waveslider
Outdoorsman
Element all the way. I bought several to replace my tank/canister extinguishers in my vehicles and my shop.
fire extinguisher recommendation requested
- Thread starter s.e.charles
- Start date
I probably extinguished half a dozen engine/fuel/rubber/grease/oil/electrical car fires before the age of 21. Extinguishers, blankets, jackets, dirt, etc. Seemed like no big deal and was just part of being a dumb hotrodder kid back then. Deciding beforehand to flee and let a small manageable fire grow and burn the vehicle up is just silly IMO. Grab your valuables, evaluate the situation, and extinguish it or not. It's not a bomb. 
patoz
Expedition Leader
The first thing you need to understand is, ABC and BC are not fire extinguishing agents. They are classifications of the different types of fires.
For each different classification you may have several different types of agents that can be used.
Corrosion...
"Moisture may combine with monoammonium phosphate based agents in post fire situations to produce mild corrosion. Because of this, prompt cleanup is recommended."
"Purple-K powder has an acrid taste and odor, is free-flowing, floating on most liquids, non-abrasive, does not wet with water and is compatible with most foam concentrates. It has violet color, to distinguish it from other dry agents. Its principal component is potassium bicarbonate (78–82% by weight), with addition of sodium bicarbonate (12–15%), mica (1–3%), Fuller's earth (1–3%), amorphous silica (0.2–%), and is made hydrophobic by methyl hydrogen polysiloxane (0.2–1%).
Purple-K is normally non-toxic, but ingestion of large amount can cause alkalosis. In high temperatures (891 °C), its main component, potassium bicarbonate, decomposes to carbon dioxide and potassium oxide, the last product is highly corrosive."
This explains it all much better than I can...
"Dry chemical is a powder-based agent that extinguishes by separating the four parts of the fire tetrahedron. It prevents the chemical reactions involving heat, fuel, and oxygen (combustion), thus extinguishing the fire. During combustion, the fuel breaks down into free radicals, which are highly reactive fragments of molecules that react with oxygen. The substances in dry chemical extinguishers can stop this process.
- Monoammonium phosphate, also known as tri-class, multipurpose, or ABC dry chemical, used on class A, B and C fires. It receives its class A rating from the agent's ability to melt and flow at 177 °C (351 °F) to smother the fire. More corrosive than other dry chemical agents. Pale yellow in color.
- Sodium bicarbonate, regular or ordinary used on class B and C fires, was the first of the dry chemical agents developed. In the heat of a fire, it releases a cloud of carbon dioxide that smothers the fire. That is, the gas drives oxygen away from the fire, thus stopping the chemical reaction. This agent is not generally effective on class A fires because the agent is expended and the cloud of gas dissipates quickly, and if the fuel is still sufficiently hot, the fire starts up again. While liquid and gas fires do not usually store much heat in their fuel source, solid fires do. Sodium bicarbonate was very common in commercial kitchens before the advent of wet chemical agents, but now is falling out of favor as it is much less effective than wet chemical agents for class K fires, less effective than Purple-K for class B fires, and is ineffective on class A fires. White or blue in color.
- Potassium bicarbonate (principal constituent of Purple-K), used on class B and C fires. About two times as effective on class B fires as sodium bicarbonate, it is the preferred dry chemical agent of the oil and gas industry. The only dry chemical agent certified for use in ARFF by the NFPA. Colored violet to distinguish it."
Apparently, there seems to be some conflicting information about corrosion from Wikipedia and it's sources.
Mixing agents...
As far as not mixing the agents in a fire extinguisher goes... Never mix ABC Dry Chemical agent with bicarbonate based dry chemicals. A chemical reaction that is harmful to the extinguisher will take place. PKP extinguishers are a specialized type of extinguisher intended specifically for fuel fires, although it will work in some other cases also. The ABC extinguishers are a generalized type and intended for all three classifications of fire, even though it doesn't work as well on fuel fires as PKP does.
