Btu (I.T., pre-1956)
The Btu (I.T., pre-1956) refers to the International Table Btu, a specific definition used before 1956. It represents the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit at a constant pressure of one atmosphere.
Foot-pounds
A foot-pound (ft-lb) is a unit of work or energy in the Imperial and U.S. customary systems that is the amount of energy required to exert a force of one pound over a distance of one foot.