R455A PT Chart
Updated October 19, 2026
R-455A
Zeotropic ternary blend with CO₂ component (3% R-744 / 21.5% R-32 / 75.5% R-1234yf mass) — A2L, GWP 146, ~22°F temperature glide. Honeywell Solstice L40X / N40 family. Low-GWP commercial refrigeration alternative to R-454C.
R-455A saturation pressure splits across its glide: dew 66.9 PSIG at 40°F, bubble 260.7 PSIG at 100°F, and 121.1–170.1 PSIG dew-to-bubble at 70°F. Use the dew column for superheat and the bubble column for subcooling. The full table below runs from −40°F to 150°F in 1°F steps.
Not yet checked against an independent source.
R-455A PT chart — printable saturation table
Looking for the R-455A 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).
R-455A PT Chart — Pressure-Temperature Saturation Table
Computed with CoolProp 7.2.0 in 1°F steps · hvacptcharts.com
| Temp (°F) | Bubble (PSIG) | Dew (PSIG) |
|---|---|---|
| −40°F | 10.7 | 1.1 in. Hg vac. |
| −39°F | 11.3 | 0.4 in. Hg vac. |
| −38°F | 11.9 | 0.2 |
| −37°F | 12.5 | 0.6 |
| −36°F | 13.1 | 1.0 |
| −35°F | 13.7 | 1.4 |
| −34°F | 14.4 | 1.9 |
| −33°F | 15.1 | 2.3 |
| −32°F | 15.7 | 2.7 |
| −31°F | 16.4 | 3.2 |
| −30°F | 17.1 | 3.6 |
| −29°F | 17.8 | 4.1 |
| −28°F | 18.5 | 4.6 |
| −27°F | 19.3 | 5.1 |
| −26°F | 20.0 | 5.6 |
| −25°F | 20.8 | 6.1 |
| −24°F | 21.5 | 6.6 |
| −23°F | 22.3 | 7.1 |
| −22°F | 23.1 | 7.6 |
| −21°F | 23.9 | 8.2 |
| −20°F | 24.8 | 8.7 |
| −19°F | 25.6 | 9.3 |
| −18°F | 26.4 | 9.9 |
| −17°F | 27.3 | 10.5 |
| −16°F | 28.2 | 11.1 |
| −15°F | 29.1 | 11.7 |
| −14°F | 30.0 | 12.3 |
| −13°F | 30.9 | 12.9 |
| −12°F | 31.8 | 13.6 |
| −11°F | 32.8 | 14.2 |
| −10°F | 33.7 | 14.9 |
| −9°F | 34.7 | 15.6 |
| −8°F | 35.7 | 16.3 |
| −7°F | 36.7 | 17.0 |
| −6°F | 37.7 | 17.7 |
| −5°F | 38.7 | 18.4 |
| −4°F | 39.8 | 19.2 |
| −3°F | 40.8 | 19.9 |
| −2°F | 41.9 | 20.7 |
| −1°F | 43.0 | 21.5 |
| 0°F | 44.1 | 22.3 |
| 1°F | 45.3 | 23.1 |
| 2°F | 46.4 | 23.9 |
| 3°F | 47.6 | 24.7 |
| 4°F | 48.7 | 25.6 |
| 5°F | 49.9 | 26.5 |
| 6°F | 51.1 | 27.3 |
| 7°F | 52.4 | 28.2 |
| 8°F | 53.6 | 29.1 |
| 9°F | 54.9 | 30.1 |
| 10°F | 56.2 | 31.0 |
| 11°F | 57.4 | 31.9 |
| 12°F | 58.8 | 32.9 |
| 13°F | 60.1 | 33.9 |
| 14°F | 61.4 | 34.9 |
| 15°F | 62.8 | 35.9 |
| 16°F | 64.2 | 36.9 |
| 17°F | 65.6 | 38.0 |
