R-134a (HFC)
R-134a PT Chart
The full R-134a pressure-temperature reference table, from -15 to 120°F. R-134a is a pure single-component refrigerant, so the chart is one saturation column with zero glide. Reference data from NIST REFPROP 9.0 (Arkema Forane, iGas), cross-checked against CoolProp.
R-134a Pressure-Temperature Table
| Pressure (psig) | Sat. Temp (°F) |
|---|---|
| 0 | -15°F |
| 2 | -10°F |
| 4 | -5°F |
| 7 | 0°F |
| 9 | 5°F |
| 12 | 10°F |
| 15 | 15°F |
| 18 | 20°F |
| 22 | 25°F |
| 26 | 30°F |
| 30 | 35°F |
| 35 | 40°F |
| 40 | 45°F |
| 45 | 50°F |
| 51 | 55°F |
| 57 | 60°F |
| 64 | 65°F |
| 71 | 70°F |
| 79 | 75°F |
| 87 | 80°F |
| 95 | 85°F |
| 104 | 90°F |
| 114 | 95°F |
| 124 | 100°F |
| 135 | 105°F |
| 146 | 110°F |
| 158 | 115°F |
| 171 | 120°F |
Read the low-side (suction) pressure and find its saturation temperature for superheat, and read the high-side (liquid) pressure and its saturation temperature for subcooling. The chart is in psig (gauge) and °F. To convert: kPa gauge = psig × 6.895; °C = (°F − 32) / 1.8.
R-134a PT Chart FAQs
What is the R-134a pressure at 40F and 100F?
On the R-134a PT chart, 40F saturation is about 35 psig and 100F is about 124 psig; 80F is about 87 psig. R-134a is a single-component refrigerant with zero glide, so the same saturation temperature serves both superheat (suction) and subcooling (liquid); there is no bubble and dew split.
Why does the R-134a chart go into a vacuum at low temperatures?
R-134a boils at about -15F at atmospheric pressure, so below roughly -15F its saturation pressure is a vacuum (inches of mercury) rather than a positive gauge pressure. This chart starts at the crossover near 0 psig and runs up in psig; medium-temp refrigeration and automotive AC operate above that point, so the positive-pressure table is what you use in the field.
Where is R-134a used?
R-134a is a medium-temperature refrigerant used in household and commercial refrigeration, water chillers, and older automotive air conditioning (newer vehicles use R-1234yf). It is being phased down under the AIM Act, so many new applications are moving to lower-GWP alternatives, but the large installed base keeps R-134a in active service.
What units is this R-134a PT chart in, and how do I convert to kPa or Celsius?
The table is in psig (gauge pressure) and degrees Fahrenheit, the field-standard units in North America. To convert pressure to kPa (gauge), multiply psig by 6.895. To convert temperature to Celsius, use C = (F - 32) / 1.8.
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