Key Conversion Factors
1 kPag = 0.14504 psig = 0.01 bar(g) = 0.001 MPa(g)
psia = psig + 14.696 (sea level)
kPaa = kPag + 101.325 (sea level)
Calgary: kPaa = kPag + 89.9 (1045 m elevation)
Pressure-Temperature Reference Tables
Select a refrigerant to view its saturation P-T data. All pressures are gauge at sea level.
| Temp (°C) | Temp (°F) | Pressure (kPag) | Pressure (psig) | Typical HVAC Context |
|---|---|---|---|---|
| -40 | -40 | 173 | 25.1 | Very low evaporating temp |
| -30 | -22 | 332 | 48.1 | Low-temp refrigeration |
| -20 | -4 | 546 | 79.2 | Cold climate suction |
| -10 | 14 | 828 | 120.1 | Typical suction (cold day) |
| -5 | 23 | 987 | 143.2 | Suction (mild winter) |
| 0 | 32 | 1165 | 169.0 | Suction (shoulder season) |
| 5 | 41 | 1365 | 198.0 | Suction (warm conditions) |
| 10 | 50 | 1589 | 230.5 | Suction (hot day) |
| 20 | 68 | 2119 | 307.4 | Condensing (mild) |
| 30 | 86 | 2764 | 400.9 | Typical condensing (summer) |
| 40 | 104 | 3541 | 513.6 | High ambient condensing |
| 50 | 122 | 4462 | 647.2 | Very high ambient / limit |
| 55 | 131 | 4975 | 721.4 | Near critical point |
R-410A (GWP 2088) -- Phase-down per Kigali Amendment and SOR/2016-137. Near-azeotropic blend: bubble and dew point pressures differ slightly. Values shown are approximate midpoints.
| Temp (°C) | Temp (°F) | Pressure (kPag) | Pressure (psig) | Typical HVAC Context |
|---|---|---|---|---|
| -40 | -40 | 200 | 29.0 | Very low evaporating temp |
| -30 | -22 | 378 | 54.8 | Low-temp suction |
| -20 | -4 | 620 | 89.9 | Cold climate suction |
| -10 | 14 | 937 | 135.9 | Typical suction (cold day) |
| -5 | 23 | 1116 | 161.9 | Suction (mild winter) |
| 0 | 32 | 1316 | 190.8 | Suction (shoulder season) |
| 5 | 41 | 1540 | 223.4 | Suction (warm conditions) |
| 10 | 50 | 1789 | 259.5 | Suction (hot day) |
| 20 | 68 | 2366 | 343.3 | Condensing (mild) |
| 30 | 86 | 3073 | 445.8 | Typical condensing (summer) |
| 40 | 104 | 3924 | 569.2 | High ambient condensing |
| 50 | 122 | 4935 | 715.9 | Very high ambient |
R-32 (GWP 675, ASHRAE A2L mildly flammable) -- Pure refrigerant; single saturation pressure at each temperature. Operates at higher pressures than R-410A. Requires A2L-rated equipment and training.
| Temp (°C) | Temp (°F) | Pressure (kPag) | Pressure (psig) | Typical HVAC Context |
|---|---|---|---|---|
| -40 | -40 | 152 | 22.0 | Very low evaporating temp |
| -30 | -22 | 299 | 43.4 | Low-temp suction |
| -20 | -4 | 508 | 73.7 | Cold climate suction |
| -10 | 14 | 784 | 113.7 | Typical suction (cold day) |
| -5 | 23 | 944 | 136.9 | Suction (mild winter) |
| 0 | 32 | 1126 | 163.3 | Suction (shoulder season) |
| 5 | 41 | 1334 | 193.5 | Suction (warm conditions) |
| 10 | 50 | 1569 | 227.6 | Suction (hot day) |
| 20 | 68 | 2128 | 308.7 | Condensing (mild) |
| 30 | 86 | 2819 | 408.9 | Typical condensing (summer) |
| 40 | 104 | 3656 | 530.4 | High ambient condensing |
| 50 | 122 | 4650 | 674.4 | Very high ambient |
R-454B / Puron Advance (GWP 466, ASHRAE A2L) -- Zeotropic blend; glide approximately 0.5 K. Pressures similar to R-410A making retrofit easier. Values shown are approximate dew point pressures.
