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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/m2) = 549.08 psi (=lbf /in2)

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 (=lbf /in2)
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.

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Phase diagram of air:

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

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

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

Air - Properties at Gas-Liquid Equilibrium Conditions
Temperature Pressure Density Heat capacity
CV
Heat capacity
CP
Thermal
conductivity
Dynamic
Viscosity
Kinematic
viscosity
[K] [°C] [bara] [g/l],
[kg/m3 ]
[kJ/kg K] [kJ/kg K] [mW/m K] [kcal(IT)/(h m K)] [μPa s] [cSt],
[m2/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
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Properties of air along the boiling and condensation curves - Imperial units:

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

Air - Properties at Gas-Liquid Equilibrium Conditions
Temperature Pressure Density Heat capacity
CV
Heat capacity
CP
Thermal
conductivity
Dynamic viscosity Kinematic
viscosity
[K] [°F] [psia] [lb/ft3 ] [sl/ft3 ] [Btu(IT)/lb °F] [Btu(IT)/lb °F] [Btu(IT)/(h ft °F)] [lbf s/ft2 *10-6] [lbm /ft s*10-6 ] [ft2/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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