I just wanted to mention a caution on the use of "dry sand."  Sand staged in an open bucket can pick up moisture from the air, depending on local humidity and season, or other contaminants like settled dust that may have some combustibility.  I recall reading (years ago, don't know the source) about hydrogen explosions occurring when burning sodium  was covered in sand that was thought (and looked) to be dry but which actually contained significant moisture.

On the question of extinguisher vs. scoopable/pourable extinguishing agents, I would venture, without personal experience, that an appropriate pourable or scoopable powder (that had been stored in a sealed container prior to use) would be effective against a small Class D fire.  As I understand it, the object of the game is to bury the burning material in the powder.  

---

Hi Brandon:

 

Our Fire Prevention/Fire Operations folks do not permit Class D fire extinguishers in labs.  There are several "flavors," if you will, of Class D fire extinguisher, depending on the potential fire.  A lab could end up with two or three different Class D extinguishers, depending on the materials in use.  Also, Class D extinguishers weigh a ton!  And they are expensive to maintain.

 

My pyrophoric/water reactives users tend towards Met-L-X or dry sand for the small quantities they work with.  Dry sand seems to be the agent of choice and most of these researchers keep a small bucket of dry sand nearby where they work.  Working in a dry box or glove box is preferred.

 

Hope this helps,

Debbie

 

Debbie M. Decker, CCHO

Safety Manager

Department of Chemistry

University of California, Davis

122 Chemistry

1 Shields Ave.

Davis, CA  95616

(530)754-7964

(530)304-6728

dmdecker**At_Symbol_Here**ucdavis.edu

 

Birkett's hypothesis: "Any chemical reaction

that proceeds smoothly under normal conditions,

can proceed violently in the presence of an idiot."

 

 

From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Brandon S. Chance
Sent: Wednesday, January 29, 2014 2:22 PM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: [DCHAS-L] Met-L-X or Lith-X Extinguishing Medium

 

DCHAS,

 

I am looking into the advantages and disadvantages of using Met-L-X or Lith-X scoopable dry powder extinguishing agent versus outfitting labs with the extremely large dry powder extinguishers that this material traditionally comes in.  I am hoping for a solution for the usual pyrophoric and reactive metal suspects; alkyllithiums, trimethyl aluminum, diethyl zinc, potassium, sodium, magnesium, etc.

 

If anyone has an experience with using or training with this extinguishing, I would appreciate any insight that you might have.  I have already contacted Ansul and am awaiting their response.

 

Regards,

 

 

Brandon S. Chance, M.S., CCHO

Program Manager, Chemical Safety

Environmental Health and Safety

Princeton University

262 Alexander Street

Princeton, NJ 08540

609-258-7882 (office)

609-955-1289 (mobile)

609-258-1804 (fax)

 

"The second I feel like I made it, the second I feel like I've arrived, that's the second someone will take my spot. And I like my spot." J.J. Watt - Houston Texans