Book - School of Science and Technology

Appendix IIIConversion factorsImperial units to SIUnit Imperial Exact ApproximateLength 1 inch 25.4 mm 25 mm1 foot 0.3048 m 0.3 m3.28 feet 1 m1 yard 0.9144 m 0.9 m1 mile 1.609 km 1.6 kmArea 1 sq. in 645.2 mm 21 sq. ft 0.092 m 210.77 sq. ft 1 m 21 sq. yd 0.836 m 21 acre 4046.9 m 2Volume 1 cu. in 16.39 mm 3 16 mm 31 cu. ft 28.32 litre 28 litre35.32 cu. ft 1 m 31 pint 0.568 litre 0.6 litre1 gallon 4.546 litre 4.5 litreMass 1 pound 0.4536 kg2.205 pounds1 kg1 ton 1.016 tonne 1 tonneDensity 1 lb/cu. ft 16.02 kg/m 3Volume flow rate 1 gall/minute (g.p.m.) 0.076 litre/s0.075 litre/s1 cu. ft/minute (c.f.m.) 0.472 litre/s0.5 litre/sVelocity 1 foot/minute 0.0051 m/s197 ft/minute 1.0 m/s1 mile/hour 0.447 m/s0.5 m/sTemperature 1 degree Fahrenheit 0.556 Ct ˆ 32 Ft ˆ 0 CHeat 1 British thermal unit (Btu) 1.055 kJ 1 kJ1 `Old' therm (100 000 Btu) 105.5 MJ 100 MJ1 Unit of electricity (kWh) 3600 kJHeat flow rate 1 Btu/hour 0.2931 W 0.3 W1 horsepower 745.7 W 750 W1 ton refrigeration(12 000 Btu/hour) 3.516 kW 3.5 kWSIContinued on facing page