Inches Of Water to Bars (inH₂O to bar)
1 inch of water equals 0.0024908891 bars exactly.
How to convert inches of water to bars
To convert inches of water to bars, multiply the number of inches of water by 0.0024908891. This factor is exact. To go the other way, multiply bars by 401.463076 (rounded).
bars = inches of water × 0.0024908891
Example: 10 inches of water = 0.024908891 bars.
About these units
Inch Of Water (inH₂O)
About 249.089 pascals (the conventional value, 25.4 mm × 9.80665 Pa). Used for air pressure in HVAC and gas appliances.
Building services and gas fitting rely on this unit. Manometers filled with water read small differences in air or gas pressure, and in North America the result is stated in inches of water column. Natural gas supplied to appliances is typically 6 to 7 inches WC, and HVAC technicians use it for pressure across coils, filters and ducts. A pipe organ's wind pressure is quoted the same way.
Which water is meant matters a little. Wikipedia gives about 249.082 Pa for water at 4 degrees Celsius, equal to 39.2 degrees Fahrenheit, and also the conventional 249.08891 Pa, which is 25.4 mm times 9.80665 and is the figure used here. NIST lists 249.082 Pa at 39.2 degrees Fahrenheit and 248.84 Pa at 60 degrees Fahrenheit, and some industry standards use 60 or 68 degrees Fahrenheit. About 27.7 inches of water equal 1 psi.
1 inch of water = 249.08891 pascals (exactly).
Sources: Wikipedia: Inch of water; NIST SP 811, Appendix B.8
Bar (bar)
Exactly 100,000 pascals, close to atmospheric pressure at sea level. Used for tire pressure, diving and industrial gauges.
Bar began as a name that meant different things to different people. It comes from the Ancient Greek baros, weight, and from 1793 to 1795 an early metric system used bar for a unit of mass equal to the modern tonne. The pressure bar was introduced by the Norwegian meteorologist Vilhelm Bjerknes, a founder of modern weather forecasting, who defined it as one megadyne per square centimeter. Some earlier writers had used bar for one dyne per square centimeter, a source of confusion.
The bar is a metric unit but not part of the SI, and its official symbol is simply bar, since the old b clashes with the barn and the bit. It has been legally recognized in EU countries since 2004, although NIST deprecates it except for limited use in meteorology.
Its size is handy because 1 bar is slightly less than average sea-level pressure, which is about 1.013 bar. In scuba diving every 10 meters of seawater adds about 1 bar and a full standard tank holds about 200 bar. Tire pressure and turbocharger boost are often quoted in bar outside the US.
1 bar = 100,000 pascals (exactly).
Sources: Wikipedia: Bar (unit); Wikipedia: Atmospheric pressure
Related conversions
- Bars to inches of water (reverse)
- Inches of water to pascals
- Inches of water to kilopascals
- Inches of water to standard atmospheres
- Inches of water to PSI
- Pascals to bars
- Kilopascals to bars
- Standard atmospheres to bars
- PSI to bars
- Hectopascals to bars
- Megapascals to bars
- Millibars to bars
- Torr to bars
- Millimeters of mercury to bars
- Inches of mercury to bars
- Gigapascals to bars
- Kilopounds per square inch to bars
See all pressure units.