Pressure
Convert bar (bar) to inch of water column (inH₂O). Pressure is force per unit area. Process engineers move constantly between SI (kPa, bar) and US (psi) units, and between absolute and gauge.
1 bar = 401.4631 inH₂O
To convert bar to inch of water column, multiply the bar value by 401.4631. To go the other way, divide by 401.4631 (or multiply by 0.002490889).
| bar | inH₂O |
|---|---|
| 1 | 401.4631 |
| 2 | 802.9262 |
| 5 | 2007.315 |
| 10 | 4014.631 |
| 25 | 10036.58 |
| 50 | 20073.15 |
| 100 | 40146.31 |
| 250 | 100365.8 |
| 500 | 200731.5 |
| 1000 | 401463.1 |
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 10 bar is 4014.631 inH₂O.
Multiply the value in bar by 401.4631 to get inH₂O. For example, 10 bar = 4014.631 inH₂O.
1 bar equals 401.4631 inH₂O.
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.