| Temp (°C) | Temp (°F) | Pressure (kPag) | Pressure (psig) | Typical HVAC Context |
|---|---|---|---|---|
| -40 | -40 | 1 | 0.1 | Near atmospheric at -40 |
| -30 | -22 | 65 | 9.4 | Very low suction |
| -20 | -4 | 145 | 21.0 | Low suction |
| -10 | 14 | 254 | 36.8 | Typical suction (cold day) |
| 0 | 32 | 397 | 57.6 | Suction (shoulder season) |
| 5 | 41 | 480 | 69.6 | Common low-side range |
| 10 | 50 | 574 | 83.3 | Suction (warm conditions) |
| 30 | 86 | 1074 | 155.8 | Typical condensing (summer) |
| 40 | 104 | 1432 | 207.8 | High ambient condensing |
| 50 | 122 | 1879 | 272.7 | Very high ambient |
R-22 (GWP 1810) -- Banned in Canada since January 2020 under SOR/2016-137. Virgin R-22 cannot be manufactured or imported. Recovered and recycled R-22 may still be used for servicing existing equipment. For legacy system data only.
| Temp (°C) | Temp (°F) | Pressure (kPag) | Pressure (psig) | Typical HVAC Context |
|---|---|---|---|---|
| -40 | -40 | -34 | -4.9 | Below atmospheric (vacuum) |
| -30 | -22 | 1 | 0.1 | Near atmospheric |
| -20 | -4 | 33 | 4.8 | Low-temp suction |
| -10 | 14 | 101 | 14.7 | Suction (cold conditions) |
| 0 | 32 | 192 | 27.9 | Typical low-side range |
| 5 | 41 | 248 | 36.0 | Typical suction |
| 10 | 50 | 314 | 45.6 | Common suction (warm) |
| 20 | 68 | 472 | 68.5 | Condensing (mild) |
| 30 | 86 | 669 | 97.1 | Typical condensing (summer) |
| 40 | 104 | 916 | 132.9 | High ambient condensing |
| 50 | 122 | 1219 | 176.8 | Very high ambient |
R-134a (GWP 1430, ASHRAE A1) -- Used in chillers, automotive A/C, and some commercial refrigeration. Also subject to phase-down under Canadian HFC regulations. Being replaced by R-1234yf in automotive and R-513A in chiller applications.
How to Use the Refrigerant Unit Converter
Choose whether your reading is gauge pressure (what your manifold shows) or absolute pressure (needed for thermodynamic calculations). The offset is 101.325 kPa (14.696 psi) at sea level -- or about 89.9 kPa in Calgary at 1045 m elevation.
Type in any of the six fields -- psig, kPag, psia, kPaa, bar, or MPa. All other units update instantly. Use the quick-reference presets to load typical R-410A and R-32 low-side and high-side operating pressures, or a standard nitrogen leak test pressure.
The result panel identifies what part of the refrigeration system your pressure corresponds to: vacuum, low-side suction, discharge, or high-side for the common refrigerants. This helps confirm a pressure reading is in the expected range before proceeding with diagnostics.
Select a refrigerant tab to view the full saturation pressure-temperature table in both kPag and psig. Cross-reference your converted pressure against the P-T table to determine the saturation temperature at that pressure -- essential for diagnosing superheat and subcooling. R-22 data is provided for legacy system service only; virgin R-22 production and import has been banned in Canada since 2020, though recovered and recycled R-22 may still be used for servicing existing equipment.
Refrigerant Pressure Units -- Complete Guide for Canadian Technicians
Refrigerant pressure measurement and conversion is a core skill for every Canadian HVAC-R technician. Manifold gauge sets read in psig; Canadian engineering drawings, refrigerant regulations, and equipment datasheets use kPa. Converting between these units accurately prevents diagnostic errors and equipment damage.
psig to kPag -- The Core Conversion
Multiply psig by 6.89476 to get kPag. To go the other way, multiply kPag by 0.14504. Quick reference: 70 psig = 482.6 kPag, 150 psig = 1034 kPag, 400 psig = 2758 kPag. These cover the most common R-410A and R-32 operating pressure ranges, using the exact factor set out in the NIST Guide to the SI, Appendix B. For R-22 legacy work, 70 psig = 482.6 kPag equals a saturation temperature of about 5 degrees C -- useful for suction line diagnostics. For dedicated single-pair pressure conversion, use the Pressure Converter.
