Pressure
Convert millimetre of mercury (mmHg) to bar (bar). Pressure is force per unit area. Process engineers move constantly between SI (kPa, bar) and US (psi) units, and between absolute and gauge.
1 mmHg = 0.001333224 bar
To convert millimetre of mercury to bar, multiply the mmHg value by 0.001333224. To go the other way, divide by 0.001333224 (or multiply by 750.0616).
| mmHg | bar |
|---|---|
| 1 | 0.001333224 |
| 2 | 0.002666448 |
| 5 | 0.006666119 |
| 10 | 0.01333224 |
| 25 | 0.0333306 |
| 50 | 0.06666119 |
| 100 | 0.1333224 |
| 250 | 0.333306 |
| 500 | 0.6666119 |
| 1000 | 1.333224 |
Line and vessel ratings, pump discharge heads, and relief set points are all specified in pressure units — usually psi or barg in the field and kPa in calculations.
Always track whether a value is absolute or gauge: 0 barg equals about 101.3 kPa absolute, and mixing the two is a common and costly error.
Worked example. A pressure of 7500.616 mmHg is 10 bar.
Multiply the value in mmHg by 0.001333224 to get bar. For example, 10 mmHg = 0.01333224 bar.
1 mmHg equals 0.001333224 bar.
Line and vessel ratings, pump discharge heads, and relief set points are all specified in pressure units — usually psi or barg in the field and kPa in calculations.