RefrigerantASHRAE R-123

R-123

Q: What is R-123 used for?

Low-pressure centrifugal chillers, dominantly. Trane CenTraVac was the most prominent R-123 chiller product line [trane]; other chiller OEMs also offered R-123 options. R-123 was the standard low-pressure chiller refrigerant from 1990 through 2020. Production was banned on 1 January 2020 under the HCFC phase-out; new chiller equipment specifies R-1233zd(E) (HCFO, A1, GWP 1, near-zero ODP) as the standard R-123 replacement.

Q: Why was R-123 phased out?

Ozone-depletion potential. R-123 contains two chlorine atoms; HCFCs were added to the Montreal Protocol controlled substances list in 1992 (Copenhagen Amendment). Despite R-123's relatively low ODP (0.02), the Montreal Protocol HCFC schedule mandated complete phase-out [montrealprotocol]. US implementation through 40 CFR Part 82 Subpart A: production banned 1 January 2020 [epacfr82].

Q: What's R-123's GWP and ODP?

GWP 79 (IPCC AR5), ODP 0.02 [ipccar5][montrealprotocol]. The GWP is low for an HCFC and dramatically lower than HFC alternatives (R-134a 1430, R-410A 2088). The ODP is small but non-zero — triggering the Montreal Protocol phase-out despite the relatively low ozone impact per kg.

Q: What replaced R-123?

R-1233zd(E) (Honeywell Solstice zd) is the standard replacement [trane]. HCFO chemistry similar to R-123 but with a carbon-carbon double bond that gives very short atmospheric lifetime (26 days) and very low GWP (1). The one chlorine atom in R-1233zd(E) gives technically-non-zero ODP (0.00034) but below regulatory de-minimis thresholds. R-1233zd(E) is operationally near-equivalent to R-123 — similar pressure envelope, similar safety class (R-1233zd(E) is A1, R-123 is B1, so R-1233zd(E) is actually safer), similar lubricant compatibility.

Q: Is R-123 still legal?

Reclaimed R-123 is legal to use indefinitely in existing equipment under EPA Section 608 rules [epasec608]. New production has been banned in the US since 1 January 2020 [epacfr82]. Supply comes from reclaimed material recovered from equipment removals.

Q: Why is R-123 B1 (higher toxicity) instead of A1?

R-123 has higher chronic toxicity than A-class refrigerants — long-term exposure produces liver effects in animal studies. ACGIH TLV is 50 ppm (8-hour TWA). The toxicity is chronic-exposure rather than acute — short refrigerant exposure during service is manageable with standard procedures, but continuous workplace exposure must be limited. ASHRAE Standard 15 requires leak detection and equipment-room ventilation for B1 refrigerants to protect against chronic worker exposure [ashrae15].

Q: What lubricant does R-123 use?

Mineral oil typically [ahri700]. Standard chiller mineral oil viscosity grades apply. R-123 is fully miscible with mineral oil at chiller operating temperatures.

Q: Can I retrofit an R-123 chiller to R-1233zd(E)?

Yes — R-1233zd(E) was designed as a near-drop-in R-123 retrofit. Trane and other chiller OEMs document R-123 to R-1233zd(E) conversion procedures. Pressure envelope is similar; safety class is improved (B1 to A1); lubricant compatibility is preserved (mineral oil works for both).

B1Toxic, non-flammableHCFC

CHCl2CF3

HCFC (2,2-dichloro-1,1,1-trifluoroethane, CHCl₂CF₃) — B1 toxic non-flammable, GWP 79, ODP 0.02. The dominant low-pressure centrifugal chiller refrigerant 1990-2020; US production banned 1 January 2020. R-1233zd(E) is the standard replacement.

Saturation @ 70°F

-3.3PSIG

GWP (IPCC AR5)

77100-yr

Temperature glide

≈0°F

Boiling point

82.1°F

Sourced facts

ASHRAE safety class: B1[src]
Chemical formula: CHCl₂CF₃[src]
ODP: 0.02[src]
GWP (100-yr): 79IPCC AR5[src]
Normal boiling point: 82.1°F (27.8°C)[src]
Production status: Banned (US)1 Jan 2020[src]
Required lubricant: Mineral oil[src]
Replacement: R-1233zd(E)[src]

R-123 PT calculator Superheat

Toxic, non-flammable

Higher toxicity (Occupational Exposure Limit < 400 ppm). No flame propagation. R-123, R-245fa, R-514A are B1. Centrifugal-chiller machine rooms require ventilation, refrigerant leak detection, and emergency egress per ASHRAE Standard 15.

