Formulas and Constants
1 hp = 33,000 / Foot-pounds of work per minute
1 hp = .746 KW = KW ÷ 1.341
1 hp= 2,547 BTU per hour
1 BTU = Heat required to raise 1 lb water 1 °F
1 BTU = 777.6 / Foot-pounds work
1 Kilowatt Hour = 3,415 BTU
Heat Value of Carbon = 14,600 BTU per pound
Latent Heat of Fusion of Ice = 143.15 BTU per pound
Latent Heat of Evaporation of Water at 212 °F. = 970.4 BTU per pound
Total Heat of Saturated Steam at Atmospheric Pressure = 1,150.4 BTU per pound
1 Ton of Refrigeration = 288,000 BTU per 24 hours
g = Acceleration of Gravity (commonly taken as 32.16 feet per second per second)
1 Radian = 57.296°
1 Meter = 100 cm = 39.37 in
1 Kilometer = .62137 mi
1 Gallon = 231 cu in
1 Barrel = 31.5 gal
Atmospheric Pressure = 14.7 lbs per sq in = 29.92 in mercury at 32 °F
1 lb per sq in Pressure = 2.3095 ft fresh water at 62 °F
= 2.0355 in mercury at 32 °F
= 2.0416 in mercury at 62 °F
Water Pressure (lbss per sq in) = .433 X height of water in ft (Fresh water at 62 °F)
Weight of 1 cu ft Fresh Water = 62.355 lbs at 62 °F = 59.76 lbs at 212 °F
Weight of 1 cu ft Air at 14.7 lbs per sq in Pressure = .07608 lbs. at 62 °F = .08073 lbs at 32 °F
Information used with permission of Dodge and Reliance Electric © 2007
