 kg/m3.\nFor stainless steel calibration weights, a density of 8 000 kg/m3 shall be used. If the material of the calibration weight is different, its density shall be known and be used. International Recommendation OIML R 111-1 Edition 2004(E) (or equivalent) from International Organization of Legal Metrology on calibration weights should be followed.\nThe following equation shall be used:\nmf=muncorr×1−ρaρw1−ρaρf\nwhere:\nPefis the corrected particulate sample mass, mg;\nPeuncorris the uncorrected particulate sample mass, mg;\nρais the density of the air, kg/m3;\nρwis the density of balance calibration weight, kg/m3;\nρfis the density of the particulate sampling filter, kg/m3.\nThe density of the air ρa shall be calculated using the following equation:\nρa=pb× MmixR× Ta\npbis the total atmospheric pressure, kPa;\nTais the air temperature in the balance environment, Kelvin (K);\nMmixis the molar mass of air in a balanced environment, 28,836 g mol–1;\nRis the molar gas constant, 8,3144 J mol–1 K–1.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/1151/annex/Sub/5/division/division/4./division/4.2./division/4.2.2./division/4.2.2.4.",
    "retrieved_at": "2026-11-01T14:44:48.753743+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."
}