Did the researcher use LN2 to extinguish the Na + kimwipe fire? If so, it appears that it worked. If not, why not?

 

From the perspective of someone whose PhD research involved working with sodium, potassium,  phosphine and phosphines, arsine and arsines, trimethyl gallium, trimethyl aluminum, trimethyl phosphine, NaK, dimethylzinc and other pyrophoric nasties, my response is ‘whatever puts the fire out immediately’. Pouring LN2 on a small fire is a valid method of extinguishing it – the cold and the N2 gas will knock down a small flame before it gets out of control. I would rather that the fire be put out immediately than in an ‘approved’ manor. I’ve seen labs be burned out when a small, easily extinguishable fire became a large fire.

 

There is a cultural issue between chemists who do/have worked with the pyrophores and the lab safety community. Implied in our lab training was ‘fires will happen – put them out as soon as possible’.

 

Just my devalued $0.02 worth.

 

John Nail

Professor of Chemistry

Oklahoma City University

 

 

 

 

Good morning:

 

I’m reviewing an incident report from one of my inorganic synthesis researchers.  A little sodium, wiped off tweezers onto a kimwipe and not properly disposed, that went badly downhill.  No one hurt but it sure got everyone’s heart pounding for a bit.

 

In the corrective action, the lab worker states they keep LN2 nearby as an extinguishing agent for small air/reactive metals fires (think size of a beaker).  That just sounds all bad.  In my guidance document, I state that dry sand, Met-L-X, lime, or soda ash are suitable extinguishing agents for small fires.  We have our own fire department and don’t provide Class D fire extinguishers (for a long list of very good reasons).

 

I’m getting some push back – that using LN2 is commonplace in this lab and the default fire extinguishing agent.

 

Thoughts?

 

 

Debbie M. Decker, CCHO

Campus Chemical Safety Officer (soon to be Chemistry Department Safety Manager)
Environmental Health and Safety
University of California, Davis
1 Shields Ave.
Davis, CA  95616
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