The Real Story Behind Fire Extinguishers: From Exploding Grenades to Sound Waves
When I sat down with Bobby Salvesen and Mike Monaco for episode 93, I thought we were going to knock out a quick chat on extinguishers. Five types, a few funny anecdotes, call it a day, right? Wrong. By the time we were done, we had an 11-page outline, several hours of recording, and what felt like a PhD-level breakdown of fire suppression.
Here’s what went down across our multi-part deep dive—some seriously useful info, a few hilarious detours, and a surprising amount of chemistry that might just save your ass.
From Gunpowder Casks to Chemical Science
We kicked things off with a bit of history, because the past is often just absurd enough to be memorable. Did you know the first recorded fire extinguisher came from England in 1723 and used gunpowder to blast out fire-suppressing liquid? Yeah, nothing says “safe firefighting” like detonating your way to safety.
Fast-forward through 19th-century soda-acid extinguishers (essentially industrial baking soda and vinegar) and into the modern age of foams and halons, and we begin to see where fire suppression starts to intersect with real science and serious risk.
Understanding Fire Classes: It’s Not Just A, B, C
If you’re new to fire classes or haven’t thought about them since the academy, here’s a quick refresher, minus the dry textbook speak:
- Class A: Your classic combustibles—wood, paper, trash.
- Class B: Flammable liquids and gases. Not just gasoline—think alcohols, ketones, oils.
- Class C: Electrical fires.
- Class D: Combustible metals—magnesium, titanium, sodium, etc.
- Class K: Cooking oils and fats. Yes, there’s a whole class for your deep fryer fire.
Each class has its own extinguishing agents and color-coded symbols. Ask a firefighter to recall the shape for Class D (yellow star), and you’ll see the trivia potential.
Foams: It’s Complicated
We spent a lot of time breaking down foam types, and for good reason—this is where things get both cool and dangerously misunderstood. Here’s what you need to know:
- Class A Foam: Wetting agents that make water more effective. Think wildland fires, wood, and deep-seated combustibles.
- Class B Foam: For liquids and gases. Synthetic surfactants spread fast but can contaminate groundwater. Protein-based foams are biodegradable but smell like fish guts and are fading out fast.
- AR-AFFF: Alcohol-Resistant Aqueous Film Forming Foam. Used for fuels like ethanol that would eat up standard AFFF.
- FFFP: Film-Forming Fluoroprotein. Great for high-heat environments like motorsports but not effective on high-ethanol fuels.
And yes, there are charts, acronyms, and side-by-sides. But what stuck with me? Bobby’s line: “If you use the wrong foam, it just pisses the fire off.” That’s real talk.
Halons and Their (Very) Complicated Legacy
Let’s talk about Halon. Yes, it’s banned under the Montreal Protocol. No, that doesn’t mean it’s gone. It’s still in use—especially in military, aviation, and even Italian branches of extinguisher manufacturers (Kitty, we see you). Halon doesn’t cool or smother; it breaks the chemical chain reaction, full stop.
It’s wildly effective, also a major ozone-depleter. That led us into Halon alternatives like Novec 1230 (aka “dry water” or “sapphire fluid”) that suck heat out of the system faster than a shop fan in August.
Exotic Agents, Insane Tactics
From Metal-X (sodium chloride that forms a molten crust) to graphite powders and Lith-X for lithium fires, we dug into the dirty work of metal extinguishment. One of the best analogies? “It’s like a Mars bar in reverse”—encase the heat source in a candy shell to stop it from breathing.
Then there’s the firebombs. Literal glass grenades filled with chemical agents that you’d throw into a room and let burst to suppress flames. They’re back, now using ABC dry chem instead of deadly vapors—but the concept’s the same.
And just when you thought it couldn’t get more sci-fi, Mike brought up low-frequency sound waves as an emerging fire suppression tool. Think bass drop meets backdraft. Germany’s working on it. So is NASA. If nothing else, it’s the first time dubstep might save a life.
The Quarter Life Rule: Know It or Get Burned
Quarter life is one of those terms that doesn’t sound important until you realize it’s everything when dealing with foam. It’s the time it takes for 25% of the foam’s water content to drain out.
If that happens too fast and you don’t reapply, you risk reignition—like what happened when a hot ember fell onto a fuel spill on the BQE and lit up the whole scene again… with a guy in a cherry picker dangling above it all.
Bottom line: Know your foam’s quarter life. Know when to refresh. Don’t trust the bubbles—they’re not doing the real work.
Quick Takes: Best and Worst in the Extinguisher World
- Best smelling: None. They all stink. Some worse than others.
- Most misunderstood: Halon, hands down.
- Most underused: Wetting agents. Cheaper than foam, but forgotten.
- Most fun: Fire suppression balls. Look like toys, work like magic.
- Most badass: CAFS (Compressed Air Foam Systems). Wildland warriors swear by it.
Final Word: Know Your Tools, Save Your Skin
This series on extinguishers wasn’t just about trivia or product specs. It was about why the right choice matters. Whether it’s picking a CO2 can over a dry chem, knowing the difference between AFFF and AR-AFFF, or recognizing when that foam blanket is about to give up on you—every decision has consequences.
So if you’re in the field, on a rig, or in charge of training, make sure your people really understand what’s in those red cans and why it matters.
Have a wild extinguisher story or favorite foam trick? Share it in the comments below, tag us with your setup photos, or hit subscribe so you don’t miss our next breakdown on hazmat tools that actually work in the real world. And hey, if you learned something, send this to the guy on your crew who always grabs the wrong can.