A vertical 120-gallon propane tank has a height of 55 inches and a diameter of 30 inches, whereas a horizontal tank of the same capacity has a diameter of 24 inches and a length of 66 inches. For expansion, a 120-gallon tank carries 96 gallons of propane.
This size vertical tank has an empty weight of 175 pounds and a filled weight of 600 pounds. A 120-gallon horizontal tank weighs 300 pounds when empty and 725 pounds when full.
These tanks provide gas to appliances such as water heaters, clothes dryers, space heaters, and ranges. In order to prevent fires, propane tanks are often located adjacent to a building, at least 10 feet away from any electric ignition source.