Tankerman · Safety — Oxygen Analyzer
Before entering a cargo tank that has been gas-freed, a competent person must verify the atmosphere contains an oxygen level of at least:
- A8 percent
- B15 percent
- C19.5 percent✓ Correct
- D25 percent
Explanation
A safe-for-entry atmosphere must read at least 19.5 percent oxygen (normal air is 20.9 percent), be below 10 percent of the LEL for flammable vapor, and be free of toxic gas above permissible limits.
Authority: Tank Vessel Operations — Enclosed Space Entry
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