Millibars (symbol: mb) are also commonly used when referencing atmospheric air pressure, where atmospheric pressure equals 1013.25 mbar (101.325 kPa). The International Bureau of Weights and Measures has specified the bar as a unit that authors should have the freedom to use but has chosen not to include the bar in the list of non-SI units accepted for use with SI. The term 'bar' comes from the Greek word 'baros,' which means weight.Ĭurrent use: Although the bar is a metric unit of pressure, it is not accepted within the International System of Units (SI) and is even deprecated within certain fields. Atmosphere (atm) Normal atmospheric pressure is defined as 1 atmosphere. Normal atmospheric pressure is 14.7 psi, which means that a column of air one square inch in area rising from the Earth's atmosphere to space weighs 14.7 pounds. History/origin: The unit, bar, was introduced by Vilhelm Bjerknes, a Norwegian meteorologist who founded modern weather forecasting. (psi, PSI, lb/in 2, lb/sq in) Commonly used in the U.S., but not elsewhere. It is equal to 0.987 atmospheres (101,325 Pa), the unit often used as a reference of standard pressure. Barĭefinition: A bar (symbol: bar) is a metric unit of pressure that is defined as exactly 100,000 pascals (symbol: Pa). This is true of most countries, including the United States. The kilopascal is more prevalent in scientific contexts such as material science, engineering, and geophysics.

Exceptions include certain countries that use either the imperial or United States customary systems of measurement, such as the United States, in which the unit of pound per square inch is more commonly used. Example: convert 15 Pa to kPa: 15 Pa 15 × 0.001 kPa 0.015 kPa. In 1971, at the 14 th General Conference on Weights and Measures, the pascal was adopted as an SI derived unit of pressure.Ĭurrent use: The kilopascal is widely used worldwide in countries that have adopted SI. 1 psi 6.8947572932 kPa 1 kPa 0.1450377377 psi Example: convert 15 psi to kPa: 15 psi 15 × 6.8947572932 kPa 103. The kilopascal is simply a multiple of the pascal, as is common within SI. History/origin: The unit, pascal, is named after Blaise Pascal, a French mathematician and physicist. A kilopascal is defined as 1,000 Pa, where 1 Pa is defined as the pressure exerted by a 1 newton force applied perpendicularly to an area of one square meter, expressed as 1 N/m 2 or 1 kg/m

Definition: A kilopascal (symbol: kPa) is a multiple of the pascal (Pa), an SI (International System of Units) derived unit of pressure used to measure internal pressure, Young's modulus, stress, and ultimate tensile strength.

325 psi to kpa