Its GWP is 1 in the US EPA reference table and its ODP is 0.

RefrigerantASHRAE R-717

R717 (Ammonia) PT Chart

Q: Why can't I use copper piping with ammonia?

Ammonia is corrosive to copper and galvanized surfaces.

Updated October 19, 2026

R-717 · Ammonia

B2L Higher toxicity, lower flammabilityNatural

AHRI Guideline N-2017 lists no container for R-717^{[4], Table 1}.

NH3

Anhydrous ammonia (NH₃): safety class B2L^[2], GWP 1^[5], ODP 0^[6].

R-717 saturation pressure is 58.6 PSIG at 40°F, 114.1 PSIG at 70°F, and 197.2 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.

Checked against the NIST Chemistry WebBook, SRD 69 — Thermophysical Properties of Fluid Systems: Ammonia, saturation properties^[1] at 19 points from −35°F to 140°F: largest difference 0.002 psi.

Saturation @ 70°F

114.1 PSIG

GWP (100-yr)

1 US EPA Technology Transitions GWP reference table

Boiling point

−28.0°F

Sourced facts

ASHRAE safety class: B2L^[2]
Chemical formula: NH₃^[2]
GWP (100-yr): 1^[5]
ODP: 0^[6]
Normal boiling point: −28.0°F (−33.3°C)^[3]
Critical temperature: 270.3°F (132.4°C)^[3]
Saturation at 70°F: 114.1 PSIG^[3]
NIOSH IDLH: 300 ppm^{[12], IDLH}

R-717 PT calculator Superheat

R-717 PT chart — printable saturation table

Looking for the R-717 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-717 PT Chart — Pressure-Temperature Saturation Table

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

R-717 · 1° increments · °F / PSIG

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

R-717 pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)	Pressure (PSIG)
−40°F	8.8 in. Hg vac.
−39°F	8.1 in. Hg vac.
−38°F	7.5 in. Hg vac.
−37°F	6.8 in. Hg vac.
−36°F	6.1 in. Hg vac.
−35°F	5.4 in. Hg vac.
−34°F	4.7 in. Hg vac.
−33°F	4.0 in. Hg vac.
−32°F	3.2 in. Hg vac.
−31°F	2.4 in. Hg vac.
−30°F	1.7 in. Hg vac.
−29°F	0.9 in. Hg vac.
−28°F NBP (atmospheric)	0.0 in. Hg vac.
−27°F	0.4
−26°F	0.8
−25°F	1.3
−24°F	1.7
−23°F	2.2
−22°F	2.6
−21°F	3.1
−20°F	3.6
−19°F	4.1
−18°F	4.6
−17°F	5.1
−16°F	5.6
−15°F	6.2
−14°F	6.7
−13°F	7.3
−12°F	7.8
−11°F	8.4
−10°F	9.0
−9°F	9.6
−8°F	10.3
−7°F	10.9
−6°F	11.5
−5°F	12.2
−4°F	12.9
−3°F	13.6
−2°F	14.3
−1°F	15.0
0°F	15.7
1°F	16.4
2°F	17.2
3°F	18.0
4°F	18.7
5°F	19.5
6°F	20.4
7°F	21.2
8°F	22.0
9°F	22.9
10°F	23.8
11°F	24.7
12°F	25.6
13°F	26.5
14°F	27.5
15°F	28.4
16°F	29.4
17°F	30.4
18°F	31.4
19°F	32.4
20°F	33.5
21°F	34.6
22°F	35.6
23°F	36.7
24°F	37.9
25°F	39.0
26°F	40.2
27°F	41.4
28°F	42.6
29°F	43.8
30°F	45.0
31°F	46.3
32°F H₂O freeze	47.6
33°F	48.9
34°F	50.2
35°F	51.5
36°F	52.9
37°F	54.3
38°F	55.7
39°F	57.1
40°F	58.6
41°F	60.1
42°F	61.6
43°F	63.1
44°F	64.7
45°F	66.2
46°F	67.8
47°F	69.5
48°F	71.1
49°F	72.8
50°F	74.5
51°F	76.2
52°F	77.9
53°F	79.7
54°F	81.5
55°F	83.3
56°F	85.2
57°F	87.1
58°F	89.0
59°F	90.9
60°F	92.9
61°F	94.9
62°F	96.9
63°F	98.9
64°F	101.0
65°F	103.1
66°F	105.3
67°F	107.4
68°F	109.6
69°F	111.8
70°F	114.1
71°F	116.4
72°F	118.7
73°F	121.0
74°F	123.4
75°F	125.8
76°F	128.3
77°F	130.7
78°F	133.2
79°F	135.8
80°F	138.4
81°F	141.0
82°F	143.6
83°F	146.3
84°F	149.0
85°F	151.7
86°F	154.5
87°F	157.3
88°F	160.2
89°F	163.0
90°F	166.0
91°F	168.9
92°F	171.9
93°F	174.9
94°F	178.0
95°F	181.1
96°F	184.2
97°F	187.4
98°F	190.6
99°F	193.9
100°F	197.2
101°F	200.5
102°F	203.9
103°F	207.3
104°F	210.8
105°F	214.3
106°F	217.8
107°F	221.4
108°F	225.0
109°F	228.7
110°F	232.4
111°F	236.1
112°F	239.9
113°F	243.7
114°F	247.6
115°F	251.5
116°F	255.5
117°F	259.5
118°F	263.5
119°F	267.6
120°F	271.7
121°F	275.9
122°F	280.2
123°F	284.4
124°F	288.8
125°F	293.1
126°F	297.5
127°F	302.0
128°F	306.5
129°F	311.1
130°F	315.7
131°F	320.3
132°F	325.1
133°F	329.8
134°F	334.6
135°F	339.5
136°F	344.4
137°F	349.3
138°F	354.3
139°F	359.4
140°F	364.5
141°F	369.7
142°F	374.9
143°F	380.1
144°F	385.5
145°F	390.8
146°F	396.3
147°F	401.8
148°F	407.3
149°F	412.9
150°F	418.5

