The P. Gagnon & Son Blog

The 80/20 Rule for Your Propane Tank

80/20 rule

Posted: June 3, 2019

If you have been a P. Gagnon & Son propane customer for a while, you have probably noticed that our propane delivery teams ever fill your tank to 100 percent capacity.

That is no accident – in fact, we do it to prevent accidents.

As you probably know, the propane inside your propane tank is stored as a liquid that must expand into a gas for burning. The difference between propane and, say, water (another liquid that expands in heat) is the speed of expansion: propane expands extremely rapidly – about 17 times the rate of a volume of water over the same temperature increase.

Our delivery technicians need to leave extra room in the tank to allow for propane to safely expand as the temperature inside your propane tank rises (while sitting in the sun on a summer day, for example*). Aboveground propane tanks are typically filled to about 80 percent capacity, which leaves 20 percent of the tank empty for expansion (we call this the “80/20 rule”); underground propane tanks be filled slightly higher, because the ground insulates the tank from big temperature swings.

As a propane safety precaution, P. Gagnon propane delivery teams use a fixed liquid level gauge to prevent overfills – one way we work to make sure that every propane delivery to your Southern Maine or Seacoast New Hampshire-area home a safe one.

For safe, reliable propane deliveries when and where you need them, trust the pros at P. Gagnon & Son. Contact us to schedule a propane delivery today!

*Propane gas expansion is also a reason why you should NEVER paint your outdoor propane tank a dark color, since dark colors absorb heat.

P. Gagnon & Son – your propane experts in South Berwick, Sanford, York, Dover, Durham, Hampton, Rochester and surrounding towns in Southern Maine and Seacoast New Hampshire.