A pressure gauge reading in PSI (red scale) and kPa (black scale)

The pound per square inch or, more accurately, pound-force per square inch (symbol: psi or lbf/in² or lb_f/in²) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch: Image File history File links Download high-resolution version (1641x1641, 528 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Pound-force per square inch ... Image File history File links Download high-resolution version (1641x1641, 528 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Pound-force per square inch ... Many techniques have been developed for the measurement of reduced or increased pressures. ... Wikipedia does not yet have an article with this exact name. ... This article is about pressure in the physical sciences. ... Stress is a measure of force per unit area within a body. ... The avoirdupois (IPA: ; French IPA: ) system is a system of weights (or, properly, mass) based on a pound of sixteen ounces. ... The pound-force is a non-SI unit of force or weight (properly abbreviated lbf or lbf). The pound-force is equal to a mass of one pound multiplied by the standard acceleration due to gravity on Earth (which is defined as exactly 9. ... A square inch is by definition the area enclosed by a square with sides each 1 inch long. ...

1 psi (6.894757 kPa) : Pascal (Pa) is the SI unit of pressure. For other uses, see Pascal. ... For other uses, see Pascal. ... Look up si, Si, SI in Wiktionary, the free dictionary. ...

Relation to other measures

Other abbreviations are used that append a modifier to "psi". However, the US National Institute of Standards and Technology recommends that, to avoid confusion, any modifiers be instead applied to the quantity being measured rather than the unit of measure[1] For example, "P_g = 100 psi" rather than "P = 100 psig". NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ...

• psia (pounds-force per square inch absolute) — gauge pressure plus local atmospheric pressure. Replace "x psia" with "P_a = x psi".
• psid (psi difference) — difference between two pressures. Replace "x psid" with "ΔP = x psi".
• psig (pounds-force per square inch gauge). Replace "x psig" with "P_g = x psi".
• psivg (psi vented gauge) — difference between the measuring point and the local pressure. Replace "x psivg" with "P_vg = x psi".
• psisg (psi sealed gauge) — difference between a chamber of air sealed at atmospheric pressure and the pressure at the measuring point. Replace "x psisg" with "P_sg = x psi".

psig

Psig (pound-force per square inch gauge) is a unit of pressure relative to atmospheric pressure at sea level. By contrast, psi measures pressure relative to a vacuum (such as that in space). Most pressure gauges, such as tire gauges, are calibrated to read zero at sea level, because most applications require the difference of pressure. For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ...

At sea level, Earth's atmosphere actually exerts a pressure of 14.695948804 psi (see below). Humans do not feel this pressure because internal pressure of liquid in their bodies matches the external pressure. If a pressure gauge is calibrated to read zero in space, then at sea level on Earth it would read 14.695948804 psi. Thus a reading of 30 psig on a tire gauge, represents an absolute pressure of 44.695948804 psi. This article is about Earth as a planet. ... For other uses, see Atmosphere (disambiguation). ...

Psi is often used incorrectly instead of psig.^[1]

ksi and kip

The ksi (kip, "kilo-pound[-force] per square inch") is 1000 psi, combining the prefix kilo with the psi abbreviation. It is occasionally used in materials science and mechanical engineering to specify stress and Young's modulus. In the United States, a kip is a unit of force that equals 1,000 pounds, i. ... The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... Mechanical Engineering is an engineering discipline that involves the application of principles of physics for analysis, design, manufacturing, and maintenance of mechanical systems. ... Stress is a measure of force per unit area within a body. ... In solid mechanics, Youngs modulus (E) is a measure of the stiffness of a given material. ...

Magnitude

• Atmospheric pressure at sea level (standard): Atmosphere= 14.6959488 psi
• Automobile tire overpressure (common): P_g = 32 psi
• Bike tire overpressure (common): P_g = 65 psi
• Air brake reservoir overpressure (common): 90 psi ≤ P_g ≤ 120 psi
• Ivan Drago's punch (fictional): P_g = 2150 psi
• Full SCBA Self Contained Breathing Apperatus for toxic atmospheres 2216 psi
• Full scuba tank overpressure (common): P_g = 3,000 psi
• Commercial jet airliner hydraulic pressure 3000 psi
• Airbus A380 hydraulic system 5000 psi

Air brake may refer to the following contexts: Air brake (aircraft) — In aeronautics these are a type of flight control system used on aircraft to reduce speed. ... Ivan Drago (Russian: ; portrayed by Dolph Lundgren) is a fictional character in the movie Rocky IV. Drago is characterized as an extremely tall (2011cm tall, as the real-life man) and powerful amateur boxing champion from the Soviet Union, as well as a former Olympic gold medalist. ... A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ... The Airbus A380 is a double-deck, wide-body, four-engine airliner manufactured by the European corporation Airbus, an EADS subsidiary. ...

Conversions

Example reading:  1 Pa = 1 N/m²  = 10⁻⁵ bar  = 10.197×10⁻⁶ at  = 9.8692×10⁻⁶ atm, etc.
Note:  mmHg is an abbreviation for millimetres of mercury. For other uses, see Pascal. ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... A technical atmosphere (symbol: at) is a non-SI unit of pressure equal to 1 kilogram-force per square centimeter, i. ... Standard atmosphere (symbol: atm) is a unit of pressure. ... The torr (symbol: Torr) or millimeter of mercury (mmHg) is a non-SI unit of pressure. ... A pressure gauge reading in PSI (red scale) and kPa (black scale) The pound-force per square inch (symbol: lbf/in²) is a non-SI unit of pressure based on avoirdupois units. ... For other uses, see Newton (disambiguation). ... In physics, the dyne is a unit of force specified in the centimetre-gram-second (cgs) system of units, symbol dyn. One dyne is equal to exactly 10-5 newtons. ... The unit kilogram-force (kgf, often just kg) or kilopond (kp) is defined as the force exerted by one kilogram of mass in standard Earth gravity. ... Standard atmosphere (symbol: atm) is a unit of pressure. ... The torr (symbol: Torr) or millimeter of mercury (mmHg) is a non-SI unit of pressure. ... The pound-force is a non-SI unit of force or weight (properly abbreviated lbf or lbf). The pound-force is equal to a mass of one pound multiplied by the standard acceleration due to gravity on Earth (which is defined as exactly 9. ...

Notes

change from (atm. presure at sea level (1 Pa = 14.5 psi) to (1 bar = 14.5 psi)

See also

• Conversion of units
• Pressure

Conversion of units refers to conversion factors between different units of measurement for the same quantity. ... This article is about pressure in the physical sciences. ...

External links

• Pressure measurement primer
• Online pressure conversions