To allow for liquid expansion, propane cylinders are only filled to what percentage of their capacity?

Propane cylinders are filled to approximately 80% of their total capacity to allow for the expansion of the liquid propane as temperatures change. This practice is crucial because propane, like many other liquids, expands when heated. If the cylinder were filled beyond this percentage, there would be insufficient space for the vaporization of propane and for the liquid to expand safely, potentially leading to increased pressure within the cylinder.

The 80% fill level is a safety standard that helps prevent overpressure situations that could result in dangerous conditions, including leaks or ruptures. By adhering to this filling guideline, operators ensure that the cylinder can safely accommodate both the liquid and vapor phases of propane during varying temperatures, promoting safe dispensing practices.