| 18°F | 67.0 | 39.0 |
| 19°F | 68.5 | 40.1 |
| 20°F | 69.9 | 41.2 |
| 21°F | 71.4 | 42.3 |
| 22°F | 72.9 | 43.5 |
| 23°F | 74.4 | 44.6 |
| 24°F | 75.9 | 45.8 |
| 25°F | 77.5 | 46.9 |
| 26°F | 79.1 | 48.1 |
| 27°F | 80.7 | 49.4 |
| 28°F | 82.3 | 50.6 |
| 29°F | 83.9 | 51.8 |
| 30°F | 85.6 | 53.1 |
| 31°F | 87.2 | 54.4 |
| 32°F H₂O freeze | 88.9 | 55.7 |
| 33°F | 90.7 | 57.0 |
| 34°F | 92.4 | 58.4 |
| 35°F | 94.2 | 59.7 |
| 36°F | 95.9 | 61.1 |
| 37°F | 97.7 | 62.5 |
| 38°F | 99.6 | 63.9 |
| 39°F | 101.4 | 65.4 |
| 40°F | 103.3 | 66.9 |
| 41°F | 105.2 | 68.3 |
| 42°F | 107.1 | 69.8 |
| 43°F | 109.0 | 71.4 |
| 44°F | 110.9 | 72.9 |
| 45°F | 112.9 | 74.5 |
| 46°F | 114.9 | 76.1 |
| 47°F | 116.9 | 77.7 |
| 48°F | 119.0 | 79.3 |
| 49°F | 121.1 | 81.0 |
| 50°F | 123.1 | 82.6 |
| 51°F | 125.3 | 84.3 |
| 52°F | 127.4 | 86.1 |
| 53°F | 129.6 | 87.8 |
| 54°F | 131.7 | 89.6 |
| 55°F | 134.0 | 91.4 |
| 56°F | 136.2 | 93.2 |
| 57°F | 138.4 | 95.0 |
| 58°F | 140.7 | 96.9 |
| 59°F | 143.0 | 98.8 |
| 60°F | 145.4 | 100.7 |
| 61°F | 147.7 | 102.6 |
| 62°F | 150.1 | 104.6 |
| 63°F | 152.5 | 106.5 |
| 64°F | 154.9 | 108.5 |
| 65°F | 157.4 | 110.6 |
| 66°F | 159.9 | 112.6 |
| 67°F | 162.4 | 114.7 |
| 68°F | 164.9 | 116.8 |
| 69°F | 167.5 | 119.0 |
| 70°F | 170.1 | 121.1 |
| 71°F | 172.7 | 123.3 |
| 72°F | 175.3 | 125.5 |
| 73°F | 178.0 | 127.8 |
| 74°F | 180.7 | 130.1 |
| 75°F | 183.4 | 132.4 |
| 76°F | 186.2 | 134.7 |
| 77°F | 188.9 | 137.0 |
| 78°F | 191.7 | 139.4 |
| 79°F | 194.6 | 141.8 |
| 80°F | 197.4 | 144.3 |
| 81°F | 200.3 | 146.7 |
| 82°F | 203.2 | 149.2 |
| 83°F | 206.2 | 151.8 |
| 84°F | 209.1 | 154.3 |
| 85°F | 212.2 | 156.9 |
| 86°F | 215.2 | 159.6 |
| 87°F | 218.2 | 162.2 |
| 88°F | 221.3 | 164.9 |
| 89°F | 224.4 | 167.6 |
| 90°F | 227.6 | 170.3 |
| 91°F | 230.8 | 173.1 |
| 92°F | 234.0 | 175.9 |
| 93°F | 237.2 | 178.8 |
| 94°F | 240.5 | 181.6 |
| 95°F | 243.8 | 184.6 |
| 96°F | 247.1 | 187.5 |
| 97°F | 250.4 | 190.5 |
| 98°F | 253.8 | 193.5 |
| 99°F | 257.2 | 196.5 |
| 100°F | 260.7 | 199.6 |
| 101°F | 264.2 | 202.7 |
| 102°F | 267.7 | 205.9 |
| 103°F | 271.2 | 209.0 |
| 104°F | 274.8 | 212.3 |
| 105°F | 278.4 | 215.5 |
| 106°F | 282.0 | 218.8 |
| 107°F | 285.7 | 222.1 |
| 108°F | 289.4 | 225.5 |
