A combustible gas indicator will operate correctly ONLY when the
Direct Answer
Option A: hydrocarbon content of the atmosphere is less than the U.E.L.
Combustible gas indicators detect flammable vapors by measuring their catalytic oxidation over a heated filament. This process requires oxygen to be present for combustion. If oxygen is absent or too low, the filament will not glow, and the instrument will not function correctly, regardless of hydrocarbon concentration.
All Options
Detailed Explanation & Context
Combustible gas indicators detect flammable vapors by measuring their catalytic oxidation over a heated filament. This process requires oxygen to be present for combustion. If oxygen is absent or too low, the filament will not glow, and the instrument will not function correctly, regardless of hydrocarbon concentration.
Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • Advanced Training for Chemical Tanker Cargo Operations (CHEMCO).
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