Which gas should never be used to test gas piping?

Which gas should never be used to test gas piping?

• A. Oxygen
• B. Nitrogen
• C. Argon
• D. Helium

Answer: (A)

Oxygen must never be used to test gas piping because it is a strong oxidizer and can make any leaked fuel gas ignite or even cause an explosion. The purpose of a test gas is to create a noncombustible or low-oxidizer environment so leaks can be found safely, so inert options like nitrogen (and sometimes argon or helium) are used instead. Using oxygen during a test would significantly raise the risk of ignition if there’s a leak, making it unsafe.

Oxygen must never be used to test gas piping because it is a strong oxidizer and can make any leaked fuel gas ignite or even cause an explosion. The purpose of a test gas is to create a noncombustible or low-oxidizer environment so leaks can be found safely, so inert options like nitrogen (and sometimes argon or helium) are used instead. Using oxygen during a test would significantly raise the risk of ignition if there’s a leak, making it unsafe.