R-500
Historical azeotropic blend of R-12 (CFC) and R-152a (HFC), 73.8/26.2 by mass. ASHRAE A1, ODP 0.605, GWP 8077. Production banned in 1996 under the Montreal Protocol. Found in legacy centrifugal chillers and 60 Hz hermetic compressor applications.
Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.
- Flammability
- None (no flame propagation)
- Toxicity
- Lower (OEL ≥ 400 ppm)
Classification per ANSI/ASHRAE Standard 34-2022. See full reference.
Saturation pressure-temperature curve
Saturation values from CoolProp 7.2.0 R500.mix. Operating pressure on a running system differs — see the operating-pressure references for in-use values.
R-500 PT chart PDF — printable saturation table
Looking for the R-500 PT chart PDF for shop reference? The complete pressure-temperature saturation table is below — every 1° increment from −40°F to 150°F (or to the refrigerant's critical temperature). Use the Print / Save as PDF button in the table header to download a clean, table-only PDF (the rest of the page is hidden from the print output). Important service temperatures (normal boiling point, freezing point of water, residential AC evap and condenser targets) are tinted and tagged in the table for at-a-glance shop reference.
R-500 PT Chart — Pressure-Temperature Saturation Table
1° increments · Source: CoolProp 7.2.0 / manufacturer datasheet · hvacptcharts.com
| Temp (°F) | Pressure (PSIG) |
|---|---|
| -40°F | -3.5 |
| -39°F | -3.2 |
| -38°F | -2.9 |
| -37°F | -2.6 |
| -36°F | -2.3 |
| -35°F | -2.0 |
| -34°F | -1.7 |
| -33°F | -1.3 |
| -32°F | -1.0 |
| -31°F | -0.7 |
| -30°F | -0.3 |
| -29°FNBP (atmospheric) | 0.1 |
| -28°F | 0.4 |
| -27°F | 0.8 |
| -26°F | 1.2 |
| -25°F | 1.6 |
| -24°F | 1.9 |
| -23°F | 2.3 |
| -22°F | 2.8 |
| -21°F | 3.2 |
| -20°F | 3.6 |
| -19°F | 4.0 |
| -18°F | 4.5 |
| -17°F | 4.9 |
| -16°F | 5.4 |
| -15°F | 5.8 |
| -14°F | 6.3 |
| -13°F | 6.8 |
| -12°F | 7.3 |
| -11°F | 7.8 |
| -10°F | 8.3 |
| -9°F | 8.8 |
| -8°F | 9.3 |
| -7°F | 9.8 |
| -6°F | 10.4 |
| -5°F | 10.9 |
| -4°F | 11.5 |
| -3°F | 12.1 |
| -2°F | 12.6 |
| -1°F | 13.2 |
| 0°F | 13.8 |
| 1°F | 14.4 |
| 2°F | 15.1 |
| 3°F | 15.7 |
| 4°F | 16.3 |
| 5°F | 17.0 |
| 6°F | 17.6 |
| 7°F | 18.3 |
| 8°F | 19.0 |
| 9°F | 19.7 |
| 10°F | 20.4 |
| 11°F | 21.1 |
| 12°F | 21.8 |
| 13°F | 22.5 |
| 14°F | 23.3 |
| 15°F | 24.0 |
| 16°F | 24.8 |
| 17°F | 25.6 |
| 18°F | 26.4 |
| 19°F | 27.2 |
| 20°F | 28.0 |
| 21°F | 28.8 |
| 22°F | 29.7 |
| 23°F | 30.5 |
| 24°F | 31.4 |
| 25°F | 32.3 |
| 26°F | 33.1 |
| 27°F | 34.0 |
| 28°F | 35.0 |
| 29°F | 35.9 |
| 30°F | 36.8 |
| 31°F | 37.8 |
| 32°FH₂O freeze | 38.8 |
| 33°F | 39.7 |
| 34°F | 40.7 |
| 35°F | 41.7 |
| 36°F | 42.8 |
| 37°F | 43.8 |
| 38°F | 44.8 |
