R-13
Pure CFC, chlorotrifluoromethane (CClF₃). Normal boiling point -114°F — one of the lowest of any commercial refrigerant. Critical temperature only 83.7°F, so the PT chart is limited to ultra-low-temperature operating ranges. Used as cascade low-stage refrigerant for environmental test chambers and cryogenic systems. Production banned in 1996; ODP 1.0, GWP 14,400.
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 R13. Operating pressure on a running system differs — see the operating-pressure references for in-use values.
R-13 PT chart PDF — printable saturation table
Looking for the R-13 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-13 PT Chart — Pressure-Temperature Saturation Table
1° increments · Source: CoolProp 7.2.0 / manufacturer datasheet · hvacptcharts.com
| Temp (°F) | Pressure (PSIG) |
|---|---|
| -40°FIndustrial LT evap | 72.7 |
| -39°F | 74.4 |
| -38°F | 76.2 |
| -37°F | 77.9 |
| -36°F | 79.7 |
| -35°F | 81.5 |
| -34°F | 83.3 |
| -33°F | 85.2 |
| -32°F | 87.1 |
| -31°F | 89.0 |
| -30°F | 90.9 |
| -29°F | 92.8 |
| -28°F | 94.8 |
| -27°F | 96.8 |
| -26°F | 98.9 |
| -25°F | 100.9 |
| -24°F | 103.0 |
| -23°F | 105.2 |
| -22°F | 107.3 |
| -21°F | 109.5 |
| -20°F | 111.7 |
| -19°F | 113.9 |
| -18°F | 116.2 |
| -17°F | 118.5 |
| -16°F | 120.8 |
| -15°F | 123.1 |
| -14°F | 125.5 |
| -13°F | 127.9 |
| -12°F | 130.3 |
| -11°F | 132.8 |
| -10°F | 135.3 |
| -9°F | 137.8 |
| -8°F | 140.4 |
| -7°F | 143.0 |
| -6°F | 145.6 |
| -5°F | 148.3 |
| -4°F | 151.0 |
| -3°F | 153.7 |
| -2°F | 156.4 |
| -1°F | 159.2 |
| 0°FIndustrial MT evap | 162.0 |
| 1°F | 164.9 |
| 2°F | 167.8 |
| 3°F | 170.7 |
| 4°F | 173.6 |
| 5°F | 176.6 |
| 6°F | 179.7 |
| 7°F | 182.7 |
| 8°F | 185.8 |
| 9°F | 188.9 |
| 10°F | 192.1 |
| 11°F | 195.3 |
| 12°F | 198.5 |
| 13°F | 201.8 |
| 14°F | 205.1 |
| 15°F | 208.4 |
| 16°F | 211.8 |
| 17°F | 215.2 |
| 18°F | 218.7 |
| 19°F | 222.2 |
| 20°F | 225.7 |
| 21°F | 229.3 |
| 22°F | 232.9 |
| 23°F | 236.5 |
| 24°F | 240.2 |
| 25°F | 243.9 |
| 26°F | 247.7 |
| 27°F | 251.5 |
| 28°F | 255.4 |
| 29°F | 259.3 |
| 30°F | 263.2 |
| 31°F | 267.2 |
| 32°FH₂O freeze | 271.2 |
| 33°F | 275.2 |
| 34°F | 279.3 |
| 35°F | 283.5 |
| 36°F | 287.7 |
| 37°F | 291.9 |
| 38°F | 296.1 |
| 39°F | 300.5 |
| 40°F | 304.8 |
| 41°F | 309.2 |
| 42°F | 313.7 |
| 43°F | 318.2 |
| 44°F | 322.7 |
| 45°F | 327.3 |
| 46°F | 331.9 |
| 47°F | 336.6 |
| 48°F | 341.4 |
| 49°F | 346.1 |
| 50°F | 351.0 |
| 51°F | 355.9 |
| 52°F | 360.8 |
| 53°F | 365.8 |
| 54°F | 370.8 |
| 55°F | 375.9 |
| 56°F | 381.0 |
| 57°F | 386.2 |
| 58°F | 391.4 |
| 59°F | 396.7 |
| 60°F | 402.1 |
| 61°F | 407.4 |
| 62°F | 412.9 |
| 63°F | 418.4 |
| 64°F | 424.0 |
| 65°F | 429.6 |
| 66°F | 435.3 |
| 67°F | 441.0 |
| 68°F | 446.8 |
| 69°F | 452.7 |
| 70°F | 458.6 |
| 71°F | 464.6 |
| 72°F | 470.6 |
| 73°F | 476.7 |
| 74°F | 482.9 |
| 75°F | 489.2 |
| 76°F | 495.5 |
| 77°F | 501.9 |
| 78°F | 508.3 |
| 79°F | 514.8 |
| 80°F | 521.5 |
| 81°F | 528.1 |
| 82°F | 534.9 |
| 83°F | 541.8 |
| Temp (°C) | Pressure (kPa) |
|---|---|
