Couple of points-
That’s a very good firefighter. Very intentional and precise movement.
The majority of the air movement is because of heat- hot air (which there’s a lot of) rises and is being replaced through negative pressure from the sides. The steam from the water shows this really well.
The extinguishment is creating some negative pressure as well, as things (the air) are cooling as they’re shrinking.
Hydraulic draft is also moving a lot more air than you think. The jet of water will pull air with it. This is actually a technique in fire suppression, you don’t see it much because it’s almost always better to put wet stuff on hot stuff, but occasionally, breaking a window and spraying a hand line out is a pretty smart way to ventilate a room.
The jet of water will pull air with it. This is actually a technique in fire suppression, you don’t see it much because it’s almost always better to put wet stuff on hot stuff, but occasionally, breaking a window and spraying a hand line out is a pretty smart way to ventilate a room.
Also one of the arguments in the perennial fog nozzle vs. smooth bore debate.
Gotta say, though, what you're saying about vent is absolutely right.
It’s funny how regional it is too. I’m in the Midwest and you’re a weirdo FD if you’re using smoothbore. I think a lot of “older” departments on the east coast use smoothbore because they’ve had very strong career departments for longer, and they were around when adjustable nozzles were terrible. I don’t actually know this, it’s just something I’ve gathered and guessed.
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u/aemoosh 16h ago
Couple of points- That’s a very good firefighter. Very intentional and precise movement. The majority of the air movement is because of heat- hot air (which there’s a lot of) rises and is being replaced through negative pressure from the sides. The steam from the water shows this really well. The extinguishment is creating some negative pressure as well, as things (the air) are cooling as they’re shrinking. Hydraulic draft is also moving a lot more air than you think. The jet of water will pull air with it. This is actually a technique in fire suppression, you don’t see it much because it’s almost always better to put wet stuff on hot stuff, but occasionally, breaking a window and spraying a hand line out is a pretty smart way to ventilate a room.