**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