# Pounds per square inch

Pounds per square inch
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 lbf/in2 or lbf/sq in or lbf/sq in) 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 psi approximately equals 6,894.757 Pa, where pascal (Pa) is the SI unit of pressure.

## Magnitude

• Blood Pressure — Average human blood pressure (120/80): 2.32psi/1.55psi
• Boost Pressure Provided By an Automotive Turbocharger(common):Pg = 6 - 15psi
• Atmospheric pressure at sea level (standard): Pa = 14.7 psi
• Automobile tire overpressure (common): Pg = 32 psi
• Bicycle tire overpressure (common): Pg = 65 psi
• Workshop or garage air tools: Pg = 90 psi
• Air brake (rail) or Air brake (road vehicle) reservoir overpressure (common): 90 psi ≤ Pg ≤ 120 psi
• Road racing bicycle tire overpressure: Pg = 120 psi
• Steam locomotive fire tube boiler (UK, 20th century): 150 psi ≤ Pg ≤ 280 psi
• Union Pacific Big Boy steam locomotive boiler: 300 psi
• Natural gas pipelines: 800 to 1000 psi
• Full SCBA Self Contained Breathing Apparatus for toxic atmospheres: 2216 psi
• Full scuba tank overpressure (common): Pg = 3000 psi
• Commercial jet airliner hydraulic pressure: 3000 psi
• Airbus A380 hydraulic system: 5000 psi
• Water jet cutter: 40,000 psi - 100,000 psi
• Young's Modulus for steel: 30 Mpsi or 30,000,000 psi

## Conversions

Pressure units
v · d · e Pascal Bar Technical atmosphere Standard atmosphere Torr Pound per square inch
Pa bar at atm torr 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 105 ≡ 106 dyn/cm2 1.0197 0.98692 750.06 14.5037744
1 at 0.980665 ×105 0.980665 ≡ 1 kp/cm2 0.96784 735.56 14.223
1 atm 1.01325 ×105 1.01325 1.0332 p0 760 14.696
1 Torr 133.322 1.3332×10−3 1.3595×10−3 1.3158×10−3 = 1 mmHg 19.337×10−3
1 psi 6.895×103 68.948×10−3 70.307×10−3 68.046×10−3 51.715 ≡ 1 lbF/in2

## References

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• pounds per square inch — noun a unit of pressure • Syn: ↑psi • Hypernyms: ↑pressure unit …   Useful english dictionary

• ton per square inch — (tnf/in2 or tsi)    a unit of pressure traditionally used in engineering. In the U.S., 1 tsi = 2000 pounds per square inch or about 13.790 megapascals (MPa). In Britain, 1 tsi = 2240 pounds per square inch or about 15.444 megapascals …   Dictionary of units of measurement

• Pounds-force per square inch — Einheit Norm Angloamerikanisches Maßsystem Einheitenname Pound force per square inch Einheitenzeichen psi, lb.p.sq.in. (psia, psig) Dimensionsname Druck Dimensionssymbol …   Deutsch Wikipedia

• Pound per square inch — Einheit Norm Angloamerikanisches Maßsystem Einheitenname Pound force per square inch Einheitenzeichen psi, lb.p.sq.in. (psia, psig) Dimensionsname Druck Dimensionssymbol …   Deutsch Wikipedia

• pound per square inch — (lbf/in2 or psi)    a traditional unit of pressure. 1 psi equals 144 pounds per square foot (psf), 6.894 75 kilopascals (kPa), 68.9475 millibars (mb), 2.036 inches of mercury (in Hg), 27.7612 inches of water (in WC), or 70.5134 centimeters of… …   Dictionary of units of measurement

• Long ton per square inch — ist eine imperiale Maßeinheit des Drucks. Einheitenzeichen: tn.p.sq.in 1 tn.p.sq.in = 2240 psi 1,575 kp/mm2 = 15,46 · 106 Pa Siehe auch Angloamerikanisches Maßsystem short ton per square inch pounds force per square inch pounds force per square… …   Deutsch Wikipedia

• Short ton per square inch — ist eine imperiale Maßeinheit des Drucks. Einheitenzeichen: tn.sh.p.sq.in 1 tn.sh.p.sq.in = 2000 psi = 1,406 kp/mm2 = 13,80 · 106 Pa Siehe auch Angloamerikanisches Maßsystem long ton per square inch pounds force per square inch pounds force per… …   Deutsch Wikipedia

• Pound-force per square inch — Einheit Norm Angloamerikanisches Maßsystem Einheitenname Pound force per square inch Einheitenzeichen psi, lb.p.sq.in. (psia, psig) Dimensionsname Druck Dimensionssymbol p …   Deutsch Wikipedia

• square inch — noun a unit of area equal to one inch by one inch square • Syn: ↑sq in • Hypernyms: ↑area unit, ↑square measure * * * noun : a unit of area equal to a square one inch long on each side see measure table * * * a unit of area measurement equal to a …   Useful english dictionary

• Pounds-force per square foot — oder auch nur pound per square foot ( Pfund pro Quadratfuß ) ist eine imperiale Maßeinheit des Drucks in einer Reihe von Staaten, die das angloamerikanische Maßsystem nutzten bzw. noch nutzen. Einheitenzeichen: lb.p.sq.ft., lb./sq.ft. 1… …   Deutsch Wikipedia