Question 873Deck Safety70% to pass
When using a high-velocity fog stream in a passageway, the possibility of a blow back must be guarded against. Blow back is most likely to occur when _______________.
AI Explanation
The correct answer is B) the only opening in a passageway is the one from which the nozzle is being advanced.
When using a high-velocity fog stream in a passageway, the possibility of blow back is most likely to occur when there is only one opening, which is the one the nozzle is being advanced through. This is because the pressurized water stream can create a back pressure in the passageway, forcing the water to blow back towards the nozzle operator. The other answer choices, such as a collapsing bulkhead or pressure drops in the fire hose, are not directly related to the specific scenario of using a high-velocity fog stream in a confined passageway.
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