The "ABC"s of fire extinguishers (1 Viewer)

Dec 4, 2018
With the build of my Land Cruiser more or less complete for now, I find myself feeling the need for a fire extinguisher. I recently installed a winch which directly connects to the battery. I thought to myself, what if this thing shorts out and starts a fire? I have NO means of putting it out, especially an electrical fire. There are things you can do to help PREVENT a fire, especially electrical fires, but you cannot think of or control everything, especially in the case of other's vehicles you may be camping or off roading with.

I am not an expert, but I spent the last few days educating myself with everything I could about fire extinguishers.
All fire extinguishers are not alike, and some can even do more damage to the vehicle long term than had you used a different fire extinguisher. This is because the dry chemical fire extinguishers that are commonly sold at the hardware store are corrosive to metal and electrical systems in your car. So its good to know what goes into each kind, what considerations there are for each kind, and what cleanup strategy you should use after you need to use one. My philosophy of use for an extinguisher is that having one could potentially save the vehicle if you catch it early. In a fully involved car fire, it's a total loss, and the type of extinguisher doesn't matter except in regard to effectiveness.

ABC fire extinguishers(Dry Chemical):
This is possibly the most common "home" style fire extinguisher you'll find in the hardware store. They are a dry chemical extinguisher that uses ammonium phosphate, colored yellow for identification, and is rated to be effective against 3 types of fires:
"A" Type fires which are organic materials like grass, wood, paper etc.
"B" Type fires which are flammable liquids like oils, gas, and some plastics etc..
"C" type fires which are electrical fires.
ammonium phosphate works by reacting with the fire chemically, disrupting combustion, and laying down a coating that smothers the fire and prevents re-ignition. These are great for putting out a camp fire that's out of hand, but absolutely terrible for your car! The chemical reacts with the fire and creates a hard coating that is corrosive and harbors moisture, and is extremely difficult to remove.It's also potentially an abrasive that could damage your engine or any other system the powder contaminates. Suggested cleanup strategy is to first vacuum the remaining powder(with a vacuum you don't care about) then neutralize the chemical with a mixture of 50% isopropryl alcohol and warm water. let sit a few minutes then wipe up with a rag.

My advice, if you plan to carry am ABC type fire extinguisher: don't plan to use it for your vehicle or anyone else's vehicle for that matter unless there is no other option. Carry one for the camp fire only.

BC type fire extinguishers(dry chemical):
These fire extinguishers have a different dry chemical element, either Sodium Bicarbonate(baking soda) or Potassium Bicarbonate(known as Purple K and colored purple for identification). These are rated for B and C type fires and would be effective at putting out a car fire or electrical fire but not effective at putting out an organic fire like a camp fire. The sodium bicarbonate works by a chemical reaction with the fire that releases CO2 and displaces the oxygen the fire needs, extinguishing it. These types of dry chemical extinguishers are mildly corrosive but can be cleaned up and washed away a bit easier than the ABC type fire extinguishers. Cleanup strategy is to first vacuum the powder, then neutralize the residue with a mixture of 98 percent water and 2 percent vinegar. Let sit for a few minutes then wash away with water. BC extinguishers with Sodium Bicarbonate are pretty cheap and is your cheapest option to get a fire extinguisher. It is a much better option than an ABC extinguisher for a vehicle fire, but you may want to still carry an ABC style if you're camping. Purple K extinguishers are more expensive than the sodium bicarbonate, but more effective and cleaned the same way. IMO you are possibly better off going with a clean agent extinguisher at that point due to the minimal price difference. Which brings us to the next style:

Clean Agent Extinguishers:
Clean agent extinguishers are usually rated for B and C type fires, but can be rated for A type if they are large enough.
The two most common types of clean agent extinguishers are Halon(or a variation of it) and CO2.

Halon extinguishers work by reacting chemically with the fire, disrupting combustion. It comes out as a liquid and quickly evaporates. It is safe to use around people as it doesn't displace oxygen and best of all doesn't require much if any cleanup. These are fantastic for a vehicle fire because there is no additional damage to the vehicle beyond the damage done by the fire itself. The down side is that they are much more expensive. A 2.5lb extinguisher is anywhere from $85 to over $200 dollars. I got mine from webstaurant store for 86 plus shipping and tax with a "vehicle" mount. This is my primary vehicle fire extinguisher for anything in the engine or cab area, and I'll mount it to the drivers front seat via a bracket from owl expedition products(a vendor on this forum).

CO2 extinguishers work my simply displacing oxygen and cooling the fire. They leave no residue but can be somewhat dangerous to use in a confined space due to the displacement of oxygen. They are typically less effective in open spaces since the CO2 quickly is blown away. CO2 is also more expensive but not quite as expensive as Halon. a 5lb CO2 extinguisher can be had for around $100 from the same source previously mentioned. This would also make a good primary go to extinguisher for a vehicle fire. A CO2 extinguisher has no pressure gauge and is instead weighed to determine if it is fully charged.

Other fire extinguishers:
There are some different types of extinguishers available as well. The Element fire extinguisher, and similar technology fire extinguishers, are a one time use fire suppression "stick," if you will, that is ignited like a flare and provides a much longer duration of fire suppression. They also are similarly non toxic and leave no residue to clean up. They put out a gas that disrupts the combustion of the fire, and when used in a somewhat enclosed area like an engine bay, can really provide a lingering and effective fire suppression effect. They are about $80 for a 50 second burn time. This would make a good backup or possibly even a primary fire extinguisher. Though, I wonder if everyone, including a bystander, will know how to use it intuitively. They also have a pretty limited range, and are probably only suitable for relatively small fires that haven't got out of control yet.

There are other options and other agents out there including simply water. But I'll leave that for discussion.

One final important note is on duration of the different extinguishers. A larger fire extinguisher doesn't always equal a longer duration of discharge. A halotron extinguisher for example has a 9 to 12 second discharge for a 2.5lb, 5 lb and even 10lb size. They simply discharge more agent in as shorter time and discharge further distances. A CO2 extinguisher on the other hand has a longer discharge with larger size but it's not linear as it may be discharging more agent as well. Dry chemical extinguishers are similar. In some situations, 2 smaller extinguishers may be better than 1 big one.

Here's my buckeye(made in USA!) Halotron 2.5lb extinguisher and my bracket made specifically for the 100 series by @Ramathorn15. I think it's important to have your extinguisher immediately available and this mount accomplishes that without being in the way. In the future I plan to add an Element extinguisher as a backup, and carry an ABC extinguisher if I go camping and plan to have as fire. If I were to cook on the back of the land cruiser like some overland rigs have set up, I'd probably carry a CO2 extinguisher near the cooking area or at least a sodium bicarbonate BC extinguisher.


Sep 18, 2014
Dallas, TX
Don't know much about fire extinguishers, but you really should not have two floor mats on the drivers side, especially with the top one not hooked to the floor.


Competent Ignoramoose
Jul 21, 2019
Don't know much about fire extinguishers, but you really should not have two floor mats on the drivers side, especially with the top one not hooked to the floor.
Yup - good way to get a stuck pedal or one that won’t depress fully.

Nevertheless, great information @Brandon Ryder ! Thanks for putting this together. I need to get an in-cab extinguisher.

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