Tankerman · Gas Hazards — Vapor Density
Most petroleum hydrocarbon vapors are:
- ALighter than air and rise quickly
- BAlways inert
- CThe same density as air
- DHeavier than air and tend to settle in low areas✓ Correct
Explanation
Hydrocarbon vapors are generally heavier than air and collect in low, poorly ventilated areas (decks, cofferdams, around the manifold), creating a flammable/toxic hazard at deck level and below.
Authority: ISGOTT (properties of petroleum)
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