R290 Pressure Temperature Chart for Industrial Refrigeration
R290 pressure-temperature data is easy to misuse when the chart is treated as a complete troubleshooting tool instead of a saturation reference. In industrial refrigeration, that can lead to incorrect assumptions about evaporating pressure, condensing pressure, refrigerant charge, or system condition.
The problem becomes more serious when pressure readings are compared against the wrong refrigerant chart. R290, CO2, ammonia, HFCs, HFOs, and refrigerant blends each have their own pressure-temperature relationship. A pressure that is normal for one refrigerant may be completely wrong for another.
This article provides an R290 pressure-temperature chart for propane refrigerant and explains how to use it correctly. The chart should be used as a reference for saturation pressure and saturation temperature only. It should not replace manufacturer data, equipment documentation, system design information, or applicable code requirements.
Download or print the R290 pressure temp chart for quick reference, just right click the image and click "Save As".
R290 Pressure Temperature Chart Table
The following R290 chart lists saturation pressure in psig at each corresponding temperature.
Temp °F
Temp °C
Pressure psig
Temp °F
Temp °C
Pressure psig
Temp °F
Temp °C
Pressure psig
-44
-42
0.0
10
-12
31.8
62
17
96.3
-40
-40
1.4
12
-11
33.6
64
18
99.7
-38
-39
2.2
14
-10
35.4
66
19
103.1
-36
-38
3.0
16
-9
37.3
68
20
106.6
-34
-37
3.9
18
-8
39.2
70
21
110.2
-32
-36
4.8
20
-7
41.1
72
22
113.9
-30
-34
5.7
22
-6
43.2
74
23
117.6
-28
-33
6.6
24
-4
45.2
76
24
121.4
-26
-32
7.6
26
-3
47.4
78
26
125.4
-24
-31
8.6
28
-2
49.6
80
27
129.3
-22
-30
9.6
30
-1
51.8
82
28
133.4
-20
-29
10.7
32
0
53.0
84
29
137.6
-18
-28
11.8
34
1
56.5
86
30
141.8
-16
-27
13.0
36
2
58.9
88
31
146.1
-14
-26
14.2
38
3
61.4
90
32
150.5
-12
-24
15.5
40
4
63.9
92
33
155.0
-10
-23
16.7
42
6
66.5
94
34
159.6
-8
-22
18.1
44
7
69.2
96
36
164.3
-6
-21
19.4
46
8
72.0
98
37
169.1
-4
-20
20.8
48
9
74.8
100
38
173.9
-2
-19
22.2
50
10
77.6
102
39
178.9
0
-18
23.7
52
11
80.6
104
40
183.9
2
-17
25.2
54
12
83.6
106
41
189.1
4
-16
26.9
56
13
86.7
108
42
194.3
6
-14
28.4
58
14
89.8
110
43
199.6
8
-13
30.2
60
16
93.0
112
44
205.1
Technical note: The pressures above are listed in psig, not absolute pressure. Verify values against approved R290 refrigerant property data or manufacturer documentation before using them for design, commissioning, service, or safety decisions.
What Is R290 Refrigerant?
R290 is propane used as a refrigerant. In a refrigeration pressure-temperature chart, R290 refers to refrigerant-grade propane, not a general fuel-gas installation or non-refrigeration propane application.
R290 is often discussed as a natural refrigerant option because it is not an HFC or HFO blend. However, the pressure-temperature chart does not determine whether R290 is suitable for a specific industrial refrigeration system. Suitability depends on the full system design, equipment ratings, refrigerant charge, safety controls, location, applicable codes, and manufacturer requirements.
For industrial refrigeration, those details matter. A cold storage or process refrigeration system may involve larger equipment, longer piping runs, different control strategies, and more complex safety requirements than a small self-contained system. A PT chart is useful, but it is only one piece of the technical review.
What Does an R290 Pressure Temperature Chart Show?
An R290 pressure-temperature chart shows the relationship between saturation temperature and saturation pressure.
When R290 is saturated, its pressure and temperature are directly related. That means a known saturation pressure can be used to find the corresponding saturation temperature, or a known saturation temperature can be used to find the corresponding saturation pressure.
For example, the chart lists:
R290 Temperature
R290 Saturation Pressure
32°F / 0°C
53.0 psig
70°F / 21°C
110.2 psig
100°F / 38°C
173.9 psig
These are saturation reference points. They are not universal “correct pressures” for every R290 system under all operating conditions.
Actual field readings depend on the measurement location, operating state, load, ambient conditions, heat exchanger performance, refrigerant feed, compressor operation, controls, and equipment design.
How to Use an R290 PT Chart
A pressure-temperature chart is most useful when it is applied to a known refrigerant under known conditions.
In practical refrigeration work, an R290 PT chart may help a qualified technician relate a measured pressure to a saturation temperature. This can support review of evaporating conditions, condensing conditions, and general system behavior.
For example:
If an R290 evaporator pressure corresponds to 20°F saturation, the chart lists 41.1 psig.
If an R290 condensing condition corresponds to 86°F saturation, the chart lists 141.8 psig.
If an R290 saturation condition corresponds to 110°F, the chart lists 199.6 psig.
The chart should be used carefully. It does not confirm system charge by itself. It does not prove that airflow is correct. It does not verify superheat, subcooling, oil return, control valve performance, compressor health, or heat exchanger condition. Those require additional measurements and system-specific documentation.
Why R290 PT Data Cannot Be Used for Other Refrigerants
Pressure-temperature charts are refrigerant-specific. An R290 chart should not be used for CO2, ammonia, R404A, R448A, R449A, R134a, R1234ze, or any other refrigerant.
