{
  "slug": "r-438a",
  "displayName": "R-438A",
  "altSpellings": [
    "R438A",
    "438A",
    "MO99",
    "Freon MO99",
    "ISCEON MO99"
  ],
  "chemicalName": "Quinary HFC blend with hydrocarbons",
  "chemicalFormula": "R-32/R-125/R-134a/R-600/R-601a (8.5/45/44.2/1.7/0.6)",
  "ashraeNumber": "R-438A",
  "type": "hfc-blend",
  "safetyClass": "A1",
  "tradeNames": [
    {
      "name": "Freon MO99",
      "manufacturer": "Chemours"
    },
    {
      "name": "ISCEON MO99",
      "manufacturer": "DuPont (historical; brand transferred to Chemours 2015)"
    }
  ],
  "composition": [
    {
      "component": "R-32",
      "massFraction": 0.085
    },
    {
      "component": "R-125",
      "massFraction": 0.45
    },
    {
      "component": "R-134a",
      "massFraction": 0.442
    },
    {
      "component": "R-600",
      "massFraction": 0.017
    },
    {
      "component": "R-601a",
      "massFraction": 0.006
    }
  ],
  "physical": {
    "boilingPointC": -42.3,
    "boilingPointF": -44.2,
    "critical": {
      "tempC": null,
      "tempF": null,
      "pressurePsia": null,
      "pressurePsig": null,
      "pressureKpaA": null,
      "pressureKpaG": null
    },
    "molarMassGPerMol": 99.1,
    "liquidDensityKgPerM3At25C": 1147,
    "temperatureGlideF": 11.2,
    "hasSignificantGlide": true
  },
  "environmental": {
    "odp": 0,
    "gwp100Ar5": 2265,
    "gwp100Ar6": 2440,
    "atmosphericLifetimeYears": null,
    "snapStatus": "Listed for R-22 retrofit; AIM Act phase-down affected"
  },
  "lubricants": {
    "compatible": [
      "MO",
      "AB",
      "POE"
    ],
    "incompatible": [],
    "notes": "Hydrocarbon components aid miscibility with mineral oil. Marketed by Chemours (Freon MO99, originally DuPont ISCEON MO99) as an R-22 retrofit compatible with existing mineral oil or alkylbenzene in most systems — no oil change required for the majority of retrofits per the Chemours Freon MO99 Retrofit Guidelines. Some complex systems (liquid receivers, screw compressors, Trane 3-D or Danfoss SM scroll compressors) require ~20% POE addition."
  },
  "applications": [
    "R-22 retrofit (commercial AC, refrigeration)",
    "Compatible with mineral oil systems"
  ],
  "replacementOptions": [
    "r-32",
    "r-454b"
  ],
  "replaces": [
    "r-22"
  ],
  "regulatoryStatus": {
    "epaPhaseoutComplete": false,
    "epaPhaseoutDate": null,
    "aimActAffected": true,
    "snapApproved": true
  },
  "ptChart": [],
  "ptTable": [
    {
      "psig": -6,
      "bubbleF": -63,
      "dewF": -51.5
    },
    {
      "psig": -5,
      "bubbleF": -59.3,
      "dewF": -47.8
    },
    {
      "psig": -4,
      "bubbleF": -55.8,
      "dewF": -44.5
    },
    {
      "psig": -3,
      "bubbleF": -52.6,
      "dewF": -41.3
    },
    {
      "psig": -2,
      "bubbleF": -49.6,
      "dewF": -38.4
    },
    {
      "psig": -1,
      "bubbleF": -46.8,
      "dewF": -35.6
    },
    {
      "psig": 0,
      "bubbleF": -44.2,
      "dewF": -33
    },
    {
      "psig": 1,
      "bubbleF": -41.7,
      "dewF": -30.6
