HVAC PT ChartsVerified saturation data · 61 refrigerants
RefrigerantASHRAE R-12

R-12

A1Non-flammableCFC Production banned · 1996
CCl2F2

Pure CFC (dichlorodifluoromethane, CCl₂F₂) — the dominant mobile AC and household refrigerator refrigerant from the 1930s through 1995. ODP 1.0 (reference value), GWP 10900. Banned globally under Montreal Protocol since 1 January 1996.

Saturation @ 70°F
70.1PSIG
GWP (IPCC AR5)
10900100-yr
Temperature glide
≈0°F
Boiling point
-21.6°F
Sourced facts
ASHRAE safety class
A1[src]
Chemical formula
CCl₂F₂[src]
ODP
1.0[src]
GWP (100-yr)
10900IPCC AR5[src]
Normal boiling point
−21.6°F (−29.8°C)[src]
Critical temperature
234°F (112°C)[src]
Production status
Banned globally1 Jan 1996[src]
Required lubricant
Mineral oil[src]
R-12 PT calculator Superheat
A1
Non-flammable

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.

01

Saturation pressure-temperature curve

Pressure
Temperature
°F
70°F: 70.1 PSIG
Quick lookup — R-12
70.1PSIG(483 kPa)
Range: -40 to 150°FOpen full PT calculator →
Common service temperatures
32°F
30PSIG
Freezing
45°F
42PSIG
Heat-pump heat
70°F
70PSIG
Standard
75°F
77PSIG
Test ref
80°F
84PSIG
Warm
95°F
108PSIG
Summer peak

Saturation values from CoolProp 7.2.0 R12. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

02

R-12 PT chart PDF — printable saturation table

Looking for the R-12 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-12 PT Chart — Pressure-Temperature Saturation Table

1° increments · Source: CoolProp 7.2.0 / manufacturer datasheet · hvacptcharts.com

R-12 · 1° increments · °F / PSIG
Tinted rows: NBP atmospheric crossover · 32°F H₂O freeze · 35°F MAC evap target · 100°F Cabin ambient · 140°F Engine bay cond
R-12 pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)Pressure (PSIG)
-40°F-5.4
-39°F-5.2
-38°F-4.9
-37°F-4.7
-36°F-4.4
-35°F-4.1
-34°F-3.9
-33°F-3.6
-32°F-3.3
-31°F-3.0
-30°F-2.7
-29°F-2.4
-28°F-2.1
-27°F-1.8
-26°F-1.5
-25°F-1.2
-24°F-0.8
-23°F-0.5
-22°F-0.1
-21°FNBP (atmospheric)0.2
-20°F0.6
-19°F0.9
-18°F1.3
-17°F1.6
-16°F2.0
-15°F2.4
-14°F2.8
-13°F3.2
-12°F3.6
-11°F4.0
-10°F4.5
-9°F4.9
-8°F5.3
-7°F5.8
-6°F6.2
-5°F6.7
-4°F7.2
-3°F7.6
-2°F8.1
-1°F8.6
0°F9.1
1°F9.6
2°F10.1
3°F10.7
4°F11.2
5°F11.8
6°F12.3
7°F12.9
8°F13.4
9°F14.0
10°F14.6
11°F15.2
12°F15.8
13°F16.4
14°F17.0
15°F17.7
16°F18.3
17°F19.0
18°F19.6
19°F20.3
20°F21.0
21°F21.7
22°F22.4
23°F23.1
24°F23.8
25°F24.6
26°F25.3
27°F26.1
28°F26.8
29°F27.6
30°F28.4
31°F29.2
32°FH₂O freeze30.0
33°F30.8
34°F31.6
35°FMAC evap target32.5
36°F33.4
37°F34.2
38°F35.1
39°F36.0
40°F36.9
41°F37.8
42°F38.7
43°F39.7
44°F40.6
45°F41.6
46°F42.6
47°F43.6
48°F44.6
49°F45.6
50°F46.6
51°F47.6
52°F48.7
53°F49.8
54°F50.9
55°F52.0
56°F53.1
57°F54.2
58°F55.3
59°F56.5
60°F57.6
61°F58.8
62°F60.0
63°F61.2
64°F62.4
65°F63.7
66°F64.9
67°F66.2
68°F67.5
69°F68.8
70°F70.1
71°F71.4
72°F72.7
73°F74.1
74°F75.5
75°F76.8
76°F78.2
77°F79.7
78°F81.1
79°F82.5
80°F84.0
81°F85.5
82°F87.0
83°F88.5
84°F90.0
85°F91.6
86°F93.2
87°F94.7
88°F96.3
89°F98.0
90°F99.6
91°F101.3
92°F102.9
93°F104.6
94°F106.3
95°F108.0
96°F109.8
97°F111.5
98°F113.3
99°F115.1
100°FCabin ambient116.9
101°F118.8
102°F120.6
103°F122.5
104°F124.4
105°F126.3
106°F128.2
107°F130.2
108°F132.1
109°F134.1
110°F136.1
111°F138.1
112°F140.2
113°F142.3
114°F144.3
115°F146.4
116°F148.6
117°F150.7
118°F152.9
119°F155.1
120°F157.3
121°F159.5
122°F161.8
123°F164.0
124°F166.3
125°F168.6
126°F171.0
127°F173.3
128°F175.7
129°F178.1
130°F180.5
131°F183.0
132°F185.5
133°F187.9
134°F190.5
135°F193.0
136°F195.6
137°F198.2
138°F200.8
139°F203.4
140°FEngine bay cond206.0
141°F208.7
142°F211.4
143°F214.2
144°F216.9
145°F219.7
146°F222.5
147°F225.3
148°F228.1
149°F231.0
150°F233.9
CoolProp 7.2.0 · PSIG/kPa = gauge · PSIA = PSIG + 14.696 · 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-12 PT chart data: CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS) or manufacturer datasheet, validated against AHRI Standard 700-2019.

