Conversion Tables for Vacuum

PRESSURE UNITS

  mbar bar torr Pa(Nm-2) atm lbf in-2 kgf cm-2 in Hg mmHg in H20 mm H2O
1 mbar = 1 1x10-3 0.75 102 9.869 x 10-4 1.45 x 10-2 1.02 x 10-3 2.953 x 10-2 0.75 0.402 10.197
1 bar = 103 1 7.5 x 102 1 x 105 0.987 14.5 1.02 29.53 7.5 x 102 4.015 x 102 1.02 x 104
1 torr = 1.333 1.333 x 10-3 1 1.333 x 102 1.316 x 10-1 1.934 x 10-2 1.36 x -3 3.937 x -2 1 0.535 13.59
1 Pa (Nm-2)= 0.01 1 x 10-5 7.5 x 10-3 1 9.87 x 10-6 1.45 x 10-4 1.02 x 10-5 2.953 x 10-4 7.5 x 10-3 4.015 x 10-3 0.102
1 atm = 1.013 x 103 1.013 7.6 x 102 1.013 x 105 1 14.7 1.033 29.92 7.6 x 102 4.068 x 102 1.033x104
1 lbin-2= 68.95 6.895 x 10-2 51.71 6.895 x 103 6.805 x 10-2 1 7.03 x 10-2 2.036 51.71 27.68 7.03 x 102
1 kgf cm-2= 9.807 x 102 0.981 7.356 x 102 9.807 x 104 0.968 14.22 1 28.96 7.356 x 102 3.937 x 102 104
1 in Hg = 33.86 3.386 x 10-2 25.4 3.386 x 103 3.342 x 10-2 0.491 3.453 x 10-2 1 25.4 13.6 3.45 x 102
1 mm Hg = 1.333 1.333 x 10-3 1 1.333 x 102 1.316 x 10-3 1.934 x 10-2 1.36 x 10-3 3.937 x 10-2 1 0.535 13.59
1 in H2O = 2.491 2.491 x 10-3 1.868 2.491 x 102 2.458 x 10-3 3.613 x 10-2 2.54 x 10-3 7.356 x 10-2 1.868 1 25.4
1 mm H2O= 9.807 x 10-2 9.807 x 10-5 7.354 x 10-2 9.807 9.677 x 10-5 1.42 x 10-3 10-4 2.896 x 10-3 7.354 x 10-2 3.394 x 10-2 1

Note also: 1 dyn cm-2 (barye) = 0.1 Pa (Nm-2) = 10-3 mbar.


LEAK RATE UNITS

  mbar l s-1 torr l s-1 atm cm3s-1 lusec atm ft3 min-1 grams per year
(Freon 12)
1 mbar l s-1 = 1 0.75 0.987 7.5 x 102 2.097 x 10-3 1.58 x 105
1 torr l s-1 = 1.333 1 1.316 103 2.795 x 10-3 2.083 x 105
1 atm cm3s-1 = 1.013 0.76 1 7.6 x 102 2.12 x 10-3 1.582 x 105
1 lusec = 1.333 x 10-3 0.001 1.32 x 10-3 1 2.79 x 10-6 2.083 x 102
1 atm ft3min-1 = 4.78 x 102 3.58 x 102 4.72 x 102 3.58 x 105 1 7.45 x 107
1 gram per year
(Freon 12)
6.4 x 10-6 4.8 x 10-6 6.32 x 10-6 4.8 x 10-3 1.34 x 10-8 1

PUMPING SPEED UNITS

  l s-1 = l min-1 ft3min-1 m3h-1
1 l s-1 = 1 60 2.12 3.60
1 l min-1 = 0.0167 1 0.0353 0.06
1 ft3min-1= 0.472 28.32 1 1.70
1 m3h-1 = 0.278 16.67 0.589 1