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
Pascal (unit) the pascal measures the stiffness, tensile strength and compressive strength of materials. In engineering use, because the pascal represents a very small quantity, the megapascal (MPa) is the preferred unit for these uses. The pascal is also equivalent to the SI unit of energy density, J/m. This applies not only to the thermodynamics of pressurised gases, but also to the energy density of electric, magnetic, and gravitational fields. In measurements of sound pressure or loudness of sound, one pascal is equal to 94 decibels SPL. The quietest sound a human can hear, known as the threshold of hearing, is 0