We had a laser fire, and I used a dry powder extinguisher. It was the right thing to do, as the thing was flaming.
But the residual powder is a disaster. It is extremely fine, and got all through the laser and the room. It is VERY corrosive. In the laser, it ate slide bearings and exposed electronics. Elsewhere, I got light oxidation of metal surfaces.
So we bought a $100 halon-type extinguisher. One of those things that I wish I had known beforehand!
We still have dry powder - it is wicked quick at stopping a fire. But it is only there for after the halon-style extinguisher is empty.
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Just an FYI..if there's still fire after discharging the Halon, the extinguisher
is too small. The best use of Halon is a total flooding, meaning the tank is
the size needed to reach the right Halon/air ratio in the room when the tank
is discharged and doors/windows are closed. It isn't really meant for a 'spot
shot' like CO2 or powder. It'll work, but it sounds like you want a bigger tank.
I don't usually hang around the engraving forum but "ABC fire extinguishers" caught my eye.
First thing I'd like to add is that a fire is nothing to take lightly. They can get out of hand very fast wether you have a extinguisher or not.
I work for a company that makes every type of extinguishing agent available. We're not into the "home" market but provide protection for commercial and industrial applications. That said here's a run down of agents and my opinion of what I'd use.
Fire extinguishing agents don't suck the oxygen out of the air, they displace it or prevent it from reaching the fire, which is how the foam agents work. Foam agents can reak havoc with electrical components. They're used mainly on class B fires.
ABC chemical, also known as Foray, is made from MAP which is corrosive and also a good fertilizer.
PKP or purple k is also corrosive.
Halon would be so hard to obtain that it's not practicle to use.
CO2 will work.
For your lasers I would use FE-36, FM-200, or a product called Sapphire. They are all what's known as "clean agents". They won't harm electronics. I've seen a demonstration of Sapphire where a cell phone was submerged and used to make a call when it was pulled out.
Just remember a 911 call before you start to fight a fire may save your shop or home. And you should kill all electrical power to the equipment or the fire may restart when you think it's safe and your extinguisher is empty.
Jerry
Confidence: The feeling you experience before you fully understand the situation
I've recently seen something called Halotron extinguishers for sale, is that different than Halon? Is there any legitimate comparison between, for example, a 15# CO2 unit and a 15# Halotron unit?
-Glen
Look for a rating number on the extinguisher or in the sales literature. The Halotron and CO2 extinguishers are typically rated for class B & C fires. B being liquid fuel fire and C being electrical. There will be a number before the B, and the larger the number, the more fire the extinguisher can handle when used by a person properly trained in using the extinguisher. There will not be a number in front of the C. A C designation merely means that the extinguisher can be safely used and is effective on electrical fires. If you are comparing ABC extinguishers, there will also be a rating number before the A for the extinguishers effectiveness on solid fuel fires. I once had the testing/rating criteria committed to memory, but as the need to know retired - so did the specific fire test sizes. Bottom line - bigger number will put out bigger fire.
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Not that I disagree with what you've written, Jerry, but your example doesn't sound like a very scientific test. Most electronics would work just fine after being doused in a standard dry chemical agent, too. It's extended exposure that destroys the electronics through corrosion, not instant exposure. It's likely this Sapphire does not corrode with extended exposure, which is good, but I just wanted to point out that spray-and-call doesn't prove that.
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I agree with Dan that quick clean-up after dry chemical use is key. I've seen large DC drive panels (400 HP) where we dumped 10 to 15 pounds of dry chem in them to extinguish a fire start back up within hours after a good clean out with compressed air and vac and then replace the components that had let their smoke escape.
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