| -40°CIndustrial LT evap | 502 |
| -39°C | 523 |
| -38°C | 545 |
| -37°C | 567 |
| -36°C | 590 |
| -35°C | 613 |
| -34°C | 638 |
| -33°C | 662 |
| -32°C | 687 |
| -31°C | 713 |
| -30°C | 740 |
| -29°C | 767 |
| -28°C | 795 |
| -27°C | 823 |
| -26°C | 852 |
| -25°C | 882 |
| -24°C | 912 |
| -23°C | 943 |
| -22°C | 975 |
| -21°C | 1,008 |
| -20°C | 1,041 |
| -19°C | 1,075 |
| -18°CIndustrial MT evap | 1,109 |
| -17°C | 1,145 |
| -16°C | 1,181 |
| -15°C | 1,218 |
| -14°C | 1,255 |
| -13°C | 1,294 |
| -12°C | 1,333 |
| -11°C | 1,373 |
| -10°C | 1,414 |
| -9°C | 1,456 |
| -8°C | 1,498 |
| -7°C | 1,542 |
| -6°C | 1,586 |
| -5°C | 1,631 |
| -4°C | 1,677 |
| -3°C | 1,724 |
| -2°C | 1,771 |
| -1°C | 1,820 |
| 0°CH₂O freeze | 1,870 |
| 1°C | 1,920 |
| 2°C | 1,972 |
| 3°C | 2,024 |
| 4°C | 2,078 |
| 5°C | 2,132 |
| 6°C | 2,188 |
| 7°C | 2,244 |
| 8°C | 2,302 |
| 9°C | 2,360 |
| 10°C | 2,420 |
| 11°C | 2,481 |
| 12°C | 2,543 |
| 13°C | 2,606 |
| 14°C | 2,670 |
| 15°C | 2,735 |
| 16°C | 2,802 |
| 17°C | 2,870 |
| 18°C | 2,939 |
| 19°C | 3,009 |
| 20°C | 3,081 |
| 21°C | 3,154 |
| 22°C | 3,228 |
| 23°C | 3,304 |
| 24°C | 3,381 |
| 25°C | 3,460 |
| 26°C | 3,541 |
| 27°C | 3,623 |
| 28°C | 3,707 |
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-13 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
Ultra-low temperature refrigerant (NBP -81.4°C). Used historically as the low-stage refrigerant in cascade systems for environmental test chambers and cryogenic applications. Critical point at 28.8°C (83.9°F) — chart is partial.
Trade names
- Freon 13Chemours (historical: DuPont)
Common applications
- Cascade low-stage refrigerant (legacy)
- Environmental test chambers (low-temperature)
- Cryogenic applications (legacy)
Properties
- Boiling point (1 atm)-81.4°C / -114.5°F
- Critical point83.7°F at 548 PSIG
- Molar mass104.46 g/mol
- Temperature glideNegligible (0.00°F)
- ODP1
- GWP (AR5, 100-yr)14400
- GWP (AR6, 100-yr)16200
- Atmospheric lifetime640 years
What is R-13?
R-13 is pure chlorotrifluoromethane (CClF₃), a single-molecule CFC. Its remarkable property is the very low normal boiling point — -114°F (-81°C) — which made it the workhorse low-stage refrigerant in cascade systems designed to reach evaporator temperatures of -100°F to -200°F. Single-stage refrigeration with conventional refrigerants can't reach those temperatures because the pressure ratio across the compressor becomes unmanageable; cascade systems with R-13 as the low-stage and R-22 or R-502 as the high-stage solve that.
The critical temperature is only 28.8°C (83.7°F) — meaning at any ambient temperature above ~84°F, R-13 cannot condense at any pressure. This is why R-13 was always the low-stage refrigerant — its condenser was internal to the cascade system, exchanging heat with the high-stage refrigerant at temperatures well below ambient (typically condensing at -20°F to 0°F).
R-13 is a CFC — ODP 1.0 (reference value, equivalent to R-11). Banned for production in the US on January 1, 1996 under the Montreal Protocol.
