Anti-flame grenades

[Kranis]

What if there is a grenade, that causes little to no damage to its surroundings, but releases a gas that removes the oxygen from the surrounding areas to take away the fires life source? Something firefighters can use without entering a room that is full of fire.. it think it would be amazing to have it, and someone should design one, or even create one. Anyone else think its a good idea?

[Joatmon]

What if there is a grenade, that causes little to no damage to its surroundings, but releases a gas that removes the oxygen from the surrounding areas to take away the fires life source? Something firefighters can use without entering a room that is full of fire.. it think it would be amazing to have it, and someone should design one, or even create one. Anyone else think its a good idea?

In a computer suite in which I worked in in the 1970's there was an automatic system that rapidly flooded the rooms with nitrogen. There was an alarm because the system would also extinguish your life if you wasted time getting out. Also the rooms (computers were that large in those days) had doors that would automatically close as the gas was released!

I doubt that something as small as a grenade could contain enough gas to do the job especially if the area in which the fire existed was not enclosed.

Edited April 25, 2012 by Joatmon

[Kranis]

In a computer suite in which I worked in in the 1970's there was an automatic system that rapidly flooded the rooms with nitrogen. There was an alarm because the system would also extinguish your life if you wasted time getting out. Also the rooms (computers were that large in those days) had doors that would automatically close as the gas was released!

I doubt that something as small as a grenade could contain enough gas to do the job especially if the area in which the fire existed was not enclosed.

 

i guess in time, all things are possible, but i see what you're getting at, makes sense.

[Phi for All]

The gas you need is bromotrifluoromethane, also known as Halon 1301. Great for putting out fires when you don't want foam or sand or water all over everything. Not great for wood or things that smolder though, since these fires can relight when oxygen is reintroduced.

 

I don't think you'd really need a grenade, though. Just a good-sized canister with a thermostat that releases the halon when it gets hot enough.

[InigoMontoya]

What if there is a grenade, that causes little to no damage to its surroundings, but releases a gas that removes the oxygen from the surrounding areas to take away the fires life source? Something firefighters can use without entering a room that is full of fire.. it think it would be amazing to have it, and someone should design one, or even create one. Anyone else think its a good idea?

 

It's such a good idea that they already exist.

 

http://www.youtube.com/watch?v=pfVzfxD1iPY

Edited April 26, 2012 by InigoMontoya

[CaptainPanic]

1 m3 of nitrogen is about 1.2 kilogram. If you would be able to make it liquid at room temperature that would be about 1.4 liters of liquid air. So, to flood even a small room, you need quite a lot of mass. You can see in the cool movie that InigoMontoya posted that the 'grenades' used to fight this fire are quite large. They need 3 'grenades' to put out the fire in each room. Still, it works.

 

I think it would start to be really useful if you could accurately shoot such grenades at a distance. The water/foam used by firefighters can only reach a certain height and distance.

 

Btw, displacing air to prevent oxygen from getting to the fire is a big part of firefighting. Water (which evaporates) does the same job. Foam blocks the air too. CO2 fire extinguishers also use the same principle. Of course, water and CO2 also cool down the fire.

[Joatmon]

Although Halon 1301 is an extremely efficient fire suppressant, it does have environmental and possible health issues and I believe it is beginning to lose favour for those reasons. To get some idea of how much inert gas you might need see the picture in the link!

http://www.wi-ltd.com/fire/Suppression_and_Extinguishing_Systems/Gas_Extinguishing/Nitrogen_Inert_Gas_Extinguishing_System

[Tres Juicy]

What about some sort of flash fire that burns off all the available oxygen?

 

Equivalent to the fire burning out naturally

[CaptainPanic]

What about some sort of flash fire that burns off all the available oxygen?

 

Equivalent to the fire burning out naturally

It would mean you essentially have 2 fires. The original fire, and the oxygen-eating fire, which compete for oxygen.

 

The problem is that the fire that burns the quickest will also be the hottest. So, if you introduce some material that would use up the oxygen quicker than the original fire, you just get a fire that burns even hotter... that's not really a solution.

[Phi for All]

Although Halon 1301 is an extremely efficient fire suppressant, it does have environmental and possible health issues and I believe it is beginning to lose favour for those reasons. To get some idea of how much inert gas you might need see the picture in the link!

http://www.wi-ltd.co...guishing_System

I think Halon 1301 is still the best gas to use for certain fires. When you have large computer facilities and are able to both evacuate the personnel quickly and control the release/recycle of the gas, Halon 1301 will stop electrical fires without further damaging the delicate systems. Probably the next best use is for automobile engine fires. Almost every other extinguisher requires you to lift the hood, adding oxygen to the engine compartment. Halon 1301 can be sprayed right into the front grill (perhaps a nitrogen system in the engine compartment which can be triggered from the dashboard could replace this use).

