Why not have a halon system of extinguishers on AC in case of a fire?

Question

I have read that many of those who die in A/C crashes do NOT die from Blunt force trauma, but from inhaling toxic fumes, would a Halon system in the Cargo bins, Cabins etc save lives, or is the weight and cost to high? Would it work? I know Halon removes O2 from the air, but with masks on, would you not survive?

Answer 1

It never ceases to amaze me how many people have a false impression of how Halon gas works as a fire suppressant. I think hollywood has done a fantastic job of misrepresenting how fire suppression systems work, but that's another topic altogether.

Although new Halon gas was banned from production in late 1993 by the Montreol Protocol, it is still in wide use and many alternative agents are available that work very much the same way Halon did. (3M's Novec-1230, Chemtura's FM-200, DuPont's FE-227 and FE-13, the list goes on...) For the record, Halon and halogenated agents DO NOT "SUCK ALL THE O2 OUT OF THE AIR!" These clean agent systems are selected specifically because they are safe for limited exposure. The process is chemical only. O2 bonds to the halogenated agents faster than they can become part of the chemical reaction of Fuel-heat-and O2 as a fire. The O2 is still there and you can STILL BREATHE! Now it is true that some particles of decomposition can occur, but they are not typically as threatening as the smoke that the fires themselves are generating. I have experienced several Halon discharges over the course of my career, and rest assured, you can breathe the gas. (Albeit you do get alittle light headed from the presence of a foreign agent.)

Someone else pointed out that Halon is an inert gas. That's not correct either. Halon and halogenated agents are synthetic agents. Inert gas system are typically Nitrogen or Argon Based. CO2 can also be considered an inert gas system, but CO2 DOES displace the oxygen and the high amounts of CO2 present can lead to fatal asphyxiation.

Halongenated agents must discharge thier entire amount of suppression agent in 10 seconds to prevent the buildup of products of decomposition. (NFPA 2001 & 12A). Inert gas systems can take longer (a minute or more), but are heavy, since the gas is stored as a gas and not a liquid as in the case of the halogenated agents. This quick release of pressurized agent can cause venting problems in a closed cabin. Where does the air in the cabin go when that much addtional pressure is released? I suppose an elaborate venting system could be developed. The cost of retrofitting entire fleets of aircraft would be almost cost prohibative, particularly in an industry that stuggles with costs all the time. Some newer aircraft do have these systems in the cargo and unoccupied areas already. Engines are also equipped with a suppression agent.

Your idea does have merit. I have often wondered if a way could be developed to lower the oxygen level to a point that wouldn't support combustion in the event of an emergency, but you will still need to insure that the passengers could breathe. Alot of newer inert gas systems (Inergen, Argonite) work on this principle and you can still breathe with O2 levels as low as 10-12%. (I know, I didn't believe it either when I first heard about it. But again, I have experienced it for myself and you can breathe. It just feels like your in Denver!)

I think better soltions may lie in better escape systems to get people out the aircraft faster in an emergency.

Good question though. It's definitely an industry that needs constant improvement.

Answer 2

Halon WILL NOT hurt or kill you, but it is an irritant and exposure for long period of time is not recommended. Personally, I think Halon should be used, as well as EPOS hoods. Unfortunately, the amount of money this would cost the airlines would put many of them out of business.

Another safety feature that should be mandatory is a nitrogen fuel scrubbing system. It makes both the fuel tank inage and ullage much safer. The FAA's final report on the 747 that went down off the coast of Long Island in 1996 was that something in the fuel tank sparked ignition. This wouldn't have happened with an aspiscrubbing system. Furthermore, the recent C-5 accident at Dover AFB would have been far worse if the airplane didn't have aspriscrubbing. The plane probably would have exploded upon impact.

C-5 A models have a halon fire extinguishing system and all C-5s are equipped with fuel scrubbing systems.

Answer 3

Integrated Halon fire extinguising systems are used in the cargo area of airliners and cargo planes since they are the most likely areas in the cabin to have a fire and the airflow moves away from the passenger cabin to the outflow valves.

This obviously wouldn't work in the passenger area without killing everyone by displacing the oxygen.

Someone mentioned smoke hoods (PBEs) and they are used by the flight crew since their survival will ensure more passengers survive, but everyone having one is impractical. Having them under each seat will mean anywhere in the cabin there is a fire they will be burned. When they are burned they will feed the fire with oxygen, which they create you you can breath with them on. This will result in a very hot fire that would destroy an aircraft in seconds.

This is what happened to the Valuejet crash, although it was the oxygen generators being transported improperly in the cargo pit that caused the fire.

The O2 masks from the ceiling might save a few people, but the O2 doesn't last very long and you can't take it with you when you are exiting the aircraft.

Also you have to consider that if this is due to an impact (you mentioned blunt force trauma) most systems would be destroyed anyways.

Answer 4

Just a little more info. The supplemental O2 that drops from the ceiling in a passenger plane, is just that, "supplemental". In no way would it provide a seal or enough pressure to overcome a smoke filled cabin. They are only designed to get a person from cruising altitude to 14,000 in 4 minutes. As stated above the weight of providing everyone a smoke mask would be costly, not to mention the training required. This would be the only way you could use a lot of Halon inside a cabin. The military aircraft I fly on, has 10 handheld Halon bottles to fight fires, but we all have O2 masks and/or firefighter masks. Also, our engine fire bottles are Halon.

Answer 5

The CRJ-200 has a total of 7 halon fire extinguishers on board. 2 bottles for the engine, 2 for the cargo compartment, 1 for the APU and 2 handhelds.

Answer 6

Halon is an inert gas that will extinguish a fire like CO2,but it works better at higher alts.It will disburse O2,but it has a more concentrated form when it turns into gases state so it is a better choice than CO2.Each choice should be used with an O2 mask.Hope you never need to use it,happy flying!

Answer 7

The most pertinent point is that halon was prohibited from mass systems by the EPA in 1993. Also, the additional weight of all of this compressed gas would be prohibitive to flight. Existing halon must be serviced and when necessary disposed under very strict guidelines.

Answer 8

even though halon is an excellent fire dispesal product production of halon gas has been stopped since january 1994 due to the clean air act and that halon is a clouro flouro carbon or cfc which is and green house ozone depleating gas

Answer 9

If the fire or smoke dont kill a person te halon will it takes all the o2 out you can not live no it dont cost to much or weight to much halon will kill you you say mask on well if you are in a crash how many masks will be on.Halon works good in an elect room where high volts of elect are it puts the fire out fast and on water.They are to unsafe to use where people are confined what happens if they go off when they are not suppost to, you got a plane load of dead people still flying on auto pilot,where is the plane going?.good thinking but dont think it will ever happen.

Answer 10

i think of they could ban autos, or a minimum of the evil constructive factors. there isn't any reason that anybody desires a very computerized transmission. they could ban severe skill gasoline tanks too. If truthfully everyone replaced into constrained to 2 or 3 gallon gasoline tanks, they might nevertheless make it from one gasoline station to a various, and could carry greater desirable 2 or 3 gallon gasoline cans in the event that they have been vacationing in factors the place there have been no longer many gasoline stations. If there replaced right into a police chase it would be over in forty miles or so. they do no longer choose severe skill engines the two. there isn't any clarification for an vehicle to be waiting to circulate over 75 miles according to hour. they could get rid of exhaust suppressors or a minimum of require a $200 tax. i think of that could get rid of various crashes in view which you may hear the different vehicle coming in the direction of you earlier the crash.