This is one of the most important points in the article. The same temperature can correspond to very different pressures depending on the refrigerant. Using the wrong chart can make a normal reading appear abnormal, or make an unsafe or incorrect condition appear acceptable.
For R290, the chart lists:
Temperature
R290 Pressure
20°F
41.1 psig
86°F
141.8 psig
100°F
173.9 psig
Those values apply to R290 saturation conditions only. They should not be transferred to another refrigerant or used to evaluate a system that has not been positively identified as R290.
R290 PT Chart vs. System Operating Pressure
A common mistake is assuming that the PT chart shows exactly what the gauge pressure “should be” at all times. It does not.
The chart shows saturation pressure at a corresponding saturation temperature. A refrigeration system can have pressure drops, superheated vapor, subcooled liquid, changing loads, and control responses that affect measured values.
A suction pressure reading may be used to estimate evaporating saturation temperature, but it still needs to be interpreted with superheat, load, airflow or product load, valve operation, and compressor performance.
A high-side pressure reading may be used to estimate condensing saturation temperature, but it still needs to be interpreted with ambient conditions, condenser or gas cooler performance, fan operation, refrigerant charge, and control strategy.
The R290 pressure-temperature chart is a reference point, not a full diagnosis.
Industrial Refrigeration Considerations for R290
Industrial refrigeration systems require a conservative approach to refrigerant data. R290 pressure-temperature values may be helpful for understanding saturation conditions, but they do not replace engineering review.
Before applying R290 in an industrial refrigeration context, the following items should be confirmed through project-specific documentation:
Item to Confirm
Why It Matters
Refrigerant identity
The PT chart is valid only for R290.
Equipment pressure ratings
Components must be rated for the expected operating and standstill pressures.
Refrigerant charge
Charge affects safety requirements and system design.
Area classification and ventilation
Requirements depend on applicable codes and installation conditions.
Leak detection and safety controls
Requirements must match the refrigerant and application.
Manufacturer instructions
Equipment may have specific operating, service, and commissioning limits.
Local code requirements
Compliance depends on jurisdiction and system configuration.
This article does not establish R290 charge limits, room requirements, ventilation rates, electrical classification, or code compliance requirements. Those details must come from applicable codes, standards, equipment documentation, and qualified engineering review.
Common Mistakes When Reading an R290 Pressure Temperature Chart
The first mistake is using the wrong refrigerant chart. R290 pressure-temperature data applies only to R290.
The second mistake is confusing psig with absolute pressure. This chart is listed in gauge pressure. Data from other references may use psia, bar, kPa, or MPa, so units must be checked before comparing values.
The third mistake is using the PT chart as a charge chart. A PT chart does not tell you whether the system has the correct refrigerant charge. Charge evaluation requires the appropriate service procedure and system-specific measurements.
The fourth mistake is ignoring operating conditions. A pressure reading taken during pull-down, defrost recovery, low load, high ambient, or abnormal airflow may not represent the same condition as a stable design operating point.
The fifth mistake is treating the chart as a substitute for equipment documentation. Manufacturer limits, pressure ratings, control settings, and service procedures take priority over a general reference chart.
Quick Reference: Common R290 Pressures
Temperature
Pressure
-20°F / -29°C
10.7 psig
0°F / -18°C
23.7 psig
20°F / -7°C
41.1 psig
32°F / 0°C
53.0 psig
40°F / 4°C
63.9 psig
70°F / 21°C
110.2 psig
86°F / 30°C
141.8 psig
100°F / 38°C
173.9 psig
110°F / 43°C
199.6 psig
These values are useful for quick reference, but the full chart should be used when a specific temperature is required.
Industrial Refrigeration Parts and R290 Components
For a pressure-temperature chart to be useful in the field, it has to be paired with the right parts and the right documentation. R290 saturation data can help technicians understand pressure and temperature relationships, but components still need to be selected according to the refrigerant, capacity range, pressure rating, connection type, application, and manufacturer instructions.
That is where IRPC can help. Through IRPC, we sell industrial refrigeration parts online, including components used in ammonia, CO2, synthetic refrigerant, and R290 applications. For R290 systems, one example is the Danfoss Thermostatic Expansion Valve TUB for R290, which should be reviewed against the manufacturer’s documentation before being applied to a specific system.
When ordering refrigeration parts, always confirm the part number, refrigerant compatibility, operating range, pressure rating, and application requirements before installation. A PT chart can support service work, but final component selection should be based on the equipment design and manufacturer data.
Frequently Asked Questions (FAQs) about R290 Refrigerant Pressure
What is R290?
R290 is propane refrigerant. The provided refrigerant comparison guide identifies hydrocarbon refrigerants with R290 as the example.
What is the pressure of R290 at 32°F?
R290 saturation pressure at 32°F / 0°C is 53.0 psig.
What is the pressure of R290 at 70°F?
R290 saturation pressure at 70°F / 21°C is 110.2 psig.
What is the pressure of R290 at 100°F?
R290 saturation pressure at 100°F / 38°C is 173.9 psig.
Can an R290 pressure-temperature chart be used for CO2?
No. CO2 has different pressure-temperature properties. The provided CO2 training material shows CO2 pressures that are much higher than the supplied R290 chart at comparable temperatures.
Is a PT chart enough to troubleshoot an R290 refrigeration system?
No. A PT chart provides saturation pressure and temperature reference data. It does not replace equipment documentation, system design information, operating procedures, code requirements, or qualified refrigeration analysis.
