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| [[Image:Psidial.jpg|thumb|250px|A [[pressure gauge]] reading in psi (red scale) and [[kPa]] (black scale)]]
| | Hello from France. I'm glad to came here. My first name is Abbey. <br>I live in a city called Bethune in western France.<br>I was also born in Bethune 31 years ago. Married in May year 2012. I'm working at the the office.<br><br>my web page: [http://tinyurl.com/kecvhhb http://tinyurl.com/kecvhhb] |
| The '''pound per square inch''' or, more accurately, '''pound-force per square inch''' (symbol: '''psi''' or '''lbf/in<sup>2</sup>''' or '''lb<sub>f</sub>/in<sup>2</sup>''' or '''lbf/sq in''' or '''lb<sub>f</sub>/sq in''')/ '''pressure per square inch''' is a unit of [[pressure]] or of [[stress (physics)|stress]] based on [[avoirdupois]] units. It has been largely replaced by the [[pascal (unit)|pascal]]. It is the pressure resulting from a force of one [[pound-force]] applied to an area of one [[square inch]]:
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| Using unit conversion:
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| 1 psi = <math> \frac{1 \text{ lbf}} {(1 \text{ in})^2} = \frac{4.4482216152605 \text{ N}} {(0.0254 \text{ m})^2} </math> ≈ 6894.757293168 N/m²
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| Therefore, one pound per square inch is approximately 6894.757 [[Pascal (unit)|Pa]].
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| Now converting the psi to [[atmosphere (unit)|standard atmospheres]]:
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| <math> \frac{1 \text{ psi}}{ 6894.757293 \text{ Pa}} | |
| \cdot \frac{1.01325 \text { x} \ 10^5 \text{ Pa}}{1 \text{ atm}}</math> ≈ 14.69594877551 psi/atm
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| Therefore, 1 atmosphere is approximately 14.696 pounds per square inch.
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| '''Pounds 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, this will be added to any pressure reading made in air at sea level. The converse is '''pounds per square inch gauge''' or '''pounds per square inch gage''' ('''psig'''), indicating that the pressure is relative to atmospheric pressure. For example a bicycle tire pumped up to 65 psi above atmospheric pressure, will have a pressure of 65 + 14.7 = 79.7 psia or 65 psig.<ref>{{cite web | url = http://www.uasinc.com/InfoGlossaryP.aspx |
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| title = Glossary of Industrial Air Cleaning Technology
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| | work = United Air Specialists, Inc
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| }}</ref><ref>{{cite web | url = http://www.dynisco.com/stuff/contentmgr/files/1/162fe0347e667528bd874845e66a40ef/pdf/gageabspress.pdf
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| | title = Gage v. Sealed v. Absolute pressure | work = Dynisco }}</ref>
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| == ksi ==
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| The '''kilopound per square inch''' is a scaled unit derived from psi, equivalent to a thousand psi.
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| 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.
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| == Magnitude ==
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| {{main|Orders of magnitude (pressure)}}
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| In liquid: pressure per square inch (psi)
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| * [[Blood Pressure]] – Average human blood pressure (120/80): 2.32 psi/1.55 psi
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| * [[Water jet cutter]]: 40,000–100,000 psi
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| * Commercial jet airliner hydraulic pressure: 3000 psi
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| * Boost Pressure Provided By an Automotive [[Turbocharger]](common):''P''<sub>g</sub> = 6–15 psi
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| * [[Atmospheric pressure]] at sea level (standard): ''P''<sub>a</sub> = 14.7 psi
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| * Automobile tyre overpressure (common): ''P''<sub>g</sub> = 32 psi
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| * Bicycle tyre overpressure (common): ''P''<sub>g</sub> = 65 psi
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| * Workshop or garage air tools: ''P''<sub>g</sub> = 90 psi
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| * [[Air brake (rail)]] or [[Air brake (road vehicle)]] reservoir overpressure (common): 90 psi ≤ ''P''<sub>g</sub> ≤ 120 psi
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| * Road racing bicycle tire overpressure: ''P''<sub>g</sub> = 120 psi
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| * Steam locomotive [[fire tube boiler]] (UK, 20th century): 150 psi ≤ ''P''<sub>g</sub> ≤ 280 psi
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| * [[Union Pacific Big Boy]] [[Steam locomotive#Boiler|steam locomotive boiler]]: 300 psi
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| * Natural gas pipelines: 800 to 1000 psi
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| * Full SCBA Self Contained Breathing Apparatus for toxic atmospheres: 2216 psi
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| * Full [[Scuba set|scuba]] tank overpressure (common): ''P''<sub>g</sub> = 3000 psi
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| * [[Airbus A380]] hydraulic system: 5000 psi
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| * Ultimate strength of ASTM [[A36 steel]]: 58,000 psi
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| * [[Inch of water]]: 0.036 psi
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| == Conversions ==
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| {{Pressure Units}}
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| == See also ==
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| * [[Conversion of units#Pressure or mechanical stress|Conversion of units: Pressure or mechanical stress]]
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| * [[Pressure#Units|Pressure: Units]]
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| == References ==
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| {{reflist}}
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| == External links ==
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| * [http://www.aeroconsystems.com/electronics/Pressure_transducer_basics/Transducer_primer.htm Pressure measurement primer]
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| * [http://www.imperialtometric.com/conversion_en.htm Online pressure conversions]
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| [[Category:Units of pressure]]
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| [[Category:Customary units of measurement in the United States]]
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| [[Category:Imperial units]]
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Hello from France. I'm glad to came here. My first name is Abbey.
I live in a city called Bethune in western France.
I was also born in Bethune 31 years ago. Married in May year 2012. I'm working at the the office.
my web page: http://tinyurl.com/kecvhhb