Which gas should be used to pressurize a system for leak testing?
Safety · EPA 608 Core. The correct answer, and the reasoning behind it.
Exposure risks, protective equipment, the 80% cylinder limit and nitrogen for leak testing.
The question
Which gas should be used to pressurize a system for leak testing?
- Oxygen
- Compressed shop air
- Acetylene
- Dry nitrogenCorrect answer
Why “Dry nitrogen” is correct
Dry nitrogen is inert and contains no moisture, so it is the gas used for pressure testing. Oxygen or compressed air mixed with compressor oil under pressure can explode, and shop air adds moisture.
Source: EPA: Test Topics
Why the other answers are wrong
- Oxygen — Oxygen with oil under pressure can explode.
- Compressed shop air — Shop air contains oxygen and moisture; under pressure with oil it can also explode.
- Acetylene — Acetylene is a fuel gas and highly flammable.
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