Which is an acceptable medium for pressure testing?

The acceptable mediums for pressure testing are typically substances that are safe, non-toxic, and provide accurate results without risking a hazardous situation. Air, nitrogen, or carbon dioxide are all commonly used for pressure testing because they are readily available and can be easily controlled. These gases allow for pressure testing of systems to ensure they are leak-free without the complications and risks associated with using liquids.

Using air or gases like nitrogen or carbon dioxide ensures that the test is efficient, quick to set up, and allows for visual inspection or sensing of any potential leaks at lower pressures. Furthermore, these gases can be safely vented without creating issues, unlike some other mediums which could pose a risk.

Water is generally used for certain applications as well, but it adds complications due to the risk of corrosion or freezing. Helium is sometimes used, particularly in sensitive environments, but it is more specialized and not as commonly accepted for general pressure testing. Chlorine, being a highly toxic and reactive gas, is not an acceptable medium for pressure testing due to safety concerns.