 

But as I said before, it's not so great with anything that smolders and can relight when oxygen returns to the area. And its environmental damage does preclude it from being used as a general firefighting solution where you can't contain or recapture the gas.

[Joatmon]

I think Halon 1301 is still the best gas to use for certain fires. When you have large computer facilities and are able to both evacuate the personnel quickly and control the release/recycle of the gas, Halon 1301 will stop electrical fires without further damaging the delicate systems. Probably the next best use is for automobile engine fires. Almost every other extinguisher requires you to lift the hood, adding oxygen to the engine compartment. Halon 1301 can be sprayed right into the front grill (perhaps a nitrogen system in the engine compartment which can be triggered from the dashboard could replace this use).

 

But as I said before, it's not so great with anything that smolders and can relight when oxygen returns to the area. And its environmental damage does preclude it from being used as a general firefighting solution where you can't contain or recapture the gas.

I wouldn't disagree with you about the effectiveness of Halon 1301 - apart from anything else its something I don't really know anything about! I started commenting simply because I remembered the earlier nitrogen based system we used in the 1970's. This led to me reading the link in my earlier post which claims it has just about been banned in the UK. It is likely that, due to its effectiveness, it is still used in the US.

[Phi for All]

I wouldn't disagree with you about the effectiveness of Halon 1301 - apart from anything else its something I don't really know anything about! I started commenting simply because I remembered the earlier nitrogen based system we used in the 1970's. This led to me reading the link in my earlier post which claims it has just about been banned in the UK. It is likely that, due to its effectiveness, it is still used in the US.

Back in the late 80s, I sold a line of household halon extinguishers, and iirc it was virgin halon. The gas was extremely effective on kitchen grease fires (personal experience) and automotive fires (also from personal experience, though not on my own car). It was also good for clearing a path to escape flames from a house fire, provided you could hold your breath long enough to pass through.

 

That got banned here along with other CFC products. I don't think Halon 1301 is in use either, now that I check on commercial sites. They have a product called Halon 1211 which seems to be sold commercially here in the states.

 

Inigo, I still can't see even nitrogen being able to put out fires involving wood or other materials that can smolder. If your building can reintroduce oxygen after the flames have been put out by the nitrogen cannister, the fire can still start again from smoldering embers. Does the nitrogen have a way to cool the flammable materials in a large building fire?

[Joatmon]

Inigo, I still can't see even nitrogen being able to put out fires involving wood or other materials that can smolder. If your building can reintroduce oxygen after the flames have been put out by the nitrogen cannister, the fire can still start again from smoldering embers. Does the nitrogen have a way to cool the flammable materials in a large building fire?

As I say, I've no experience in this field. I would think you are right about wood and similar materials because (IMO) unless the oxygen was completely replaced with the nitrogen for long enough to completely stop the burning process plus time for cooling below a certain temperature the wood could easily reignite. If the oxygen was not completely replaced then it seems to me you would have the conditions to slowly change wood to charcoal. I don't know, but can smouldering wood continue to smoulder without oxygen? I've just googled charcoal production and it seems that oxygen is not necessary - this even more supports what you say!

[InigoMontoya]

Inigo, I still can't see even nitrogen being able to put out fires involving wood or other materials that can smolder. If your building can reintroduce oxygen after the flames have been put out by the nitrogen cannister, the fire can still start again from smoldering embers. Does the nitrogen have a way to cool the flammable materials in a large building fire?

Which may not be an issue as long as the O2 is reintroduced at a suitably low rate. More to the point, your operation could look something like this....

 

1) Fire breaks out.

2) People toss in grenades, knocking the flames down if even for a few minutes gaining precious time until....

3) The Fire Department arrives to fight a fire that is MUCH smaller than it would have been had the fire gone unchecked.

 

And that step 3 could become....

 

3a) Fire Department tosses in a few grenades knocking down the flames while they're running hoses and such.

3b) Fire Department kicks in the door, sprays some water around to cool the place off, and the fire is defeated quickly with little or no risk to personnel.

[Kranis]

It's such a good idea that they already exist.

 

http://www.youtube.c...h?v=pfVzfxD1iPY

 

That is awesome.