Where R-13 is used
- Cascade low-stage refrigerant for environmental test chambers (-100°F to -200°F operating range) — legacy equipment only
- Cryogenic refrigeration for medical, scientific, and industrial cooling (legacy)
- Aerospace component testing chambers (legacy)
- No new equipment since 1996; reclaimed R-13 supports any remaining systems
Regulatory & phase-down status
R-13 production has been banned for almost three decades. Atmospheric lifetime of 640 years means molecules released even decades ago continue to deplete ozone — R-13 was a particularly damaging CFC because of its very long lifetime combined with full chlorine reactivity in the stratosphere.
For remaining cascade low-temperature equipment, R-23 (HFC, GWP 14,800 still high but lower than R-13) is the modern replacement low-stage refrigerant. Newer systems use R-744 (CO₂, GWP 1) in cascade — CO₂ has a high triple-point pressure that complicates ultra-low-temp use but works well for the -40°F to -100°F range many cascade systems target. Autocascade systems with mixed-refrigerant blends are another modern approach.
Service notes
Mineral oil (MO) is compatible. POE is not. EPA Section 608 Type II certification covers R-13. Recovery is required; venting was illegal under Clean Air Act §608 from 1990.
R-13's combination of low critical temperature and very low boiling point makes service work distinct from typical HVAC: the high side of the cascade may operate at moderate pressures while the low side reaches deep into negative °F territory. Equipment design accommodates this; field service requires understanding the cascade architecture.
Operating cycle
R-13 is used in: Cascade low-stage refrigerant (legacy), Environmental test chambers (low-temperature), Cryogenic applications (legacy) — applications with much lower condensing temperatures than residential AC.
Phase-down timeline
Global warming potential, in context
Industrial refrigeration & cascade systems
Retrofit and replacement paths
Replacements for R-13
Frequently asked
›Why was R-13 used in cascade systems instead of just a single-stage refrigerant?
No single-stage refrigerant can practically reach -100°F to -200°F evaporator temperatures. The pressure ratio across the compressor becomes excessive (typically >10:1 limits compressor efficiency and reliability), and at very low temperatures the suction pressure approaches vacuum, which complicates leak-tightness and lubrication. A cascade system uses two separate refrigeration loops: a high-stage loop with a conventional refrigerant (R-22, R-404A historically) that condenses against ambient, and a low-stage loop with an ultra-low-temperature refrigerant (R-13, R-23, R-503) that condenses against the cold side of the high-stage evaporator. The two loops are coupled thermally but not refrigerant-wise. R-13's low boiling point made it ideal for the low-stage role.
›What's an environmental test chamber?
A controlled-temperature enclosure used for testing electronic components, aerospace materials, and biomedical samples at extreme temperatures. Common test ranges: -100°F to +250°F for aerospace component qualification, -40°F to +185°F for automotive electronics, -150°F to +200°F for some biomedical work. The cold side of these chambers historically used R-13 cascade systems; modern designs use R-23 cascades, autocascade with HFC blends, or mechanical cryocoolers.
›Why is R-13's critical temperature so low?
Small molecular size and high vapor pressure. The chlorotrifluoromethane molecule is small (4 atoms) and the molecular interactions in the liquid phase are weak — the critical point (where liquid and vapor phases become indistinguishable) occurs at relatively low temperature. This is a general pattern for small, highly-fluorinated molecules: R-744 (CO₂) has critical temperature 88°F; R-23 has 78°F; R-13 has 84°F; R-14 (tetrafluoromethane) has -49°F. Low critical temperatures make these refrigerants unsuitable for air-cooled condensing at normal ambient.
›What replaced R-13 in cascade low-stage applications?
R-23 (HFC-23, trifluoromethane, CHF₃) was the immediate replacement when CFCs were phased out in the 1990s. R-23 has similar physical properties to R-13 (NBP -116°F, Tcrit 78.6°F) but is HFC rather than CFC — zero ODP, though still high GWP (14,800). For modern low-GWP cascade systems, R-744 (CO₂) is increasingly used as the low-stage refrigerant despite its higher triple-point pressure complicating very-low-temperature operation. Autocascade systems with mixed refrigerants are another modern approach.
›What is the ODP and GWP of R-13?
ODP 1.0 (the reference value, same as R-11). GWP 14,400 per IPCC AR5. Atmospheric lifetime 640 years — among the longest of any commercial refrigerant. R-13 was a worst-case CFC for environmental damage: high ODP, very high GWP, extremely persistent.