Safety & Environmental Protection (Deck) USCG Question #709 (Set 21)

You are using an oxygen indicator. How long should you wait after the sample is drawn into the instrument before reading the meter?

Official USCG Answer & Rule Citation

Correct Answer: Option B — At least 10 seconds

Chemical and electrochemical oxygen indicators require a stabilization interval after sample introduction for the sensor to react fully. Waiting at least 10 seconds ensures the needle settles completely, yielding a reliable and accurate measurement of the compartment's oxygen content.

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