03

At a glance

Chemistry

CCl2F2
Dichlorodifluoromethane

Lubricant compatibility

MOABPOE

Mineral oil was standard in R-12 systems. Industry standard for residential refrigerators and mobile AC for decades before HFC transition.

Trade names

  • Freon 12Chemours (historical: DuPont)
  • Genetron 12Honeywell

Common applications

  • Mobile air conditioning (historical, pre-1995)
  • Domestic refrigerators (legacy)
  • Medium-temperature commercial refrigeration (legacy)
04

Properties

  • Boiling point (1 atm)
    -29.8°C / -21.6°F
  • Critical point
    233.6°F at 585 PSIG
  • Molar mass
    120.91 g/mol
  • Temperature glide
    Negligible (0.00°F)
  • ODP
    1
  • GWP (AR5, 100-yr)
    10900
  • GWP (AR6, 100-yr)
    12500
  • Atmospheric lifetime
    100 years
05

What is R-12?

R-12 is pure dichlorodifluoromethane (CCl₂F₂) — a chlorofluorocarbon (CFC) that was the dominant refrigerant in mobile air conditioning, household refrigerators, and centrifugal chillers from the 1930s through the early 1990s [ashrae34]. R-12's properties — moderate pressure envelope, A1 non-flammable, single-component simplicity, high compatibility with mineral oil — made it the universal refrigerant of the post-WWII refrigeration industry.

R-12 is the reference value for the ozone-depletion potential scale: its ODP is exactly 1.0 [montrealprotocol]. The 1985 discovery of the Antarctic ozone hole, attributed to atmospheric CFC accumulation, drove the 1987 Montreal Protocol mandate to phase out CFC production. R-12 production was completely banned in developed countries on 1 January 1996 [epacfr82].