R-717 pressure-temperature saturation table in Celsius and kPa
Temp (°C)	Pressure (kPa)
−40°C	−30
−39°C	−26
−38°C	−22
−37°C	−17
−36°C	−13
−35°C	−8
−34°C	−3
−33°C NBP (atmospheric)	2
−32°C	7
−31°C	12
−30°C	18
−29°C	24
−28°C	30
−27°C	37
−26°C	43
−25°C	50
−24°C	57
−23°C	65
−22°C	72
−21°C	80
−20°C	89
−19°C	97
−18°C	106
−17°C	115
−16°C	125
−15°C	135
−14°C	145
−13°C	156
−12°C	166
−11°C	178
−10°C	189
−9°C	201
−8°C	214
−7°C	227
−6°C	240
−5°C	253
−4°C	267
−3°C	282
−2°C	297
−1°C	312
0°C H₂O freeze	328
1°C	344
2°C	361
3°C	378
4°C	396
5°C	414
6°C	433
7°C	452
8°C	472
9°C	493
10°C	513
11°C	535
12°C	557
13°C	580
14°C	603
15°C	627
16°C	651
17°C	676
18°C	702
19°C	729
20°C	756
21°C	783
22°C	812
23°C	841
24°C	871
25°C	901
26°C	933
27°C	965
28°C	997
29°C	1,031
30°C	1,065
31°C	1,100
32°C	1,136
33°C	1,173
34°C	1,210
35°C	1,249
36°C	1,288
37°C	1,328
38°C	1,369
39°C	1,411
40°C	1,453
41°C	1,497
42°C	1,541
43°C	1,587
44°C	1,633
45°C	1,680
46°C	1,729
47°C	1,778
48°C	1,828
49°C	1,879
50°C	1,932
51°C	1,985
52°C	2,039
53°C	2,095
54°C	2,151
55°C	2,209
56°C	2,267
57°C	2,327
58°C	2,388
59°C	2,450
60°C	2,513
61°C	2,577
62°C	2,643
63°C	2,710
64°C	2,778
65°C	2,847
66°C	2,917

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-717 PT chart data: CoolProp 7.2.0 (published Helmholtz equations of state / mixture models — see the source citations above).

