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 cost US$0.10 and 1 Therm (CH4) US$0.50 cents in the year 1995)

1 BTU = 1.055 kJ              1 Erg = 1 mJ            1 Therm = 105.5 MJ (59¢)

1 Cal(food) = 4.187 kJ 1 cal = 4.187 J      1 kW-Hr = 3.6 MJ (10¢)

1 kg(kilo)Calorie = 4.187 kJ  (in USA Calorie means a Food Calorie = 4.187 kJ)

1 Horsepower-Hour = 2.6845 MJ 1 Ft-Pound force = 1.3558 J  

1 BTU/ft3 = 0.0373 MJ/m3      1 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-R      1 Ton of Refrigeration = 3.517 kW

1 MJ of Nat. Gas = 0.56¢      1 MJ of Electricity = 2.78¢ (5 times pricier than gas)

Temperature:

^oC = 5*(^oF-32)/9         ^oR = ^oF+460        K = ^oC+273

Viscosity:

1 Centipoise = 1 mPa.s (absolute)   1 Centistoke = 1 mm2/s (kinematic) 

---------------------------CONSTANTS (within reasonable accuracy)----------------

Quantity SI English

Standard temperature          25^oC (298K),       60^oF (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;

C_p,air                       1.005 kJ/kg.K,    0.24 BTU/lbm-R

kair = CP/Cv                  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