Engineering · Safety — Enclosed Spaces
A safe oxygen level for entering an enclosed space is:
- AAnything above 8%
- B19.5% to 23.5% by volume✓ Correct
- CExactly 50%
- DBelow 16%
Explanation
Normal air is about 20.9% oxygen. Entry limits are 19.5% (minimum, below which is oxygen-deficient) to 23.5% (maximum, above which is oxygen-enriched and a fire hazard).
Authority: Engine-Room Safety (USCG engineering topic)
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