foot of water column
The foot of water column is the pressure at the bottom of a one foot column of water, conventionally taken with water at 1000 kg/m³ and standard gravity, giving about 2989.07 pascals. It is a conventional unit rather than an exact one, because real water density changes with temperature and different reference temperatures are in use. It is the natural unit of pump head, where a pump that lifts water 100 ft is described as producing 100 ft of head regardless of the fluid's pressure in psi.
Watch out: Head in feet of water is only equal to pressure when the fluid is water. A centrifugal pump develops a head in feet that is nearly independent of fluid density, but the pressure it produces is proportional to density, so pumping a fluid of specific gravity 1.3 gives 30 percent more pressure for the same head. Also check the reference temperature: values quoted at 39.2 °F, 60 °F and 68 °F differ in the fourth digit.
| 1 | 2.9890669 |
One foot of water column in every pressure unit
| 29,890.7 | microbar (μbar) | |
| 29,890.7 | barye (Ba) | |
| 22,419.8 | millitorr (mTorr) | |
| 2,989.07 | pascal (Pa) | convert → |
| 304.8 | millimeter of water column (mmH₂O) | |
| 62.428 | pound per square foot (lb/ft²) | |
| 30.48 | centimeter of water column (cmH₂O) | |
| 29.8907 | hectopascal (hPa) | |
| 29.8907 | millibar (mbar) | |
| 22.4198 | torr (Torr) | |
| 22.4198 | millimeter of mercury (mmHg) | convert → |
| 12 | inch of water column (in w.g.) | convert → |
| 2.98907 | kilopascal (kPa) | convert → |
| 1 | foot of water column (ft H₂O)this unit | |
| 0.882671 | inch of mercury (inHg) | convert → |
| 0.433528 | pound per square inch (psi) | convert → |
| 0.3048 | meter of water column (m H₂O) | |
| 0.298907 | decibar (dbar) | |
| 0.03048 | kilogram-force per square centimeter (kgf/cm²) | |
| 0.0298907 | bar (bar) | convert → |
| 0.0294998 | atmosphere (atm) | convert → |
| 0.00298907 | megapascal (MPa) | convert → |
| 0.000433528 | kip per square inch (ksi) | |
| 0.00000298907 | gigapascal (GPa) | |
| 4.33528e-07 | million pounds per square inch (Mpsi) |