{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-2/division-2.1/division-2.1.6/division-2.1.6.2",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-2/division-2.1/division-2.1.6/division-2.1.6.2.json",
  "legislation": "eur/2017/654",
  "legislation_title": "Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-654",
  "path": "annex/VII/division/2/division/2.1/division/2.1.6/division/2.1.6.2",
  "kind": "division",
  "number": "2.1.6.2",
  "heading": "Tracer measurement method",
  "text": "This involves measurement of the concentration of a tracer gas in the exhaust gas. The instantaneous exhaust gas flow q mew,i [kg/s] shall be calculated by means of equation (7-16):\nq m ew, i = q V t × ρ e 10 − 6 × c mix, i − c b\n(7-16)\nwhere:\nqV t tracer gas flow rate [m3/s]\nc mix, i instantaneous concentration of the tracer gas after mixing [ppm]\nρ e density of the raw exhaust gas [kg/m3]\nc b background concentration of the tracer gas in the intake air [ppm]\nThe background concentration of the tracer gas c b may be determined by averaging the background concentration measured immediately before the test run and after the test run. When the background concentration is less than 1 % of the concentration of the tracer gas after mixing c mix, i at maximum exhaust gas flow, the background concentration may be neglected.",
  "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/eur/2017/654/annex/VII/division/2/division/2.1/division/2.1.6/division/2.1.6.2",
    "retrieved_at": "2026-11-01T14:45:01.864924+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."
}