Propane tanks come is all sizes from a small 2lb tank for a small grill or heater to a large 1,000 gallon
tank for commercial or industrial use.
Strangely, a 57 lb tank holds 46 lbs of propane, a 120 lb tank holds 96 lbs of propane, a 500 lb tank holds 400 lbs of propane, and a 1,000 gallon tank holds 800 lbs of propane.
The 80% fill rule is a preventative safety measure against the
fluctuations that happen inside a tank. Propane, like water, will expand
when heat is added to it. Propane, however, will increase in volume
nearly 17 times greater than water over the same temperature increase.
To allow for this expansion, propane containers are filled to only 80% of their capacity.
It is difficult to know how to dispose of these tanks after they have outlived
their usefulness. Careful measures should be taken when disposing of used, and presumed empty, propane tanks. Tanks that seem to be empty actually do contain a small amount of propane that should be extracted before the tank is thrown out.
"Propane dealers are able to safely recover the product in the tank.
After all of the propane is safely transferred to another tank and the cylinder
is depressurized, all of the valves and fittings are removed and the
tank is scrapped. Tank connections, valves and gauges from unusable
cylinders that are discarded are often of no further use, have little or
no value and are scrapped as well."
Taking unwanted propane tanks back to a propane dealer is the most responsible way to dispose of them. Throwing them into your regular trash poses safety and hazard issues that can easily be prevented.
For more information on waste and recycling visit www.wasteawaygroup.com.