We show this very issue in probie school/FF1 with hay/pallet fires. We allow students to use the fog slightly off straight and watch as the hay and fire blows around the room, the smoke drops to the floor and the temperature you feel sharply increases. Then on their next evolution we keep the nozzle on straight stream and show how when properly applied, the fire (even hay) stays in place, the smoke stays up better (less steam) and the heat does not increase much at all. While hay is much lighter than most ordinary combustibles in a home the effects will be the same though not as exaggerated.Todd, I agree with what you say about how the fog nozzle operates during hydraulic ventillation but it would be interesting to see whether that entrainment of air really affects a fire if water is still being applied too. It could depend on many factors including fire load and the condition of the room (if it's close to flashover).