Date: Wed, 27 Apr 2011 19:21:54 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: ILPI <info**At_Symbol_Here**ILPI.COM>
Subject: Re: Safe Procedure?
circumstances, the reaction works as planned, the formic acid condenses,
and essentially no fumes are released. And if something goes
wrong, the fume hood will be the Last Line of
In the case you presented, the Last
Line of Defense has been taken out, and the researcher has made attempts
to reduce the probability of Something Unexpected happening.
Essentially, he's trying to revise the procedure so that the fume
hood is not needed.
Unfortunately, one can not
anticipate all possible Something Unexpected scenarios and the
researcher has only taken steps to avert one obvious failure scenario -
runaway heating. He/she has not planned for cooling water
failure. So if the water fails, all of the formic acid goes out
into the lab. Which won't hurt anyone right away as the lab will
be empty, but will corrode all sorts of things and no doubt work its way
into other occupied spaces and have numerous unintended
On the other hand, if the
condenser water outlet had a flow indicator that would cut power to the
heater in the event of cooling water failure, then perhaps the risk
becomes acceptable. A sensor that will switch off the heater and
fire off a solenoid to shut the water supply (in the event of a popped
hose, for example) is about $800 and the solenoid is about $170 based on
the price sheet I have for the models we are will be selling in the near
Or maybe not, because something *else*
Unexpected could also happen. Ah, the joy of risk
Safety Emporium - Lab & Safety Supplies featuring brand
On Apr 27, 2011, at 4:33 PM,
Cody, Regina J. (GSFC-6910) wrote:
My colleague is seeking advice
as to whether the following procedure was a safe way to deal with a fume
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
an unsafe action?
for your comments.
NASA Goddard Space Flight