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UNITS OFTEN USED FOR PRESSURE
| psi (1) | in.H2O (2) | in.Hg (3) | kPa | millibar | cm H2O (4) | mm Hg (5) | psi | 1.000 | 27.680 | 2.036 | 6.8947 | 68.947 | 70.308 | 51.715 | in.H2O | 3.6127 10-2 | 1.000 | 7.3554 10-2 | 0.2491 | 2.491 | 2.5400 | 1.8683 | in.Hg | 0.4912 | 13.596 | 1.000 | 3.3864 | 33.864 | 34.532 | 25.400 | kPa | 0.14504 | 4.0147 | 0.2953 | 1.000 | 10.000 | 10.1973 | 7.5006 | millibar | 0.01450 | 0.40147 | 0.02953 | 0.100 | 1.000 | 1.01973 | 0.7355 | cm H2O | 1.4223 10-2 | 0.3937 | 2.8958 10-2 | 0.09806 | 0.9806 | 1.000 | 0.7355 | mm Hg (torr) | 1.9337 10-2 | 0.53525 | 3.9370 10-2 | 0.13332 | 1.3332 | 1.3595 | 1.000 |
(1) pounds per square inch
(2) at 39 �F
(3) at 32 �F
(4) at 4 �C
(5) at 0 �C
Also:
High pressures are often expressed in units of atmospheres (1 atm =1.01325 105 Pa), bar ( 1 bar= 105Pa), megapascal ( 1Mpa=106), or even megabar ( 1 Mbar = 106). Low pressures of a high vacuum are commonly evaluated in units of torr( 1torr = 1 mmHg) or micrometers of mercury ( m Hg).
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