Pounds per square inch
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
The pound per square inch or, more accurately, pound-force per square inch (symbol: psi or lbf/in² or lbf/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:
1 [[]] (Expression error: Unexpected round operator [[]]) : Pascal (Pa) is the SI unit of pressure.
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[2] For example, "Pg = 100 psi" rather than "P = 100 psig".
- psia (pounds-force per square inch absolute) — gauge pressure plus local atmospheric pressure. Replace "x psia" with "Pa = 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 "Pg = x psi".
- psivg (psi vented gauge) — difference between the measuring point and the local pressure. Replace "x psivg" with "Pvg = 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 "Psg = x psi".
psig
Psig (pound-force per square inch gauge) is a unit of pressure relative to atmospheric pressure at sea level. By contrast, psia 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.
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.
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.
Magnitude
- Atmospheric pressure at sea level (standard): Atmosphere= 14.6959488 psi
- Automobile tire overpressure (common): Pg = 32 psi
- Bike tire overpressure (common): Pg = 65 psi
- Air brake (rail) or Air brake (road vehicle) reservoir overpressure (common): 90 psi ≤ Pg ≤ 120 psi
- Ivan Drago's punch (fictional): Pg = 2150 psi
- Full SCBA Self Contained Breathing Apperatus for toxic atmospheres 2216 psi
- Full scuba tank overpressure (common): Pg = 3,000 psi
- Commercial jet airliner hydraulic pressure 3000 psi
- Airbus A380 hydraulic system 5000 psi
Conversions
| pascal (Pa) | bar (bar) | technical atmosphere (at) | atmosphere (atm) | torr (Torr) | pound-force per square inch (psi) | |
|---|---|---|---|---|---|---|
| 1 Pa | ≡ 1 N/m2 | 10−5 | 1.0197×10−5 | 9.8692×10−6 | 7.5006×10−3 | 145.04×10−6 |
| 1 bar | 100,000 | ≡ 106 dyn/cm2 | 1.0197 | 0.98692 | 750.06 | 14.504 |
| 1 at | 98,066.5 | 0.980665 | ≡ 1 kgf/cm2 | 0.96784 | 735.56 | 14.223 |
| 1 atm | 101,325 | 1.01325 | 1.0332 | ≡ 1 atm | 760 | 14.696 |
| 1 torr | 133.322 | 1.3332×10−3 | 1.3595×10−3 | 1.3158×10−3 | ≡ 1 Torr; ≈ 1 mmHg | 19.337×10−3 |
| 1 psi | 6,894.76 | 68.948×10−3 | 70.307×10−3 | 68.046×10−3 | 51.715 | ≡ 1 lbf/in2 |
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.
Notes
change from (atm. presure at sea level (1 Pa = 14.5 psi) to (1 bar = 14.5 psi)
See also
External links
ca:PSI (unitat)
cs:Psi (jednotka)
da:PSI
de:Pound-force per square incheu:PSI
fr:PSI (unité)
hr:psi (tlak)
it:PSI (unità di misura)
he:PSI
ja:重量ポンド毎平方インチ
nn:PSIfi:Psi (mittayksikkö)
sv:Psi (tryckenhet)
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
