Regina:

Were there any other controls – overheating, run-dry, etc?

This was an unattended operation.  Were there any periodic checks?

This extraction does not normally generate copious mists.

How was reentry into the lab performed?

Was any type of review of the modified procedure performed or was this just a “wing it”

Basically, I am trying to assess the actual risk post facto

My colleague is seeking advice as to whether the following procedure was a safe way to deal with a fume hood failure.

Here is his description of what occurred.  I have a picture (96 kb) of the initial setup if needed and the list server can handle.

A 48 hour reflux to extract 19 g of powdered rocky material in 68 g of 95% formic acid was needed.    A 250 mL single neck (14/20 joint) round bottom flask on an electric heating mantle with a Liebig Condenser in a fume hood.  When heat was applied, a glass beaker was inverted and placed over the top of the condenser to prevent any particulates from contaminating the system (without risking a pressurization).  One day into the extraction the building fume hood fans stopped.  The lab manager decided that terminating the procedure would compromise the rare meteorite sample and elected to proceed as follows.  He added a second identical water cooled Liebig Condenser above the first, closed the hood sash, and evacuated the 17,600 ft^3 lab (with proper warning signs on all the doors) until the completion of the experiment on the following day. 

 

Was this an unsafe action?

 

Thank you for your comments.

Regina Cody

*************************

Regina Cody

NASA Goddard Space Flight Center

Code 691

Greenbelt, MD 20771

Office: 301-286-3782

Fax: 301-286-1683

Email address: regina.cody**At_Symbol_Here**nasa.gov