Gauge vs. Absolute Pressure
All manifold gauge sets read gauge pressure -- relative to local atmospheric pressure. Thermodynamic property tables, refrigerant enthalpy calculations, and COP analysis require absolute pressure. At sea level: psia = psig + 14.696, and kPaa = kPag + 101.325. In Calgary at 1045 m, atmospheric pressure is approximately 89.9 kPa, so kPaa = kPag + 89.9. This altitude difference matters when looking up saturation temperatures from property tables calibrated at sea level conditions -- a pressure of 483 kPag reads as 584 kPaa at sea level but only 573 kPaa in Calgary. Use the Temperature Converter alongside this tool for saturation temperature work.
Canadian Refrigerant Regulations
Canada's SOR/2016-137 (Ozone-depleting Substances and Halocarbon Alternatives Regulations) implements the Kigali Amendment HFC phase-down schedule. R-22 was banned for new systems in 2010 and banned entirely (including imports) from January 1, 2020. R-410A is in active phase-down -- production quotas are declining annually with a 70% HFC phase-down target by 2029 and 85% by 2036. New refrigerant systems in Canada must use lower-GWP alternatives: R-32 (GWP 675), R-454B (GWP 466), R-466A (GWP 733), or other A1/A2L alternatives depending on the application. HVAC technicians working with A2L mildly flammable refrigerants must follow updated CSA B52 (Mechanical Refrigeration Code) requirements for leak detection, ignition source management, and charge limits, which the Refrigerant Charge Calculator helps verify against room size.
Reading Pressure-Temperature Charts
Saturation pressure and temperature are linked for any pure refrigerant or azeotropic blend -- fix one and you fix the other. For zeotropic blends like R-454B, there's a small temperature glide: the bubble point (100% liquid) and dew point (100% vapour) occur at slightly different temperatures at the same pressure. For R-410A (near-azeotropic), this glide is less than 0.2 K and is typically ignored in field diagnostics. Use the P-T tables above to find saturation temperature from your gauge pressure reading, then calculate superheat (suction line temperature minus saturation temperature) and subcooling (saturation temperature minus liquid line temperature) for system performance diagnostics with the Superheat Calculator.
Pressure Testing per CSA B52
CSA B52 (Mechanical Refrigeration Code) requires pressure testing with dry nitrogen before charging refrigerant. Test pressure is typically 1.1 to 1.5 times the design pressure depending on the system component. A residential R-410A system rated for 4136 kPag (600 psig) high-side design pressure would be tested at approximately 4550-6200 kPag (660-900 psig) with nitrogen. Never pressure test with refrigerant or with oxygen -- refrigerant-air mixtures can be explosive, and oxygen creates a fire hazard with refrigerant oil. Use the converter above to check your test pressure against both psig and kPag specifications on the equipment data plate.
Frequently Asked Questions
Multiply psig by 6.89476 to get kPag. Common values: 70 psig = 482.6 kPag, 150 psig = 1034 kPag, 400 psig = 2758 kPag. To go the other way, multiply kPag by 0.14504. This is the most frequent pressure conversion in Canadian refrigeration work since manifold gauges read psig while Canadian engineering specifications and SOR/2016-137 regulatory documents reference kPa. The converter above handles all six pressure units simultaneously.
R-410A saturation pressure at 0 degrees C is approximately 1165 kPag (169 psig) gauge at sea level. At the typical evaporating temperature of -5 degrees C, pressure is about 987 kPag (143 psig). At a typical summer condensing temperature of 35 degrees C, pressure is about 3100 kPag (450 psig). Use these reference points for quick field sanity checks when commissioning or diagnosing R-410A equipment. See the R-410A P-T table above for the full range.
Gauge pressure (psig, kPag) is what your manifold reads -- relative to local atmospheric pressure. Absolute pressure (psia, kPaa) adds atmospheric pressure on top: at sea level, kPaa = kPag + 101.325. Manifold gauges and field diagnostics use gauge. Thermodynamic tables, COP calculations, and refrigerant property software use absolute. In Calgary at about 1045 m elevation, atmospheric pressure is only 89.9 kPa -- so the offset is 89.9, not 101.325. Use the gauge/absolute toggle in this converter to switch between both modes.
The main R-410A replacements in Canada are R-32 (GWP 675, A2L), R-454B/Puron Advance (GWP 466, A2L), and R-466A (GWP 733, A1 non-flammable). All operate at pressures similar to R-410A, making equipment adaptation practical. A2L refrigerants are mildly flammable and require updated CSA B52-compliant equipment, leak detection, and technician training. The phase-down under SOR/2016-137 targets 85% HFC reduction by 2036 relative to the 2011-2013 baseline. Check with your equipment manufacturer for approved refrigerant conversions for existing R-410A equipment.