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Subject: Re: [DCHAS-L] Repurpose Perchloric Acid Hood
Date: Wednesday, February 10, 2021 at 1:37:22 PM
Author: Dr Bob <drbob**At_Symbol_Here**FLOWSCIENCES.COM> 		Next by Date:
Subject: [DCHAS-L] EPA Registers Copper Surfaces for Residual Use Against Coronavirus
Date: Wed, 10 Feb 2021 14:52:28 -0500
Author: CHAS membership chair

From: Gerald Solley <0000141b027de643-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] Repurpose Perchloric Acid Hood
Date: Wed, 10 Feb 2021 11:16:30 -0800
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID: B8B26E6F-0BD9-4D2B-96BC-1F39BE283288**At_Symbol_Here**aol.com
In-Reply-To


I imagine it should work.   PCA hoods have to be made of material that are resistant to oxidation, prevent explosion and have a rinse cycle. 

Most common materials should be okay to use.   I would check the manufacturers specifications to see what it's made of, then look up the incompatibility information of said material in the Handbook of Chemistry and Physics or similar 
reference. 

On Feb 10, 2021, at 10:02 AM, Harry J. Elston <harry**At_Symbol_Here**midwestchemsafety.com> wrote:

=EF=BB=BF
Stephen,

Just because you can do something, doesn't mean you should.  Perchloric acid hoods are typical stainless steel and nozzles for the washdown system are typically brass or bronze (though I've seen some plastic ones in newer systems).  Converting the hood to "general use" typically involves using hydrochloric acid, which will chew up the stainless steel and bronze/brass nozzles pretty quickly.  Hot acid vapors will also chew up any brass/bronze in the hood.   (Also know that hot acid vapors will chew up galvanized ductwork and metal fan blades too.)

If you can restrict the hood to non-acid use, you can get the ductwork cleaned out and use it.  

Standard warnings and cautions apply with respect to perchlorates in the hood when performing maintenance or conversion.

Harry

On Wed, Feb 10, 2021 at 11:02 AM Stephen Beaton <Steve.Beaton**At_Symbol_Here**dal.ca> wrote:

Hello all, 

 

Can a perchloric acid hood be repurposed as a standard fume hood for typical chemistry reactions? Are there any limitations?

 

There are some older perchloric acid hoods, but the wash down cycle is no longer functional (perchlorates have been addressed). There is no anticipated work with perchloric acid. The exhaust fan is still operational, and can draw an appropriate face velocity.

 

Thoughts?

Thank you.

 

Stephen Beaton, MSc, CHO, CRSP
Chemical Safety Manager

Environmental Health and Safety Office
902.494.1934 | steve.beaton**At_Symbol_Here**dal.ca
Dalhousie University

dal.ca/safety

 

 

--- 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


--
++++++
Harry J. Elston, Ph.D., CIH, PMP
Principal, Midwest Chemical Safety, LLC

--- 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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