Search results
Results From The WOW.Com Content Network
The converse is pound per square inch gauge (psig), indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psig in a local atmospheric pressure at sea level (14.7 psi) will have a pressure of 79.7 psia (14.7 psi + 65 psi).
The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m 2, or kg·m −1 ·s −2). This name for the unit was added in 1971; [7] before that, pressure in SI was expressed in newtons per square metre. Other units of pressure, such as pounds per square inch (lbf/in 2) and bar, are also in common use.
The pound per square inch (psi) is still in widespread use in the US and Canada, for measuring, for instance, tire pressure. A letter is often appended to the psi unit to indicate the measurement's zero reference; psia for absolute, psig for gauge, psid for differential, although this practice is discouraged by the NIST. [3]
K-Factors have also previously been calculated and published using the United States customary units of pound per square inch (psi) and gallon per minute (gpm). Within the United States, US measurements are still often used instead of metric. [3] [4]
Pressure (unit unit-code symbol or abbrev. sample default conversion gigapascal: GPa GPa 1.0 GPa (150,000 psi) megapascal: MPa MPa 1.0 MPa (150 psi) kilopascal: kPa kPa 1.0 kPa (0.15 psi)
In North America, air and other industrial gases are often measured in inches of water when at low pressure. This is in contrast to inches of mercury or pounds per square inch (psi, lbf/in 2) for larger pressures. One usage is in the measurement of air ("wind") that supplies a pipe organ and is referred simply as inches.
Within firearms, chamber pressure is the pressure exerted by a cartridge case's outside walls on the inside of a firearm's chamber when the cartridge is fired. The SI unit for chamber pressure is the megapascal (MPa), while the American SAAMI uses the pound per square inch (psi, symbol lbf/in 2) and the European CIP uses bar (1 bar is equal to 0.1 MPa).
Pound per square inch, unit of pressure; PSI (computational chemistry), software; J/psi meson, subatomic particle; Porous silicon; Water potential, denoted Ψ, in physical chemistry, the potential energy of a water solution relative to pure water; Wave function, denoted ψ, in quantum mechanics