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# Air - Properties at Gas-Liquid Equilibrium Conditions

At standard conditions, air is a mixture of gases. However, at low temperature and high pressures the gas mixture becomes a liquid. The air phase diagram shows the phase behavior with changes in temperature and pressure. The curve between the triple point and the critical point shows the air boiling point with changes in pressure.

Critical point: The end point of the pressure-temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas cannot be liquefied by pressure alone. At the critical point, defined by the critical temperature T c and the critical pressure P c , phase boundaries vanish.
Critical temperature of air:           132.63 K = -140.52 °C = -220.94 °F
Critical pressure of air:                37.363 atm = 37.858 bar = 3.7858 MPa (MN/m 2 ) = 549.08 psi (=lb f /in 2 )

Triple point: The temperature and pressure at which the three phases (gas, liquid, and solid) of a substance coexist in thermodynamic equilibrium
Triple point pressure of air:         0.05196 atm = 0.05265 bar = 5265 Pa = 0.7636 psi (=lb f /in 2 )
Triple point temperature of air:    59.75 K = -213.40 °C = -352.12 °F

The figures below show the changes in thermophysical properties along the air boiling and condensation curves: Vapour pressure , density , viscosity , heat capacity , thermal conductivity .

Tabulated values given in SI and imperial units, and unit converters are given below the figures.

Phase diagram of air:

The following figures show how the properties of air changes along the boiling and condensation curves (shown in the figure above) - SI units:

Properties of air along the boiling and condensation curves - SI units:

For full table with thermal conductivity, dynamic and kinematic viscosity - rotate the screen!

 Temperature Pressure Density Heat capacity C V Heat capacity C P Thermal conductivity Dynamic Viscosity Kinematic viscosity [K] [°C] [bara] [g/l], [kg/m 3 ] [kJ/kg K] [kJ/kg K] [mW/m K] [kcal(IT)/(h m K)] [μPa s] [cSt], [m 2 /s*10 -6 ] Liquid 59.75 -213.40 0.05265 957.6 1.174 1.901 171.4 0.1474 376.6 0.3933 65 -208.2 0.1432 935.9 1.118 1.902 162.9 0.1401 292.4 0.3124 70 -203.2 0.31908 914.6 1.102 1.908 154.7 0.1330 234.8 0.2567 75 -198.2 0.63326 892.7 1.072 1.919 146.5 0.1260 192.4 0.2155 80 -193.2 1.1462 870.2 1.045 1.938 138.2 0.1188 160.4 0.1843 85 -188.2 1.9262 846.7 1.020 1.964 129.8 0.1116 135.8 0.1604 90 -183.2 3.0475 822.2 0.9981 2.003 121.4 0.1044 116.4 0.1415 95 -178.2 4.5886 796.2 0.9786 2.056 112.9 0.09709 100.7 0.1264 100 -173.2 6.6313 768.5 0.9617 2.130 104.4 0.08978 87.61 0.1140 105 -168.2 9.2606 738.6 0.9477 2.236 95.93 0.08249 76.41 0.1035 110 -163.2 12.564 705.6 0.9373 2.389 87.55 0.07528 66.54 0.0943 115 -158.2 16.633 668.5 0.9314 2.628 79.34 0.06822 57.57 0.0861 120 -153.2 21.557 625.3 0.9325 3.048 71.36 0.06136 49.13 0.0786 125 -148.2 27.427 571.4 0.9473 4.001 63.66 0.05474 40.76 0.0713 130 -143.2 34.295 488.4 1.010 8.846 58.05 0.04992 31.07 0.0636 132.63 -140.52 37.858 302.6 17.83 0.0589 Gas 59.75 -213.40 0.02432 0.1421 0.7183 1.009 5.294 0.004552 4.220 29.69 65 -208.2 0.07756 0.4182 0.7219 1.017 5.844 0.005025 4.606 11.01 70 -203.2 0.19431 0.9787 0.7275 1.030 6.376 0.005482 4.970 5.078 75 -198.2 0.42282 2.006 0.7354 1.050 6.920 0.005950 5.333 2.658 80 -193.2 0.82321 3.711 0.7459 1.078 7.485 0.006436 5.694 1.534 85 -188.2 1.4665 6.336 0.7589 1.116 8.082 0.006949 6.057 0.9560 90 -183.2 2.4320 10.16 0.7746 1.166 8.725 0.007502 6.427 0.6327 95 -178.2 3.8047 15.50 0.7928 1.232 9.439 0.008116 6.810 0.4393 100 -173.2 5.6742 22.77 0.8137 1.320 10.26 0.008819 7.215 0.3169 105 -168.2 8.1341 32.49 0.8375 1.440 11.24 0.009662 7.659 0.2357 110 -163.2 11.282 45.42 0.8651 1.614 12.47 0.01072 8.163 0.1797 115 -158.2 15.223 62.75 0.8981 1.887 14.15 0.01216 8.770 0.1398 120 -153.2 20.067 86.57 0.9399 2.373 16.64 0.01430 9.552 0.1103 125 -148.2 25.949 121.5 0.9981 3.474 20.97 0.01803 10.68 0.0879 130 -143.2 33.084 182.7 1.095 8.031 31.81 0.02735 12.78 0.0699 132.63 -140.52 37.858 302.6 17.83 0.0589

Properties of air along the boiling and condensation curves - Imperial units:

For full table with thermal conductivity, dynamic and kinematic viscosity - rotate the screen!

