CONVERSION FACTORS      NCEES 8th Ed update

Conversion Factors - NCEES Handbook
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Units,  Metric Prefixes, Equivalents, Temperature,  Constants

Multiply By To Obtain
acre 43,560  ft2 
amp-hour (A-hr) 3,600 coulombs (C)
ångstrõm (Å) 1 x 10-10 m
atmosphere (atm) 76 cm of mercury (Hg)
atm, std 29.92 in of mercury (Hg)
atm, std 14.7 lbf/in2 abs (psia)
atm, std 33.90 ft, water
atm, std 1.013 x 105 pascal (Pa)
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bar 1 x 105 Pa
barrels-oil 42 galons-oil
BTU 1,055  joule(J)
BTU 2.2928 x 10-4 kilowatt-hr  (kWh)
BTU 778 ft-lbf
Btu/hr 3.930 x 10-4 horsepower (hp)
Btu/hr 0.293 watts (W)
Btu/hr 0.216 ft-lbf/sec
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calorie (g-cal) 3.968 x 10-3 Btu
cal 1.560 x 10-6 hp-hr
cal 4.186 joule (J)
cal/sec 4.186 watt (W)
centimeter (cm) 3.281 x 10-2 foot (ft)
cm 0.394 inch (in)
centipoise (cP) 0.001 pascal · sec   (Pa · sec)
centipoise (cP) 1 g/m-s
centistokes (cSt) 1 x 10-6 m2/sec  (m2/s)
cubic feet/sec (cfs) 0.646317 million gallons per day (mgd)
cubic feet (ft3) 7.481 gallon (gal)
cubic meters (m3) 1,000 Liters
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electronvolt (eV) 1.602 x 10-19 joule (J)
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foot (ft) 30.48 cm
ft 0.3048 meter (m)
ft-lbf 1.285 x 10-3 Btu
ft-lbf 3.766 x 10-7 kilowatt-hrs (kWh)
ft-lbf 0.324 calaries (g-cal)
ft-lbf 1.356 joule (J)
ft-lbf/sec 1.818 x 10-3 horsepower (hp)
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gallon (US Liq) 3.785 liter (L)
gallon (US Liq) 0.134 ft3
gallons of water 8.3453 lbs of water
gamma (g, G) 1 x 10-9 tesla (T)
gauss 1 x 10-4 T
gram (g) 2.205 10-3 pound (lbm)
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hectar 1 x 104 square meters (m2)
hectar 2.47104 acres
horsepower (hp) 42.4 Btu/min
hp 745.7 watt (W)
hp 33,000 (ft-lbf)/min
hp 550 (ft-lbf)/sec
hp-hr 2,544 Btu
hp-hr 1.98 x 106 ft-lbf
hp-hr 2.68 x 106 joule (J)
hp-hr 0.746 kWh
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inch (in) 2.540 centimeter (cm)
in of Hg 0.0334 atm
in of Hg 13.6 in of H2O
in of  H2O 0.0736 in of Hg
in of  H2O 0.0361 lbf/in2 (psi)
in of  H2O 0.002458 atm
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joule (J) 9.478 x 10-4 Btu
J 0.7376 ft-lbf
J 1 newton-m (N-m)
J/s 1 watt (W)
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kilogram (kg) 2.205 pound (lbm)
kgf 9.8066 newton (N)
kilometer (km) 3,281 feet (ft)
km/hr 0.621 mph
kilopascal (kPa) 0.145 lbf/in2 (psi)
kilowatt (kW) 1.341 horsepower (hp)
kW 3,413 Btu/hr
kW 737.6 (ft-lbf)/sec
kW-hours (kWh) 3,413 Btu
kWh 1.341 hp-hr
kWh 3.6 x 106 joule (J)
kip (K) 1,000 lbf
K 4,448 newton (N)
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liter (L) 61.02 in3
L 0.264 gal (US Liq)
L/second (L/s) 2.119 ft3/min (cfm)
L/s 15.85 gal (US)/min (gpm)
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meter (m) 3.281 feet (ft)
m 1.094 yard
m/second (m/s) 196.8 ft/min
mile (statute) 5,280 ft
mile (statute) 1.609 kilometer (km)
mile/hr (mph) 88.0 ft/min (fpm)
mph 1.609 km/h
mm of Hg 1.316 x 10-3 atm
mm of H2O 9.678 x 10-5 atm
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newton (N) 0.225 lbf
newton (N) 1 kg-m/s2
N · m 0.7376 ft-lbf
N · m 1 joule (J)
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pascal (Pa) 9.869 x 10-6 atmospheres (atm)
Pa 1 newton/m2  (N/m2)
Pa  · sec (Pa·s) 10 poise  (P)
pound (lbm, avdp) 0.454 kilograms (kg)
lbf 4.448 N
lbf-ft 1.356 N · m
lbf/in2 (psi) 0.068 atm
psi 2.307 ft of  H2O
psi 2.036 in of Hg
psi 6,895 Pa
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radian 180/p degree
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stokes 1 x 10-4 m2/sec
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therm 1 x 105 Btu
ton 2,000 pounds (lb)
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watt (W) 3.413 Btu/hr
W 1.341 x 10-3 horsepower (hp)
W 1 joule/sec (J/s)
weber/m2 (Wb/m2) 10,000 gauss

