So, what you are probably re â¦ ferring to is 'energy'. The SI unit of energy is the joule (J). An alternative unit, used by electricity utility companies for the purpose of billing its consumers, is the kilowatt hour (kW.h).
a typical steel 30 pound liquid propane tank weighs about 25-28 pounds empty. propane tank markings (on collar) propane weighs about 4.125 pounds per gallon and a 30 po â¦ und tank will hold about 7.5 gallons so a full tank will weigh about 55 pounds or so. /source: wiki.answers.com/.
The nominal weight of a tank - like a 20# or 100# cylinder - is the amount of gas it will hold. The tare weight, which is stamped T.W. on the handle of the cylinder, is the weight of the empty tank. Those weights added together will give you the weight of a full tank. For example, a 20# cylinder with a tare weight of 19.2 lbs will weigh 39.2 lbs. full.