    },
    {
      "psig": 2,
      "bubbleF": -39.3,
      "dewF": -28.2
    },
    {
      "psig": 3,
      "bubbleF": -37,
      "dewF": -26
    },
    {
      "psig": 4,
      "bubbleF": -34.8,
      "dewF": -23.9
    },
    {
      "psig": 5,
      "bubbleF": -32.7,
      "dewF": -21.8
    },
    {
      "psig": 6,
      "bubbleF": -30.7,
      "dewF": -19.8
    },
    {
      "psig": 7,
      "bubbleF": -28.8,
      "dewF": -18
    },
    {
      "psig": 8,
      "bubbleF": -26.9,
      "dewF": -16.1
    },
    {
      "psig": 9,
      "bubbleF": -25.1,
      "dewF": -14.4
    },
    {
      "psig": 10,
      "bubbleF": -23.4,
      "dewF": -12.6
    },
    {
      "psig": 12,
      "bubbleF": -20.1,
      "dewF": -9.4
    },
    {
      "psig": 14,
      "bubbleF": -16.9,
      "dewF": -6.3
    },
    {
      "psig": 16,
      "bubbleF": -13.9,
      "dewF": -3.4
    },
    {
      "psig": 18,
      "bubbleF": -11.1,
      "dewF": -0.6
    },
    {
      "psig": 20,
      "bubbleF": -8.4,
      "dewF": 2
    },
    {
      "psig": 22,
      "bubbleF": -5.8,
      "dewF": 4.6
    },
    {
      "psig": 24,
      "bubbleF": -3.4,
      "dewF": 7
    },
    {
      "psig": 26,
      "bubbleF": -1,
      "dewF": 9.3
    },
    {
      "psig": 28,
      "bubbleF": 1.3,
      "dewF": 11.6
    },
    {
      "psig": 30,
      "bubbleF": 3.5,
      "dewF": 13.7
    },
    {
      "psig": 32,
      "bubbleF": 5.7,
      "dewF": 15.8
    },
    {
      "psig": 34,
      "bubbleF": 7.7,
      "dewF": 17.8
    },
    {
      "psig": 36,
      "bubbleF": 9.7,
      "dewF": 19.8
    },
    {
      "psig": 38,
      "bubbleF": 11.7,
      "dewF": 21.7
    },
    {
      "psig": 40,
      "bubbleF": 13.6,
      "dewF": 23.5
    },
    {
      "psig": 42,
      "bubbleF": 15.4,
      "dewF": 25.3
    },
    {
      "psig": 44,
      "bubbleF": 17.2,
      "dewF": 27.1
    },
    {
      "psig": 46,
      "bubbleF": 18.9,
      "dewF": 28.8
    },
    {
      "psig": 48,
      "bubbleF": 20.6,
      "dewF": 30.4
    },
    {
      "psig": 50,
      "bubbleF": 22.3,
      "dewF": 32.1
    },
    {
      "psig": 52,
      "bubbleF": 23.9,
      "dewF": 33.7
    },
    {
      "psig": 54,
      "bubbleF": 25.5,
      "dewF": 35.2
    },
    {
      "psig": 56,
      "bubbleF": 27,
      "dewF": 36.7
    },
    {
      "psig": 58,
      "bubbleF": 28.6,
      "dewF": 38.2
    },
    {
      "psig": 60,
      "bubbleF": 30.1,
      "dewF": 39.6
    },
    {
      "psig": 62,
      "bubbleF": 31.5,
      "dewF": 41.1
    },
    {
      "psig": 64,
      "bubbleF": 32.9,
      "dewF": 42.5
    },
    {
      "psig": 66,
      "bubbleF": 34.3,
      "dewF": 43.8
    },
    {
      "psig": 68,
      "bubbleF": 35.7,
      "dewF": 45.2
    },
    {
      "psig": 70,
      "bubbleF": 37.1,
      "dewF": 46.5
    },
    {
      "psig": 75,
      "bubbleF": 40.3,
      "dewF": 49.7
    },
    {
      "psig": 80,
      "bubbleF": 43.5,
      "dewF": 52.7
    },
    {
      "psig": 85,
      "bubbleF": 46.5,
      "dewF": 55.7
