Why should compressed shop air not be used to pressurize an R-22 system for a leak test?
Safety · EPA 608 Type II. The correct answer, and the reasoning behind it.
Hermetic compressors under vacuum and other high-pressure hazards.
The question
Why should compressed shop air not be used to pressurize an R-22 system for a leak test?
- It is lighter than nitrogen
- It is exempt from the venting rules
- It cannot be regulated
- It carries oxygen and moisture into the systemCorrect answer
Why “It carries oxygen and moisture into the system” is correct
Air contains oxygen, which can form a combustible mix with compressor oil under pressure, and it carries moisture into the system. Dry nitrogen avoids both problems.
Source: EPA: Test Topics
Why the other answers are wrong
- It is lighter than nitrogen — Weight is not the reason air is unsuitable.
- It is exempt from the venting rules — Venting rules are not why air is avoided.
- It cannot be regulated — Air pressure can be regulated; the gas itself is the problem.
Practice more of this
More EPA 608 Type II practice questions, or see every EPA 608 practice test.
Unofficial, not affiliated with the EPA or any EPA-approved certifying organization. Questions are original practice written from public EPA material, not real exam questions.