Since Purple-K is commonly used in oil refineries, airport ramps, service stations, military facilities, naval warships, power plants, and other places where large volumes of flammable liquids are handled, you rarely see PKP used along side of ABC type extinguishers in the civilian world. The few times I have seen both used together, I didn't really notice any conflicting action taking place.
My recommendation...
Before we taught Fire Extinguishment we always taught Fire Prevention. In this case it means making sure your electrical and fuel systems are in tip top shape, with all possible hazards removed beforehand. I have responded to hundreds of vehicle fires in my career, and just about everyone was started due to an electrical or fuel system malfunction. Although, a few of them were started by arson or the catalytic converter while the vehicle was parked in tall grass while running.
My recommendation is skip the 2 1/2 lb. size and start with at least a 5 lb. ABC unit, which takes up just a little more space. The 2 1/2 lb. size is just enough to get started and then runs dry as the fire flares back up. I would carry at least one of these and one just for electrical fires, such as CO2, Halon, or a Halon replacement such as Halotron-1.
An electrical fire is not going to go out until it is de-energized, therefore a master battery disconnect is required also. The switch needs to be as close to the battery as possible, but still accessible if the hood can't be opened. Most modern vehicle hoods are unlocked via a metal cable enclosed in a plastic sheath, which is the first thing to be compromised in a hot fire, preventing the hood from being opened. I have considered designing a disconnect switch with a metal throttle type cabe attached to it, so the battery could be disconnected from the cab even if the hood couldn't be opened.
I hope this helps rather than confuses you...
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Outdoorsben
Observer
I did as well.
4xdog
Explorer
After reading the technical description of how those work (which is somewhere between gobbletygook and imcompleteness) it's still not clear what those things are. The idea that alkali earth oxides (which seem to be the byproduct of neutralization after the aerosol jet does its thing) plus water (ubiquitous) leaves no residue seems odd to this writer (after most of a lifetime around chemicals and chemistry). The chemical that would seem to result would be potassium hydroxide, a strong alkali that I sure wouldn't want deposited in my engine compartment or behind my dash. Where's another chemist... -- calling Hilldweller...
s.e.charles
Well-known member
so I could most likely rule out "wood" in most automotive fire situations, but how does the casual observer determine what is causing the fire and what is actually burning?
or is that what the ABC unit covers?
and what do the prefixial (?) numbers mean? I always assume higher is better.
Kidde
Pro 340 3-A:40-B:C Fire Extinguisher
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Ducky's Dad
Explorer
Pelican Parts has just started a group buy on the Element Fire Extinguishers.
http://forums.pelicanparts.com/pors...ail&utm_term=0_e247719183-c1a99c4740-70116145
http://forums.pelicanparts.com/pors...ail&utm_term=0_e247719183-c1a99c4740-70116145
Ducky's Dad
Explorer
Deleted duplicate post.
waveslider
Outdoorsman
Smaller? - Check
Non-pressurized? - Check
Safe to Breathe? - Check
Never Expires? - Check
4x the discharge time? - Check
EDIT: Never having to ask which way you're supposed to carry your Fire Extinguisher or wonder if it was charged correctly......priceless.
What's not to like? I'd bet 75% of the BC extinguishers in overland vehicles today are expired. My Elements are lifetime equipment - unless they get used of course.
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s.e.charles
Well-known member
which is the better way to carry an ABC extinguisher: upright or horizontal? I understand the powder packs and needs external agitation periodically.
waveslider
Outdoorsman
I edited my post above. LOL
patoz
Expedition Leader
It doesn't really matter, but if I had to pick one I'd say carry it upright if possible. Most modern ABC extinguishers have a drying agent in them to keep the powder from packing and flowing freely. Of course, a vehicle mounted extinguisher will settle quicker than one that is mounted in a building, etc., due to the constant bouncing up and down movement.
We carried 20 lb. PKP extinguishers on our Crash Fire Rescue Vehicles, and once a month we would have to remove the Nitrogen charging canister, invert the extinguisher, and tap all around the bottle with a rubber hammer starting at the neck and working our way around and up to the base of it.
In my 35 year firefighting career, I have never had an ABC or PKP extinguisher fail as long as it was charged properly.