{
  "url": "https://openlegislation.uk/air-navigation-noise-certification-order-1990/schedule-2",
  "json_url": "https://openlegislation.uk/air-navigation-noise-certification-order-1990/schedule-2.json",
  "legislation": "uksi/1990/1514",
  "legislation_title": "The Air Navigation (Noise Certification) Order 1990",
  "legislation_url": "https://openlegislation.uk/air-navigation-noise-certification-order-1990",
  "path": "schedule/2",
  "kind": "schedule",
  "number": "2",
  "heading": null,
  "text": "“An International Standard Atmosphere at sea level” means an atmosphere having the following characteristics—\n(a) the air is a perfect dry gas;\n(b) the physical constants are—\n(i) sea level mean molecular weight:\nM0 28.9644\n(ii) sea level atmospheric pressure:\nP0\n= 1013.250 millibars\n= 1.013250 × 105 newtons−2\n(iii) sea level temperature:\nt0 = 15°C\nT0 = 288.15°K\n(iv) sea level atmospheric density:\nP0 = 1.2250 kg m−3\n(v) temperature of the ice point:\nTi = 273.15°K\n(vi) universal gas constant:\nR = 8.31432 joules (°K)−1 mol−1",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1990/1514/schedule/2",
    "retrieved_at": "2026-10-29T15:11:26.873786+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."
}