Shop Fires !

I think most of us have had a shop vac fire in our early days. It seems simple to stick the hose under the grinder and suck up all that stuff coming off .... right????

I had built a slide diverter that switched the path from directly to the vac for wood dust, or to a spark trap in the line when grinding metal. I forgot to pull the diverter when I came in to grind a blade ... and sent sparks to the vac. The shop was almost immediately filled with smoke. I grabbed the whole shop vac and took it outside, where I opened it up and hosed off the burning filter. The dust inside was smouldering, too.
 
razor-edge-knives said:
Thanks for the tip and reminder!! I don't grind mag but water seems to put ti fires out just fine... It all goes into a big 10-12" cone that goes through a 5" opening into a water bucket and haven't had any issues so far. I only turn the vacuum on if I'm grinding wood/micarta/g10 etc.
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Only because of the part / water ratio

The parts are small enough to be cooled by the water.

If not - different story
 
Lieblad said:
Class ”D” fires are burning alkaline metals. Various dry powders are used to extinguish. Smother the fire & draw heat out.

Fwiw, if one believes the press, Magnesium disaster OP mentioned was caused by the buildings sprinkler system wetting molten magnesium. The Fire Brigade did nothing but deal with aftermath. Further, the plant safety seems dodgy based on various violations in recent times.
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Dang, I had no idea this was true. I've only got an ABC fire extinguisher in my shop. Anybody have a recommendation on an affordable place to buy a Class D extinguisher? A quick Google search shows that they're quite expensive...
 
I am not a fire marshal.

Most of us will have wood, steel dust and oil fires. A,B,C extinguishers will work with these. If you do some Ti or Al work, you might be in danger of a small class D fire but it will only be the match to your ABC fire. Unless you are making LARGE quantities of dust with these materials, it shouldn't be a problem. Keep your dust system properly maintained

... and just use common sense... if your quench tank catches fire, don't dump your slack tub on it.
 
We dont worry about it. At least We dont have a class ”D” extinguisher.
Firstly good housekeeping is our best defense. Overall our shop is filthy, but we dont allow large amounts of metal fragment accumulation.
We are basically homegamers as 2-3 man operation, and just produce very little combustable metal fragments anyway. If any were to ignite, our regular fire suppression will be adequate if not to outright subdue small metals fire, would easily subdue subsequent fire of the ordinary combustables the short lived metals fire ignited.
 
Michael Black said:
Dang, I had no idea this was true. I've only got an ABC fire extinguisher in my shop. Anybody have a recommendation on an affordable place to buy a Class D extinguisher? A quick Google search shows that they're quite expensive...
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All the commercial ones i have seen are 20 pounds plus - on a wheeled cart
- not practical for most small shops.

I called my local fire extinguisher shop - they will refill a "normal" 5 or 10 pounder with class D powder


FYI
ABC is baking soda - that's why baking soda is so effective on kitchen stove fires
D powder is salt.
 
Michael Black said:
Anybody have a recommendation on an affordable place to buy a Class D extinguisher? A quick Google search shows that they're quite expensive...
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They are expensive. How about a 5 gallon bucket filled with dry sand ?
 
Spalted said:
They are expensive. How about a 5 gallon bucket filled with dry sand ?
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Dumping sand on it is just fine if burning material is a surface what can be smothered over. Extinguishers designed this job, their powder is designed to stick to hot metal to assist smothering & absorb heat.
 
Ti fires scare me. This is why I always ground Ti outside after thoroughly soaking the surrounding area with a hose before moving to waterjet lol. Now I get my parts and grind them so slowly with my VFD and 2x72 that I don't even get sparks. Just long shavings.
 
I don't work with Ti.
I have a medium sized CO2 extinguisher that should displace most of the oxygen in my shop as I exit. I also have a compressed air/water extinguisher on the other side, and water buckets at each grinder.
 
I should have worded it different. A fire extinguisher is best to have by far but if you cant afford one a bucket of sand is better than nothing.
 
Bill DeShivs said:
I don't work with Ti.
I have a medium sized CO2 extinguisher that should displace most of the oxygen in my shop as I exit. I also have a compressed air/water extinguisher on the other side, and water buckets at each grinder.
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And a metal lid for every quench tank ?
 
Larrin said:
Another reason to use steel instead.
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You can start that on fire too. We had one of our chip dumpsters start in fire once. Figure it was a combination of fines and something smoldering from the burn table. That was exciting. Fire department said we're just here to protect the building, so I drug it away with the end loader and let it burn.


My recent scare was pulling my garden tractor into the shop to weld on a new muffler. I draped my leather apron under where I was welding but it wasn't sufficient. Leaking oil/diesel + dry grass packed into everything + welding = oh hell where did I put that extinguisher???
 
kuraki said:
You can start that on fire too. We had one of our chip dumpsters start in fire once. Figure it was a combination of fines and something smoldering from the burn table. That was exciting. Fire department said we're just here to protect the building, so I drug it away with the end loader and let it burn.


My recent scare was pulling my garden tractor into the shop to weld on a new muffler. I draped my leather apron under where I was welding but it wasn't sufficient. Leaking oil/diesel + dry grass packed into everything + welding = oh hell where did I put that extinguisher???
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I’ll never believe your lies about steel!
 
That mag fire was 15 minutes away from me and the FD arrived after the sprinkler system sprayed water on the fire causing the explosion and worsening of the fire. Many people near me lost jobs over some fool not understanding magnesium and water. I hear the company regularly had many safety violations. I once had a small fire inside a hand held woodworking style belt sander messing around with some Ti.
 
That reminds me -- we had a call from a company that had switched from about 5 % of their work to 95 % with hard maple .They were getting a good number of fires in the sanding machine !! Ah the distinct smell of burning maple ! The solution there was to use abrasive paper that had reduced coverage of the abrasive . Not 100 % but a smaller coverage maybe 70 % . Some other variables there too !
 
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