Which substance is commonly used during a leak test?

The use of nitrogen or a leak detection solution during a leak test is common practice because nitrogen is an inert gas, which means it does not react with the materials being tested. This inertness makes it suitable for pressurizing systems without introducing contaminants or altering the chemical properties of the substances involved.

Moreover, a leak detection solution can be applied to identify leaks easily. These solutions often contain surfactants that form bubbles when there is a leak, making it visible and easier to locate. This combination of nitrogen and a leak detection solution is effective for ensuring the integrity of HVAC systems, refrigeration systems, and various other pressurized applications.

In contrast, other options present substances that are less suitable or not typically utilized for leak testing due to their reactivity or inability to provide clear indications of leaks. For example, carbon dioxide can be reactive in certain conditions, and while helium is an excellent tracer gas, it may not be practical for all leak tests depending on the equipment and procedures used. Oxygen is not suitable due to the risk of combustion in specific environments, while moisture detection solutions may not provide the same effectiveness in identifying gas leaks. This makes nitrogen and a leak detection solution the most reliable choice for performing leak tests.