| 109°F | 293.1 | 228.9 |
| 110°F | 296.9 | 232.3 |
| 111°F | 300.7 | 235.8 |
| 112°F | 304.5 | 239.3 |
| 113°F | 308.4 | 242.9 |
| 114°F | 312.3 | 246.5 |
| 115°F | 316.2 | 250.1 |
| 116°F | 320.1 | 253.8 |
| 117°F | 324.1 | 257.5 |
| 118°F | 328.2 | 261.3 |
| 119°F | 332.2 | 265.1 |
| 120°F | 336.3 | 268.9 |
| 121°F | 340.4 | 272.8 |
| 122°F | 344.6 | 276.7 |
| 123°F | 348.8 | 280.7 |
| 124°F | 353.0 | 284.7 |
| 125°F | 357.3 | 288.7 |
| 126°F | 361.6 | 292.8 |
| 127°F | 365.9 | 297.0 |
| 128°F | 370.3 | 301.2 |
| 129°F | 374.7 | 305.4 |
| 130°F | 379.1 | 309.7 |
| 131°F | 383.6 | 314.0 |
| 132°F | 388.1 | 318.4 |
| 133°F | 392.6 | 322.8 |
| 134°F | 397.2 | 327.3 |
| 135°F | 401.8 | 331.8 |
| 136°F | 406.5 | 336.4 |
| 137°F | 411.2 | 341.0 |
| 138°F | 415.9 | 345.7 |
| 139°F | 420.6 | 350.4 |
| 140°F | 425.4 | 355.2 |
| 141°F | 430.2 | 360.0 |
| 142°F | 435.1 | 364.9 |
| 143°F | 440.0 | 369.8 |
| 144°F | 444.9 | 374.8 |
| 145°F | 449.9 | 379.9 |
| 146°F | 454.9 | 385.0 |
| 147°F | 459.9 | 390.2 |
| 148°F | 465.0 | 395.4 |
| 149°F | 470.1 | 400.7 |
| 150°F | 475.2 | 406.0 |
| Temp (°C) | Bubble (kPa) | Dew (kPa) |
|---|---|---|
| −40°C | 74 | −4 |
| −39°C | 81 | 1 |
| −38°C | 89 | 6 |
| −37°C | 97 | 11 |
| −36°C | 105 | 16 |
| −35°C | 113 | 22 |
| −34°C | 122 | 28 |
| −33°C | 131 | 34 |
| −32°C | 140 | 40 |
| −31°C | 150 | 46 |
| −30°C | 159 | 53 |
| −29°C | 170 | 60 |
| −28°C | 180 | 67 |
| −27°C | 191 | 74 |
| −26°C | 202 | 81 |
| −25°C | 213 | 89 |
| −24°C | 225 | 97 |
| −23°C | 236 | 106 |
| −22°C | 249 | 114 |
| −21°C | 261 | 123 |
| −20°C | 274 | 132 |
| −19°C | 288 | 142 |
| −18°C | 301 | 151 |
| −17°C | 315 | 161 |
| −16°C | 330 | 172 |
| −15°C | 344 | 182 |
| −14°C | 359 | 193 |
| −13°C | 375 | 205 |
| −12°C | 391 | 216 |
| −11°C | 407 | 228 |
| −10°C | 424 | 241 |
| −9°C | 441 | 253 |
| −8°C | 458 | 266 |
| −7°C | 476 | 280 |
| −6°C | 494 | 293 |
| −5°C | 513 | 307 |
| −4°C | 532 | 322 |
| −3°C | 552 | 337 |
| −2°C | 572 | 352 |
| −1°C | 592 | 368 |
| 0°C H₂O freeze | 613 | 384 |
| 1°C | 635 | 401 |
| 2°C | 657 | 418 |
| 3°C | 679 | 435 |
| 4°C | 702 | 453 |
| 5°C | 725 | 471 |
| 6°C | 749 | 490 |
| 7°C | 773 | 509 |
| 8°C | 798 | 529 |
| 9°C | 823 | 549 |
| 10°C | 849 | 570 |
| 11°C | 875 | 591 |
| 12°C | 902 | 613 |
