Another 787 electrical/smoke incident (on ground)
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Metallic Lithium, surely. But Lithium salts? Then there are those Dendrites.
Extinguishment is for Firefolks. Starting fires is the province of airframer.
As in, don't do it....
Extinguishment is for Firefolks. Starting fires is the province of airframer.
As in, don't do it....
Extinguishment is for Firefolks. Starting fires is the province of airframer.
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Myself and a few other chemists decided to do a little "experiment" with Li-ion batteries. Connected a few laptop and mobile batteries in series and then deliberately shorted them. We managed to get a thermal runaway and ignition. Wasn't spectacular, but when we put it out with CO2 it did reignite. We then tried dry ice, and that put it out but it reignited, we did know the answer which was to quench it with loads of water, which of course worked.
Only problem with this on board an aircraft is that;
a) You don't really want water sloshing about in an electronics bay, and unless you are refilling distilled water every turn around then there will be ions present, hence conductive.
b) The water will react with the Li, forming hydrogen, now that's OK in my back garden, probably not so great in an enclosed space with electronics in it.
As for Halon, I don't know, problem is that isn't it banned, and also there is no use in inerting the compartment as Li batteries have their own oxidizing agent. I'd love to give it a go in the lab though.
Conclusion - I won't fly on an A/C with Li for quite a while
Only problem with this on board an aircraft is that;
a) You don't really want water sloshing about in an electronics bay, and unless you are refilling distilled water every turn around then there will be ions present, hence conductive.
b) The water will react with the Li, forming hydrogen, now that's OK in my back garden, probably not so great in an enclosed space with electronics in it.
As for Halon, I don't know, problem is that isn't it banned, and also there is no use in inerting the compartment as Li batteries have their own oxidizing agent. I'd love to give it a go in the lab though.
Conclusion - I won't fly on an A/C with Li for quite a while
Last edited by Ex Cargo Clown; 15th Jan 2013 at 19:43.
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Water is actually one of the best fire extinguishers also for low voltage installations. Clean water will not conduct low voltages and water is one of the best substances to cool down the burning material. The water vapor will be about 1600x the water volume and efficiently replace oxygen.
Polluted water and salt water CAN conduct even low voltages like 220V, so make sure the water is clean. Never use water on burning liquids or high voltage installations.
Polluted water and salt water CAN conduct even low voltages like 220V, so make sure the water is clean. Never use water on burning liquids or high voltage installations.
Water is an extremely efficient coolant, hence why it's used as such in so many applications. Any reference to electrical conductivity etc is by this stage immaterial, the prime objective is to cool the thing down by whatever means is available. Water is typically available and is ideal for that purpose. It's not distilled, and even if it was, it would become instantly contaminated by the time it was put to the intended use.
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It is an old 'truth' that you cannot put out a low voltage fire with water, but it is simply not correct. As long as you keep at least a 1 meter water column between you and the conducting parts, there is no real hazard. This is also a part of the Norwegian DSB's recomendation (google translate it).
You can also take a look at this dude that testet 110V in hos own sink at way below 1 meter Hairdryer in Bathtub Myth 3 - bare wires underwater - YouTube.
Electrical flow is all about a having a path or circuit. If the path isn't there, the electricity doesn't flow. So for a battery that is not connected to the ground you are standing on, there is no danger even if the voltage is higher. That is also why the recommendations for putting out ~600v EV battery fires are water. Water it is the only thing that can stop the thermal runaway and in that case you will not get a circuit anyway as long as you do not touche the vehicle at the same time.
I would not hesitate to stand 5 meters away and use a water hose on a 220v fire, not sure about the bathtub test....
You can also take a look at this dude that testet 110V in hos own sink at way below 1 meter Hairdryer in Bathtub Myth 3 - bare wires underwater - YouTube.
Electrical flow is all about a having a path or circuit. If the path isn't there, the electricity doesn't flow. So for a battery that is not connected to the ground you are standing on, there is no danger even if the voltage is higher. That is also why the recommendations for putting out ~600v EV battery fires are water. Water it is the only thing that can stop the thermal runaway and in that case you will not get a circuit anyway as long as you do not touche the vehicle at the same time.
I would not hesitate to stand 5 meters away and use a water hose on a 220v fire, not sure about the bathtub test....
As the aft EE bay is not accessible in flight, how is one supposed to extinguish this fire? Or are we considering grounding the fleet and an expensive mod?