Where R-12 is used

  • Legacy mobile air conditioning — vehicles built before 1992 (US)
  • Legacy household refrigerators — appliances built before 1994 (US)
  • Legacy centrifugal chillers — equipment installed before mid-1990s
  • Service of remaining legacy equipment (reclaimed R-12 supply only)
  • Historical and reference context — defining the GWP/ODP scale

Regulatory & phase-down status

R-12 production has been completely banned in developed countries since 1 January 1996 [epacfr82]. The Montreal Protocol phase-out applies globally — developing countries followed by 2010. Only reclaimed R-12 remains legally available for service of pre-1996 equipment.

The R-12 installed base has largely aged out through normal equipment replacement cycles. Mobile AC: virtually all vehicles built before 1992 have been retired or had MAC systems retrofitted. Household refrigerators: similar attrition. Service supply is increasingly scarce; reclaimed R-12 prices reflect the very small remaining market.

Service notes

Reclaimed R-12 is legal to use indefinitely in existing equipment under EPA Section 608 rules [epasec608]. The supply chain is small and pricing reflects scarcity — typical wholesale prices in 2026 are 50-200× the 1995 baseline.

Mineral oil compatible. EPA Section 608 Type II or Universal certification required for service. R-12 service equipment is largely museum-quality at this point — 1/4" SAE service ports, low-pressure manifold gauges adequate.

07

Operating cycle

CompressorRaises pressureCondenserRejects heat to outdoorsExpansion deviceDrops pressureEvaporatorAbsorbs heat from indoorsDischarge: 136 PSIG, 180°FLiquid: 136 PSIG, 100°FEvap inlet: 37 PSIG, 40°F (two-phase)Suction: 37 PSIG, 50°FTypical residential cooling cycle for R-12 (40°F evap, 110°F condenser, 10°F superheat, 10°F subcooling)
08

Phase-down timeline

19962000200520102015202020252028today (2026-06-05)
1996-01-01
US production banned (Montreal Protocol)
Regulatory timeline for R-12
09

Global warming potential, in context

Mobile air conditioning

R-1234yf4R-134a1.4kR-1211kEU F-Gas (150)EPA AIM Act (700)
10

Retrofit and replacement paths

Replacements for R-12

Reading the R-12 PT chart

R-12's PT chart is a single saturation curve (pure CFC, no glide). At 70°F R-12 saturation is approximately 70 PSIG (CoolProp 7.2.0) — coincidentally very close to R-134a (71 PSIG), which is why R-134a was the natural HFC replacement for R-12.

Pressure envelope is moderate — standard 500 PSI manifold gauges (the pre-R-410A standard) handle R-12 with comfortable margin. R-12 service equipment is largely historical at this point.

CFC chemistry — two chlorines, two fluorines, no hydrogen

R-12 is dichlorodifluoromethane: CCl₂F₂. The two chlorine atoms are the chemistry feature that made R-12 ozone-depleting; the absence of hydrogen is why R-12's atmospheric lifetime is so long (~100 years).

Without hydrogen, OH radical attack (the primary atmospheric breakdown mechanism for HFCs) can't break down R-12. The molecule persists in the atmosphere for a century, eventually reaching the stratosphere where UV photolysis releases the chlorine atoms that catalyze ozone destruction.

The 100-year atmospheric lifetime is also what gives R-12 its very high GWP (10900). Long persistence × strong radiative forcing per molecule = very high warming impact per kg released.

ODP 1.0 — R-12 is the ozone-depletion potential reference

R-12's ODP is exactly 1.0 by definition — it's the reference value against which other refrigerants' ozone-depletion potency is measured. R-22 has ODP 0.055 (5.5% of R-12's potency); R-123 has ODP 0.02; R-1233zd(E) has ODP 0.00034.

The 1985 Antarctic ozone hole discovery (NASA Nimbus-7 satellite, then confirmed by ground-based Dobson spectrometer measurements) was attributed to atmospheric CFC accumulation [nasaozone]. R-12's market dominance from the 1930s through the 1980s meant it was the largest single contributor to stratospheric chlorine loading.

The Montreal Protocol (1987) mandated CFC phase-out; the US implemented complete R-12 production ban on 1 January 1996 [epacfr82]. The 1996 production ban is recognized as one of the most successful global environmental agreements — atmospheric chlorine concentrations have stabilized and begun declining, with stratospheric ozone recovery projected through 2070.