| 13°C | 930 | 635 |
| 14°C | 958 | 658 |
| 15°C | 986 | 681 |
| 16°C | 1,015 | 705 |
| 17°C | 1,045 | 729 |
| 18°C | 1,075 | 754 |
| 19°C | 1,106 | 779 |
| 20°C | 1,137 | 806 |
| 21°C | 1,169 | 832 |
| 22°C | 1,202 | 859 |
| 23°C | 1,235 | 887 |
| 24°C | 1,268 | 916 |
| 25°C | 1,303 | 945 |
| 26°C | 1,338 | 975 |
| 27°C | 1,373 | 1,005 |
| 28°C | 1,409 | 1,036 |
| 29°C | 1,446 | 1,068 |
| 30°C | 1,484 | 1,100 |
| 31°C | 1,522 | 1,133 |
| 32°C | 1,560 | 1,167 |
| 33°C | 1,600 | 1,201 |
| 34°C | 1,640 | 1,237 |
| 35°C | 1,681 | 1,272 |
| 36°C | 1,722 | 1,309 |
| 37°C | 1,764 | 1,347 |
| 38°C | 1,807 | 1,385 |
| 39°C | 1,850 | 1,424 |
| 40°C | 1,895 | 1,463 |
| 41°C | 1,939 | 1,504 |
| 42°C | 1,985 | 1,545 |
| 43°C | 2,031 | 1,588 |
| 44°C | 2,078 | 1,631 |
| 45°C | 2,126 | 1,675 |
| 46°C | 2,175 | 1,719 |
| 47°C | 2,224 | 1,765 |
| 48°C | 2,274 | 1,812 |
| 49°C | 2,325 | 1,859 |
| 50°C | 2,376 | 1,908 |
| 51°C | 2,428 | 1,957 |
| 52°C | 2,481 | 2,008 |
| 53°C | 2,535 | 2,059 |
| 54°C | 2,590 | 2,111 |
| 55°C | 2,645 | 2,165 |
| 56°C | 2,701 | 2,220 |
| 57°C | 2,758 | 2,275 |
| 58°C | 2,815 | 2,332 |
| 59°C | 2,874 | 2,390 |
| 60°C | 2,933 | 2,449 |
| 61°C | 2,993 | 2,509 |
| 62°C | 3,054 | 2,571 |
| 63°C | 3,116 | 2,633 |
| 64°C | 3,178 | 2,697 |
| 65°C | 3,241 | 2,763 |
| 66°C | 3,305 | 2,829 |
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-455A PT chart data: CoolProp 7.2.0 (published Helmholtz equations of state / mixture models — see the source citations above).
Lower toxicity. Flame propagates in air at 60°C, but with a low burning velocity (≤ 10 cm/s) and a heat of combustion < 19,000 kJ/kg. ASHRAE safety group A2L: lower toxicity and lower flammability. R-32, R-454B, R-1234yf, R-1234ze(E), R-452B, R-454C, R-455A, R-516A are A2L.
- Flammability
- Low (burning velocity ≤ 10 cm/s)
- Toxicity
- Lower (OEL ≥ 400 ppm)
Classification per ANSI/ASHRAE Standard 34-2022[1], safety group definitions and refrigerant safety classifications. See full reference.
Saturation pressure-temperature curve
Saturation values from CoolProp 7.2.0 mixture model: R-744/R-32/R-1234yf, 3/21.5/75.5% by mass[6]. Operating pressure on a running system differs — see the operating-pressure references for in-use values.
