|British thermal unit|
|btu, Abbrevs: BThU a unit of heat in the fps system equal to the quantity of heat required to raise the temperature of 1 pound of water by 1°F. 1 British thermal unit is equivalent to 1055.06 joules or 251.997 calories|
British thermal unit n.
The quantity of heat required to raise the temperature of one pound of water from 60° to 61°F at a constant pressure of one atmosphere.
The quantity of heat equal to 1/180 of the heat required to raise the temperature of one pound of water from 32° to 212°F at a constant pressure of one atmosphere.
|British thermal unit (brĭt'ĭsh) Pronunciation Key
A unit used mainly to measure heat but also applied to other forms of energy. One British thermal unit is equal to the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit, or 251.997 calories.
british thermal unit
a measure of the quantity of heat, defined since 1956 as approximately equal to 1,055 joules, or 252 gram calories. It was defined formerly as the amount of heat required to raise the temperature of one pound of water 1 F. The definition was changed because it was dependent on the initial temperature of the water. Gas utilities frequently use a larger unit, the therm, defined as 100,000 BTU, as a measure of gas consumption
Learn more about British thermal unit with a free trial on Britannica.com.