The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in2;[1] abbreviation: psi) 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. In SI units, 1 psi is approximately equal to 6895 Pa.
The pound per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi (101 kilopascals), this will be added to any pressure reading made in air at sea level. 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).[2][3] When gauge pressure is referenced to something other than ambient atmospheric pressure, then the unit would be pound per square inch differential (psid).
"Ksi" redirects here. For the English YouTuber, rapper and boxer, see KSI.
The kilopound per square inch (ksi) is a scaled unit derived from psi, equivalent to a thousand psi (1000 lbf/in2).
ksi are not widely used for gas pressures. They are mostly used in materials science, where the tensile strength of a material is measured as a large number of psi.[4]
The conversion in SI units is 1 ksi = 6.895 MPa, or 1 MPa = 0.145 ksi.
The megapound per square inch (Mpsi) is another multiple equal to a million psi. It is used in mechanics for the elastic modulus of materials, especially for metals.[5]
The conversion in SI units is 1 Mpsi = 6.895 GPa, or 1 GPa = 0.145 Mpsi.
^IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units), IEEE Std 260.1™-2004 (Revision of IEEE Std 260.1-1993)
^. United Air Specialists, Inc. Archived from the original on August 1, 2011.
^"Gage v. Sealed v. Absolute pressure" (PDF). Dynisco.
^"Tensile Strength of Steel and Other Metals". All Metals & Forge Group. 18 April 2013. Retrieved 2016-07-26. A metal's yield strength and ultimate tensile strength values are expressed in tons per square inch, pounds per square inch or thousand pounds (ksi) per square inch. For example, a tensile strength of a steel that can withstand 40,000 pounds of force per square inch may be expressed as 40,000 PSI or 40 KSI (with K being the [multiplier] for thousands of pounds). The tensile strength of steel may also be shown in MPa, or megapascal.
^. Archived from the original on 2016-12-16. Retrieved 2015-06-06.
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The pound per square inch or more accurately pound force per square inch symbol lbf in2 1 abbreviation psi 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 In SI units 1 psi is approximately equal to 6895 Pa Pound per square inchA pressure gauge reading in psi red scale and kPa black scale General informationUnit systemImperial units US customary unitsUnit ofPressure StressSymbolpsi or lbf in2Conversions1 psi in is equal to SI units 6 894757 kPaThe pound per square inch absolute psia is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure Since atmospheric pressure at sea level is around 14 7 psi 101 kilopascals this will be added to any pressure reading made in air at sea level 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 2 3 When gauge pressure is referenced to something other than ambient atmospheric pressure then the unit would be pound per square inch differential psid Contents 1 Multiples 2 Magnitude 3 Conversions 4 See also 5 References 6 External linksMultiples Edit Ksi redirects here For the English YouTuber rapper and boxer see KSI The kilopound per square inch ksi is a scaled unit derived from psi equivalent to a thousand psi 1000 lbf in2 ksi are not widely used for gas pressures They are mostly used in materials science where the tensile strength of a material is measured as a large number of psi 4 The conversion in SI units is 1 ksi 6 895 MPa or 1 MPa 0 145 ksi The megapound per square inch Mpsi is another multiple equal to a million psi It is used in mechanics for the elastic modulus of materials especially for metals 5 The conversion in SI units is 1 Mpsi 6 895 GPa or 1 GPa 0 145 Mpsi Magnitude EditMain article Orders of magnitude pressure Inch of water 0 036 psid Blood pressure clinically normal human blood pressure 120 80 mmHg 2 32 psig 1 55 psig Natural gas residential