    },
    {
      "psig": 90,
      "bubbleF": 49.4,
      "dewF": 58.5
    },
    {
      "psig": 95,
      "bubbleF": 52.2,
      "dewF": 61.2
    },
    {
      "psig": 100,
      "bubbleF": 54.9,
      "dewF": 63.9
    },
    {
      "psig": 105,
      "bubbleF": 57.5,
      "dewF": 66.4
    },
    {
      "psig": 110,
      "bubbleF": 60.1,
      "dewF": 68.9
    },
    {
      "psig": 115,
      "bubbleF": 62.6,
      "dewF": 71.3
    },
    {
      "psig": 120,
      "bubbleF": 65,
      "dewF": 73.6
    },
    {
      "psig": 125,
      "bubbleF": 67.3,
      "dewF": 75.9
    },
    {
      "psig": 130,
      "bubbleF": 69.6,
      "dewF": 78.1
    },
    {
      "psig": 135,
      "bubbleF": 71.8,
      "dewF": 80.3
    },
    {
      "psig": 140,
      "bubbleF": 73.9,
      "dewF": 82.4
    },
    {
      "psig": 145,
      "bubbleF": 76,
      "dewF": 84.4
    },
    {
      "psig": 150,
      "bubbleF": 78.1,
      "dewF": 86.4
    },
    {
      "psig": 155,
      "bubbleF": 80.1,
      "dewF": 88.4
    },
    {
      "psig": 160,
      "bubbleF": 82.1,
      "dewF": 90.3
    },
    {
      "psig": 165,
      "bubbleF": 84,
      "dewF": 92.1
    },
    {
      "psig": 170,
      "bubbleF": 85.9,
      "dewF": 94
    },
    {
      "psig": 175,
      "bubbleF": 87.8,
      "dewF": 95.8
    },
    {
      "psig": 180,
      "bubbleF": 89.6,
      "dewF": 97.5
    },
    {
      "psig": 185,
      "bubbleF": 91.4,
      "dewF": 99.2
    },
    {
      "psig": 190,
      "bubbleF": 93.1,
      "dewF": 100.9
    },
    {
      "psig": 195,
      "bubbleF": 94.8,
      "dewF": 102.6
    },
    {
      "psig": 200,
      "bubbleF": 96.5,
      "dewF": 104.2
    },
    {
      "psig": 205,
      "bubbleF": 98.2,
      "dewF": 105.8
    },
    {
      "psig": 210,
      "bubbleF": 99.8,
      "dewF": 107.4
    },
    {
      "psig": 215,
      "bubbleF": 101.4,
      "dewF": 108.9
    },
    {
      "psig": 220,
      "bubbleF": 103,
      "dewF": 110.5
    },
    {
      "psig": 225,
      "bubbleF": 104.6,
      "dewF": 112
    },
    {
      "psig": 230,
      "bubbleF": 106.1,
      "dewF": 113.4
    },
    {
      "psig": 235,
      "bubbleF": 107.6,
      "dewF": 114.9
    },
    {
      "psig": 240,
      "bubbleF": 109.1,
      "dewF": 116.3
    },
    {
      "psig": 245,
      "bubbleF": 110.5,
      "dewF": 117.7
    },
    {
      "psig": 250,
      "bubbleF": 112,
      "dewF": 119.1
    },
    {
      "psig": 255,
      "bubbleF": 113.4,
      "dewF": 120.5
    },
    {
      "psig": 260,
      "bubbleF": 114.8,
      "dewF": 121.8
    },
    {
      "psig": 265,
      "bubbleF": 116.2,
      "dewF": 123.1
    },
    {
      "psig": 270,
      "bubbleF": 117.6,
      "dewF": 124.4
    },
    {
      "psig": 275,
      "bubbleF": 118.9,
      "dewF": 125.7
    },
    {
      "psig": 280,
      "bubbleF": 120.3,
      "dewF": 127
    },
    {
      "psig": 285,
      "bubbleF": 121.6,
      "dewF": 128.3
    },
    {
      "psig": 290,
      "bubbleF": 122.9,
      "dewF": 129.5
    },
