Tanks (or cylinders) that propane dealers most often fill are identified as “20.0 lb. tanks” – the most commonly used tanks for gas grills, bug zappers, and patio heaters.

The propane industry fills propane tanks by weight.

  • The Grill Gauge was engineered and custom calibrated to measure the “maximum allowable fill weight” of liquid propane for standard 20.0 lb. grill tanks.
  • The “maximum allowable fill weight” (determined by DOT regulations) ranges between 18 1/2 and 19 3/4 lbs. of liquid propane per 20.0 lb. tank (depending on the tank’s water capacity).
  • Not all propane dealers fill 20.0 lb. LP tanks to their “maximum allowable fill weights.”
  • Check the label on the propane tank to see what the net weight fill amount is:
    – For an example: a tank only filled to 15.0 lbs. of liquid propane is actually under-filled by approximately 25% of its “maximum safe-fill capacity.”
    – Propane fillers must label their cylinders with the lowest amount of gas that might be in their cylinders, not the maximum allowed capacity.
  • The darkest green (“F”) area of the Grill Gauge scale is calibrated for “net fill weights” between 18.0 and 19 3/4 lbs. of liquid propane – indicating the “maximum allowable net fill weight” for 20.0 lb. tanks
    – A 20.0 lb. tank that is “filled” less than the “maximum allowable net fill weight” will show less than FULL on the Grill Gauge, again because the Grill Gauge is calibrated for the maximum allowable net fill weight!

When filling by weight, propane re-fillers look for two very important things prior to hooking up the fill hose with the cylinder on the scale. These two things are the water capacity and tare weight. The water capacity is how much water the propane tank will hold in pounds. For example, the “WC” stamped on the tank followed by a number such as “47.6” means the tank will hold 47.6 pounds of water. The tare weight (empty weight) indicated by “TW” is also followed by a number such as “18” meaning the tank weighs 18 pounds when empty. The numbers here would likely be found on the collar of a 5 gallon propane tank (also known as a 20 pound cylinder) used for a barbeque grill.

The tank filling station will generally have a cylinder filling chart that converts water capacity (WC) to pounds of propane that the filler will refer to before filling the tank. D.O.T. regulations limit propane fill levels not to exceed 42% of the water capacity of the tank. A typical gas grill tank holds 47 pounds of water, which converts to 19 3/4 pounds of propane. In other words, a propane tank that will hold 47 pounds of water will hold a safe-fill maximum net weight of 19 3/4 pounds of propane.

How does the Grill Gauge help?

The Grill Gauge provides an instant and very reliable indication of your tank’s liquid propane weight in comparison to the legal safe-fill allowable capacity of 19 3/4 pounds of propane, as determined by the D.O.T. These specifications are calibrated into each and every Grill Gauge. You’ll know how much you have from “FULL” to “EMPTY.”

Posted in: News.
Last Modified: February 27, 2018