Flammability: None
Toxicity: Higher (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-123

Temp:°F

-3.3PSIG(-22 kPa)

Range: -40 to 150°FOpen full PT calculator →

Common service temperatures

32°F

-10PSIG

Freezing

45°F

-8PSIG

Heat-pump heat

70°F

-3PSIG

Standard

75°F

-2PSIG

Test ref

80°F

-1PSIG

Warm

95°F

4PSIG

Summer peak

Saturation values from CoolProp 7.2.0 R123. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

R-123 PT chart PDF — printable saturation table

Looking for the R-123 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-123 PT Chart — Pressure-Temperature Saturation Table

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

R-123 · 1° increments · °F / PSIG

Tinted rows: NBP atmospheric crossover · 32°F H₂O freeze · 40°F Chiller evap LCHW · 100°F Cond saturation · 130°F High-side limit

R-123 pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)	Pressure (PSIG)
-40°F	-14.2
-39°F	-14.2
-38°F	-14.1
-37°F	-14.1
-36°F	-14.1
-35°F	-14.1
-34°F	-14.1
-33°F	-14.0
-32°F	-14.0
-31°F	-14.0
-30°F	-13.9
-29°F	-13.9
-28°F	-13.9
-27°F	-13.9
-26°F	-13.8
-25°F	-13.8
-24°F	-13.8
-23°F	-13.8
-22°F	-13.7
-21°F	-13.7
-20°F	-13.7
-19°F	-13.6
-18°F	-13.6
-17°F	-13.5
-16°F	-13.5
-15°F	-13.5
-14°F	-13.4
-13°F	-13.4
-12°F	-13.3
-11°F	-13.3
-10°F	-13.3
-9°F	-13.2
-8°F	-13.2
-7°F	-13.1
-6°F	-13.1
-5°F	-13.0
-4°F	-13.0
-3°F	-12.9
-2°F	-12.8
-1°F	-12.8
0°F	-12.7
1°F	-12.7
2°F	-12.6
3°F	-12.6
4°F	-12.5
5°F	-12.4
6°F	-12.3
7°F	-12.3
8°F	-12.2
9°F	-12.1
10°F	-12.1
11°F	-12.0
12°F	-11.9
13°F	-11.8
14°F	-11.8
15°F	-11.7
16°F	-11.6
17°F	-11.5
18°F	-11.4
19°F	-11.3
20°F	-11.2
21°F	-11.1
22°F	-11.1
23°F	-10.9
24°F	-10.8
25°F	-10.7
26°F	-10.6
27°F	-10.5
28°F	-10.4
29°F	-10.3
30°F	-10.2
31°F	-10.1
32°FH₂O freeze	-10.0
33°F	-9.8
34°F	-9.7
35°F	-9.6
36°F	-9.5
37°F	-9.3
38°F	-9.2
39°F	-9.1
40°FChiller evap LCHW	-8.9
41°F	-8.8
42°F	-8.6
43°F	-8.5
44°F	-8.3
45°F	-8.2
46°F	-8.0
47°F	-7.9
48°F	-7.7
49°F	-7.5
50°F	-7.4
51°F	-7.2
52°F	-7.0
53°F	-6.8
54°F	-6.7
55°F	-6.5
56°F	-6.3
57°F	-6.1
58°F	-5.9
59°F	-5.7
60°F	-5.5
61°F	-5.3
62°F	-5.1
63°F	-4.9
64°F	-4.6
65°F	-4.4
66°F	-4.2
67°F	-4.0
68°F	-3.7
69°F	-3.5
70°F	-3.3
71°F	-3.0
72°F	-2.8
73°F	-2.5
74°F	-2.3
75°F	-2.0
76°F	-1.7
77°F	-1.4
78°F	-1.2
79°F	-0.9
80°F	-0.6
81°F	-0.3
82°F	-0.0
83°FNBP (atmospheric)	0.3
84°F	0.6
85°F	0.9
86°F	1.2
87°F	1.5
88°F	1.8
89°F	2.2
90°F	2.5
91°F	2.8
92°F	3.2
93°F	3.5
94°F	3.9
95°F	4.2
96°F	4.6
97°F	5.0
98°F	5.3
99°F	5.7
100°FCond saturation	6.1
101°F	6.5
102°F	6.9
103°F	7.3
104°F	7.7
105°F	8.1
106°F	8.5
107°F	9.0
108°F	9.4
109°F	9.8
110°F	10.3
111°F	10.7
112°F	11.2
113°F	11.7
114°F	12.1
115°F	12.6
116°F	13.1
117°F	13.6
118°F	14.1
119°F	14.6
120°F	15.1
121°F	15.6
122°F	16.1
123°F	16.6
124°F	17.2
125°F	17.7
126°F	18.3
127°F	18.8
128°F	19.4
129°F	20.0
130°FHigh-side limit	20.6
131°F	21.1
132°F	21.7
133°F	22.3
134°F	22.9
135°F	23.6
136°F	24.2
137°F	24.8
138°F	25.5
139°F	26.1
140°F	26.8
141°F	27.4
142°F	28.1
143°F	28.8
144°F	29.5
145°F	30.2
146°F	30.9
147°F	31.6
148°F	32.3
149°F	33.0
150°F	33.8

