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 of electrical current: Ampere - (symbol A) Unit of temperature: Kelvin - (symbol K) Unit of luminosity: Candle - (symbol CD)
Pressure. Old measuring units: Kilo-pond per Cm²: Kp/Cm² Meter of water column: mH₂O Millimetre of mercury column: mm-Hg Metric Atmosphere: at Atmosphere: ATM They were replaced in the SI from Pascal. One pascal corresponds to the pressure of 1 Newton, which is acting on the area of 1 m². Unit Pa is a very low value and for standard industrial applications, the Bar (symbol bar) is used. 1 bar = 0.1 Mega-pascal (symbol Mpa = 1.000.000 Pa). The conversion from the old unit of measure to the new one (SI0 is the following: 1 Kp/Cm² = 0.981 bar 1 bar = 1.02 Kp/Cm² The conversion in the SI unit is also possible where the metric system is not yet used. Conversion: 1 bar = 14.50 psi 1 psi = 0.07 bar = 7.000 Pa Pressure values, except specific references, are referred to the atmospheric pressure.