At a glance
Chemistry
Lubricant compatibility
POE required. A2L. Very low GWP — meets EU F-Gas <150 threshold. CO2 component contributes a significant temperature glide (~7-9 K).
Blend composition
- CO2 3.0%
- R-32 21.5%
- R-1234yf 75.5%
Trade names
- Solstice L40X — Honeywell
Common applications
- Commercial refrigeration (low and medium temp)
- Supermarket cases
- R-404A retrofit (Honeywell L40X product line)
Properties
- Boiling point (1 atm)bubble −62.1°F (−52.3°C), dew −38.6°F (−39.2°C)
- Critical pointNo single point — blend critical locus
- Molar mass87.45 g/mol
- Temperature glide22.1°F
- ODP0
- GWP (100-yr)146 US EPA value, 40 CFR 84.64(b) IPCC: AR4 not assessed · AR5 146 · AR6 166
- New-equipment status (US)AIM Act HFC, 84.64 GWP 146 — below every 40 CFR 84.54 limit; no new-equipment restriction.
What is R-455A?
R-455A is a ternary zeotropic blend combining R-744 (CO₂), R-32, and R-1234yf in 3/21.5/75.5 mass proportions[1]. The R-744 component is unusual — only 3% by mass — but contributes significant volumetric capacity and slightly raises the operating pressure envelope. The R-1234yf component (75.5%, GWP 1) is the GWP-diluting majority component; the R-32 component (21.5%, GWP 675) provides primary capacity.
The defining trade-off is a very large temperature glide of approximately 22°F — among the largest of any commercial refrigerant. The glide is the price of the very-low GWP (146, identical to R-454C) and the wide range of pure-component boiling points (R-744 at −109°F, R-32 at −61°F, R-1234yf at −21°F).
Where R-455A is used
- Low-temperature commercial refrigeration — walk-in freezers, frozen food cases (new equipment)
- Self-contained commercial refrigeration equipment
- Honeywell Solstice L40X / N40 trade names
Regulatory & phase-down status
R-455A is a low-GWP A2L blend for new commercial refrigeration equipment under AIM Act and EU F-Gas Regulation[2][3]. GWP 146 sits below 150, the limit in 517/2014 Annex III rows 11 and 13, and provides comfortable headroom under AIM Act commercial refrigeration thresholds.
R-454C and R-455A serve as competing low-GWP A2L choices with identical GWP. The differences are composition-specific: R-455A includes the 3% R-744 component for capacity and slightly different pressure characteristics; R-454C is a binary R-32/R-1234yf blend with simpler chemistry.
Service notes
POE oil required — same lubricant family as R-410A and R-32. A2L safety class requires A2L-listed equipment, charge limits per UL 60335-2-89 and ASHRAE 15, and A2L-rated leak detection in some installations[4][5].
Use dew temperature for superheat math (suction line) and bubble temperature for subcooling (liquid line). The R-744 component requires attention to fractionation behavior during partial charging — full recovery and recharge is the correct service approach.
Temperature glide
R-455A is a zeotropic blend: at constant pressure it boils across a temperature range rather than at a single point. Use the dew curve for superheat, bubble curve for subcooling.
Operating cycle
Phase-down timeline
R-455A contains HFC-32, a regulated substance under the AIM Act. Its GWP under 40 CFR 84.64 is 146 — below every 40 CFR 84.54 GWP limit, so no 84.54 new-equipment limit restricts it.
R-455A is not restricted in new supermarket systems: its GWP (146) is under every limit for that subsector, including those that start on January 1, 2032.[2], §84.54(c)(12)
HFC production & consumption allowances step down to 30% of baseline in 2029–2033, 20% of baseline in 2034–2035, and 15% of baseline in 2036 and later (42 U.S.C. 7675(e)(2)(C)).
