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Comment by endisneigh | Hacker News Reader

What’s the best way to put out the fire in that video? I assume a regular fire extinguisher isn’t equipped to resolve an electrical fire

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You dont even try putting it out. Your best bet is some kind of cover (metal bucket) and throwing it outside as fast as possible. Or you know, dont keep Chinese scooters indoors.

Apple has a policy of keeping a container filled with sand close by when working with batteries.

This. You don't put it out, the fire is caused by a chemical reaction in a closed case. You can't stop it, only insulate it from damaging everything around it by dumping it in sand.

The fire is just a byproduct of the extremely fast exothermic reaction taking place in the battery.

In the US (I'd assume Europe has a similar thing with different specifics), most fire extinguishers are certified for some or all of three categories of fire: normal, flammable liquid (think grease fire), or electrical. Most extinguishers actually work fine on electrical fires, but it is important to check as a few contain a conductive suppressant (like water) that can cause an electrocution.

Grease fires are actually class K. Small ones, like a frying pan, can be extinguished with a class B extinguisher, but if there is enough grease/oil, or it gets too hot, you need something more powerful.

Actually I believe lithium ion fires are considered flammable liquid and not electric fires. It's a chemical reaction in the battery which isn't making electricity at the time but rather heat. Even then it's not a normal liquid fire since the oxidizer is in the battery rather than in the air.

An electric scooter is somewhere around 12v-60v. Is it really plausible that electricity will arch from a battery on fire towards the extinguisher?

No. The chemical reaction is just really intense and next to impossible to stop.

With an intense lithium-ion battery fire the only thing you can do is calm it down a bit (with a ton of water or sand) and make sure it doesn't spread.

What about the hydroflouric acid if it happens indoors? I wouldn't want to inhale that stuff! I actually thought about what to do when it happens here. Only thing I could think of was to try to put it into a metal bucket which I don't have, only empty paint cans, or baking tray from the oven, and get it out onto the balcony ASAP, if possible at all.

Drop it in the swimming pool.

https://www.firehouse.com/operations-training/news/21236083/...

In the US, electrical fires are class C fires. Many fire extinguishers available are ABC extinguishers, which means they can deal with class A (material), B (liquid), and C (electrical) fires. Extinguishers for class D (metal) and class K (high temperature grease/cooking oil) are not common in households.

Isn't this a chemical fire not an electrical one since it's a chemical reaction in the battery that is causing the fire? The fact that normally that chemical reaction makes electricity rather than violent heat seems moot. The battery also has the oxidizer in it so an extinguisher that tries to block oxygen won't work at all.

https://resources.impactfireservices.com/how-do-you-put-out-... You may be right.

However, it doesn't really matter. Buy an ABC extinguisher for your kitchen and for your garage, and just use it if needed. You don't need to overthink this.

Yes and no, the exothermic reaction ignites the electrolyte solvent, usually a blend of organic carbonates (depending on the type of battery). So it's almost a liquid fire, a chemical fire and an electrical fire all in one. It doesnt have an oxidizer, but the chemicals do contain oxygen. But ultimately there are 3 ingredients needed for a fire, fuel, oxygen and heat. An extinguisher targets two of these by cooling it down and limiting oxygen.

The exothermic reaction will also slow down when cooled which will further help contain the problem

Whoever FireRescue1.com is says that a class B fire extinguisher is good for a cooking oil fire, but that first (presumably more usefully) you should cover it and smother it in salt.

https://www.firerescue1.com/community/articles/how-to-put-ou...

Very small cooking oil fires, yes. :)

Pull the thing out of the house and let it burn outside. It is a relatively small battery so outside it won't do much harm, this in contrast to what it seems to do in that room. Tossing it in the pool is also possible but given the small size that'd be a waste of pool water which would need to be replaced. Just let it burn outside. Use a rake, broom or whatever other long thing at hand to pull the thing outside.

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