R-507A pressure–temperature table and P–h diagram

R-125/143a (50/50) — an azeotropic blend of R-125 and R-143a, 50 / 50 % by mass. Bubble and dew pressures from −70 to 68 °C, every 2 K, and a pressure–enthalpy diagram to read any state from, computed with CoolProp. Also written R507A.

Safety class A1GWP 3,985 (AR4), 4,775 (AR6)ODP 0Sources

Pressure–enthalpy diagram

log P · h

Pressure (kPa abs)

Specific enthalpy (kJ/kg)

Point anywhere on the diagram to read the state there

Pressure: —
Temperature: —
Specific enthalpy: —
Specific entropy: —
Density: —
Specific volume: —
Saturation: —
Superheat or subcooling: —

Values come from a CoolProp 7.2.1dev tabulation of R-507A (88 pressures, each with states across its liquid, two-phase and vapour spans), interpolated between the points of that grid, and must be verified by a qualified professional before they're relied on.

Enthalpy and entropy are on the IIR datum: h = 200 kJ/kg and s = 1 kJ/(kg·K) for saturated liquid at 0 °C, the bubble-point liquid for a blend.

Points

CoolProp

R-507A critical and boiling points
Reading	Value	Basis
Critical temperatureCoolProp, from its equation of state	70.62°C	CoolProp, from its equation of state
Critical pressureCoolProp, from its equation of state	3,704.9kPa	CoolProp, from its equation of state
Bubble pointAt 101.325 kPa, solved by CoolProp	−46.74°C	At 101.325 kPa, solved by CoolProp
Dew pointAt 101.325 kPa, solved by CoolProp	−46.74°C	At 101.325 kPa, solved by CoolProp
GlideDew point less bubble point, at 101.325 kPa	0.00K	Dew point less bubble point, at 101.325 kPa

Saturation pressure

kPa abs · bar g

R-507A saturation bubble and dew pressures by temperature, in kPa absolute and bar gauge
T (°C)	Bubble (kPa abs)	Dew (kPa abs)	Bubble (bar g)	Dew (bar g)
−70	28.4	28.4	−0.73	−0.73
−68	32.1	32.1	−0.69	−0.69
−66	36.2	36.2	−0.65	−0.65
−64	40.7	40.7	−0.61	−0.61
−62	45.6	45.6	−0.56	−0.56
−60	51.1	51.0	−0.50	−0.50
−58	57.0	57.0	−0.44	−0.44
−56	63.4	63.4	−0.38	−0.38
−54	70.5	70.5	−0.31	−0.31
−52	78.1	78.1	−0.23	−0.23
−50	86.4	86.4	−0.15	−0.15
−48	95.3	95.3	−0.06	−0.06
−46	105.0	105.0	0.04	0.04
−44	115.4	115.4	0.14	0.14
−42	126.6	126.6	0.25	0.25
−40	138.7	138.7	0.37	0.37
−38	151.6	151.6	0.50	0.50
−36	165.4	165.4	0.64	0.64
−34	180.2	180.2	0.79	0.79
−32	196.0	196.0	0.95	0.95
−30	212.9	212.8	1.12	1.12
−28	230.8	230.8	1.30	1.29
−26	249.9	249.8	1.49	1.49
−24	270.2	270.1	1.69	1.69
−22	291.7	291.6	1.90	1.90
−20	314.5	314.4	2.13	2.13
−18	338.6	338.5	2.37	2.37
−16	364.2	364.0	2.63	2.63
−14	391.1	390.9	2.90	2.90
−12	419.6	419.3	3.18	3.18
−10	449.5	449.3	3.48	3.48
−8	481.1	480.8	3.80	3.79
−6	514.3	514.0	4.13	4.13
−4	549.2	548.9	4.48	4.48
−2	585.9	585.5	4.85	4.84
0	624.4	624.0	5.23	5.23
2	664.7	664.3	5.63	5.63
4	707.0	706.5	6.06	6.05
6	751.3	750.7	6.50	6.49
8	797.6	797.0	6.96	6.96
10	846.0	845.4	7.45	7.44
12	896.6	895.9	7.95	7.95
14	949.4	948.6	8.48	8.47
16	1,004.5	1,003.7	9.03	9.02
18	1,061.9	1,061.1	9.61	9.60
20	1,121.8	1,120.9	10.20	10.20
22	1,184.2	1,183.2	10.83	10.82
24	1,249.1	1,248.1	11.48	11.47
26	1,316.7	1,315.6	12.15	12.14
28	1,386.9	1,385.7	12.86	12.84
30	1,460.0	1,458.7	13.59	13.57
32	1,535.8	1,534.5	14.35	14.33
34	1,614.7	1,613.3	15.13	15.12
36	1,696.5	1,695.0	15.95	15.94
38	1,781.4	1,779.8	16.80	16.79
40	1,869.5	1,867.9	17.68	17.67
42	1,960.9	1,959.2	18.60	18.58
44	2,055.6	2,053.9	19.54	19.53
46	2,153.9	2,152.0	20.53	20.51
48	2,255.7	2,253.8	21.54	21.52
50	2,361.2	2,359.2	22.60	22.58
52	2,470.5	2,468.5	23.69	23.67
54	2,583.8	2,581.8	24.82	24.80
56	2,701.2	2,699.1	26.00	25.98
58	2,822.8	2,820.8	27.21	27.19
60	2,948.9	2,946.9	28.48	28.46
62	3,079.6	3,077.8	29.78	29.76
64	3,215.3	3,213.6	31.14	31.12
66	3,356.2	3,354.8	32.55	32.53
68	3,502.9	3,501.9	34.02	34.01

