RefrigerantASHRAE R-500

R500 PT Chart

Updated October 12, 2026

R-500

A1 Lower toxicity, no flame propagationCFC blend (azeotrope) ODS — CFC · AIM Act HFC Production banned · 1996

Illustration of a refrigerant cylinder painted light green gray (RAL 7044), the color AHRI Guideline N-2017 calls for on all new refrigerant containers from 2020^{[2], section 4.8}. Label: R-500, safety class A1, GWP 8,077. No red band: AHRI Guideline N-2017 reserves it for flammable refrigerants^{[2], section 4.7}.

R-12/R-152a (73.8/26.2)

Historical azeotropic blend of R-12 (CFC) and R-152a (HFC), 73.8/26.2 by mass. ASHRAE A1, ODP 0.605, GWP 8,077. Production banned in 1996 under the Montreal Protocol. Found in legacy centrifugal chillers and 60 Hz hermetic compressor applications.

R-500 saturation pressure is 47.0 PSIG at 40°F, 86.6 PSIG at 70°F, and 142.7 PSIG at 100°F. These are the gauge readings on a static, fully-saturated system; a running system's high side sits well above them. The full table below runs from −40°F to 150°F in 1°F steps.

Not yet checked against an independent source.

Saturation @ 70°F

86.6 PSIG

GWP (100-yr)

8,077 US EPA value, 40 CFR 84.64(b)

Temperature glide

under 0.1°F

Boiling point

−29.1°F

Sourced facts

Temperature glide: under 0.1°F at a 40°F dew point^[4]

R-500 PT calculator Superheat

R-500 PT chart — 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).

R-500 PT Chart — Pressure-Temperature Saturation Table

Computed with CoolProp 7.2.0 in 1°F steps · hvacptcharts.com

R-500 · 1° increments · °F / PSIG

Tinted rows: NBP atmospheric crossover · 32°F H₂O freeze

R-500 pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)	Pressure (PSIG)
−40°F	7.2 in. Hg vac.
−39°F	6.6 in. Hg vac.
−38°F	6.0 in. Hg vac.
−37°F	5.3 in. Hg vac.
−36°F	4.7 in. Hg vac.
−35°F	4.1 in. Hg vac.
−34°F	3.4 in. Hg vac.
−33°F	2.7 in. Hg vac.
−32°F	2.0 in. Hg vac.
−31°F	1.3 in. Hg vac.
−30°F	0.6 in. Hg vac.
−29°F NBP (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	15.0
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	32.2
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°F H₂O freeze	38.7
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	57.3
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	78.9
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

R-500 pressure-temperature saturation table in Celsius and kPa
Temp (°C)	Pressure (kPa)
−40°C	−24
−39°C	−21
−38°C	−17
−37°C	−13
−36°C	−9
−35°C	−5
−34°C NBP (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	160
−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°C H₂O 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	1,761
62°C	1,802
63°C	1,844
64°C	1,886
65°C	1,929
66°C	1,972

CoolProp 7.2.0 · PSIG/kPa = gauge · PSIA = PSIG + 14.6959 · kPa(abs) = kPa(gauge) + 101.325

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 (published Helmholtz equations of state / mixture models — see the source citations above).

Lower toxicity, no flame propagation

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

Pressure

Temperature

Highlight at°F

Quick lookup — R-500

Temp:°F

86.6PSIG(597 kPa)

Range: −40 to 150°F Open full PT calculator →

Common service temperatures

32°F

39PSIG

Freezing

45°F

53PSIG

Heat-pump heat

70°F

87PSIG

Standard

75°F

95PSIG

Test ref

80°F

103PSIG

Warm

95°F

132PSIG

Summer peak

Saturation values from CoolProp 7.2.0 mixture model: R-12/R-152a, 73.8/26.2% by mass^[4]. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

At a glance

Chemistry

R-12/R-152a (73.8/26.2)

Azeotropic CFC/HFC blend

Lubricant compatibility

MOABPOE

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-12 73.8%
R-152a 26.2%

Common applications

Centrifugal chillers (legacy)
Commercial refrigeration (legacy)

Properties

Boiling point (1 atm)
bubble −29.1°F (−34.0°C), dew −28.7°F (−33.7°C)
Critical point
No single point — blend critical locus
Molar mass
99.30 g/mol
Temperature glide
under 0.1°F
ODP
0.605
GWP (100-yr)
8,077 US EPA value, 40 CFR 84.64(b) IPCC: AR4 8,077 · AR5 7,564 · AR6 9,268
New-equipment status (US)
Class I ODS (CFC) — US production/import ended January 1, 1996.

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.

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 use the dew column for superheat and the bubble column for subcooling.

Operating cycle

Phase-down timeline

R-500 contains HFC-152a, a regulated substance under the AIM Act. Its GWP under 40 CFR 84.64 is 32.

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)).

Full 40 CFR 84.54 new-equipment rules for R-500 →

R-500 is also an ozone-depleting substance controlled under the US Clean Air Act (class I — CFC). Milestones below are US production/import limits.

January 1, 1996 — CFC-12: US ban on production and import took effect^[1].

US new-equipment rules (40 CFR 84.54)

R-500 contains HFC-152a, a regulated substance under the AIM Act. Under 40 CFR 84.64(b) its GWP is 32: 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.

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-500 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-500 equipment in supermarket systems, refrigerated transport or automatic commercial ice makers must be done with reclaimed refrigerant^[3].

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

Retrofit and replacement paths

Replacements for R-500

R-500 vs R-134a, R-450A: saturation pressure

Saturation pressure (PSIG, gauge) for R-500 vs R-134a, R-450A — zeotropic blends shown as dew / bubble. Each column shows the percent difference from R-500. Sources: R-500 and R-134a: CoolProp 7.2.0 dataset; R-450A: CoolProp 8.0.0 dataset.
Temp	R-500	R-134a	R-450A
0°F	13.8	6.5(−53%)	3.8 / 4.3(−69%)
40°F	47.0	35.0(−25%)	28.9 / 29.8(−37%)
70°F	86.6	71.1(−18%)	60.6 / 62.0(−28%)
100°F	142.7	124.2(−13%)	107.3 / 109.3(−23%)

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 601) replaced R-134a in some applications as the next phase-down step. For new chillers, R-1234ze(E) (HFO, A2L, GWP 1) 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, mass-weighted from R-12 (10,900) 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.

Download this dataset

Full PT chart for R-500 · CC BY 4.0 · attribute the source

CSV JSON

Sources & citations

[1]
Phaseout of Class I Ozone-Depleting Substances. US EPA. last updated March 10, 2026. https://www.epa.gov/ods-phaseout/phaseout-class-i-ozone-depleting-substances (accessed October 5, 2026)
[2]
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)
[3]
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
[4]
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