You are testing a tank that contained gasoline by using a combustible gas indicator. Under testing, the tank sample caused the needle to move rapidly to 100 on the dial then fall to zero. What is the concentration of flammable gas?
Direct Answer
Option C: Over the flammable range
ISGOTT guidelines state that a combustible gas indicator reading 100% LEL then falling to zero signifies an atmosphere over the flammable range. This occurs because the gas concentration is so high (above UEL) that there isn't enough oxygen for the sensor's filament to burn, indicating a gas-rich, oxygen-deficient environment.
All Options
Detailed Explanation & Context
ISGOTT guidelines state that a combustible gas indicator reading 100% LEL then falling to zero signifies an atmosphere over the flammable range. This occurs because the gas concentration is so high (above UEL) that there isn't enough oxygen for the sensor's filament to burn, indicating a gas-rich, oxygen-deficient environment.
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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