piped in for consumer appliance 4 6 psig Boost pressure provided by an automotive turbocharger common 6 15 psig NFL football 12 5 13 5 psig Atmospheric pressure at sea level standard 14 7 psia Automobile tire overpressure common 32 psig Bicycle tire overpressure common 65 psig Workshop or garage air tools 90 psig Air brake rail or air brake road vehicle reservoir overpressure common 90 120 psig Road racing bicycle tire overpressure 120 psig Steam locomotive fire tube boiler UK 20th century 150 280 psig Union Pacific Big Boy steam locomotive boiler 300 psig US Navy steam boiler pressure 800 psi Natural gas pipelines 800 1000 psig Full SCBA self contained breathing apparatus for IDLH non fire atmospheres 2216 psig Nuclear reactor primary loop 2300 psi Full SCUBA self contained underwater breathing apparatus tank overpressure common 3000 psig Full SCBA self contained breathing apparatus for interior firefighting operations 4500 psig Airbus A380 hydraulic system 5000 psig Land Rover Td5 diesel engine fuel injection pressure 22 500 psi Ultimate strength of ASTM A36 steel 58 000 psi Water jet cutter 40 000 100 000 psigConversions EditThe conversions to and from SI are computed from exact definitions but result in a repeating decimal 6 7 P Pa P PSI 0 45359237 kg 9 80665 m s 2 lbf 0 0254 m in 2 displaystyle P text Pa P text PSI times frac 0 45359237 text kg times 9 80665 mathrm m s 2 text lbf 0 0254 text m text in 2 P PSI P Pa 0 0254 m in 2 0 45359237 kg 9 80665 m s 2 lbf displaystyle P text PSI P text Pa times frac 0 0254 text m text in 2 0 45359237 text kg times 9 80665 mathrm m s 2 text lbf As the pascal is a very small unit relative to industrial pressures the kilopascal is commonly used 1000 kPa 145 lbf in2 Approximate conversions rounded to some arbitrary number of digits except when denoted by are shown in the following table Pressure units vte Pascal Bar Technical atmosphere Standard atmosphere Torr Pound per square inch Pa bar at atm Torr lbf in2 1 Pa 1 Pa 10 5 bar 1 Pa 1 0197 10 5 at 1 Pa 9 8692 10 6 atm 1 Pa 7 5006 10 3 Torr 1 Pa 0 000145 037 737 730 lbf in21 bar 105 1 0197 0 98692 750 06 14 503773 773 0221 at 98066 5 0 980665 0 967841 105 3541 735 5592401 14 223343 307 12031 atm 101325 1 01325 1 0332 760 14 695948 775 51421 Torr 133 322368 421 0 001333 224 0 001359 51 1 760 0 001315 789 0 019336 7751 lbf in2 6894 757293 168 0 068947 573 0 070306 958 0 068045 964 51 714932 572 See also EditConversion of units Pressure or mechanical stress Pressure UnitsReferences Edit IEEE Standard Letter Symbols for Units of Measurement SI Units Customary Inch Pound Units and Certain Other Units IEEE Std 260 1 2004 Revision of IEEE Std 260 1 1993 Glossary of Industrial Air Cleaning Technology United Air Specialists Inc Archived from the original on August 1 2011 Gage v Sealed v Absolute pressure PDF Dynisco Tensile Strength of Steel and Other Metals All Metals amp Forge Group 18 April 2013 Retrieved 2016 07 26 A metal s yield strength and ultimate tensile strength values are expressed in tons per square inch pounds per square inch or thousand pounds ksi per square inch For example a tensile strength of a steel that can withstand 40 000 pounds of force per square inch may be expressed as 40 000 PSI or 40 KSI with K being the multiplier for thousands of pounds The tensile strength of steel may also be shown in MPa or megapascal An example of the use of Mpsi in mechanics for the elastic moduli of several materials Archived from the original on 2016 12 16 Retrieved 2015 06 06 BS 350 Part 1 1974 Conversion factors and tables British Standards Institution 1974 p 49 ISBN 0 580 08471 X NIST Special Publication 811 Guide for the Use of the International System of Units SI PDF National Institute of Standards and Technology 2008 p 66 External links EditPressure measurement primer Online pressure conversions Retrieved from https en wikipedia org w index php title Pound per square inch amp oldid 1143930043, wikipedia, wiki, book, books, library,
