What is the most effective way to determine the amount of oxygen in a portable, high-pressure cylinder?

Reading the pressure gauge mounted on the cylinder is the most effective way to determine the amount of oxygen in a portable, high-pressure cylinder because pressure directly correlates to the amount of gas remaining. The pressure gauge provides a real-time measurement of the gas pressure inside the cylinder, allowing for an accurate assessment of how much oxygen is left.

Unlike methods such as checking the weight of the cylinder, which can be affected by other factors like the cylinder's material or impurities, or inspecting the color, which does not provide relevant information about the contents, the pressure gauge offers a straightforward and reliable indication of the remaining volume of gas. Additionally, chemical testing methods are not practical for assessing the quantity of oxygen in high-pressure cylinders and may pose safety risks.

Using the pressure gauge ensures that users have a clear understanding of their oxygen supply, enabling them to make informed decisions about when to refill or replace the cylinder before it is critically low.