Fire Extinguisher...get one!

I've been meaning to select and install an extinguisher in the truck for a long while. This thread when it first started motivated me to finally get it all together and installed on my trip the past week (I live far away from my truck so mods take a little more thought and preparation to get done).

There are a lot of choices in what to get - and certainly no perfect choice either. Did an extensive write up of some of the options and trade offs in my build thread if anyone is interested: Cab Mounted Fire Extinguisher.

I ended up doing a 2.5lb Amerex Purple K mounted in front of the driver seat. As others have mentioned already this is mostly about giving an improved chance for egress and could only actually save property if the fire is caught very, very early. But as the OP illustrated sometimes you do catch a fire very, very early!

Since I also camp in my truck I'll be eventually selecting a different extinguisher for the back of the truck in case there is some sort of cooking related fire when camping.

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Good for life saving bad for electronic equipment. In other words your truck will be scrap after you dump this in it.

As long as you know going in that when you use that Purple K all of your electronics is toast that comes in contact with that powder. It is corrosive and will get into very nook and cranny.

Purple-K is normally non-toxic, but ingestion of large amount can cause alkalosis. In high temperatures it decomposes to carbon dioxide and potassium oxide, which is toxic and highly corrosive.

 

Got mine mounted behind my driver's seat (Pick is before I actually had it secured) I used reusable zip ties so its extremely well secured but i can pull it out in less than 5 seconds. When you're talking about fire, every second counts.

 

Yes, all the dry chemicals are very bad for electronics. If you have to fire one under the dash expect bad things down the road. Depending on where they might be fired into the engine compartment similarly bad things down the road. Some of the dry chems are worse than others for electronics but I suspect the distinction is moot as they are probably all sufficiently bad enough.

Purple K and Sodium Bicarbonate are however pretty benign to the frame and other metal parts on the truck and can be cleaned up with effort as well as being flushable with sufficient water (for things that don't mind water at least). Monoammonium Phosphate (the ABC dry chem) on the other hand melts onto things when exposed to heat and is also vastly more corrosive to steel than the bicarbonates so it can potentially cause a lot of damage even if it doesn't get into electronics.

Halotron is safe to use on everything but way less effective on fuel fires than the bicarbonates. The five pound Halotron can put out 12.5 sq ft of fuel while the five pound Purple K can put out 75 sq ft of fuel.

So really if you want the option to protect property or life depending on the situation you want two extinguishers. Some sort of dry chem if the fire is large and property is no longer the concern. Some sort of more benign media (like Halotron) if you have a small electrical fire you want to tackle.

 

BC (sodium bicarbonate) is pretty darn safe for electronics and isn't sticky. It can be vacuumed and swept up. They are all I use on my boat and in my vehicles.

I'm really intrigued by the Element extinguishers though.
https://www.elementfire.com/ELEMENT-E50-p/ele-e50.htm

 

Yes while all dry chems are not recommended for "sensitive" electronics there is a huge difference in corrosion issues between ABC and either BC or Purple K. ABC is banned from being anywhere near a flight line while Purple K is extensively used on flight lines. The reason is the significant difference in corrosion between the two. This is referenced in a few different books on firefighting as well as some technical notes from aviation manufacturers. I haven't been able to find much of anything comparing Na vs. K bicarbonates extinguishers (BC/Purple K) and corrosion other than both are way less awful than NH3 phosphate (ABC). I wouldn't want to shoot any of them into electronics - but I wouldn't want to shoot an ABC anywhere near electronics or any other metal I might care about.

That is interesting - but god do I hate the marketing weasel words some of these places use. This extinguisher is better because of its long discharge time! We aren't UL approved because our technology is too revolutionary! Or maybe it isn't UL listed because it would be impossible for an operator to get close enough to the minimum 1A or 1B test fires to extinguish the fire without burning themselves.

That said it does look like an interesting option for small fires where there is a concern about property damage. The fact that it is so stable compared to the little aerosol can mini-extinguishers (that also don't carry UL ratings) is desirable. Thanks for the link - I've been trying to decide on what my second small extinguisher would be and wasn't aware of these things. Time to do some more homework!