GWP 10900 — worst commercial refrigerant by climate impact

R-12's GWP of 10900 (IPCC AR5) is the highest among mainstream commercial refrigerants by a wide margin [ipccar5]. The very long atmospheric lifetime (100 years) drives the very high GWP — long persistence × strong radiative forcing per molecule.

For comparison: R-22 (1810), R-410A (2088), R-404A (3922) — all are 2-6× lower GWP than R-12. R-12 release has 7-10× the climate impact per kg of even the worst modern mainstream HFCs.

R-12's environmental impact (high ODP + very high GWP) is the defining environmental catastrophe of late-20th-century refrigerant chemistry. The Montreal Protocol's ozone-focused phase-out also dramatically reduced future climate impact — eliminating R-12 production prevented decades of additional climate burden.

R-12 history — refrigerant universal solvent of the 20th century

R-12 was developed in 1928 by Thomas Midgley Jr. at General Motors as a non-flammable, non-toxic, low-cost refrigerant alternative to the dangerous early refrigerants (ammonia, sulfur dioxide, methyl chloride, propane). R-12 commercialization through the 1930s-1940s revolutionized refrigeration safety and availability — household refrigerators became practical mass-market appliances.

By the 1950s-1970s, R-12 was the universal refrigerant: household refrigerators, freezers, commercial refrigeration, mobile AC, centrifugal chillers, aerosol propellant, foam blowing agent. The 1985 ozone hole discovery began the unraveling; the 1987 Montreal Protocol mandated phase-out; the 1996 production ban completed the transition to alternatives.

The R-12 to R-134a transition (in mobile AC and household refrigerators) and R-12 to R-123/R-11 (in chillers) was the largest refrigerant industry transition in history at the time. The current R-22 to R-410A and R-410A to R-32/R-454B transitions echo the R-12 transition's scale.

How to think about R-12 in 2026 and beyond

R-12 is essentially a historical refrigerant in 2026. The installed base of R-12 equipment is tiny — household refrigerators built before 1994 have largely been replaced; vehicles built before 1992 are mostly retired classic cars; chillers from the pre-1996 era have been replaced.

Service supply via reclaimed R-12 continues but pricing reflects very limited market. Typical 2026 wholesale prices are 50-200× the 1995 baseline.

For the rare situations where R-12 service is needed (classic car restoration, historical chiller museum installations, specialty applications), reclaimed R-12 remains legal under EPA Section 608. EPA Type II or Universal certification required for service work.

R-12's primary continuing relevance is as a historical reference — defining the GWP and ODP scales, the Montreal Protocol case study, the largest refrigerant industry transition before the modern HFC phase-down era.

11

Frequently asked

›Why was R-12 banned?

Ozone-depletion potential. R-12 contains two chlorine atoms per molecule; UV breakdown in the stratosphere releases chlorine radicals that catalyze ozone destruction. The 1985 discovery of the Antarctic ozone hole, attributed to atmospheric CFC accumulation, drove the 1987 Montreal Protocol mandate for CFC phase-out.

Developed countries banned CFC production on 1 January 1996 [epacfr82]. Developing countries followed by 2010 under amended Montreal Protocol schedules.

›Is R-12 still legal?

Reclaimed R-12 is legal to use indefinitely in existing equipment under EPA Section 608 rules [epasec608]. New production has been banned in the US since 1996; supply comes entirely from reclaimed material recovered from equipment removals.

›What's R-12's GWP and ODP?

ODP 1.0 (the reference value for the scale) and GWP 10900 per IPCC AR5 [montrealprotocol][ipccar5]. R-12 is the reference benchmark for both environmental metrics — every other refrigerant's ODP is measured relative to R-12's ozone-depletion potency.

The very high GWP (10900) means R-12 release has approximately 7.6× the climate impact per kg of R-410A (2088) and 5× the impact of R-404A (3922). R-12 is the worst possible refrigerant by GWP standards among mainstream HVAC refrigerants.

