Centimetre or millimetre of water
A centimetre or millimetre of water (US spelling centimeter or millimeter of water) are less commonly used measures of pressure based on the pressure head of water.
Centimetre of water
| centimetre of water | |
|---|---|
| Unit of | Pressure |
| Symbol | cmH2O |
| Conversions | |
| 1 cmH2O in ... | ... is equal to ... |
| SI units | 98.0665 Pa |
| English Engineering units | 1.422334×10−2 psi |
A centimetre of water
The centimetre of water unit is frequently used to measure the
1 cmH2O (conventional) = 98.0665 pascals[2] = 0.01 metre water (mH2O), metre water column (m wc) or metre water gauge (m wg) = 10 mm wg= 0.980665 mbar or hPa ≈ 0.3937008 inH2O ≈ 0.0009678411 atm≈ 0.7355592 torr ≈ 0.7355591 mm Hg≈ 0.02895902 inHg ≈ 0.01422334 psi
Millimetre of water
| millimetre of water | |
|---|---|
| Unit of | Pressure |
| Symbol | mmH2O |
| Conversions | |
| 1 mmH2O in ... | ... is equal to ... |
| SI units | 9.80665 Pa |
| English Engineering units | 1.422334×10−3 psi |
Millimetre of water (US spelling millimeter of water)
1 mmH2O (conventional) = 9.80665 pascals[2] = 0.001 metre water (mH2O), metre water column (m.wc) or metre water gauge (m wg) = 0.1 cm wg= 0.0980665 mbar or hPa ≈ 0.03937008 inH2O ≈ 9.678411×10−5 atm≈ 0.07355592 torr ≈ 0.07355591 mmHg≈ 0.002895902 inHg ≈ 0.001422334 psi
In limited and largely historic contexts it may vary with temperature, using the equation:
- P = ρ·g·h/1000,
- where
- P: pressure in Pa
- ρ: density of water (conventionally 1000 kg/m3 at 4 °C)
- g: acceleration due to gravity (conventionally 9.80665 m/s2 but sometimes locally determined)
- h: water height in millimetres.
The unit is often used to describe how much water
See also
References
External links
- Pressure conversion calculator at Cornell University website