R-404A PT Chart
A1 GWP 3922Zeotropic blend (R-125/R-143a/R-134a). HFC Blend.
Phase-down (high GWP)
About R-404A
R-404A has been the workhorse of US commercial refrigeration, including walk-in freezers, reach-ins, ice machines and supermarket racks. Its GWP of 3922 puts it at the top of the EPA's phase-down list, and new systems are moving to R-448A, R-449A, R-454C, CO₂ and propane. Its glide is only about 1°F, so the liquid and vapor columns are nearly identical.
Saturation pressures at typical operating points, taken from the table below:
- Freezer evaporator (−20°F): 16.8 PSIG liquid / 16.0 PSIG vapor
- Medium-temp evaporator (20°F): 56.6 PSIG liquid / 55.3 PSIG vapor
- Condensing (105°F): 254.2 PSIG liquid / 252.1 PSIG vapor
The table covers -80°F to 155°F in 5°F steps. Below about -51°F the liquid saturation pressure is below atmospheric, so gauges read in vacuum (shown in blue in the table).
R-404A Pressure-Temperature Graph (Bubble & Dew)
R-404A Saturation Pressure Table
R-404A is a zeotropic blend with temperature glide, so it has two saturation pressures at each temperature. Use Vapor (dew) PSIG to find evaporator saturation for superheat, and Liquid (bubble) PSIG to find condenser saturation for subcooling. PSIA, kPa and bar columns are liquid (bubble) pressures. Blue values indicate vacuum.
| °F | °C | Liquid PSIG (bubble) |
Vapor PSIG (dew) |
PSIA | kPa | bar |
|---|---|---|---|---|---|---|
| -80 | -62.2 | -8.3 | -8.6 | 6.37 | 43.9 | 0.439 |
| -75 | -59.4 | -7.3 | -7.6 | 7.44 | 51.3 | 0.513 |
| -70 | -56.7 | -6.0 | -6.4 | 8.66 | 59.7 | 0.597 |
| -65 | -53.9 | -4.7 | -5.1 | 10.02 | 69.1 | 0.691 |
| -60 | -51.1 | -3.1 | -3.6 | 11.56 | 79.7 | 0.797 |
| -55 | -48.3 | -1.4 | -1.9 | 13.27 | 91.5 | 0.915 |
| -50 | -45.6 | 0.5 | -0.1 | 15.17 | 104.6 | 1.046 |
| -45 | -42.8 | 2.6 | 2.0 | 17.28 | 119.2 | 1.192 |
| -40 | -40.0 | 4.9 | 4.3 | 19.62 | 135.3 | 1.353 |
| -35 | -37.2 | 7.5 | 6.8 | 22.2 | 153.1 | 1.531 |
| -30 | -34.4 | 10.3 | 9.6 | 25.03 | 172.6 | 1.726 |
| -25 | -31.7 | 13.4 | 12.7 | 28.14 | 194.0 | 1.94 |
| -20 | -28.9 | 16.8 | 16.0 | 31.53 | 217.4 | 2.174 |
| -15 | -26.1 | 20.5 | 19.7 | 35.23 | 242.9 | 2.429 |
| -10 | -23.3 | 24.6 | 23.6 | 39.26 | 270.7 | 2.707 |
| -5 | -20.6 | 28.9 | 27.9 | 43.63 | 300.8 | 3.008 |
| 0 | -17.8 | 33.7 | 32.6 | 48.36 | 333.4 | 3.334 |
| 5 | -15.0 | 38.8 | 37.7 | 53.47 | 368.6 | 3.686 |
| 10 | -12.2 | 44.3 | 43.1 | 58.98 | 406.6 | 4.066 |
| 15 | -9.4 | 50.2 | 49.0 | 64.91 | 447.5 | 4.475 |
| 20 | -6.7 | 56.6 | 55.3 | 71.28 | 491.5 | 4.915 |
| 25 | -3.9 | 63.4 | 62.1 | 78.12 | 538.6 | 5.386 |
| 30 | -1.1 | 70.7 | 69.3 | 85.43 | 589.0 | 5.89 |
