Water tends to evaporate or vaporize by projecting molecules into the space above its surface. If the space is confined the partial pressure exerted by the molecules increases until the rate at which molecules reenter the liquid is equal to the rate at which they leave. The vapour pressure of water is the pressure at which water vapour is in thermodynamic equilibrium with its condensed state . At higher pressureswaterwould condense . At this equilibrium condition the vapor pressure is the saturation pressure .
Online Water saturation pressure Calculator
The calculator below can be used to calculate the water saturation pressure at given temperatures.
The output pressure is given as kPa, bar, atm, psi (lb/in2) and psf (lb/ft2).
Temperatur must be within the ranges 0-370 °C, 32-700 °F, 273-645 K and 492-1160 °R
The saturation pressure of water depends on temperature as shown below:
See Water and Heavy Water for thermodynamic properties at standard condtions.
See also other properties of Water at varying temperature and pressure : Boiling points at high pressure , Boiling points at vacuum pressure , Density and specific weight , Dynamic and kinematic viscosity , Enthalpy and entropy , Heat of vaporization , Ionization Constant, pK w , of normal and heavy water , Melting points at high pressure , Prandtl number , Properties at Gas-Liquid Equilibrium Conditions , Specific gravity , Specific heat (heat capacity) , Specific volume , Thermal conductivity , Thermal diffusivity and Vapour pressure at gas-liquid equilibrium .
Saturation pressure at temperatures given in degree Celcius and pressure given in kiloPascals [kPa], bars, atmospheres [atm] and pounds per square inch [psi]:
Water - Saturation Pressure vs. Temperature| Temperature | Water saturation pressure |
|---|
| [°C] | [kPa], [100*bar] | [atm] | [psi] |
|---|
| 0.01 | 0.61165 | 0.0060 | 0.088712 |
| 2 | 0.70599 | 0.0070 | 0.10240 |
| 4 | 0.81355 | 0.0080 | 0.11800 |
| 10 | 1.2282 | 0.0121 | 0.17814 |
| 14 | 1.5990 | 0.0158 | 0.23192 |
| 18 | 2.0647 | 0.0204 | 0.29946 |
| 20 | 2.3393 | 0.0231 | 0.33929 |
| 25 | 3.1699 | 0.0313 | 0.45976 |
| 30 | 4.2470 | 0.0419 | 0.61598 |
| 34 | 5.3251 | 0.0526 | 0.77234 |
| 40 | 7.3849 | 0.0729 | 1.0711 |
| 44 | 9.1124 | 0.0899 | 1.3216 |
| 50 | 12.352 | 0.122 | 1.7915 |
| 54 | 15.022 | 0.148 | 2.1788 |
| 60 | 19.946 | 0.197 | 2.8929 |
| 70 | 31.201 | 0.308 | 4.5253 |
| 80 | 47.414 | 0.468 | 6.8768 |
| 90 | 70.182 | 0.693 | 10.179 |
| 96 | 87.771 | 0.866 | 12.730 |
| 100 | 101.42 | 1.001 | 14.710 |
| 110 | 143.38 | 1.42 | 20.796 |
| 120 | 198.67 | 1.96 | 28.815 |
| 130 | 270.28 | 2.67 | 39.201 |
| 140 | 361.54 | 3.57 | 52.437 |
| 150 | 476.16 | 4.70 | 69.061 |
| 160 | 618.23 | 6.10 | 89.667 |
| 180 | 1002.8 | 9.90 | 145.44 |
| 200 | 1554.9 | 15.35 | 225.52 |
| 220 | 2319.6 | 22.89 | 336.43 |
| 240 | 3346.9 | 33.03 | 485.43 |
| 260 | 4692.3 | 46.31 | 680.56 |
| 280 | 6416.6 | 63.33 | 930.65 |
| 300 | 8587.9 | 84.76 | 1245.6 |
| 320 | 11284 | 111.4 | 1636.6 |
| 340 | 14601 | 144.1 | 2117.7 |
| 360 | 18666 | 184.2 | 2707.3 |
| 370 | 21044 | 207.7 | 3052.2 |
Saturation pressure at temperatures given in degree Fahrenheit and pressure given in pounds per square inch [psi], pounds per square foot [psf], kiloPascals [kPa] and bars:
Water - Saturation Pressure vs. Temperature| Temperature | Water saturation pressure |
|---|
| [°F] | [psi] | [psf] | [kPa], [100*bar] |
|---|
| 32.02 | 0.088712 | 12.775 | 0.612 |
| 34 | 0.09624 | 13.858 | 0.664 |
| 39.2 | 0.11800 | 16.991 | 0.814 |
| 40 | 0.12170 | 17.524 | 0.839 |
| 50 | 0.17814 | 25.651 | 1.228 |
| 60 | 0.25633 | 36.912 | 1.767 |
| 70 | 0.36341 | 52.330 | 2.506 |
| 80 | 0.50759 | 73.092 | 3.500 |
| 90 | 0.69915 | 100.7 | 4.821 |
| 100 | 0.95055 | 136.9 | 6.554 |
| 110 | 1.2766 | 183.8 | 8.802 |
| 120 | 1.6949 | 244.1 | 11.686 |
| 130 | 2.2258 | 320.5 | 15.347 |
| 140 | 2.8929 | 416.6 | 19.946 |
| 150 | 3.7232 | 536.1 | 25.671 |
| 160 | 4.7474 | 683.6 | 32.732 |
| 170 | 5.9999 | 864.0 | 41.368 |
| 180 | 7.5196 | 1083 | 51.846 |
| 190 | 9.3495 | 1346 | 64.462 |
| 200 | 11.537 | 1661 | 79.547 |
| 212 | 14.710 | 2118 | 101.42 |
| 220 | 17.203 | 2477 | 118.6 |
| 240 | 25.001 | 3600 | 172.4 |
| 260 | 35.263 | 5078 | 243.1 |
| 280 | 49.286 | 7097 | 339.8 |
