The 80/20 Rule for Propane Tanks

Have you come home after a propane delivery, checked the gauge and thought, “Wait a minute, I asked for the tank to be filled! Why is it sitting at only 80 percent full?”

Why? Science, that’s why! But no, seriously, there’s a reason for this:

Propane, like water, expands in the heat, only a lot more so. The volume of propane increases almost 17 times the volume of water over the same increase in temperature. And, as propane expands, it needs room to expand. If you have a 500-gallon propane tank, it can only safely hold 400 gallons of propane to meet the 80/20 rule for propane safety.

That room for expansion is what the 20 percent of empty space in your propane tank provides, and why your Poore’s Propane delivery driver will not fill your aboveground propane tank more than 80 percent full.

Safety is also why you should never paint your propane tank a dark color. Lighter shades reflect the outside heat, while darker colors absorb it, creating dangerous levels of propane expansion.

Underground propane tanks may be filled slightly more than 80 percent, as they are insulated from the heat.

There may be times that when there are fast temperature swings here in Delaware and Maryland, like a hot day to a cool night, there may be some fluctuation in your tank gauge levels. That’s OK. It’s normal as the density of the propane in your tank adjusts to changing temperatures. You still have the same amount of propane, it’s just taking up more room, or going back down to normal.

Speaking of checking your gauges, you don’t have to worry about checking your propane tank gauge with our automatic delivery program, you know! We track how much propane your home or business will use, depending on weather, and schedule a delivery before your tank gets too low. Be sure to reach out to us today and leave the refueling to us.

The professionals at Poore’s can be counted on for dependable, safe propane delivery throughout the Delmarva area. Contact us today to schedule your propane delivery!

Poore’s Propane and Oil – serving Kent and Sussex Counties in Delaware, and Cecil, Kent, Queen Anne’s, Caroline and Talbot Counties in Maryland.