The amount of Lithium in these cells is negligeable. It is <1,5% of the mass. And it is in bound form ,not pure.
So, yes pure Lithium will burn when getting in contact with water. A Lithium Battery: Not so. I have seen discharged defective cells cut open and water dripped on them. No obvious reaction.
I've personally extinguished a fire of a 1 lbs 5 cell Lithium Polymer battery with water. Works excellently. You need enough water but it extinguished the fire instantly but couldn't prevent the neigbouring cells from going off as well. So each cell had to be extinguished consecutively. Once started it was almost impossible to stop the runaway.
Each of the cells weighing roughly 5 ounces produced a fireball of nearly 0,5m diameter.
Edit: The amount of water to extinguish was almost a litre for each cell so for the 1lbs battery pack it was about 4 litres it took to put it out. And that didn't prevent the next cell from overheating. Therefore you would have needed more permanent cooling and thus more water. It was easier to extinguish the fire than to prevent it from going off in the first place once the runaway started.
Last edited by henra; 15th Jan 2013 at 21:57.
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Myself and a few other chemists decided to do a little "experiment" with Li-ion batteries. Connected a few laptop and mobile batteries in series and then deliberately shorted them. We managed to get a thermal runaway and ignition.
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Lithium metal will burst into flame in contact with water, the same as potassium metal and sodium metal. Lithium compounds do not burst into flame in contact with water, just as potassium compounds and sodium compounds do not (e.g. sodium chloride – table salt).
I suppose de-ionised water does not conduct electricity but, if it can dissolve any of the battery chemicals, then it will conduct electricity. I don't think there is ever a situation where any kind of water is recommended for any kind of electrical fire. Maybe packing in dry ice (solid carbon dioxide) would be a safer way to cool.
I suppose de-ionised water does not conduct electricity but, if it can dissolve any of the battery chemicals, then it will conduct electricity. I don't think there is ever a situation where any kind of water is recommended for any kind of electrical fire. Maybe packing in dry ice (solid carbon dioxide) would be a safer way to cool.
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How did you manage to defeat the internal fusing and current limiting?
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To be fair, I have just found a FAA document which recommends fire fighting methods for lithium type batteries in portable electronic devices, which states:
"Utilise a Halon, Halon replacement or water extinguisher to extinguish the fire and prevent its spread to additional flammable materials.
After extinguishing the fire, douse the device with water or other non-alcoholic liquids to cool the device and prevent additional battery cells from reaching thermal runaway.
Do not use ice to cool the device."
Still, I don't know if I'd want to use water for a battery in a compartment with other electrical equipment and wiring.
"Utilise a Halon, Halon replacement or water extinguisher to extinguish the fire and prevent its spread to additional flammable materials.
After extinguishing the fire, douse the device with water or other non-alcoholic liquids to cool the device and prevent additional battery cells from reaching thermal runaway.
Do not use ice to cool the device."
Still, I don't know if I'd want to use water for a battery in a compartment with other electrical equipment and wiring.
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dmw,
well, you and others have noted a disconnect, and that is context.
Three issues here...
thermal runwaway,
associated fire,
and context.
While the 'standard' may be to use Halon for fire (which I thought was outlawed on vessels with people), then use water to cool the cells..
it would appear that sequence will not work very well on a passenger aircraft in flight...nor in an electrical bay.
I do agree with the 'standard'..the alcohol should never be used on the aircraft...
alcohol is far better utilized for the crew attempting to put this out in-flight, and the passengers...
A333......"An inflight entertainment system's display set in front of a passenger seat near the toilet is suspected as cause of the smell."
well, you and others have noted a disconnect, and that is context.
Three issues here...
thermal runwaway,
associated fire,
and context.
While the 'standard' may be to use Halon for fire (which I thought was outlawed on vessels with people), then use water to cool the cells..
it would appear that sequence will not work very well on a passenger aircraft in flight...nor in an electrical bay.
I do agree with the 'standard'..the alcohol should never be used on the aircraft...
alcohol is far better utilized for the crew attempting to put this out in-flight, and the passengers...
apparently another one ANA in Japan this (wednesday) morning. smoke in cabin.
Last edited by FlightPathOBN; 15th Jan 2013 at 23:47.
Everything is under control.
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Voice of America reports that ANA confirms "battery problem" forced emergency landing for Boeing 787 at Takamatsu, Japan. (today Wednesday). Also Bloomberg reports all ANA 787s grounded.
Last edited by Eboy; 16th Jan 2013 at 00:41. Reason: typo
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I also thought water would be bad for a lithium battery fire but ...
