Unit Conversion and Some Important Numbers Length/Velocity: 1 Foot = 0.3048 m; 1 inch = 25.4 mm 1 mile = 1.61 km 1 mile = 5280 Feet 1 mile (nautical) = 1.85 km 1 mile/hour = 0.447 m/s 1 km/hour = 0.2777 m/s Volume/Flow Rate: 1 Cubic Feet = 0.02832 m3 1 Gallon = 3.785 l 1 l = 1x10-3 m3 1 Gallon = 0.1336 ft3 1 in3 = 1.6387x10-5 m3 1 Quart = 0.9464 l 1 Quart = 0.25 Gallon 1 Ounce = 29.574 ml 1 Pint = 0.473 l 1 Gallon/hour = 3.711x10-5 ft3/s 1 G/hr=1.0514x10-6 m3/s Mass: 1 Slug = 14.594 kg 1 lbm = 0.4536 kg 1 Ton (long) = 1016 kg 1 Ounce = 28.35 g Force: 1 Pound-Force = 4.448 N 1 kg-Force = 9.81 N 1 Ounce-Force = 0.278 N 1 Dyne = 10 mN 1 KIP = 4448.2 N Pressure: 1 psi = 6.895 kPa 1 bar = 100 kPa 1 inch of Hg = 3.374 kPa 1 inch of water = 0.2486 kPa 1 mm of Hg = 0.1333 kPa 1 Torr = 1 mm of Hg Energy: (1 kW-Hr is 10 cents, and 1 Therm is 50 cents) 1 BTU = 1.055 kJ 1 Erg = 1 mJ 1 Therm = 105.5 MJ (59¢) 1 Kg Calorie = 4.187 kJ 1 Calorie = 4.187 J 1 kW-Hr = 3.6 MJ (10¢) 1 Horsepower-Hour = 2.6845 MJ 1 Ft-Pound force = 1.3558 J 1 BTU/ft3 = 0.0373 MJ/m31 BTU/lbm = 2.3258 kJ/kg 1 cal/g = 4.187 kJ/kg 1 BTU/Hour = 0.2931 W 1 Horsepower = 0.7457 kW 1 BTU=778 ft-lbf/lbmol-R1 Ton of Refrigeration = 3.517 kW 1 MJ of Nat. Gas = 0.56¢ 1 MJ of Electricity = 2.78¢ (5 times more expensive than gas) Temperature: oC = \f(5,9) oF-32 oR = oF+460 K = oC+273 Viscosity: 1 Centipoise = 1 mPa.s (absolute) 1 Centistoke = 1 mm2/s (kinematic) ------------------------------------------------------------------------------------------------------------ Quantity SI English Standard temperature 25oC (298K) 60oF (520R) Standard pressure of air 101 kPa 14.7 psia g 9.81 m/s2 32.2 ft/s2 R_bar 8.314 kJ/kg.Kmol 1545.3 ft-lbf/lbmol-R Mol wt (kg/kmol): Air=29; CO2=44; N2=28; O2=32; Cp,air 1.005 kJ/kg.K 0.24 BTU/lbm-R kair = CP/Cv 1.4 1.4 Density of water 103 kg/m3 62.4 lbm/ft3 Density of air* 1.2 kg/m3 0.075 lbm/ft3 SG of Hg 13.6 13.6 Kinematic viscosity of water* 1.22x10-5 ft2/s 1.13x10-6 m2/s Enthalpy of water at 100 oC 419-2676 kJ/kg 180-1150 Btu/lb