Provided by the Bucks County Department of Consumer Protection:
Question: During the warmer months I use my gas grill to cook most of my family’s dinner meals. I often wondered if my exchange tank is truly “filled” when I take it to our local retailer that refills gas grill tanks. How much can my propane tank hold? How is propane weighed and measured? – Sal C, Perkasie
Answer: Propane tanks are most commonly referred to by their water capacity volume, and propane tanks are normally filled to 80% of its water capacity. For example, a 20 gallon tank will hold approximately 5 gallons of propane when completely full. Since propane is stored in a liquid state under pressure, it needs room to expand into a vapor. This extra “room” that is in the tank allows for that expansion. Depending on the ambient temperature outside, propane may expand more or less.
Propane can be measured in a few manners. The most common way is by gallons. It can also be measured by pounds (one gallon = 4.2lbs). When measured in gallons, a meter at the pump is used to determine the amount of propane that has been filled into a tank.
When measured in pounds, the tare (empty starting) weight of the tank must be known first. After this weight is taken into account, the tank is then filled to capacity with the correct volume. (i.e. A BBQ tank is commonly referred to as a 20lb tank. This is because these tanks hold 20lbs or approximately five gallons of propane).
If you are purchasing propane by weight in Bucks County, make sure that you look for the Bucks County Weights and Measures Seal of inspection. This will tell you that the scale the retailer is using has been registered and inspected for accuracy.
It very important to keep your gas grill in good shape so, as an additional word of advice, always make sure that the grill burner controls are turned off when you are done cooking and always keep the cylinder valve closed when not in use. If the cylinder vale is left in the open position it is possible that propane will leak out if the burner switch is left in the on position.
Check the connector hoses to make sure that they are in good shape. Check for wear and possible holes where propane can leak from.
For more information and Weights & Measures tips, please visit us at http://www.buckscounty.org/government/CommunityServices/ConsumerProtection/WeightsandMeasures