| 35 | 1.7 | 78.6 | 77.1 | 93.25 | 643.0 | 6.43 |
| 40 | 4.4 | 86.9 | 85.4 | 101.6 | 700.5 | 7.005 |
| 45 | 7.2 | 95.8 | 94.2 | 110.49 | 761.8 | 7.618 |
| 50 | 10.0 | 105.3 | 103.6 | 119.96 | 827.1 | 8.271 |
| 55 | 12.8 | 115.3 | 113.6 | 130.02 | 896.4 | 8.964 |
| 60 | 15.6 | 126.0 | 124.2 | 140.7 | 970.1 | 9.701 |
| 65 | 18.3 | 137.3 | 135.5 | 152.02 | 1048.1 | 10.481 |
| 70 | 21.1 | 149.3 | 147.4 | 164.01 | 1130.8 | 11.308 |
| 75 | 23.9 | 162.0 | 160.1 | 176.69 | 1218.2 | 12.182 |
| 80 | 26.7 | 175.4 | 173.4 | 190.09 | 1310.6 | 13.106 |
| 85 | 29.4 | 189.5 | 187.5 | 204.24 | 1408.2 | 14.082 |
| 90 | 32.2 | 204.5 | 202.4 | 219.17 | 1511.1 | 15.111 |
| 95 | 35.0 | 220.2 | 218.1 | 234.9 | 1619.6 | 16.196 |
| 100 | 37.8 | 236.8 | 234.7 | 251.47 | 1733.8 | 17.338 |
| 105 | 40.6 | 254.2 | 252.1 | 268.91 | 1854.1 | 18.541 |
| 110 | 43.3 | 272.6 | 270.4 | 287.25 | 1980.5 | 19.805 |
| 115 | 46.1 | 291.8 | 289.7 | 306.53 | 2113.4 | 21.134 |
| 120 | 48.9 | 312.1 | 309.9 | 326.78 | 2253.1 | 22.531 |
| 125 | 51.7 | 333.4 | 331.2 | 348.05 | 2399.7 | 23.997 |
| 130 | 54.4 | 355.7 | 353.6 | 370.38 | 2553.7 | 25.537 |
| 135 | 57.2 | 379.1 | 377.0 | 393.82 | 2715.3 | 27.153 |
| 140 | 60.0 | 403.7 | 401.7 | 418.43 | 2885.0 | 28.85 |
| 145 | 62.8 | 429.6 | 427.7 | 444.29 | 3063.2 | 30.632 |
| 150 | 65.6 | 456.8 | 455.0 | 471.47 | 3250.7 | 32.507 |
| 155 | 68.3 | 485.4 | — | 500.11 | 3448.2 | 34.482 |
Properties
| ASHRAE Designation | 404A |
| Safety Classification | A1 (non-flammable, low toxicity) |
| GWP (AR4, 100-yr) | 3922 |
| ODP | 0 |
| Molecular Weight | 97.6 g/mol |
| Boiling Point (1 atm) | -51.2°F / -46.2°C |
| Critical Temperature | 161.8°F / 72.1°C |
| Critical Pressure | 541.7 psia / 37.35 bar |
| Category | HFC Blend |
Common Applications
- Commercial refrigeration
- Transport refrigeration
- Cold storage
Frequently Asked Questions
What pressure should R-404A be at 70°F?
At 70°F, R-404A has a saturation pressure of 149.3 PSIG (164.0 PSIA). Typical R-404A suction pressure at −20°F (freezer evaporator) is about 16.8 PSIG, and at 0°F is about 33.7 PSIG.
What is replacing R-404A in commercial refrigeration?
R-449A (Opteon XP40) is the primary low-GWP replacement for R-404A and R-507A. At 70°F, R-449A has a nearly identical pressure (151.0 vs 149.3 PSIG). GWP drops from 3922 to 1397 — a 64% reduction.
Is R-404A still available?
R-404A is still available in the US for servicing existing equipment, but faces HFC phasedown under the EPA AIM Act due to its high GWP (3922). Most new commercial refrigeration equipment now uses R-449A, R-448A, or natural refrigerants.