conventional foot of mercury

{
  "id": "NISTu330",
  "unitsml_id": "u:ft_Hg",
  "name": "conventional foot of mercury",
  "names": [
    {
      "value": "conventional foot of mercury",
      "lang": "en"
    },
    {
      "value": "foot of mercury, conventional",
      "lang": "en"
    },
    {
      "value": "foot of mercury",
      "lang": "en"
    }
  ],
  "symbols": {
    "unicode": "′Hg",
    "ascii": "'Hg",
    "html": "′Hg",
    "latex": "\\ensuremath{\\mathrm{'Hg}}",
    "id": "prime_Hg",
    "mathml": "<mi mathvariant='normal'>&#8242;Hg</mi>"
  },
  "identifiers": [
    {
      "type": "nist",
      "id": "NISTu330"
    },
    {
      "type": "unitsml",
      "id": "u:ft_Hg"
    }
  ],
  "references": [
    {
      "type": "informative",
      "authority": "qudt",
      "uri": "http://qudt.org/vocab/unit/FT_HG"
    }
  ],
  "short": "ft_Hg",
  "root": true,
  "composite": false,
  "quantities": [
    {
      "id": "NISTq15",
      "name": "pressure",
      "type": "derived"
    },
    {
      "id": "NISTq16",
      "name": "stress",
      "type": "derived"
    }
  ],
  "dimension": {
    "id": "NISTd14",
    "name": "pressure",
    "expression": "L-1·M·T-2",
    "components": [
      {
        "key": "length",
        "symbol": "L",
        "power": -1
      },
      {
        "key": "mass",
        "symbol": "M",
        "power": 1
      },
      {
        "key": "time",
        "symbol": "T",
        "power": -2
      }
    ],
    "dimensionless": false
  },
  "scale": {
    "id": "continuous_ratio",
    "name": "continuous ratio scale"
  },
  "systems": [
    {
      "id": "non-SI_not_acceptable",
      "name": "non-SI and not acceptable",
      "short": "nonsi-unacceptable",
      "acceptable": false
    }
  ],
  "root_units": null
}