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Oxygen starving firefighting technique.
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Previously:
https://www.homemadetools.net/forum/...061#post207338
https://www.homemadetools.net/forum/...382#post150757
https://www.homemadetools.net/forum/...198#post211212
https://www.homemadetools.net/forum/...090#post164909
https://www.homemadetools.net/forum/...792#post152292
It looks neat, but I don't understand this. Why are they spraying something out of the window? Is it water? Is it nitrogen? If they were inerting the atmosphere inside the building I would have expected them to spray something in. Is there a second hose supplying inert gas into a window on the other side of the building that we can't see? I have questions.
This is just an uneducated guess, but what I think they're doing is is using the mass and velocity of water to create a vacuum in the structure. The water "pulls" the air out faster than it can be replenished, so the fire is starved. The spigot has to be right at the opening to work, which is why the pole is shaped like a shepherd's hook. I assume that this would only work for mostly sealed enclosures, else it would draw in air from the other openings.Quote:
Originally Posted by nova_robotics
Neil
it might not be pulling the oxygen out, but rather pulling out the superheated air above the room, and that air coming out reduces the overall energy in the room,and reduces flashover and backdraft, etc.
From compartment training, the thermocline (line between the layers of gases at different temperatures) dictates how "survivable" it is inside the room. Standard door entry is to check the level (wet the door and look), then crack the door with some "puffs" of water into the upper layer to pull the temp down. Repeat the checks and puffs until the level is high enough to enter - otherwise your head will be in gases exceeding 600 degrees Celcius. That same superheated gas also increases pyrolisation of the material lower down in the room, and increases the fuel in the room as a result.
ventilation (forced or otherwise) is used to get that layer of superheated gas out of the room/ compartment because with that gone the overall temperature of the fire decreases, and that makes the structure last longer, increases survivability for victims, and firefighters, and it reduces damage and spread.
My 2 cents.
This is not starving the fire of Oxygen. It is a variation of Hydraulic Forced Ventilation. Normally done with the FireFighters inside pointing the hose out the window.
By ventilating in this fashion, the heat and gasses are drawn out of the building in the location they want them to come out. This not only reduces interior temperatures, but it keeps the fire from spreading to areas where they don't want it to go. It will also clear the smoke so the entry team can get to the seat of the fire quickly, as well as improve chances for survivors.
I would guess there is probably an entry team attacking from inside, or they set this fire exactly perfect to not have the interior burning, just the area around the window.
My guess is the translation from a non-english language translated to Oxygen when it should have translated to air or hot air.
Looks like a very useful tool, but only usable in specific situations. Lot of storage space on the Engine for a tool not used often.