R-123 pressure-temperature saturation table in Celsius and kPa
Temp (°C)	Pressure (kPa)
-40°C	-98
-39°C	-98
-38°C	-97
-37°C	-97
-36°C	-97
-35°C	-96
-34°C	-96
-33°C	-96
-32°C	-95
-31°C	-95
-30°C	-95
-29°C	-94
-28°C	-94
-27°C	-93
-26°C	-93
-25°C	-92
-24°C	-92
-23°C	-91
-22°C	-91
-21°C	-90
-20°C	-89
-19°C	-89
-18°C	-88
-17°C	-87
-16°C	-86
-15°C	-86
-14°C	-85
-13°C	-84
-12°C	-83
-11°C	-82
-10°C	-81
-9°C	-80
-8°C	-79
-7°C	-78
-6°C	-77
-5°C	-76
-4°C	-74
-3°C	-73
-2°C	-72
-1°C	-70
0°CH₂O freeze	-69
1°C	-67
2°C	-66
3°C	-64
4°CChiller evap LCHW	-62
5°C	-61
6°C	-59
7°C	-57
8°C	-55
9°C	-53
10°C	-51
11°C	-49
12°C	-46
13°C	-44
14°C	-42
15°C	-39
16°C	-37
17°C	-34
18°C	-31
19°C	-29
20°C	-26
21°C	-23
22°C	-20
23°C	-17
24°C	-13
25°C	-10
26°C	-7
27°C	-3
28°CNBP (atmospheric)	1
29°C	4
30°C	8
31°C	12
32°C	16
33°C	20
34°C	25
35°C	29
36°C	34
37°C	38
38°CCond saturation	43
39°C	48
40°C	53
41°C	58
42°C	64
43°C	69
44°C	75
45°C	80
46°C	86
47°C	92
48°C	98
49°C	105
50°C	111
51°C	118
52°C	124
53°C	131
54°CHigh-side limit	138
55°C	146
56°C	153
57°C	161
58°C	169
59°C	176
60°C	185
61°C	193
62°C	201
63°C	210
64°C	219
65°C	228

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-123 PT chart data: CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS) or manufacturer datasheet, validated against AHRI Standard 700-2019.

At a glance

Chemistry

CHCl2CF3

2,2-Dichloro-1,1,1-trifluoroethane

Lubricant compatibility

MOABPOE

Low-pressure refrigerant for centrifugal chillers. Higher toxicity (B1) compared with most HCFCs — proper ventilation is required.

Trade names

Freon 123Chemours (historical: DuPont)
Genetron 123Honeywell

Common applications

Low-pressure centrifugal chillers (large commercial buildings)
Industrial process cooling

Properties

Boiling point (1 atm)
27.8°C / 82.1°F
Critical point
362.6°F at 518 PSIG
Molar mass
152.93 g/mol
Temperature glide
Negligible (0.00°F)
ODP
0.02
GWP (AR5, 100-yr)
77
GWP (AR6, 100-yr)
79
Atmospheric lifetime
1.3 years

What is R-123?

R-123 is 2,2-dichloro-1,1,1-trifluoroethane (CHCl₂CF₃) — a hydrochlorofluorocarbon (HCFC) with B1 safety classification and a unique application niche [ashrae34]. The two chlorine atoms give R-123 small but non-zero ODP (0.02); the molecular structure produces very low vapor pressure and a unique high boiling point (82°F) that suits low-pressure centrifugal chiller applications.