| 39°F | 45.9 |
| 40°F | 47.0 |
| 41°F | 48.1 |
| 42°F | 49.2 |
| 43°F | 50.3 |
| 44°F | 51.4 |
| 45°F | 52.6 |
| 46°F | 53.8 |
| 47°F | 54.9 |
| 48°F | 56.1 |
| 49°F | 57.4 |
| 50°F | 58.6 |
| 51°F | 59.8 |
| 52°F | 61.1 |
| 53°F | 62.4 |
| 54°F | 63.6 |
| 55°F | 65.0 |
| 56°F | 66.3 |
| 57°F | 67.6 |
| 58°F | 69.0 |
| 59°F | 70.3 |
| 60°F | 71.7 |
| 61°F | 73.1 |
| 62°F | 74.6 |
| 63°F | 76.0 |
| 64°F | 77.5 |
| 65°F | 79.0 |
| 66°F | 80.4 |
| 67°F | 82.0 |
| 68°F | 83.5 |
| 69°F | 85.0 |
| 70°F | 86.6 |
| 71°F | 88.2 |
| 72°F | 89.8 |
| 73°F | 91.4 |
| 74°F | 93.0 |
| 75°F | 94.7 |
| 76°F | 96.4 |
| 77°F | 98.1 |
| 78°F | 99.8 |
| 79°F | 101.5 |
| 80°F | 103.3 |
| 81°F | 105.0 |
| 82°F | 106.8 |
| 83°F | 108.7 |
| 84°F | 110.5 |
| 85°F | 112.3 |
| 86°F | 114.2 |
| 87°F | 116.1 |
| 88°F | 118.0 |
| 89°F | 120.0 |
| 90°F | 121.9 |
| 91°F | 123.9 |
| 92°F | 125.9 |
| 93°F | 127.9 |
| 94°F | 130.0 |
| 95°F | 132.0 |
| 96°F | 134.1 |
| 97°F | 136.2 |
| 98°F | 138.3 |
| 99°F | 140.5 |
| 100°F | 142.7 |
| 101°F | 144.9 |
| 102°F | 147.1 |
| 103°F | 149.3 |
| 104°F | 151.6 |
| 105°F | 153.9 |
| 106°F | 156.2 |
| 107°F | 158.5 |
| 108°F | 160.9 |
| 109°F | 163.3 |
| 110°F | 165.7 |
| 111°F | 168.1 |
| 112°F | 170.5 |
| 113°F | 173.0 |
| 114°F | 175.5 |
| 115°F | 178.0 |
| 116°F | 180.6 |
| 117°F | 183.2 |
| 118°F | 185.8 |
| 119°F | 188.4 |
| 120°F | 191.0 |
| 121°F | 193.7 |
| 122°F | 196.4 |
| 123°F | 199.2 |
| 124°F | 201.9 |
| 125°F | 204.7 |
| 126°F | 207.5 |
| 127°F | 210.3 |
| 128°F | 213.2 |
| 129°F | 216.1 |
| 130°F | 219.0 |
| 131°F | 221.9 |
| 132°F | 224.9 |
| 133°F | 227.9 |
| 134°F | 230.9 |
| 135°F | 234.0 |
| 136°F | 237.1 |
| 137°F | 240.2 |
| 138°F | 243.3 |
| 139°F | 246.5 |
| 140°F | 249.7 |
| 141°F | 252.9 |
| 142°F | 256.1 |
| 143°F | 259.4 |
| 144°F | 262.7 |
| 145°F | 266.1 |
| 146°F | 269.4 |
| 147°F | 272.8 |
| 148°F | 276.3 |
| 149°F | 279.7 |
| 150°F | 283.2 |
| Temp (°C) | Pressure (kPa) |
|---|---|
| -40°C | -24 |
| -39°C | -21 |
| -38°C | -17 |
| -37°C | -13 |
| -36°C | -9 |
| -35°C | -5 |
| -34°CNBP (atmospheric) | -0 |
| -33°C | 4 |
| -32°C | 9 |
| -31°C | 14 |
| -30°C | 19 |
| -29°C | 24 |
| -28°C | 30 |
| -27°C | 35 |
| -26°C | 41 |
| -25°C | 47 |
| -24°C | 53 |
| -23°C | 59 |
| -22°C | 66 |
| -21°C | 72 |
| -20°C | 79 |
| -19°C | 86 |
| -18°C | 94 |
| -17°C | 101 |
| -16°C | 109 |
| -15°C | 117 |
| -14°C | 125 |
| -13°C | 134 |
| -12°C | 142 |
| -11°C | 151 |
| -10°C | 161 |
| -9°C | 170 |
| -8°C | 180 |
| -7°C | 190 |
| -6°C | 200 |
| -5°C | 210 |
| -4°C | 221 |
| -3°C | 232 |
| -2°C | 244 |
| -1°C | 255 |
| 0°CH₂O freeze | 267 |
| 1°C | 279 |
| 2°C | 292 |
| 3°C | 305 |
| 4°C | 318 |
| 5°C | 331 |
| 6°C | 345 |
| 7°C | 359 |