Gauge pressure is absolute pressure less a standard atmosphere, 101.325 kPa; below it, gauge pressure is negative. Bubble: saturated liquid. Dew: saturated vapour.

Identity

Kelvin’s refrigerant library

Designation: R-507A (also written R507A)
Name: R-125/143a (50/50)
Kind: azeotropic blend of R-125 and R-143a
Composition: R-125 50 % / R-143a 50 % by mass

Environment and safety

Cited

Safety class: A1Lower toxicity, no flame propagation. The class assigned in ISO 817 or ANSI/ASHRAE 34, as tabled in UNEP RTOC 2018; the Australian Government lists A1 (AS/NZS ISO 817).
GWP, 100-year (AR4): 3,985The mass-weighted sum of its components' figures from IPCC AR4 (2007): 50 % × 3,500 (R-125) + 50 % × 4,470 (R-143a).
GWP, 100-year (AR6): 4,775The mass-weighted sum of its components' figures from IPCC AR6 (2021): 50 % × 3,740 (R-125) + 50 % × 5,810 (R-143a).
ODP: 0None of its components is an ozone-depleting substance in the Montreal Protocol's annexes.

Two GWPs, both for a 100-year horizon. AR4 is the assessment that Australia's Ozone Protection and Synthetic Greenhouse Gas Management Act 1989 and the Montreal Protocol count HFCs in, so it is the figure behind Australia's HFC import phase-down (DCCEEW). The Montreal Protocol's Annexes A, C and F list the same AR4 figures for the CFCs, HCFCs and HFCs they control. AR6 is the IPCC's most recent assessment. The GHG Protocol's table of IPCC GWPs (version 2.0, August 2024) recommends using these latest values.

Sources

UNEP RTOC 2018: Annex I to Chapter 2, Tables 2.I-1 to 2.I-3: safety classes as assigned in ISO 817:2014 or ANSI/ASHRAE Standard 34-2016.
DCCEEW (Australian Government): Hydrofluorocarbon refrigerants – global warming potential values and safety classifications (last updated 13 December 2024): AR4 GWPs as used under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989, safety classes from AS/NZS ISO 817:2016.
IPCC AR4 (2007): Working Group I, Chapter 2, Table 2.14, 100-year GWP (as corrected in the Working Group I errata).
IPCC AR6 (2021): Working Group I, Chapter 7 Supplementary Material, Table 7.SM.7, GWP-100.
Montreal Protocol: Annex A, Group I (CFCs), and Annex C, Group I (HCFCs): ozone-depleting potentials.
ASHRAE refrigerant designations: Refrigerant blends (zeotropes and azeotropes): each blend's components and composition by mass.
GHG Protocol (2024): IPCC Global Warming Potential Values, version 2.0 (7 August 2024): the recommendation to use AR6.

Source

Computed with: CoolProp 7.2.1dev, HEOS backend — open-source software under the MIT licence
Fluid: R507A, CoolProp's pseudo-pure model of the blend
Equation of state: Lemmon-IJT-2003 (CoolProp’s reference key)
Cite: Bell, I.H., Wronski, J., Quoilin, S., Lemort, V. (2014). Pure and pseudo-pure fluid thermophysical property evaluation and the open-source thermophysical property library CoolProp. Ind. Eng. Chem. Res. 53(6), 2498-2508.

Components: R-125, R-143a
In R-number order: Before: R-502 · After: R-508A
Every refrigerant: All refrigerant tables

Use R-507A in Kelvin

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Note

Verify before relying on these figures

The property figures are computed with CoolProp from published equations of state. The GWP, ODP and safety class are the named sources’ figures, a blend’s GWP and ODP summed from its composition. They must be verified by a qualified professional before they’re relied on.