US new-equipment rules (40 CFR 84.54)
R-455A contains HFC-32, a regulated substance under the AIM Act. Under 40 CFR 84.64(b) its GWP is 146: each component's GWP times its mass fraction; components without a GWP under 84.64 are left out (84.64(c)). That value is compared against each 40 CFR 84.54 subsector limit below.
Its GWP (146) is under every 40 CFR 84.54 limit for supermarket systems, so those restrictions don't apply there.
- R-455A is not restricted in new supermarket systems: its GWP (146) is under every limit for that subsector, including those that start on January 1, 2032.
Servicing. 40 CFR 84.54 restricts new manufacture/import, later sale/distribution, and installation. "Installation" is defined in 84.54(e); repairing or servicing existing R-455A equipment is not an installation unless it meets 84.54(e), so existing systems can keep being serviced. From January 1, 2029, servicing or repairing R-455A equipment in supermarket systems, refrigerated transport or automatic commercial ice makers must be done with reclaimed refrigerant[8].
Source: 40 CFR 84.54, current through 91 FR 31329 (May 26, 2026). Installation defined at 40 CFR 84.54(e).
Global warming potential, in context
Commercial refrigeration — medium temperature
Retrofit and replacement paths
R-455A replaces
Reading the R-455A PT chart — very large glide demands careful curve selection
R-455A is a ternary zeotropic blend with approximately 22°F glide — among the largest of any commercial refrigerant. The PT chart shows two distinct curves (bubble and dew) with substantial vertical separation. Reading the chart requires deliberate attention to which curve applies for each measurement.
For suction-line superheat measurement, use the dew curve. The dew temperature at the measured suction pressure is the saturation reference. For liquid-line subcooling measurement, use the bubble curve. Using the wrong curve introduces measurement error equal to the glide — for R-455A this is up to 22°F, large enough to make charging decisions catastrophically wrong.
R-455A's glide is unusually large because of the three-component composition with widely-different pure-component boiling points. Even compared to other zeotropic blends (R-454C at 14°F, R-407C at 11°F, R-448A at 10°F), R-455A's glide is substantially larger. Service measurement on R-455A demands the most careful curve selection of any common commercial refrigerant.
R-455A vs R-404A, R-22: saturation pressure
| Temp | R-455A | R-404A | R-22 |
|---|---|---|---|
| 0°F | 22.3 / 44.1 | 33.7(−24%) | 24.0(−46%) |
| 40°F | 66.9 / 103.3 | 86.9(−16%) | 68.6(−34%) |
| 70°F | 121.1 / 170.1 | 149.3(−12%) | 121.4(−29%) |
| 100°F | 199.6 / 260.7 | 236.8(−9%) | 195.9(−25%) |
Frequently asked
›What is the normal operating pressure of R-455A?
Operating pressure depends on evaporator load and ambient. The saturation pressures are in the PT table and the comparison table on this page.
›Why does R-455A have such large glide (22°F)?
Because the three components have widely different boiling points: R-744 (CO₂) at −109°F, R-32 at −61°F, R-1234yf at −21°F — an 88°F range across pure components. The 3/21.5/75.5 mass blend inherits a temperature glide of approximately 22°F at typical operating pressures.
The glide is the trade-off for the unique capacity benefit of the R-744 component combined with very-low GWP. R-455A delivers slightly higher volumetric capacity than R-454C (the binary alternative) because of the high-pressure CO₂ contribution, at the cost of more difficult service measurement due to the wider glide.
›What's the difference between R-455A and R-454C?
Both are A2L low-GWP commercial refrigeration blends with GWP 146. R-454C is binary (R-32/R-1234yf 21.5/78.5) with ~14°F glide. R-455A is ternary (R-744/R-32/R-1234yf 3/21.5/75.5) with ~22°F glide.
R-455A's R-744 component delivers slightly higher volumetric capacity. The cost is the larger glide and the fractionation concern during partial charging. R-454C is operationally simpler; R-455A delivers more capacity per compressor displacement.
›What lubricant does R-455A use?