The CAA tested water based fire extinguishers on lithium battery fires...
http://www.caa.co.uk/docs/33/capap2003_04.pdf
They say water works ok.
and in the marine environment...
Lithium Batteries and Marine Seismic
They say..
Bit concerned about that last bit. Is it possible that water is fine initially but not ok after the battery has burned for awhile and damaged it's casing?
The CAA tested water based fire extinguishers on lithium battery fires...
http://www.caa.co.uk/docs/33/capap2003_04.pdf
They say water works ok.
and in the marine environment...
Lithium Batteries and Marine Seismic
They say..
"There is an industry misconception on the use of water to fight or prevent Lithium fires.
- Water has better extinguishing properties on burning Lithium batteries
- Water will cool down the battery and the surrounding batteries preventing an escalation
- Water can be applied from a safer distance
- Water is readily available
- Our batteries are hermetically sealed and direct contact with lithium metal is not possible on intact batteries
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Lots of cycles
Japan has a LOT of people on a few closely spaced islands. And they are very good at fast-loading and unloading the SLF. This means a lot of cycles on the shuttle routes, maybe an aircraft can be getting 10 cycles a day, which may means 10 hookups to ground equipment and 10 charge cycles a day ...
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One lives and learns.
I once set a car on fire whilst welding the floorpan (plastic petrol-pipe melted) 2x 2-gallon foam extinguishers proved ineffective but a hosepipe and cardboard sheets solved the problem......water chilled the petrol below it's flashpoint, now sodden cardboard contained any fumes under the "hot-spot"....doors and windows left closed ensured the upholstery ran out of oxygen and self-extinguished!.
The practical issue here, however, is the lack of practicality. hoses that will stretch several thousand miles and supply suficient water at 30,000 feet are a bit thin on the ground 9or in the air)
If water dousing is reckoned practical, then a large tank and a distribution system will be required......Having read many a thread about tankering surplus fuel, I conclude that carting this fire-fighting system around is not cost-effective....just change the batteries for something with lower energy-density but greater inherent stability.
Halon has specific exemptions for usage in certain situations. When it was first outlawed for GENERAL use, the legislators actually thought it through!
AFAIK, Aircraft are one of those exemptions.
Risks with Lipo's are well-known in the model-flying world, but people accept the risk with a MODEL as it is far outweighed by the quietness and extraodinary power offered. Also, of course, instant starts, no messy fuel .smoke,smell and oil-residue. Also, the duration is pretty good and packs can be quickly swapped-over.....the downside is the Russian Roulette of "if/when" will it burst into flames
In commercial Aviation , this is a totally unnecessary risk. IMHO, it's technology for it's own sake.
I once set a car on fire whilst welding the floorpan (plastic petrol-pipe melted) 2x 2-gallon foam extinguishers proved ineffective but a hosepipe and cardboard sheets solved the problem......water chilled the petrol below it's flashpoint, now sodden cardboard contained any fumes under the "hot-spot"....doors and windows left closed ensured the upholstery ran out of oxygen and self-extinguished!.
The practical issue here, however, is the lack of practicality. hoses that will stretch several thousand miles and supply suficient water at 30,000 feet are a bit thin on the ground 9or in the air)
If water dousing is reckoned practical, then a large tank and a distribution system will be required......Having read many a thread about tankering surplus fuel, I conclude that carting this fire-fighting system around is not cost-effective....just change the batteries for something with lower energy-density but greater inherent stability.
Halon has specific exemptions for usage in certain situations. When it was first outlawed for GENERAL use, the legislators actually thought it through!
AFAIK, Aircraft are one of those exemptions.
Risks with Lipo's are well-known in the model-flying world, but people accept the risk with a MODEL as it is far outweighed by the quietness and extraodinary power offered. Also, of course, instant starts, no messy fuel .smoke,smell and oil-residue. Also, the duration is pretty good and packs can be quickly swapped-over.....the downside is the Russian Roulette of "if/when" will it burst into flames
In commercial Aviation , this is a totally unnecessary risk. IMHO, it's technology for it's own sake.
You want to make sure to keep some distance to the burning cells (which you want to do anyway
) and not to inhale it directly. That could be a bit of a problem when a huge mass of these cells has to be extinguished in a closed encapsulation (read fuselage). 70 lbs of batteries could potentially be a problem in that regard.
Last edited by henra; 16th Jan 2013 at 19:18.