How do you differentiate between a full and an empty oxygen cylinder?

The most effective method to differentiate between a full and an empty oxygen cylinder is by checking the gauge pressure. This approach involves reading the pressure gauge attached to the cylinder, which displays the amount of oxygen in the tank measured in psi (pounds per square inch). A full cylinder will typically show a pressure close to its maximum rated pressure, whereas an empty or nearly empty cylinder will indicate a significantly lower pressure. This provides a direct and accurate measurement of the oxygen available in the cylinder.

Using weight to differentiate between full and empty cylinders can be less reliable, as different sizes and materials can significantly affect weight. Visual inspection might not provide a definitive answer, as cylinders can appear visually the same regardless of how much oxygen they contain. Lastly, while there are color codes for gas cylinders (such as green for oxygen in many regions), relying on color alone is not a foolproof method since the paint may wear off or differ by manufacturer. Therefore, checking the gauge pressure is the most precise and commonly accepted way to determine the oxygen content in a cylinder.