R-143a PT Chart and Refrigerant Profile

Where you will find R-143a

R-143a (HFC-143a, 1,1,1-trifluoroethane) is a blend component, not a refrigerant you charge on its own. It makes up about half of R-404A and R-507A, the HFC blends that replaced R-502 in commercial refrigeration:

BITZER also lists it in R-461A and R-462A. So when you work on a supermarket rack, walk-in freezer or ice machine on R-404A or R-507A, about half the charge is R-143a. See R-404A vs R-507A for how those two compare.

It is also the main reason those blends have such high GWPs. At 4,470, R-143a is above even R-125 (3,500); in R-404A its 52% share accounts for about 2,324 of the 3,922 total (GWP chart).

Pressures and handling

As a pure fluid, R-143a has no glide: one pressure applies at each temperature, 88.3 psig at 40°F and 237.2 psig at 100°F on this chart. R-404A reads 85.4 psig dew at 40°F, so the pure component and the blend sit close together.

We found no manufacturer charging guidance and no EPA SNAP refrigeration listing for neat R-143a. Use the PT chart as a reference, for example to identify a cylinder by its standing pressure, not as a charging target. Do not add pure R-143a to an R-404A or R-507A system to “adjust” it; a leaked or contaminated charge gets recovered and replaced with the blend.

Oil and compatibility

BITZER lists POE, PVE and AB for R-143a. In service the oil follows the blend and the compressor: R-404A and R-507A systems run POE. Check the compressor maker’s approval list (refrigerant oil guide).

Safety, handling and recovery

R-143a is A2L: lower toxicity, mildly flammable. BITZER and the ICC’s Table 1103.1 list it as A2L, and the ICC table shows the change from A2. Older references still print A2. The blends built on it, R-404A and R-507A, are A1 as formulated.

If you ever handle neat R-143a, treat it like any A2L (flammability classes):

• keep ignition sources away and ventilate the work area
• recover with a machine certified for flammable refrigerants (40 CFR 82.158 Appendix B4, which adds UL 1963 Supplement SB to AHRI 740; see recovery machine compatibility)
• expect a red band on the cylinder shoulder or top, which AHRI Guideline N-2017 section 4.7 calls for on flammable compounds

Guideline N Table 1 assigns R-143a no legacy color. New containers since Jan 1 2020 are light green-gray (RAL 7044) (cylinder colors).

Under 40 CFR 82.152 it is a high-pressure refrigerant: its liquid saturation pressure at 104°F is 265.6 psia (250.9 psig). Type II or Universal certification covers appliances that use it, venting is prohibited, and HFC sales have been limited to certified technicians since Jan 1 2018. Recover appliances made after Nov 15 1993 to 0 in Hg under 200 lb of charge and 10 in Hg at 200 lb or more (refrigerant recovery).

Status

HFC-143a is a regulated substance under the AIM Act with an exchange value of 4,470 (40 CFR 84 Appendix A). Production and import allowances are 60% of baseline in 2024–2028, 30% in 2029–2033, 20% in 2034–2035 and 15% from 2036. As a neat refrigerant its GWP is above every Technology Transitions limit for new systems.

The practical effect lands on its blends. R-404A and R-507A carry the highest GWPs of the common commercial refrigerants, and most lower-GWP replacements leave R-143a out. Servicing existing R-404A and R-507A systems remains legal. See R-404A replacement and the R-404A profile for the options.