 

UNITS     (Top of Page)

The Fe Exam uses both the metric system of units and the U.S. customary System (USCS). In the USCS system of units, both force and mass are called pounds. Therefore, one must distinguish the pound-force (lbf) from the pounds-mass (lbm).
  

For USCS units:
 
  1 lbf accelerates 1 lbm 32.174 ft/s2 

Newton's Second Law
     F = ma/gc 
          F in units of lbf
          m in units of lbm
          a in units of ft/s2
          gc = unit conversion factor = 32.174 lbm-ft/lbf-s2 

Kinetic Energy
     KE = mv2/2gc, where KE has units ft-lbf

Potential Energy
     PE = mgh/gc, where PE has units ft-lbf

Fluid Pressure
     p = rgh/gc where p has units lbf/ft2

Specific Weight
     SW = rg/gc, where SW has units lbf/ft3

Shear Stress
   t =  (m/gc)(dv / dy ), where t has units lbf/ft2 

     

METRIC PREFIXES      (Top of Page)

10-18 a, auto

10-2

 c, centi 106 M, mega
10-15 f, femto 10-1 d, deci 109 G, giga
10-12 p, pico 101 da, deka 1012 T, tera
10-9 n, nano 102 h, hecto 1015 P, peta
10-6 u, micro 103 k, kilo 1018 E, exa
10-3 m, milli
    

EQUIVALENTS      (Top of Page)

1 gal of water = 8.34 lbf
1 ft3 of water = 62.4 lbf
1 in3 of mercury = 0.491 lbf
1 m3 of water = 1,000 kilograms
    

TEMPERATURE      (Top of Page)

oF = 1.8 ( oC ) + 32
oC = ( oF - 32 ) / 1.8
oR = oF+ 459.69
oK = oC + 273.15
       

CONSTANTS      (Top of Page)

Symbol Name Value Units
e electron charge 1.6022 x 10-19  C (coulombs)
 F Faraday's Constant  96,485  coulombs/mol
R gas constant (metric)  8,314 J / (kmol · oK)
R gas constant (metric)  8,314  (kPa · m3) / (kmol · oK)
R gas constant (USCS) 1,543 (ft-lbf) / ( lb mol · oR)
G gravitation - Newtonian 6.673 x 10-11  (m3 / kg · sec2)
G gravitation - Newtonian  6.673 x 10-11 (N · m2 / kg2)
g gravity acceleration (metric) 9.807 m/sec2 
g gravity acceleration (USCS) 32.174 ft/sec2
Vm molar volume (ideal gas, T @ 273.15 K, P @ 101.3 kPa)  22,414  L / kmol
c speeds of light 299,792,000 m/s
s Stephan-Boltzmann constant  5.67 x 10-8  W/(m2-K4)
        

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