    {
      "psig": 295,
      "bubbleF": 124.2,
      "dewF": 130.7
    },
    {
      "psig": 300,
      "bubbleF": 125.4,
      "dewF": 131.9
    },
    {
      "psig": 310,
      "bubbleF": 127.9,
      "dewF": 134.3
    },
    {
      "psig": 320,
      "bubbleF": 130.4,
      "dewF": 136.6
    },
    {
      "psig": 330,
      "bubbleF": 132.7,
      "dewF": 138.9
    },
    {
      "psig": 340,
      "bubbleF": 135.1,
      "dewF": 141.1
    },
    {
      "psig": 350,
      "bubbleF": 137.4,
      "dewF": 143.3
    },
    {
      "psig": 360,
      "bubbleF": 139.6,
      "dewF": 145.4
    },
    {
      "psig": 370,
      "bubbleF": 141.8,
      "dewF": 147.5
    },
    {
      "psig": 380,
      "bubbleF": 143.9,
      "dewF": 149.5
    },
    {
      "psig": 390,
      "bubbleF": 146.1,
      "dewF": 151.5
    },
    {
      "psig": 400,
      "bubbleF": 148.1,
      "dewF": 153.4
    }
  ],
  "primaryDatasheet": {
    "manufacturer": "Chemours",
    "tradeName": "Freon MO99",
    "publicationDate": "2009-09",
    "url": "https://www.chemours.com/en/brands-and-products/freon-refrigerants/freon-mo99",
    "resolution": "native pressure-indexed, irregular steps"
  },
  "dataSource": {
    "ptChartSource": "DuPont ISCEON® MO99™ (R-438A) Pressure-Temperature Chart, Publication K-22220-1 (September 2009). Same table reproduced as Appendix B of the Chemours Freon™ MO99 Refrigerant Retrofit Guidelines, Publication C-10862 (August 2016).",
    "ptChartGeneratedAt": "2026-07-14T13:42:31.547Z",
    "ptChartVerifiedAgainst": [
      "Chemours Freon MO99 Retrofit Guidelines C-10862 (Aug 2016)",
      "DuPont ISCEON MO99 PT Chart K-22220-1 (Sep 2009)"
    ],
    "propertiesSource": "Chemours Freon MO99 Retrofit Guidelines Table 2 (REFPROP 9.0) + ASHRAE Standard 34-2022",
    "gwpSource": "IPCC AR5 Table 8.A.1 (composition-weighted)",
    "dataStatus": "manufacturer-datasheet",
    "primarySources": [
      {
        "type": "manufacturer-datasheet",
        "citation": "DuPont Fluorochemicals, ISCEON® MO99™ (R-438A) Pressure-Temperature Chart, Publication K-22220-1, September 2009. The MO99 brand transferred to Chemours in 2015 and is now marketed as Freon™ MO99; the 2009 PT chart remains the authoritative published data source.",
        "url": "https://www.chemours.com/en/brands-and-products/freon-refrigerants/freon-mo99",
        "scope": "Pressure-indexed table with saturated R-22 temperature column and R-438A bubble/dew columns for direct comparison. Range: -6 to 400 psig."
      },
      {
        "type": "manufacturer-retrofit-guidelines",
        "citation": "The Chemours Company FC, LLC, Freon™ MO99 Refrigerant (R-438A) Retrofit Guidelines, Publication C-10862, August 2016.",
        "url": "https://www.chemours.com/en/brands-and-products/freon-refrigerants/freon-mo99",
        "scope": "Composition (Table 3: 8.5/45/44.2/1.7/0.6 R-32/R-125/R-134a/R-600/R-601a), physical properties (Table 2, computed with REFPROP 9.0), retrofit procedure, and PT chart reproduced as Appendix B."
      }
    ]
  }
}