| 8°C | 374 |
| 9°C | 389 |
| 10°C | 404 |
| 11°C | 419 |
| 12°C | 435 |
| 13°C | 451 |
| 14°C | 468 |
| 15°C | 485 |
| 16°C | 502 |
| 17°C | 520 |
| 18°C | 538 |
| 19°C | 557 |
| 20°C | 576 |
| 21°C | 595 |
| 22°C | 615 |
| 23°C | 635 |
| 24°C | 655 |
| 25°C | 676 |
| 26°C | 698 |
| 27°C | 719 |
| 28°C | 742 |
| 29°C | 764 |
| 30°C | 788 |
| 31°C | 811 |
| 32°C | 835 |
| 33°C | 860 |
| 34°C | 885 |
| 35°C | 910 |
| 36°C | 936 |
| 37°C | 963 |
| 38°C | 990 |
| 39°C | 1,017 |
| 40°C | 1,045 |
| 41°C | 1,074 |
| 42°C | 1,103 |
| 43°C | 1,132 |
| 44°C | 1,162 |
| 45°C | 1,193 |
| 46°C | 1,224 |
| 47°C | 1,256 |
| 48°C | 1,288 |
| 49°C | 1,321 |
| 50°C | 1,354 |
| 51°C | 1,388 |
| 52°C | 1,423 |
| 53°C | 1,458 |
| 54°C | 1,494 |
| 55°C | 1,530 |
| 56°C | 1,567 |
| 57°C | 1,605 |
| 58°C | 1,643 |
| 59°C | 1,682 |
| 60°C | 1,721 |
| 61°C | 1,762 |
| 62°C | 1,802 |
| 63°C | 1,844 |
| 64°C | 1,886 |
| 65°C | 1,929 |
Full saturation values at 1° increments — toggle between °F / PSIG and °C / kPa. Use Print / Save as PDF for laminated shop reference, or download the CSV / JSON below for use in other tools. R-500 PT chart data: CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS) or manufacturer datasheet, validated against AHRI Standard 700-2019.
At a glance
Chemistry
Lubricant compatibility
Azeotropic CFC blend with no glide. Historically used in 60 Hz markets as a higher-capacity alternative to R-12 in 50 Hz applications. Banned for production.
Blend composition
- R-1273.8%
- R-152a26.2%
Common applications
- Centrifugal chillers (legacy)
- Commercial refrigeration (legacy)
Properties
- Boiling point (1 atm)-34.0°C / -29.1°F
- Critical point214.7°F at 588 PSIG
- Molar mass99.30 g/mol
- Temperature glideNegligible (-0.05°F)
- ODP0.605
- GWP (AR5, 100-yr)8077
What is R-500?
R-500 is an azeotropic blend of R-12 (CCl₂F₂, CFC-12) and R-152a (CH₃CHF₂, HFC-152a) in 73.8/26.2 mass ratio. The R-12 component carries the ozone-depletion liability — production was banned in the United States on January 1, 1996 under the Montreal Protocol CFC phase-out. As a CFC-containing blend, R-500 was banned alongside pure R-12.
The original commercial logic for R-500: in the 1950s-1980s, US 60 Hz hermetic compressor manufacturers found that the same compressor design that worked at European 50 Hz with R-12 had insufficient capacity at 60 Hz with R-12 alone — the higher motor speed needed a refrigerant with slightly higher pressure to maintain capacity per displacement. R-500 (with the higher-vapor-pressure R-152a component) provided that capacity boost. The "50 Hz vs 60 Hz" framing is partly historical folklore — the real value was the capacity gain — but it remains in the literature.
