From: NEAL LANGERMAN <neal**At_Symbol_Here**CHEMICAL-SAFETY.COM>
Subject: Re: [DCHAS-L] Acid Stills...
Date: Fri, 29 Mar 2019 16:54:24 -0700
Reply-To: neal**At_Symbol_Here**CHEMICAL-SAFETY.COM
Message-ID: 00af01d4e68a$c1be3350$453a99f0$**At_Symbol_Here**chemical-safety.com
In-Reply-To


Margaret:

Conceptually, an acid still is a semi-closed version of an
acid etching or passivating bath. The hazard identification
and associated risk management is very similar. Engineering
must be done to resist the acid, liquid or vapor. As Ralph
points out, the mists destroy metal duct work, so
engineering to ensure that all wetted surfaces are
polypropylene with leak-tight seams is critical. Mist
control is frequently done with a water quench of the
mist/air mixture. Engineering to prevent worker inhalation
and skin/eye exposure must be implemented. On dip tanks,
respirators are usually worn, but the semi-closed still and
placing it in a properly constructed hood should reduce that
route of exposure. All electrical systems must be sealed as
the acid mist will destroy copper quickly.

A robust equipment integrity/maintenance/inspection program
is a must.

Monitoring for exposure and occasional fugitive emissions is
essential.

Training and high level (ongoing) supervision of the workers
is necessary.

The electronics industry uses acid etch systems routinely;
they can be operated safely.

Get the MFGs information and customize their recommendations
to your needs. If you want to pursue this further, ping me
offline.

Neal


------------------------------------------------------------
------------------------
Safety is the practice of fixed and unbendable principles,
the first of which is to be flexible at all times.
Paraphrase of Everett Dirksen.
The information contained in this message is privileged and
confidential and protected from disclosure. If the reader of
this message is not the intended recipient, or an employee
or agent responsible for delivering this message to the
intended recipient, you are hereby notified that any
dissemination, distribution or copying of this communication
is strictly prohibited. If you have received this
communication in error, please notify us immediately by
replying to the message and deleting it from your computer.

ACSafety has a new address:
NEAL LANGERMAN, Ph.D.
ADVANCED CHEMICAL SAFETY, Inc.
PO Box 152329
SAN DIEGO CA 92195
011(619) 990-4908 (phone, 24/7)
www.chemical-safety.com

We no longer support FAX.

Please contact me before sending any packages or courier
delivery. The address for those items is:
5340 Caminito Cachorro
San Diego CA 92105


-----Original Message-----
From: ACS Division of Chemical Health and Safety
On Behalf Of Stuart, Ralph
Sent: Friday, March 29, 2019 2:33 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Acid Stills...

> >So these are sub-boiling stills...not sure what
temperature is used (yet) but obviously elevated to some
degree but below boiling. According to the mfg : " High
purity acid vapor is produced, while metallic impurities in
the acid feedstock remain in the liquid phase"...
>
I have had experience with reviewing the condition of
ventilation ductwork after several years of this type of
work has been conducted in two or three labs. The results
were not pretty, to say the least. My experience is that
this is not a standard lab design problem, either for the
lab workers, the building designers or the facility
operators.

I would strongly suggest that you and the faculty member
visit someone who is doing similar work to see what steps
are taken to protect the building from the chemistry and to
see how successful those steps have been. It's not a
situation where general repurposing of standard lab
equipment works well.

Good luck!

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859

ralph.stuart**At_Symbol_Here**keene.edu

---
For more information about the DCHAS-L e-mail list, contact
the Divisional membership chair at membership**At_Symbol_Here**dchas.org
Follow us on Twitter **At_Symbol_Here**acsdchas

---
For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org
Follow us on Twitter **At_Symbol_Here**acsdchas

Previous post   |  Top of Page   |   Next post



The content of this page reflects the personal opinion(s) of the author(s) only, not the American Chemical Society, ILPI, Safety Emporium, or any other party. Use of any information on this page is at the reader's own risk. Unauthorized reproduction of these materials is prohibited. Send questions/comments about the archive to secretary@dchas.org.
The maintenance and hosting of the DCHAS-L archive is provided through the generous support of Safety Emporium.