normal atmospheric pressure is 1.013 x 105 Pa or 101.3 kPa at sea level, the air pressure decreases as you go up in altitude because the pressure is exerted by the column of atmosphere.

The column of fluid, and its pressure at its base, is maximum, at sea level, and it decreases until it becomes zero in the space. it decreases by a factor of 10 every time it rises 16 km (half at 5 500 m). It is thus possible to use pressure to measure the height, which is the basic principle of the altimeter used in aerospace and mountaineering.

A barometer, measures the atmospheric pressure. Normal atmospheric pressure supports a column of mercury 760 mm high, what is meant by 760 mm Hg or 760 torr .

Boiling temperature of the liquid depends on the pressure: At high altitudes, the lower air pressure allows boiling water to 70 degrees, while at sea level it takes 100 degrees. Cavitation is a form of boiling caused by the pressure drop, it is easier, to make pump cavitation or fluid network with low pressure atmosherique. A system, pumping or fluid flow, must consider this parameter ...

With Mecaflux software,

Atmospheric pressure occurs in the calculation of the pumping system, Indeed, when the tanks are in the open air, the pressure in the reservoirs, is that of the atmospheric pressure. This Air pressure. ambient in the tanks do not take into account the hydrostatic pressure suction or discharge, but is dependent on temperature and altitude.

Altitude is a parameter to be included in the tab systems pumps and turbines, a value of ambient pressure is calculated and given as a function of temperature.