| 300 | 67.264 | 9686 | 463.8 |
| 350 | 134.73 | 19402 | 929.0 |
| 400 | 247.01 | 35570 | 1703.1 |
| 450 | 422.32 | 60814 | 2911.8 |
| 500 | 680.56 | 98001 | 4692.3 |
| 550 | 1045.0 | 150485 | 7205.3 |
| 600 | 1542.1 | 222066 | 10632.6 |
| 625 | 1851.2 | 266570 | 12763 |
| 650 | 2207.8 | 317922 | 15222 |
| 675 | 2618.7 | 377092 | 18055 |
| 700 | 3092.0 | 445243 | 21318 |
See also Air Psychrometrics and
Saturation Vapor Pressure of some other Liquids at 68 oF or 20 oC
Saturation Vapor Pressure of some other Liquids at 68 oF or 20 oC| Liquid | Saturation Vapor Pressure |
|---|
| [psi] | [Pa] |
|---|
| Carbon tetrachloride,CCl 4 | 1.9 | 13100 |
| Gasoline | 8.0 | 55200 |
| Mercury | 0.000025 | 0.17 |
- 1 Pa = 10-6 N/mm2= 10 -5 bar = 0.1020 kp/m2= 1.02x10-4 m H2O = 9.869x10-6 atm = 1.45x10-4 psi (lbf /in2)
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Evaporation of water from a water surface - like a swimming pool or an open tank - depends on water temperature, air temperature, air humidity and air velocity above the water surface - online calculator.Evaporative Cooling
Evaporative cooling tutorial.Gases Solved in Water - Diffusion Coefficients
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Thermodynamic properties of heavy water (D2O) like density, melting temperature, boiling temperature, latent heat of fusion, latent heat of evaporation, critical temperature and more.Ice and Water - Melting Points vs. Pressure
Online calculator, figures and tables with melting points of ice to water at pressures ranging from 0 to 29000 psia (0 to 2000 bara). Temperature given as °C, °F, K and °R.Liquids - Densities vs. Pressure and Temperature Change
Densities and specific volume of liquids vs. pressure and temperature change.Liquids - Vapor Pressures
Vapor and saturation pressure for some common liquids.Moist Air - Degree of Saturation
Humidity ratio of moist air to humidity ratio of saturated moist air.Moist Air - Relative Humidity
Relative humidity in moist air is the ratio of partial vapor pressure to air pressure.Moist Air - Vapor Pressure
Vapor pressures vs. dry and wet bulb temperatures in moist air.Moist Air - Water Vapor and Saturation Pressure
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Online calculator, figures and tables giving the boiling temperatures of water in varying vacuum, SI and Imperial units.Water - Density, Specific Weight and Thermal Expansion Coefficients
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Figures and tables showing the enthalpy and entropy of liquid water as function of temperature - SI and Imperial Units.Water - Heat of Vaporization vs. Temperature
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Ionization constant (= dissociation constant = self-ionization constant = ion product = autoprotolysis constant ) of water and heavy water, given as function of temperature (°C and °F) in figures and tables.Water - Properties at Gas-Liquid Equilibrium Conditions
Figures and tables showing how the properties of water changes along the boiling/condensation curve (vapor pressure, density, viscosity, thermal conductivity, specific heat, Prandtl number, thermal diffusivity, entropy and enthalpy). Water - Saturation Pressure and Specific Weight vs. Temperature
Vapor pressure and specific weight of water at temperatures ranging 32 to 212 oF - Imperial Units.Water - Specific Gravity vs. Temperature
Figures and tables showing specific gravity of liquid water in the range of 32 to 700 °F or 0 to 370°C, using water density at four different temperatures as reference.Water - Specific Heat vs. Temperature
Online calculator, figures and tables showing specific heat of liquid water at constant volume or constant pressure at temperatures from 0 to 360 °C (32-700 °F) - SI and Imperial units.Water - Thermal Conductivity vs. Temperature
Figures and tables showing thermal conductivity of water (liquid and gas phase) with varying temperature and pressure, SI and Imperial units.Water - Thermal Diffusivity vs. Temperature and Pressure
Figures and tables with thermal diffusivity of liquids and gaseous water at varying temperarures and pressures - SI and Imperial units.Water vs. Steam - Critical and Triple Points
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