PT chart · ASHRAE A3
R-600a PT Chart
R-600a pressure–temperature chart in psig and °F/°C. Isobutane: household refrigerators and freezers. It is an A3 (highly flammable) refrigerant: only for equipment designed for it, with A3 handling rules.
Vacuum readings are shown in inches of mercury (″ Hg) below atmospheric pressure.
| °F | °C | Pressure, psig |
|---|---|---|
| -50 | -45.6 | 23.6″ Hg |
| -45 | -42.8 | 22.6″ Hg |
| -40 | -40.0 | 21.4″ Hg |
| -35 | -37.2 | 20.2″ Hg |
| -30 | -34.4 | 18.8″ Hg |
| -25 | -31.7 | 17.2″ Hg |
| -20 | -28.9 | 15.4″ Hg |
| -15 | -26.1 | 13.5″ Hg |
| -10 | -23.3 | 11.4″ Hg |
| -5 | -20.6 | 9.0″ Hg |
| 0 | -17.8 | 6.4″ Hg |
| 5 | -15.0 | 3.6″ Hg |
| 10 | -12.2 | 0.5″ Hg |
| 15 | -9.4 | 1.4 |
| 20 | -6.7 | 3.2 |
| 25 | -3.9 | 5.1 |
| 30 | -1.1 | 7.2 |
| 35 | 1.7 | 9.4 |
| 40 | 4.4 | 11.9 |
| 45 | 7.2 | 14.5 |
| 50 | 10.0 | 17.3 |
| 55 | 12.8 | 20.3 |
| 60 | 15.6 | 23.5 |
| 65 | 18.3 | 27.0 |
| 70 | 21.1 | 30.6 |
| 75 | 23.9 | 34.5 |
| 80 | 26.7 | 38.7 |
| 85 | 29.4 | 43.1 |
| 90 | 32.2 | 47.8 |
| 95 | 35.0 | 52.7 |
| 100 | 37.8 | 57.9 |
| 105 | 40.6 | 63.5 |
| 110 | 43.3 | 69.3 |
| 115 | 46.1 | 75.5 |
| 120 | 48.9 | 82.0 |
| 125 | 51.7 | 88.8 |
| 130 | 54.4 | 95.9 |
| 135 | 57.2 | 103.5 |
| 140 | 60.0 | 111.4 |
| 145 | 62.8 | 119.6 |
| 150 | 65.6 | 128.3 |
Source: NIST Chemistry WebBook, SRD 69, saturation properties. Converted from absolute pressure (psia) to psig. Reference only; verify against the equipment manufacturer's data.
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