Safety, Fire & Survival · Enclosed Spaces — Atmosphere Testing Order
Before entering an enclosed space, in what order should the atmosphere be tested?
- AThe order does not matter as long as all three are checked
- BToxic gases first, then oxygen, then flammables
- CFlammable gases first, then toxic, then oxygen
- DOxygen content first, then flammable gases/vapors, then toxic gases✓ Correct
Explanation
Test oxygen first (instruments for flammables and many toxics rely on a normal O2 level to read correctly), then flammable gas/vapor concentration, then toxic gases such as H2S and CO. Testing is done at several depths with calibrated, properly functioning instruments before any entry.
Authority: SOLAS XI-1 Reg 7; IMO enclosed-space resolution; ISGOTT
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