A high-velocity fog stream can be used in fire fighting situations to drive heat and smoke ahead of the fire fighters in a passageway. This technique should only be used when __________.

Correct Answer: Option A — there is an outlet for the smoke and heat

High-velocity fog streams push massive volumes of air, heat, and toxic gases ahead of firefighters, creating a severe backdraft or trapping hazard unless a clear, unblocked outlet exists to vent the displaced atmosphere overboard.