A "+" indicates that the cylinder qualified for a what percent overfill?

The "+" mark on a cylinder signifies that it has successfully passed a pressure test and is authorized for a 10% overfill beyond its rated capacity. This overfill tolerance allows for practical distribution and handling without compromising safety. It is essential in various applications where liquid gases are stored and transported, ensuring that there is an allowance for thermal expansion and variations in pressure without exceeding safe operational limits. Understanding this marking increases awareness of safe handling practices and regulatory compliance in using gas cylinders in different settings.