General conversion factors (to five significant digits) | ||
---|---|---|
Quantity | U.S. unit | SI equivalent |
Length | 1 in | 0.025400 m |
1 ft | 0.30480 m | |
1 mile | 1609.3 m | |
Area | 1 in2 | 0.64516 × 10−3 m2 |
1 ft2 | 0.092903 m2 | |
1 acre | 4046.9 m2 | |
Volume | 1 in3 | 0.016387 × 10−3 m3 |
1 ft3 | 0.028317 m3 | |
1 US gallon | 3.7854 × 10−3 m3 |
Conversion factors for stress analysis | ||
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Quantity | U.S. unit | SI equivalent |
Density | 1 slug/ft3 = 1 lbf s2/ft4 | 515.38 kg/m3 |
1 lbf s2/in4 | 10.687 × 106 kg/m3 | |
Energy | 1 ft lbf | 1.3558 J (N m) |
Force | 1 lbf | 4.4482 N (kg m/s2) |
Mass | 1 slug = 1 lbf s2/ft | 14.594 kg (N s2/m) |
1 lbf s2/in | 175.13 kg | |
Power | 1 ft lbf/s | 1.3558 W (N m/s) |
Pressure, Stress | 1 psi (lbf/in2) | 6894.8 Pa (N/m2) |
Conversion factors for heat transfer analysis | ||
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Quantity | U.S. unit | SI equivalent |
Conductivity | 1 Btu/ft hr °F | 1.7307 W/m °C |
1 Btu/in hr °F | 20.769 W/m °C | |
Density | 1 lbm/in3 | 27680. kg/m3 |
Energy | 1 Btu | 1055.1 J |
Heat flux density | 1 Btu/in2 hr | 454.26 W/m2 |
Power | 1 Btu/hr | 0.29307 W |
Specific heat | 1 Btu/lbm °F | 4186.8 J/kg °C |
Temperature | 1 °F | 5/9 °C |
Temp °F | 9/5 × Temp °C + 32° | |
9/5 × Temp °K − 459.67° |
Important constants | ||
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Constant | U.S. unit | SI unit |
Absolute zero | −459.67 °F | −273.15 °C |
Acceleration of gravity | 32.174 ft/s2 | 9.8066 m/s2 |
Atmospheric pressure | 14.694 psi | 0.10132 × 106 Pa |
Stefan-Boltzmann constant | 0.1714 × 10−8 Btu/hr ft2 °R4 | 5.669 × 10−8 W/m2 °K4 |
where °R = °F + 459.67 | where °K = °C + 273.15 |
Approximate properties of mild steel at room temperature | ||
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Quantity | U.S. unit | SI unit |
Conductivity | 28.9 Btu/ft hr °F | 50 W/m °C |
2.4 Btu/in hr °F | ||
Density | 15.13 slug/ft3 (lbf s2/ft4) | 7800 kg/m3 |
0.730 × 10−3 lbf s2/in4 | ||
0.282 lbm/in3 | ||
Elastic modulus | 30 × 106 psi | 207 × 109 Pa |
Specific heat | 0.11 Btu/lbm °F | 460 J/kg °C |
Yield stress | 30 × 103 psi | 207 × 106 Pa |