Pressure
Convert inch of water column (inH₂O) 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 inH₂O = 0.002490889 bar
To convert inch of water column to bar, multiply the inH₂O value by 0.002490889. To go the other way, divide by 0.002490889 (or multiply by 401.4631).
| inH₂O | bar |
|---|---|
| 1 | 0.002490889 |
| 2 | 0.004981778 |
| 5 | 0.01245444 |
| 10 | 0.02490889 |
| 25 | 0.06227223 |
| 50 | 0.1245445 |
| 100 | 0.2490889 |
| 250 | 0.6227223 |
| 500 | 1.245445 |
| 1000 | 2.490889 |
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 4014.631 inH₂O is 10 bar.
Multiply the value in inH₂O by 0.002490889 to get bar. For example, 10 inH₂O = 0.02490889 bar.
1 inH₂O equals 0.002490889 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.