Why Does My Propane Tank Gauge Never Read 100%?
Following the 80/20 Rule for Propane Tanks
Have you ever noticed that right after your New York propane supplier delivered your fuel, they didn’t fill your propane tank all the way up to the 100% level?
Don’t worry. Your propane supplier is not doing anything wrong. Quite the contrary. They’re looking after you by following what’s known in the industry as the “80/20 rule.” This rule is followed for a very important reason: safety.
Propane: From Liquid to Gas
The propane in your tank is stored as a liquid. The liquid changes into gas before it leaves the tank. That’s why it’s called liquid petroleum gas (LPG).
Like any liquid, propane will expand when its temperature rises. The difference with propane is that it expands a lot, and quickly. Its volume increases nearly 17 times the volume of water over the same increase in temperature.
This is why your propane delivery driver needs to leave extra space in your tank. This enables propane to safely expand. Aboveground propane tanks are typically filled to about 80% capacity; underground tanks can be filled slightly higher because they are insulated against the heat.
That extra space in the tank provides a cushion against the pressure that builds up inside the tank. For example, a 500-gallon tank filled to 80% will safely hold 400 gallons of propane.
This safeguard is especially important in hot weather—when liquid propane expands the most. It’s important to note that the amount of gas in the tank doesn’t change during periods of expansion and contraction–only its density does. For example, if you notice that the tank gauge reading fluctuates slightly during quick temperature swings (hot day, cool night), again, don’t worry because that’s perfectly normal.
Propane gas expansion is also a reason why you should never paint your outdoor propane tank a dark color. This is because dark colors absorb more heat.
Preventing Propane Tank Runouts
Life can get busy with work, family and other obligations. And sometimes, you might forget to go outside and check your tank gauge to see how much propane is in your tank. If the reading is 30% or less, you know it’s time to call your New York propane supplier to schedule a delivery.
If you forget to check your tank, however, you risk running low or completely running out of propane. That means the expense and hassle of an emergency propane delivery. And if you run out of propane, you also need a propane professional to perform a required pressure test on your propane system and relight the pilots on all your appliances. That’s another expense.
Many of New York’s propane companies offer a solution with their automatic delivery service, which relies on your customer history and the current weather to estimate your propane usage. Then they deliver more fuel before you run low. Some companies even offer propane tank monitoring. Tank monitors use wireless and cellular technology to send real-time data about your propane levels. Your company will know precisely when you need fuel, and you can often watch your own tank with a wireless app.
If your propane company doesn’t offer automatic delivery, or if you prefer the control of always calling in your order, you need to be vigilant about monitoring your propane tank gauge levels and request a delivery when your tank is between 25% and 30% full. While your propane dealer may be able to make a delivery within a day in case of an emergency, it is always best to provide a few days’ notice. This advance notice is necessary for scheduling your home into a propane company’s delivery route.
Please check with your propane company to find out what services and options they offer.