Common Conversions

1 Bar = 14.5 PSI
25.4mm = 1 Inch
1 HP = 42.4 BTU/Min
1 US Gallon Oil = 7.08 lbs
1 GPM at 1500 PSI = 1 H.P. (General Rule)
1 US Gallon = 231 Cubic Inches = 3.7854 Litres

Application Formulae

1714 x Pump Efficiency
    PSI = 1714 x Pump Efficiency x HP
GPM = 1714 x Pump Efficiency x HP
    HP = Torque (in.lbs) x RPM
Torque = HP x 63025
    RPM = HP x 63025

Electric Motors

At 440Va 3 Phase Motor Draws 1.25 AMP/HP
At 220Va 3 Phase Motor Draws 2.5 AMP/HP
At 110Va Single Phase Motor Draws 10 AMP/HP

Other Conversions

eg to convert Atmospheres to Bar : Multiply Atmospheres by the Factor (1.01325) = Bar
to convert Bar to Atmospheres : Divide Bar by the Factor (1.01325) = Atmospheres
Unit   Symbol   Unit   Symbol   Factor   
Atmospheres Atm bar bar 1.01325
BTU/hour Btu/h kilowatts kW 0.293071 x 103
Cubic centimetres cm3 litres I 0.001
Cubic centimetres cm3 millilitres ml 1
Cubic feet ft3 cubic metres m3 0.0283168
Cubic feet ft3 litres I 28.3161
Cubic inches in3 cubic centimetres cm3 16.3871
Cubic inches in3 litres I 0.0163866
Degrees (angle) 0radians rad 0.0174533
Feet ft metres m 0.3048
Feet of water ft H2O bar bar 0.0298907
Fluid ounces UK UK fl oz cubic centimetres cm3 28.413
Fluid ounces US US fl oz cubic centimetres cm3 29.5735
Foot pounds f. fl Ibf joules J 1.35582
Foot pounds/minute ft Ibf/min watts W 81.3492
Gallons, UK UK gal litres l 4.54596
Gallons, US US gal litres l 3.78531
Horsepower hp kilowatts kW 0.7457
Inches of mercury in Hg millibar mbar 33.8639
Inches of water in H20 millibar mbar 2.49089
Inches in centimetres cm 2.54
Inches in millimetres mm 25.4
Kilogramme force Kgf newtons N 9.80665
Kilogramme f. metre Kgfm newton metres Nm 9.80665
Kilogramme f./sq. centimetre Kgf/cm2 bar bar 0.980665
Kilopascals kPa bar bar 0.01
Metric horsepower* * kilowatts kW 0.735499
Microinches uin microns um 0.0254
Millimetres of mercury mm Hg millibar mbar 1.33322
Millimetres of water mm H20 millibar mbar 0.09806
Newtons/square centimetre N/cm2 bar bar 0.1
Newtons/square metre N/m2 bar bar 10-3
Pascals (newtons/sq metre) Pa bar bar 10-3
Pints, UK UK pt litres l 0.568245
Pints, US US pt litres l 0.473163
Pounds (mass) lb kilogrammes Kg 0.4536
Pounds/cubic foot lb/ft3 kilogrammes/cubic metre Kg/m 16.0185
Pounds/cubic inch lb/in3 kilogrammes/cubic centimetre Kg/cm3 0.0276799
Pounds force lbf newtons N 4.44822
Pounds f. feet lbf ft newton metres Nm 1.35582
Pounds f. inches lbf in newton metres Nm 0.112985
Pounds f./square inch lbf/in2 bar bar 0.06894
Revolutions/minute r/min radians/second rad/s 0.10472
Square feet ft2 square metres m2 0.092903
Square inches in2 square metres m2 6.4516 x 10-2
Square inches in2 square centimetres cm26.4516