›What replaced R-12 in cars?

R-134a (HFC, GWP 1430) replaced R-12 in new vehicle MAC starting in 1992-1995 (Chrysler 1992, Ford 1993, GM 1994). The R-12 to R-134a transition required new compressor oil (mineral oil to PAG), different service ports (smaller R-134a ports), and updated MAC system designs.

R-134a was itself replaced by R-1234yf (HFO, GWP 4) in new vehicle MAC starting in 2017 (EU) and 2017-2021 (US) under EU MAC Directive 2006/40/EC and AIM Act pressure.

›What replaced R-12 in household refrigerators?

R-134a (HFC) initially, in the early 1990s. Modern household refrigerators have largely transitioned to R-600a (isobutane, hydrocarbon, GWP 3) since the 2010s. The R-12 to R-134a transition was for ozone-depletion reasons; the R-134a to R-600a transition is for GWP reduction.

›Why is R-12 so expensive now?

Reclaim-only supply for a small and shrinking market. Production has been banned since 1996; supply comes entirely from refrigerant recovered from equipment removals. The R-12 installed base is now tiny — vehicles and refrigerators built before 1995 are nearly all retired. Typical wholesale prices in 2026 are 50-200× the 1995 baseline.

›Can I retrofit an R-12 system to R-134a?

For vehicles: yes, with new compressor oil (PAG instead of mineral oil), service-port conversion (R-134a smaller ports), and sometimes compressor replacement. The retrofit was common in the late 1990s and early 2000s for R-12 vehicles that needed major AC service.

For household refrigerators: typically not — refrigerator replacement is more economical than refrigerant retrofit.

›Is R-12 the same as Freon?

"Freon" is a Chemours/DuPont trademark applied to many fluorinated refrigerants. R-12 was historically marketed as Freon 12 — perhaps the most famous Freon product. The colloquial use of "Freon" as a generic refrigerant term derives from R-12's market dominance in the mid-20th century.

Honeywell's equivalent brand was Genetron 12. Both manufacturers ceased R-12 production in 1996.

Download this dataset

Full PT chart for R-12 · CC BY 4.0 · attribute the source

CSV JSON
13

Sources & citations

  1. [1]
    ASHRAE Standard 34-2022
    2022https://www.ashrae.org/technical-resources/standards-and-guidelines
  2. [2]
    IPCC AR5 (2014) Working Group I, Chapter 8, Table 8.A.1
    2014https://www.ipcc.ch/report/ar5/wg1/
  3. [3]
    Montreal Protocol on Substances that Deplete the Ozone Layer — CFC complete phase-out 1996
    1987, full CFC ban 1 Jan 1996 in developed countrieshttps://ozone.unep.org/treaties/montreal-protocol
  4. [4]
    EPA 40 CFR Part 82 Subpart A — CFC production and consumption ban
    CFC production banned 1 Jan 1996https://www.epa.gov/ods-phaseout
  5. [5]
    EPA Section 608 — Stationary Refrigeration and AC Regulations
    https://www.epa.gov/section608
  6. [6]
    CoolProp 7.2.0
    2014 (continually updated)http://www.coolprop.org/doi:10.1021/ie4033999
  7. [7]
    AHRI Standard 700-2019
    2019https://www.ahrinet.org/search-standards
  8. [8]
    NASA Ozone Watch — Stratospheric ozone depletion measurement and history
    https://ozonewatch.gsfc.nasa.gov/

Data sources & provenance

PT chart
CoolProp 7.2.0 R12
Cross-checked against
CoolProp 7.2.0 (R12); ASHRAE Handbook of Refrigeration 2022
Properties
CoolProp 7.2.0 + ASHRAE Standard 34-2022
GWP
IPCC AR5 Table 8.A.1
Generated
2026-06-05

Reference material. Always verify pressure values against the equipment data plate and manufacturer service literature before charging or troubleshooting a specific system. Saturation pressure differs from operating pressure — see superheat & subcooling fundamentals.