|
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= 105 Pa), megapascal ( 1Mpa=106), or even megabar ( 1 Mbar = 106). Low pressures of a high vacuum are commonly evaluated in units of torr ( 1 torr = 1 mmHg) or micrometers of mercury (  m
Hg). |
|
|
| 1 microbar = 0.1 Pa | 1 in.H2O = 248.8 Pa |
| 1
m
Hg =0.1333 Pa |
1 kPa = 1000 Pa |
| 1 N/m2 = 1 Pa | 1 ft H2O = 2986 Pa |
| 1 mm H2O = 9.795 Pa | 1 in. Hg = 3386 Pa |
| 1 mbar = 100 Pa | 1 psi = 6895 Pa |
| 1 mmHg = 133.3 Pa | 1 bar = 105 Pa |
| 1 torr = 133.3 Pa | 1 atm = 101325 Pa |
| Derived Units: Bold Units have Assigned Symbols, Plain Units do not have Assigned Special Symbols |