R600a (Isobutane) pressure temperature chart (PT)
An R600a pressure temperature chart (PT chart) is a saturation lookup for isobutane (R600a): it relates temperature and saturation pressure when liquid and vapor coexist in equilibrium. This is useful for thermodynamic interpretation, but it is not a universal “normal running pressure” diagnostic chart.
Pressure basis: absolute vs gauge
The table below uses absolute pressure (kPa(a), bar(a), psi(a)). Many gauges display gauge pressure (relative to ambient). Converting requires local atmospheric pressure:
Learn more: Gauge vs absolute pressure (psig vs psia).
Safety note
Isobutane (R600a) is a hydrocarbon refrigerant and is flammable. This page is educational and provides property reference data only — always follow applicable codes, OEM procedures, and local safety requirements.
R600a saturation pressure vs temperature (reference table)
Generated using CoolProp (the same property engine used by FluidTool) at Q=0 saturation. Values are rounded for readability.
| T (°C) | T (°F) | Psat (kPa(a)) | Psat (bar(a)) | Psat (psi(a)) |
|---|---|---|---|---|
| -20 | -4 | 72.5 | 0.725 | 10.5 |
| -10 | 14 | 108.5 | 1.085 | 15.7 |
| 0 | 32 | 157.0 | 1.570 | 22.8 |
| 10 | 50 | 220.6 | 2.206 | 32.0 |
| 20 | 68 | 302.2 | 3.022 | 43.8 |
| 30 | 86 | 404.7 | 4.047 | 58.7 |
| 40 | 104 | 531.2 | 5.312 | 77.0 |
| 50 | 122 | 684.9 | 6.849 | 99.3 |
| 60 | 140 | 869.2 | 8.692 | 126.1 |
| 70 | 158 | 1087.5 | 10.875 | 157.7 |
How to verify any row in FluidTool
- Open FluidTool with isobutane selected: /?fluid=IsoButane
- Choose a Two-phase input pair (Temperature & Quality / T + Q).
- Set Q=0 and enter the temperature from the table to read Psat.
Related
- Isobutane (R600a) data sheet: identifiers and thermodynamic context.
- Refrigerant PT chart: what Tsat(P)/Psat(T) means and common pitfalls.
- Superheat & Subcooling: interpret measured line temperature vs saturation temperature.