Polyolester (POE) oil — same lubricant family as R-410A, R-32, and R-454C. Use the oil the equipment maker specifies.
POE is hygroscopic — evacuate to the equipment maker's micron target and confirm the vacuum holds before charging. The R-744 component doesn't change the lubricant choice; the blend's overall behavior is determined by the 97% HFC/HFO content.
›How do I measure superheat on R-455A?
Use the dew temperature at suction pressure. R-455A's 22°F glide means using the bubble curve overstates superheat by about the glide — large enough to cause major charging errors. The dew curve corresponds to the suction-line state where refrigerant has fully evaporated.
Manual measurement requires reading the dew column on the published R-455A PT chart with deliberate attention to the curve choice.
›Why does R-455A include the 3% R-744 component?
Volumetric capacity. R-744 (CO₂) has very high vapor pressure. Adding a small mass fraction of R-744 to the blend raises the overall vapor density at any operating condition, increasing refrigerant mass flow per unit compressor displacement and thus increasing refrigeration capacity.
The 3% R-744 fraction is a deliberate compromise — enough to meaningfully boost capacity (~5-10% above pure R-32/R-1234yf alternatives) without making the blend behave like R-744 in terms of pressure envelope or service requirements.
›Is R-455A safe to handle?
ASHRAE class A2L — lower flammability with low burning velocity. Equipment design accommodates per UL 60335-2-89 (A2L-listed equipment, charge limits, A2L-rated leak detection in some installations)[4].
The 3% R-744 component doesn't change the overall safety class — the blend is A2L. Treating R-455A as if it were A1 R-404A is a safety error.
›Can I retrofit R-404A to R-455A?
Not safely without OEM evaluation. R-404A equipment is A1-rated and not designed for A2L flammability. Most R-404A equipment is not authorized for A2L refrigerant retrofit. R-404A retrofits that preserve A1 classification use R-448A or R-449A (both A1, GWP ~1,390).
R-455A is for new equipment specifically designed for A2L operation and the very-large glide handling.
Sources & citations
- [1]ANSI/ASHRAE Standard 34-2022, Designation and Safety Classification of Refrigerants (free read-only version). ASHRAE. 2022. https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards (accessed October 2, 2026)
- [2]40 CFR 84.54 — Restrictions on the use of hydrofluorocarbons. eCFR (Office of the Federal Register). up to date as of 9/29/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-B/section-84.54 (accessed October 2, 2026)
- [3]Regulation (EU) No 517/2014 on fluorinated greenhouse gases. EUR-Lex. OJ L 150, 20.5.2014 (replaced by (EU) 2024/573 from March 11, 2024). https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R0517 (accessed October 2, 2026)
- [4]UL 60335-2-89 / IEC 60335-2-89 — Safety standard for commercial refrigerating appliances. UL / IEC. https://www.ul.com/services/ul-60335-standards (accessed October 2, 2026)
- [5]ANSI/ASHRAE Standard 15-2022, Safety Standard for Refrigeration Systems. ASHRAE. 2022. https://www.ashrae.org/technical-resources/standards-and-guidelines (accessed October 2, 2026)
- [6]CoolProp 7.2.0. CoolProp (I. H. Bell, J. Wronski, S. Quoilin, V. Lemort). https://coolprop.org/ (accessed October 2, 2026). Bell, I. H.; Wronski, J.; Quoilin, S.; Lemort, V. Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp. Ind. Eng. Chem. Res. 53, 2498–2508 (2014). https://doi.org/10.1021/ie4033999
- [7]2017 Guideline for Assignment of Refrigerant Container Colors (AHRI Guideline N-2017). AHRI. 2017. https://www.ahrinet.org/system/files/2023-06/AHRI_Guideline_N_2017.pdf (accessed October 2, 2026)
- [8]40 CFR 84.112 — Reclamation. eCFR (Office of the Federal Register). up to date as of 9/25/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-C/section-84.112 (accessed October 2, 2026). 89 FR 82859, Oct. 11, 2024