DCHAS-L Discussion List Archive
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Subject: Re: question
Date: Mon, 20 Jun 2011 14:05:41 -0400
Author: Kristi Ohr
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Subject: Re: question
Date: Mon, 20 Jun 2011 19:02:26 -0500
Author: Todd Perkins
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Date: Mon, 20 Jun 2011 14:05:21 -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: question
In-Reply-To: <8C28F3F9C0708141A611C73B4D80E70E0D70DEF16F**At_Symbol_Here**VA3DIAXVS461.RED001.local>
This sounds more like a
labeling (and, secondarily, training) issue than anything. Base
baths in my research labs all had NFPA and DOT Corrosive labels on them.
Adding the words FLAMMABLE and CORROSIVE might be a good idea as
well.
The funny thing here is that base baths
are always located next to a sink (and some folks store them IN the
sink, but let's not go there....) which is an easier source of water
than opening the lid....which begs the questions was there a lid at all,
why was the lid off, or did he/she open the lid? Again, a
training and labeling issue. Add KEEP COVERED AT ALL TIMES to the
labeling suggestion.
While soap, water and
scrubbing can get most glassware clean, nothing works quite as well and
easily as a base bath for routine work, particularly in inorganic and
organometallic labs where the residues can be very difficult to remove
from inaccessible interior surfaces. Base usually works better
than acid (for example, Nochromix) because base actually eats the
surface of the glass. Glass rinsed off after exiting a base bath
usually runs off in a clean film with no beading. And, for the
most part, base baths last a long time without any need for disposing of
them as waste as long as the users clean most of the major crud off the
glassware before soaking - at most they usually need an occasional
"topping up".
I have heard of folks using
aqueous KOH plus potassium phosphate which avoids the flammability
issue, but have never tried it myself and can't vouch for its
effectiveness. Another way of reducing the flammability risk is to
go to a higher-boiling alcohol or polyol, but then you run into health
and environmental issues, most likely.
Flame
drying glassware is still done on rare occasions for the most
highly-sensitive water-sensitive materials, mostly for small-scale
reactions performed on high vacuum systems. I can't comment on the
appropriateness of the method in this case with the information at hand,
of course.
Rob
Toreki
=======================================================
Safety Emporium - Lab & Safety Supplies featuring brand
names
On Jun 20, 2011, at 12:24 PM,
Demer, Frank R - (demer) wrote:
One of our labs had a base
bath fire over the weekend. A researcher forgot there was alcohol
in the bath and tried to extinguish a match, used to light a propane
torch, in the bath. Besides the obvious problem of using matches
instead of a striker and the questionable use of a propane torch to dry
glassware for a moisture sensitive reaction, can anyone recommend an
alternative to a base bath containing KOH solution, iso-propanol and
ethanol?
Frank R. Demer, MS, CIH, CSP
Health Safety
Officer
Industrial Hygiene and
Safety
University of Arizona
Department of Risk Management Services
Phone:
520.621.3585
Fax:
520.621.3706
Mailing Address: P.O. Box 210300, Tucson, AZ
85721-0300
Street Address: 220 W. 6th
St., Tucson, AZ 85701 (2nd floor, East Bldg.)
Web Address: risk.arizona.edu
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