Half a croissant, on a plate, with a sign in front of it saying '50c'
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Fight fire with fire

Use exploding / vacuum effects as fire extinguishers
  [vote for,

We all know it is not because of the greek myth 'water element beats fire element' that fires can be extinguished. Rather, it is oxygen deprivation -such as pouring a non-flammable substance on the fire source- that achieves combustion stop. Here I present an idea that may beat any fire-extinguishing device. Bombs can be used in two efficient, fire-stopping ways: 1) Blowing fire down. That is the sample principle applied whenever we strongly, quickly breathe out on a candle flame. The sudden break in the constant, low rate of oxygen consumption shuts down the combustion process. Sure, outbreath air still has oxygen in it, but the 'knock out strike' blows the flame out as if some solid object had fell on it. 2) Either the standard bomb's vacuum after-effect or, a set of vacuum bombs along a fire front, would make the perfect 'fire can't breathe' strike we need for any fire-extinguisher to work properly. The small vacuum devices have yet another advantage in that they may be deployed on forest grounds long before any fire starts.

Kind of funny, evolution has provided some pine trees species with a very subtle form of 'survival of the hottest': in Mediterranean environments, where summer fires occur quite often, these 'pyrophytic' pine trees develop 'heat activated reproduction'. That is, the ground around them is a pool of sterile, grenade-like pine-fruits, which DEPEND on fire to become fertile, crack open and let pine seeds out. No fire, no problem. Fire alarm? Then, wait until the moment everything else has been burned above the ground level; those heat-activated seeds will re-conquer the land and sprout up, well in advance of any other species' seeds.

mayihave, Aug 01 2007

Red Adair http://en.wikipedia.org/wiki/Red_Adair
[jutta, Aug 01 2007]

Not the Better Business Bureau Borate_20Bouncing_20Bettys
[normzone, Aug 03 2017]

Fireweed https://en.wikipedi...erion_angustifolium
Mentioned in my anno [notexactly, Apr 22 2018]


       You will need some way to keep oxygen away from the fuel long enough for the fuel to cool below combustion temperature, otherwise returning oxygen will just respark the blaze.   

       This is why halon works well for electronics, but not so well for wood and paper. It displaces the oxygen for a few seconds so that the immediately burning bits stop burning, but the actual burning parts are pretty small so they cool quickly.
Galbinus_Caeli, Aug 01 2007

       cool note about the pine trees. worth reading the whole thing just to know that.   

       Also, it was the only part I understood...
k_sra, Aug 01 2007

       This is a fairly (I thought) well-known principle with limited, but significant, applications.   

       The US TV series "Mythbusters" recently did an episode where they used explosions of various sizes to put out (gas-fed) fires of various sizes.   

       The team of a firefighter Paul "Red" Adair famously used explosions to put out hard-to-extinguish oil and gas well fires.
jutta, Aug 01 2007

       I am not familiar with vacuum bombs. I might be able to use one in the garage.
bungston, Aug 01 2007

       Me too, except I doubt I could fit it in there.
jutta, Aug 01 2007

       You can get compressed vacuums, if space is a limitation.
MaxwellBuchanan, Aug 01 2007

       //You will need some way to keep oxygen away from the fuel long enough for the fuel to cool below combustion temperature, otherwise returning oxygen will just respark the blaze.//   

       In most situations your fuel source is nowhere near its spontaneous ignition temperature so just removing the oxygen is sufficient to stop things.
jhomrighaus, Aug 01 2007

       Thank you very much for your comments. So, already baked for terrifying oil well fires... Thanks for the link, jutta.   

       As for 'vacuum bombs', well, I imagine 'very-low-pressure gas container' could possibly explain that much better. You just pump the air out of such a container until, say, only 1/1000 (or even less) of the original gas remains, then close the vacuum valve. (Of course, this container should be made the same material as high-pressure gas containers, in order to avoid imploding.)   

       When activated, this container would bang a 999/1000 fraction of its volume INTO it, so that surrounding air would be sucked in, and the oxygen supply for the fire would suddenly stop. So, I guess, this product already 'sucks'.
mayihave, Aug 02 2007

       MIH: stop for a moment and consider just how much gas you will be sucking up with that evacuated container of yours....   

       Bombs do indeed create vacuums, post blast. More than half of the damage of car bombs is often caused by the returning air rushing to fill the vacuum, sweeping broken glass, bomb fragments, and other detritus in its path.   

       But clearly a bomb can create a very much larger volume of vacuum than your average fire extinguisher.
DrCurry, Aug 06 2007

       No, it wouldn't. But from a practical point of view, a suitably energetic detonation at the start of the fire would have efficiently prevented any of the tenants surviving, reducing the number of complaints to a much more manageable level, and incidentally greatly diminishing the necessity for paying out compensation.
8th of 7, Aug 03 2017

       But then you'd generate complaints and compensation claims from people in neighbouring buildings affected by blast and fragmentation, necessitating an even bigger detonation which...   

       Ah. I think I see where you're going with this.
pertinax, Aug 04 2017

       Bomber Harris would have loved that; pre-installed incendiaries ...   

       Imagine the saving in aircrew lives, and fuel. Dresden, at EasyJet prices.   

       // I think I see where you're going with this. //   

       Ahhh, you've got one of those thermal cameras for seeing through smoke and flames ... ?
8th of 7, Aug 04 2017

       TIL there are pine trees in Mediterranea.   

       There's also a flower called fireweed [link] that does the same heat-activated reproduction thing, and is even named for it.
notexactly, Apr 22 2018


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