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Appendix A:
Conversion Factors
SI FPS or Other Conversion Factor
Energy: E J BTU 1 BTU = 1055.1 J
1 kcal = 4186.8 J
Force: F
Torque: T
N
(1 N = 1 kg·m/s
2
)
N·m
lb
f
poundal
lb
f
·ft
1 lb
f
(32.2 lb
m
ft/s
2
) = 4.4482 N
1 poundal (1 lb
m
ft/s
2
) = 0.138255 N
1 lb
f
ft = 1.355818 N·m
Length: L m ft
ins. (12″ = 1 ft)
1 ft = 0.3048 m
1″ (1 inch) = 2.54 cm
Mass: M kg lb
m
1 lb
m
= 0.45359 kg
2.2046 lb
m
= 1 kg
1 slug = 14.5939 kg
Power: W W
(1 W = 1 J/s)
BTU/h
horsepower (hp)
1 BTU/h = 0.29308 W
1 hp = 745.70 W
Pressure: P Pa or kPa
(1 Pa = 1 N/m
2
)
psi
(lbs/sq inch)
1 psi (lb
f
/in
2
) = 6.895 kPa
1 bar = 10
5
Pa
1 standard atm = 101.325 kPa
1 at (1 kg
f
/cm
2
) = 98.067 kPa
1 mm Hg = 0.13333 kPa
1″ H