Question 934 Deck Safety

70% to pass

The rated operating time of a self-contained breathing device may be reduced in actual use because of _______________.

A spaces containing poisonous vapors
B the physical exertion of the person wearing the device
C pressure differences in the atmosphere
D the length of the hose attached to the facepiece
AI Explanation

The correct answer is B) the physical exertion of the person wearing the device. The rated operating time of a self-contained breathing apparatus (SCBA) can be reduced in actual use due to the increased oxygen consumption caused by the physical exertion of the person wearing the device. The more strenuous the activity, the higher the oxygen demand, which can deplete the SCBA's air supply faster than the rated duration. The other options are incorrect because: A) poisonous vapors would not directly affect the SCBA's operating time, C) pressure differences in the atmosphere would not significantly impact a closed-circuit SCBA, and D) the length of the hose would not reduce the rated operating time of the SCBA itself.

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Official Resources
46 CFR Lifesaving Equipment USCG Marine Safety Center USCG National Maritime Center
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