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
Torr Torr The torr (symbol: Torr) is a unit of pressure based on an absolute scale, now defined as exactly of a standard atmosphere (101325 Pa). Thus one torr is exactly (≈ ). Historically, one torr was intended to be the same as one "millimeter of mercury". However, subsequent redefinitions of the two units made them slightly different (by less than ). The torr is not part of the International System of Units (SI), but it is often combined with the metric prefix milli to name one millitorr (mTorr) or 0.001 Torr. The unit was named after Evangelista Torricelli, an Italian