Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives regarding pressure are specified in the unit bar. Though the bar is not a SI unit like the pascal, nor a cgs unit, it is accepted for use with the SI by the US National Institute of Standards and Technology. The bar is widely used in descriptions of pressure because it is only about 1.3% smaller than "standard" atmospheric pressure, and is legally recognized in countries of the European Union. Conversion between the units bar and the MPa is however easy since 10 bar = 1 MPa. If there are any contradictions between new decisions and preceding decisions adopted at
Pressure Pressure is distributed to solid boundaries or across arbitrary sections of fluid "normal to" these boundaries or sections at every point. It is a fundamental parameter in thermodynamics, and it is conjugate to volume. The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m, or kg·m·s). This name for the unit was added in 1971; before that, pressure in SI was expressed simply in newtons per square metre. Other units of pressure, such as pounds per square inch and bar, are also in common use. The CGS unit of pressure is the barye