 

Nice find, thanks for posting


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Let me ķnow what you learn.

 

I just did a bunch of searchin' with little results, other than their site.
Know someone in the fire protection industry, I'll hit up this week.
He may not know, but is apt to find more info than I.


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Its certified by TUV which is a nationally recognized testing laboratory comparable to America's UL. I trust a TUV certification. CE isn't so impressive but is better than nothing.

Edit - I tried searching for a copy of the actual certification on TUV's site and came up empty. It doesn't seem to be as easy to use as the UL site.

 

So it appears this is essentially a variation on a dry chem extinguisher. The fire fighting principle is the same - small particles of certain salts disrupt flame propagation chemically by capturing free radicals to stop the chemical chain reaction. There is no "smothering" (i.e. cutting off of oxygen) nor removal of heat so the same issues of potential re-flare-up as you have with a standard dry chem.

In a standard dry chem the powder is preformed to a certain particle size, some additives make the particles flow better and the particles are discharged via stored gas pressure. The smaller the particles the more effective the extinguisher for a given mass of charge.

In the "Element 50" extinguisher and a bunch of similar devices ("Fire Stick" is another) the very same kinds of salts are used but instead of preformed particles in a powder the salt particles are formed by vaporizing the media and then allowing it to condense as it is ejected from the extinguisher. These condensed particles are very small compared to the powders used in a standard dry chem extinguisher. Therefore for a given mass of charge they tend to be more effective. To get things hot enough to vaporize a pyrotechnic gas generator is used. This same gas generator also provides the pressure that discharges the particles out the end of the extinguisher.

Beyond that basic summary there seems to be quite a bit of variation in specific implementation and what the various manufacturers claim. It seems in some cases the salt itself is part of the pyrotechnic generator whereas in others it seems there is a separate pyrotechnic gas generator that outputs through the salt media presumably vaporizing it and carrying it along. These handheld units are all full of BS marketing crap and poorly worded English translations that seem to intentionally obfuscate what is actually going on.

That said the same technology is used in commercial and industrial units - so the technology is certainly real. Commercial/industrial ad copy is much more reserved than the consumer devices and makes it clear these aren't exactly perfect. Some more academic papers around also make it clear there are some trade-offs with the technology. It isn't clear they are as non-corrosive as claimed nor that they are particularly safe for occupied spaces. But as already mentioned it seems there is more than one way to implement them so it is extremely difficult to disentangle marketing BS from actual fact.

I also could find nothing about the TUV certification nor any specifics about what exactly it is certified as. Cold Fire uses similar obfuscation in its ad copy claiming UL certification - and it is UL certified as a wetting agent. Of course I can give UL a bottle of lemon fresh scented Joy and a check and they will properly certify that my dish soap is also a wetting agent so it isn't exactly clear what good the Cold Fire UL certification is to an end consumer. I have my suspicions that the TUV certification is of a similar vein.

We really need some sort of honest evaluation of these "secondary" extinguishers. It is definitely a useful market segment but they all also make fantastical claims. I know a few years ago CR tested a bunch of the aerosol can extinguishers and found that some marketed for kitchen fires and claiming class K capability actually made kitchen fires flare up badly instead.

Anyway will look at some more later - I like the stability aspect of these pyrotechnic dry chems.

 

Thanks for that link! In a short search I found a couple of other companies making similar products. Most appear to be electronically ignited, meaning they have a battery. I think I like the striker better. They also vary greatly in discharge time. The PFE-1 is only 12 seconds, but appears to put out a higher volume of discharge. Availability here in the states is limited on most of them. Here is one: http://www.marinechandlery.com/firetool-pfe-series-portable-aerosol-fire-extinguisher.

I think these things have promise, and I may switch to them. I would definitely keep a welding gauntlet glove with them to protect my hand from heat in close spaces.

 

Another safe option would be this one:

https://www.x-tinguish.com/ It is a foam, but will blast up to 15 feet away and safe, biodegradable and not a pressurized bomb.