R-123 was the dominant low-pressure centrifugal chiller refrigerant from 1990 through 2020, replacing CFC R-11 in chiller equipment after the 1996 CFC phase-out. R-123's low pressure envelope (sub-atmospheric on the evaporator side at typical chiller temperatures) is well-suited to large centrifugal chiller compressor designs. US production was banned on 1 January 2020 under the Montreal Protocol HCFC schedule [epacfr82].

Where R-123 is used

Low-pressure centrifugal chillers (Trane CenTraVac, others) installed 1990-2020
Legacy chiller equipment requiring service with reclaimed R-123
Specialty heat-transfer applications
Replaced in new equipment by R-1233zd(E) (A1, GWP 1, near-zero ODP)

Regulatory & phase-down status

R-123 US production was banned on 1 January 2020 under the HCFC schedule [epacfr82]. The phase-out parallels R-22's: complete ban on new production, with reclaimed supply remaining legal for service of existing equipment under EPA Section 608 [epasec608].

For existing R-123 chillers, service supply will continue via reclaimed R-123 indefinitely. The remaining R-123 chiller installed base is significant (large centrifugal chillers from the 1990s-2010s era) and will continue operating for decades. Replacement chillers increasingly specify R-1233zd(E) for new equipment.

Service notes

R-123 is B1 — higher toxicity than typical A-class refrigerants. ASHRAE Standard 15 requires specific equipment-room provisions for B1 refrigerants: leak detection, emergency ventilation, machine room exclusion zone provisions [ashrae15].

Mineral oil compatible. Standard chiller service procedures apply with B1 toxicity precautions. EPA Section 608 Type I (for low-pressure appliances) or Universal certification required for service.

R-123 operates at very low pressures — sub-atmospheric on the evaporator side at typical chiller temperatures. Equipment includes purge units to remove non-condensable atmospheric contamination from sub-atmospheric operation.

Operating cycle

Phase-down timeline

R-123 is not currently regulated by AIM Act or EU F-Gas phase-down. Its very low GWP (77) places it below regulatory thresholds. No published phase-down milestones exist for this refrigerant — it is a forward-compatible option for the current low-GWP transition rather than a refrigerant being phased out.

Properties: GWP (AR5) 77 · ODP 0.02 · Not AIM Act-affected · type: hcfc

Global warming potential, in context

Low-pressure centrifugal chillers

Retrofit and replacement paths

R-123 replaces

R-11A1 · GWP 4750

Replacements for R-123

Reading the R-123 PT chart — very low pressures, sub-atmospheric on chiller evaporator

R-123's PT chart shows very low pressures across the chiller operating range. At 70°F R-123 saturation is approximately 0 PSIG (atmospheric); at typical chiller evaporator temperatures (35-45°F), saturation is well below atmospheric — chiller evaporator runs at vacuum.

Single saturation curve (pure refrigerant, no glide). The operational concern is vacuum operation and air-ingress prevention rather than high-pressure safety.

HCFC chemistry — two chlorines, three fluorines

R-123 is 2,2-dichloro-1,1,1-trifluoroethane: CHCl₂CF₃. The two chlorine atoms on one carbon and the three fluorine atoms on the other produce R-123's distinctive properties — low vapor pressure (high boiling point), B1 toxicity classification, and small but non-zero ODP.

The molecular structure with chlorine content is what triggered Montreal Protocol HCFC phase-out. The hydrogen atom (the "H" in HCFC) provides atmospheric breakdown chemistry that gives HCFCs shorter atmospheric lifetime than CFCs — R-123 atmospheric lifetime is ~1.3 years vs R-12's 100 years. The shorter lifetime is why R-123's ODP (0.02) is much lower than R-12's (1.0) despite both molecules containing chlorine.

B1 toxicity — equipment-room provisions per ASHRAE 15

R-123's B1 classification reflects higher chronic toxicity than A-class refrigerants. ASHRAE Standard 15 specifies equipment-room provisions for B1 refrigerants: refrigerant leak detection, emergency exhaust ventilation, machine room exclusion zones during refrigerant release events [ashrae15].

ACGIH TLV (8-hour time-weighted average exposure limit) is 50 ppm for R-123. The toxicity concern is chronic — long-term worker exposure to low concentrations can produce liver effects. Acute exposure during service is manageable with standard procedures; the concern is workplace contamination over extended operating periods.

For chiller machine room design, B1 refrigerants require dedicated ventilation systems and leak detection beyond what A1 chillers need. The R-1233zd(E) replacement (A1 classification) eliminates this requirement — one reason R-1233zd(E) is the preferred replacement.

