# Hydrostatic Pressure

## Relationship between depth and pressure

Sponsored Links

Hydrostatic pressure in a liquid can determined using the following equation:

*p = h ρ g (1)*

*where *

*p = pressure (N/m ^{2}, Pa, lb_{f}/ft^{2}, psf)*

*h = height of fluid column, or depth in the fluid at which the pressure is measured (m, in)*

*ρ = density of liquid (kg/m ^{3}, slugs/ft^{2}) *

*g = the gravitational constant (9.81 m/s ^{2}, 32.17405 ft/s^{2})*

Hydrostatic pressure in a water column (*density 1000 kg/m ^{3}*) - or depth - is indicated below:

### Example - Pressure acting in water at deep *1 m *

The density of water at *4 ^{o}C* is

*. The pressure acting in water at*

*1000 kg/m*^{3}*1 m*can be calculated as

*p = h ρ g *

* = (1 m) ( 1000 kg/m^{3}) (9.81 m/s^{2})*

* = 9810 Pa*

### Example - Pressure acting in water at deep *3 ft *

The density of water at *32 ^{o}F* is

*. The pressure acting in water at*

*1.940 slugs/ft*^{3}*3 ft*can be calculated as

*p = h ρ g *

* = (3 ft) ( 1.940 slugs/ft^{3}) (32.17405 ft/s^{2})*

* = 187.3 lb _{f}/ft^{2} (psf)*

* = **1.3 lb _{f}/in^{2} (psi)*

Sponsored Links