From: J. Steven Bonnell <jsbonnell**At_Symbol_Here**CINCI.RR.COM>
Subject: Re: [DCHAS-L] Magnesium/Dry Ice Demonstration - fire extinguisher?
Date: Fri, 12 Aug 2016 13:26:09 -0400
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 9EA1B4BA-8D5E-4208-B796-883AAC205EC7**At_Symbol_Here**


Our chemists use small quantities of sodium. We agreed that having a Class D extinguisher would be prudent. We obtained a small pail of Met-L-X and keep it handy (makes a fine door stop). The agent is essentially sand so, the inspection amounted to 'still there, not leaking'. You ought to be able to stage a worse case test and determine the quantity you would need, double that amount and put that amount in a small container to accompany the set up.

You are absolutely correct to avoid toting an unwieldy quantity that hinders the response and encourages the demonstrator to eliminate it.

As part of the demonstration, consider lighting off a second ribbon to demonstrate the effectiveness and usage technique for the extinguishing agent. That forces occasional stock replenishment. 


Sent from my iPhone

On Aug 12, 2016, at 12:30 PM, Debbie M. Decker <dmdecker**At_Symbol_Here**UCDAVIS.EDU> wrote:



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=E2=80™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 =E2=80" in favor of having just our ABC dry chem extinguisher on site.


What do you all think?





Debbie M. Decker, CCHO, ACS Fellow

Safety Manager

Department of Chemistry

University of California, Davis

3467 Chemistry Annex

1 Shields Ave.

Davis, CA  95616

(530)754-7964 (T)/(530)304-6728 (cell)



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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