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--- 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**acsdchasNatalie:
That unit is about what I expected. Over the years, the last rinse tank, cool or warm, rarely if ever, has metalwork ions in it. On occasion, we have found pH changes, usually associated with very odd-shaped pieces. The most common justification for having the last tank exhausted is "operator comfort"; that is, avoiding breathing the high-humidity air in the immediate vicinity of the tank. As the installations I have worked with were all on large, open manufacturing floors, we never considered humidity control as a factor, but Peter does have a point to consider if installed in a small room, such as a lab.
While personal exposure monitoring is needed, the easiest method to monitor potential for exposure is tank water analysis. This can be used to guide rinse water change frequency. It is essential for quality control. Monitoring the combined point of discharge to the local disposal system is often also needed to ensure compliance with local and federal discharge regulations.
I hope this helps. Continue to post interesting questions for both answers and to stimulate CHAS members.
Neal
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Stay healthy and prosper
NEAL LANGERMAN, Ph.D.
ADVANCED CHEMICAL SAFETY, Inc. (Retired)
5340 Caminito Cachorro
SAN DIEGO CA 92105
+1 (619) 990-4908
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Natalie Merrill
Sent: Monday, April 4, 2022 8:45 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Electro polish "hot rinse" ventilation Q
Hi, Neal, and colleagues, here is the requested link:
Monona, the unit is passivating stainless steels, and does have air bubbling through it.
On Mon, Apr 4, 2022 at 10:46 AM <neal**At_Symbol_Here**chemical-safety.com> wrote:
Please provide a link to information on the unit. Every electropolishing installation I worked with has ventilation on all baths. Monitoring picked up acid mists at all baths, though those past initial drag-out were highly intermittent.
NL
------------------------------------------------------------------------------------
Stay healthy and prosper
NEAL LANGERMAN, Ph.D.
ADVANCED CHEMICAL SAFETY, Inc. (Retired)
+1 (619) 990-4908
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Natalie Merrill
Sent: Monday, April 4, 2022 4:35 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] Electro polish "hot rinse" ventilation Q
Hello Colleagues,
For an electro polish system which comes equipped with good ventilation at the phosphoric acid/sulfuric acid bath, there are three more water baths in succession with the final one being warmed to 115F with deionized water. Because we have an installation of an additional ventilation trunk dedicated to the fourth (warm water) bath, which the manufacturer does not require (and isn't shown in the equipment design) I wondered what that ventilation over the water bath might be needed for?
Q: In the electro polish of stainless steels, would there be any expected evolution at the warm water rinse step? The first rinse is cool water "drag out", then a water "pre-rinse", then the final warm rinse. (This system does come complete with in-room water treatment and a large neutralization system, that is not what I'm asking about). The water supplied to the baths is filtered and deionized.
Natalie Merrill
ACS PSS
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Natalie Merrill, ACS PSS Chair
namerrill**At_Symbol_Here**gmail.com--- 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
--
Natalie Merrill, ACS PSS Chair
namerrill**At_Symbol_Here**gmail.com--- 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
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