B2L

Higher toxicity, lower flammability

Higher toxicity. Flame propagates with low burning velocity (≤ 10 cm/s). NIOSH IDLH for ammonia is 300 ppm. Industrial-refrigeration regulations (IIAR standards, EPA RMP, OSHA PSM) apply at charges above ~10,000 lb.

Flammability: Lower (burning velocity ≤ 10 cm/s)
Toxicity: Higher

Classification per ANSI/ASHRAE Standard 34-2022^{[2], safety group definitions and refrigerant safety classifications}. See full reference.

Saturation pressure-temperature curve

Pressure

Temperature

Highlight at°F

Quick lookup — R-717

Temp:°F

114.1PSIG(787 kPa)

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

Common service temperatures

32°F

48PSIG

Freezing

45°F

66PSIG

Heat-pump heat

70°F

114PSIG

Standard

75°F

126PSIG

Test ref

80°F

138PSIG

Warm

95°F

181PSIG

Summer peak

Saturation values from CoolProp 7.2.0^[3]. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

At a glance

Chemistry

NH3

Ammonia

Lubricant compatibility

MOABPAOPOE

Class B2L: higher toxicity and lower flammability^[2]. Exposure limits: OSHA PEL 50 ppm (8-hour TWA); NIOSH REL 25 ppm (10-hour TWA), 35 ppm short-term; IDLH 300 ppm^[12]. Ammonia is corrosive to copper and galvanized surfaces^[12].

Common applications

New cold storage warehouses (EPA SNAP: acceptable)^[7]
New centrifugal chillers (EPA SNAP: acceptable)^[8]

Properties

Boiling point (1 atm)
−28.0°F (−33.3°C)
Critical point
270.3°F (132.4°C) at 1,633 PSIG
Molar mass
17.03 g/mol
ODP
0
GWP (100-yr)
1 US EPA Technology Transitions GWP reference table IPCC: AR4 not assessed · AR5 not assessed · AR6 not assessed IPCC does not assess ammonia as a greenhouse gas; 40 CFR 84.64(b) lists 1.
Atmospheric lifetime
0.01 years
New-equipment status (US)
Not an AIM Act regulated substance; 40 CFR 84.54 GWP limits don't apply.

What is R-717?

R-717 is anhydrous ammonia (NH₃), with a GWP of 1^[5] and an ODP of 0^[6]. Its ASHRAE safety class, B2L, means higher toxicity (B) and lower flammability with a burning velocity of 10 cm/s or less (2L)^[2].

EPA's SNAP program lists ammonia as acceptable in new cold storage warehouses, supermarket systems and centrifugal chillers^[7]^[6]^[8].

Where R-717 is used

New cold storage warehouses (EPA SNAP: acceptable)^[7]

Regulatory & phase-down status

R-717 is not an AIM Act regulated substance, so the HFC phase-down and the 40 CFR 84.54 limits don't apply to it^{[9], 42 U.S.C. 7675(c)(1)}.

EPA's Risk Management Program (40 CFR Part 68) and OSHA's Process Safety Management standard (29 CFR 1910.119) both set a 10,000 lb threshold quantity for anhydrous ammonia^{[10], Table 1}^{[11], Appendix A}.

Service notes

NIOSH lists an IDLH of 300 ppm for ammonia and a recommended exposure limit of 25 ppm (10-hour TWA); OSHA's PEL is 50 ppm (8-hour TWA)^[12].

Ammonia is corrosive to copper and galvanized surfaces^[12].

Processes with 10,000 lb or more of anhydrous ammonia fall under OSHA's Process Safety Management standard, which requires process hazard analyses, written operating procedures, mechanical integrity programs, emergency planning and compliance audits at least every three years^{[11], (e), (f), (j), (n), (o)}.

Operating cycle

Phase-down timeline

R-717 is not an AIM Act regulated substance (not one of the 18 HFCs in 42 U.S.C. 7675(c), and not a blend containing one). The 40 CFR 84.54 GWP limits don't apply.

