Flinn's website (below) says "Dry sand also works well." I always suspected that pouring sand on a Mg fire would leave us with a Mg fire burning until it ran out of fuel/oxidizer and a pile of really hot sand.
Does it work?
Sheila M. Kennedy, C.H.O.
Safety Coordinator | Teaching Laboratories
Chemistry & Biochemistry |University of California, San Diego
9500 Gilman Dr. | La Jolla, CA 92093-0303
(858) 534 - 0221 | MC 0303 | YORK HALL 3150
I concur with having the ABC dry chem extinguisher handy for anything else that ignites. If you want to have Class D capacity on hand sufficient to handle a coil of magnesium ribbon, Flinn Scientific will sell you a 500 g jar of a Class D fire extinguishing powder for a mere $16.95. (Catalog No. SE3004) that would be perfect to pour onto the burning ribbon.
Bryn Mawr College
Bryn Mawr, PA
From: DCHAS-L Discussion List <dchas-l**At_Symbol_Here**med.cornell.edu> on behalf of Debbie M. Decker <dmdecker**At_Symbol_Here**UCDAVIS.EDU>
Sent: Friday, August 12, 2016 12:30:04 PM
Subject: [DCHAS-L] Magnesium/Dry Ice Demonstration - fire extinguisher?
We currently do a magnesium/dry ice demonstration in which about a meter of magnesium ribbon, closely coiled, is put into a well drilled into a block of dry ice. The ribbon is ignited using an electric lighter and another block of dry ice is slid over the magnesium. Cue spectacular bright flamage, sparks, and a glowing chunk of dry ice. One of my personal faves.
We've defaulted to having a Class D fire extinguisher on site for this particular demo. All of the other demos that produce flame can be managed with an ABC dry chem extinguisher.
But the Class D extinguisher is heavy (>75 pounds) and difficult to use. The fire extinguisher maintenance folks don't want to maintain it, our on-site fire department would rather we not have it and would probably just let the metal fire burn itself out. I've also done a bit of digging and ABC dry chem will work on a magnesium fire, perhaps not as effectively as the Class D but it'll work.
I'm inclined to stop hauling this thing around - it's a back injury/workers comp claim waiting to happen - in favor of having just our ABC dry chem extinguisher on site.
What do you all think?
Debbie M. Decker, CCHO, ACS Fellow
Department of Chemistry
University of California, Davis
3467 Chemistry Annex
1 Shields Ave.
Davis, CA 95616
Birkett's hypothesis: "Any chemical reaction
that proceeds smoothly under normal conditions,
can proceed violently in the presence of an idiot."
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