ODP 0.02 and GWP 79 — low for an HCFC, but Montreal Protocol mandates phase-out

R-123's ODP of 0.02 is small but non-zero — much lower than R-22 (0.055) and R-12 (1.0). The Montreal Protocol HCFC schedule mandated complete phase-out despite the lower ODP because all chlorine-bearing refrigerants contribute to long-term stratospheric ozone burden.

GWP 79 is low for an HCFC — much lower than HFC alternatives (R-134a 1430, R-410A 2088). R-123's environmental profile was favorable on the GWP axis but unfavorable on the ODP axis; modern policy preserves the favorable GWP positioning through R-1233zd(E) replacement (HCFO chemistry, GWP 1, near-zero ODP).

How to think about R-123 in 2026 and beyond

R-123 occupies a defined legacy niche in 2026 — service of low-pressure centrifugal chillers installed 1990-2020. The installed base is significant (thousands of large commercial chillers in the US) and these chillers will continue operating for decades. Service supply via reclaimed R-123 will continue indefinitely.

For new chiller equipment, R-1233zd(E) is the standard low-pressure replacement. The replacement provides operational equivalence (similar pressure envelope, mineral oil compatibility) with environmental and safety improvements (A1 vs B1, GWP 1 vs 79, near-zero vs 0.02 ODP).

For existing R-123 chillers, the decision tree: continue on reclaimed R-123 for systems with remaining life and acceptable pricing; retrofit to R-1233zd(E) for systems where the B1 toxicity provisions are inconvenient or where major chiller refurbishment is planned anyway. Replacement decision parallels R-22 retrofit-vs-replace logic at the chiller scale.

For service technicians, R-123 work requires B1 toxicity awareness — leak detection, ventilation, exclusion zones during refrigerant operations. EPA Section 608 Type I or Universal certification.

Frequently asked

›What is R-123 used for?

Low-pressure centrifugal chillers, dominantly. Trane CenTraVac was the most prominent R-123 chiller product line [trane]; other chiller OEMs also offered R-123 options. R-123 was the standard low-pressure chiller refrigerant from 1990 through 2020.

Production was banned on 1 January 2020 under the HCFC phase-out; new chiller equipment specifies R-1233zd(E) (HCFO, A1, GWP 1, near-zero ODP) as the standard R-123 replacement.

›Why was R-123 phased out?

Ozone-depletion potential. R-123 contains two chlorine atoms; HCFCs were added to the Montreal Protocol controlled substances list in 1992 (Copenhagen Amendment). Despite R-123's relatively low ODP (0.02), the Montreal Protocol HCFC schedule mandated complete phase-out [montrealprotocol].

US implementation through 40 CFR Part 82 Subpart A: production banned 1 January 2020 [epacfr82].

›What's R-123's GWP and ODP?

GWP 79 (IPCC AR5), ODP 0.02 [ipccar5][montrealprotocol]. The GWP is low for an HCFC and dramatically lower than HFC alternatives (R-134a 1430, R-410A 2088). The ODP is small but non-zero — triggering the Montreal Protocol phase-out despite the relatively low ozone impact per kg.

›What replaced R-123?

R-1233zd(E) (Honeywell Solstice zd) is the standard replacement [trane]. HCFO chemistry similar to R-123 but with a carbon-carbon double bond that gives very short atmospheric lifetime (26 days) and very low GWP (1). The one chlorine atom in R-1233zd(E) gives technically-non-zero ODP (0.00034) but below regulatory de-minimis thresholds.

R-1233zd(E) is operationally near-equivalent to R-123 — similar pressure envelope, similar safety class (R-1233zd(E) is A1, R-123 is B1, so R-1233zd(E) is actually safer), similar lubricant compatibility.

›Is R-123 still legal?

Reclaimed R-123 is legal to use indefinitely in existing equipment under EPA Section 608 rules [epasec608]. New production has been banned in the US since 1 January 2020 [epacfr82]. Supply comes from reclaimed material recovered from equipment removals.

›Why is R-123 B1 (higher toxicity) instead of A1?

R-123 has higher chronic toxicity than A-class refrigerants — long-term exposure produces liver effects in animal studies. ACGIH TLV is 50 ppm (8-hour TWA). The toxicity is chronic-exposure rather than acute — short refrigerant exposure during service is manageable with standard procedures, but continuous workplace exposure must be limited.

ASHRAE Standard 15 requires leak detection and equipment-room ventilation for B1 refrigerants to protect against chronic worker exposure [ashrae15].

›What lubricant does R-123 use?