Units of measure

In the international system (SI) the physical and technical units are validated as follows :

Unit of length	Meter (symbol m)
Unit of mass	Kilogram (symbol Kg)
Unit of time	Second (symbol s)
Unit electrical current	Ampére (symbol A)
Unit of temperature	Kelvin (symbol K)
Unit of luminosity	Candela (symbol cd)
Pressure
Old measuring unit:
Kilopond per cm²	Kp/cm²
Meter of water column	mH20
Millimeter of mercury column	mmHg
Metric atmosphere	at
Atmosphere	atm
They were replaced in the SI from Pascal

One Pascal corresponds at the pressure of 1 Newton to act on the area of 1 m².

1 Pascal =	1N	(symbol Pa)
	1m2

Unit Pa is a very low value and for the standard industrial is used the

Bar (symbol bar) = 0.1 MegaPascal (symbol Mpa=1.000.000 Pa).
The conversion from the old unit of measure to the new one SI is the following:1 Kp/cm² = 0,981 bar
1 bar = 1,02 Kp/cm²The conversion in the SI unit is possible also in the countries

where is not yet used the metric system.
Conversion:1 bar = 14,50 psi
1 psi = 0,07 bar =7.000 Pa

Pressure values, except specific references, are relative to the atmospheric pressure.