Global warming potential, in context

Industrial refrigeration & cascade systems

Reading the R-717 pressure-temperature chart

R-717's PT chart is a single saturation curve — ammonia is a pure substance with no temperature glide and no bubble/dew distinction^[2]. The table runs from −40°F to 150°F; ammonia's critical temperature is 270.3°F^[3].

For service measurement: standard pressure-to-temperature lookup applies. Superheat at the suction line = suction line temp − saturation temp at suction pressure. Subcooling at the liquid line = saturation temperature at liquid-line pressure − liquid-line temperature. No glide correction needed.

Specialty gauge equipment required

Frequently asked

›What is the normal operating pressure of R-717?

Operating pressure depends on evaporator load and ambient. The saturation pressures are in the PT table on this page.

›What's R-717's GWP?

Its GWP is 1 in the US EPA reference table^[5] and its ODP is 0^[6].

›Why can't I use copper piping with ammonia?

Ammonia is corrosive to copper and galvanized surfaces^[12].

›Is R-717 flammable?

Yes, with lower flammability: the 2L in B2L means a burning velocity of 10 cm/s or less^[2]. Its explosive range in air is 15% to 28% by volume; propane's (R-290) lower limit is 2.1%^[12]^[13].

Its IDLH, 300 ppm (0.03% by volume), is far below its lower explosive limit of 15% (150,000 ppm)^[12].

Download this dataset

Full PT chart for R-717 · CC BY 4.0 · attribute the source

CSV JSON

Sources & citations

[1]
NIST Chemistry WebBook (SRD 69) saturation data for ammonia (R-717). NIST. https://webbook.nist.gov/cgi/fluid.cgi?TLow=-40&THigh=150&TInc=10&Digits=6&ID=C7664417&Action=Load&Type=SatT&TUnit=F&PUnit=psia&DUnit=lbm%2Fft3&HUnit=Btu%2Flbm&WUnit=ft%2Fs&VisUnit=uPa*s&STUnit=lb%2Fin&RefState=DEF (accessed October 5, 2026)
[2]
ANSI/ASHRAE Standard 34-2022, Designation and Safety Classification of Refrigerants (free read-only version). ASHRAE. 2022. https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards (accessed October 2, 2026)
[3]
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
[4]
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)
[5]
Technology Transitions GWP Reference Table. US EPA. updated April 2, 2026. https://www.epa.gov/hfcs/technology-transitions-gwp-reference-table (accessed October 2, 2026)
[6]
Substitutes in Typical Supermarket Systems. US EPA (SNAP). last updated March 20, 2026. https://www.epa.gov/snap/substitutes-typical-supermarket-systems (accessed October 5, 2026)
[7]
Substitutes in Cold Storage Warehouses. US EPA (SNAP). last updated March 19, 2026. https://www.epa.gov/snap/substitutes-cold-storage-warehouses (accessed October 5, 2026)
[8]
Substitutes in Centrifugal Chillers. US EPA (SNAP). last updated March 19, 2026. https://www.epa.gov/snap/substitutes-centrifugal-chillers (accessed October 5, 2026)
[9]
42 U.S.C. 7675 — American Innovation and Manufacturing Act. US Code (via Cornell LII). current. https://www.law.cornell.edu/uscode/text/42/7675 (accessed October 2, 2026)
[10]
40 CFR 68.130 — List of substances. eCFR (Office of the Federal Register). up to date as of 10/1/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-68/subpart-F/section-68.130 (accessed October 5, 2026)
[11]
29 CFR 1910.119 — Process safety management of highly hazardous chemicals. eCFR (Office of the Federal Register). up to date as of 10/1/2026. https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XVII/part-1910/subpart-H/section-1910.119 (accessed October 5, 2026)
[12]
NIOSH Pocket Guide to Chemical Hazards — Ammonia. CDC/NIOSH. web page. https://www.cdc.gov/niosh/npg/npgd0028.html (accessed October 5, 2026)
[13]
NIOSH Pocket Guide to Chemical Hazards — Propane. CDC/NIOSH. web page. https://www.cdc.gov/niosh/npg/npgd0524.html (accessed October 2, 2026)