Where R-500 is used
- Centrifugal chillers (legacy, pre-1996 installations)
- Commercial refrigeration in 60 Hz market hermetic compressors (legacy)
- Some industrial process cooling (legacy)
- No new equipment since 1996; service supply was always limited
Regulatory & phase-down status
R-500 production has been banned for almost three decades. There is essentially no remaining R-500 equipment in active service — the centrifugal chillers that used it have aged out and been replaced through normal equipment-replacement cycles. Service refrigerant (reclaimed R-500) is technically available but practically nonexistent at scale.
For any remaining R-500 equipment encountered in the field, the path is full replacement with modern equipment. Direct retrofit to R-134a or R-450a (the typical CFC chiller replacements) typically requires compressor changes, expansion device changes, and seal replacements — economically equivalent to a full replacement.
Service notes
Mineral oil (MO) and alkylbenzene (AB) are compatible. POE is NOT compatible — R-500's CFC base is incompatible with the POE chemistry used in HFC retrofits. EPA Section 608 Type II certification covers R-500 (or Universal); recovery is required and venting has been illegal under Clean Air Act §608 since 1990.
R-500 is azeotropic (glide ~0.05°F per CoolProp at 0°C) — for service purposes treat it as a single-fluid refrigerant with no special bubble/dew handling.
Operating cycle
Phase-down timeline
Global warming potential, in context
No peer-comparison group is defined for R-500. Its 100-year GWP per IPCC AR5 is 8077 — above the EPA AIM Act 700 GWP cap and well above the EU F-Gas 150 cap.
Peer-comparison groups are defined for refrigerants that compete in the same application sector (residential AC, commercial MT/LT, chillers, mobile AC). Specialty or research-grade refrigerants without a clear peer set don't appear in any group; their GWP is shown above in absolute terms instead.
Retrofit and replacement paths
Replacements for R-500
Frequently asked
›Is R-500 still legal to use?
Reclaimed R-500 (recovered from existing equipment, refined to specification, certified) is legal to use indefinitely in existing equipment under current EPA rules. New production has been banned in the US since January 1, 1996 under the Montreal Protocol CFC phase-out. In practice the reclaimed supply is extremely limited because so little equipment remains.
›Why was R-500 banned?
The R-12 component (73.8% of R-500) is a chlorofluorocarbon — CCl₂F₂. CFCs release chlorine atoms in the stratosphere that catalyze ozone destruction. The Montreal Protocol (1987, amended several times) mandated phase-out of all CFCs. The US implemented the CFC production ban on January 1, 1996. R-500 and other CFC-containing blends were banned alongside pure CFCs.
›What replaced R-500?
R-134a (HFC) was the primary replacement for R-500 and R-12 in centrifugal chillers and similar applications. R-450a (HFO/HFC blend, GWP 547) replaced R-134a in some applications as the next phase-down step. For new chillers, R-1234ze(E) (HFO, A2L, GWP 7) and R-514A (HFO blend, low GWP) are the modern choices. Direct retrofit of R-500 to R-134a or R-450a requires compressor or expansion-device changes in most cases.
›Is R-500 an azeotrope or zeotrope?
Azeotrope. R-500 has effectively zero temperature glide at typical operating pressures — bubble and dew points coincide. The 73.8/26.2 ratio of R-12/R-152a was chosen specifically to produce azeotropic behavior, making R-500 behave like a single-fluid refrigerant in terms of saturation handling. This was a feature of the original design — service techs could handle R-500 without the bubble/dew curve complexity of zeotropic blends.
›What is the GWP of R-500?
8077 per IPCC AR5, mass-weighted from R-12 (10,200) at 73.8% and R-152a (124) at 26.2%. The high GWP is dominated by R-12; if R-500 production had not been banned for ozone-depletion reasons, the GWP alone would still place it well above any modern phase-down threshold. By 2026 standards R-500 is unviable on multiple criteria (ODP, GWP) — the 1996 ban removed it from new equipment well before GWP became the constraining concern.