History of the BTU

[mark440]

Can anyone help me out with the history of the BTU (British Thermal Unit)? I know what it is, what is stands for and so on. I am curious about it though and when it came about into the Fire Service. If it is British, do they still use the measurements of 1 gallon of water and 1 degree farenhieght? Shouldn't they use liters and celcius?

*Mark

[PaulGRIMWOOD]

The British Thermal Unit (Btu) is a precise measure of energy. It is the amount of energy required to raise the temperature of 1 pound of water 1 degree Fahrenheit when the water is near 39.2 degrees Fahrenheit.

Temperature is a measure of the average translational kinetic energy of the molecules of a system. Heat is commonly expressed in either of two units: the calorie, an older metric unit, and the British thermal unit (Btu), an English unit commonly used in the United States. Scientists express heat in terms of the joule, a unit used for all forms of energy.

The scientific pioneers of heat energy and heat transfer (thermodynamics) defined the calorie as the amount of heat energy required to raise the temperature of one gram of water 1 Celsius degree. This unit of heat energy has stuck. However, encourage use of the joule as the basic unit of heat energy.

We can easily convert from calories to joules, and joules to calories.


1cal =4.18J or 1J=.0.24cal

Brits DO use litres and Celcius! or at least - Brits under 40 years of age


James Prescott Joule (1818 - 1889). Born in Salford, England. A physicist, he shared in discovering the law of the conservation of energy. Two German physicists, Hermann von Helmholtz and Julius von Mayer, and English physicist Lord Kelvin, also worked on the law of physics. The law states that energy used up in one form reappears in another and is never lost. In 1840, he stated a law, now called Joule's Law, that heat is produced in an electrical conductor. The International unit of energy, the joule, is named in his honor.

[mark440]

Mr. Grimwood, Thank you!

*Mark