 Temperature Pressure Density Heat capacity C V Heat capacity C P Thermal conductivity Dynamic viscosity Kinematic viscosity [K] [°F] [psia] [lb/ft 3 ] [sl/ft 3 ] [Btu(IT)/lb °F] [Btu(IT)/lb °F] [Btu(IT)/(h ft °F)] [lb f s/ft2 *10-6] [lb m /ft s*10 -6 ] [ft 2 /s*10 -6 ] Liquid 59.75 -352.12 0.76363 59.79 1.858 0.2805 0.4541 0.09905 7.866 253.1 4.233 65 -343.7 2.077 58.43 1.816 0.2671 0.4543 0.09413 6.107 196.5 3.363 70 -334.7 4.6279 57.10 1.775 0.2632 0.4557 0.08940 4.904 157.8 2.763 75 -325.7 9.1847 55.73 1.732 0.2560 0.4584 0.08464 4.017 129.3 2.319 80 -316.7 16.624 54.32 1.688 0.2495 0.4628 0.07982 3.350 107.8 1.984 85 -307.7 27.937 52.86 1.643 0.2437 0.4692 0.07499 2.836 91.24 1.726 90 -298.7 44.200 51.33 1.595 0.2384 0.4783 0.07013 2.431 78.20 1.524 95 -289.7 66.552 49.71 1.545 0.2337 0.4911 0.06524 2.103 67.65 1.361 100 -280.7 96.179 47.98 1.491 0.2297 0.5088 0.06033 1.830 58.87 1.227 105 -271.7 134.31 46.11 1.433 0.2264 0.5339 0.05543 1.596 51.35 1.114 110 -262.7 182.23 44.05 1.369 0.2239 0.5707 0.05059 1.390 44.71 1.015 115 -253.7 241.24 41.73 1.297 0.2225 0.6278 0.04584 1.202 38.69 0.927 120 -244.7 312.66 39.04 1.213 0.2227 0.7279 0.04123 1.026 33.01 0.846 125 -235.7 397.80 35.67 1.109 0.2263 0.9556 0.03678 0.8512 27.39 0.768 130 -226.7 497.41 30.49 0.9477 0.2411 2.113 0.03354 0.6490 20.88 0.685 132.63 -220.94 549.08 18.89 0.5872 0.3724 11.98 0.634 Gas 59.75 -352.12 0.3527 0.00887 0.000276 0.1716 0.2409 0.003059 0.0881 2.836 319.562 65 -342.7 1.1249 0.02611 0.000811 0.1724 0.2429 0.003377 0.0962 3.095 118.544 70 -333.7 2.8182 0.06110 0.001899 0.1738 0.2460 0.003684 0.1038 3.340 54.663 75 -324.7 6.1325 0.1253 0.003893 0.1757 0.2508 0.003998 0.1114 3.583 28.608 80 -315.7 11.940 0.2317 0.00720 0.1782 0.2574 0.004325 0.1189 3.826 16.514 85 -306.7 21.270 0.3956 0.01229 0.1813 0.2665 0.004670 0.1265 4.070 10.290 90 -297.7 35.273 0.6341 0.01971 0.1850 0.2785 0.005041 0.1342 4.319 6.811 95 -288.7 55.183 0.9677 0.03008 0.1894 0.2942 0.005454 0.1422 4.576 4.729 100 -279.7 82.297 1.421 0.04418 0.1943 0.3152 0.005926 0.0119 0.381 3.411 105 -270.7 117.98 2.028 0.06304 0.2000 0.3440 0.006493 0.1600 5.146 2.537 110 -261.7 163.63 2.836 0.08814 0.2066 0.3855 0.007207 0.1705 5.486 1.934 115 -252.7 220.79 3.917 0.1218 0.2145 0.4506 0.008173 0.1832 5.893 1.504 120 -243.7 291.05 5.405 0.1680 0.2245 0.5668 0.009612 0.1995 6.419 1.188 125 -234.7 376.36 7.583 0.2357 0.2384 0.8298 0.01212 0.2231 7.177 0.947 130 -225.7 479.84 11.41 0.3545 0.2616 1.918 0.01838 0.2668 8.584 0.753 132.63 -220.94 549.08 18.89 0.5872 0.3724 11.98 0.634

Unit converters:

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