Date: Mon, 19 Jul 2010 18:54:31 -0400
Reply-To: g.c.walton**At_Symbol_Here**
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: George Walton <g.c.walton**At_Symbol_Here**REACTIVES.COM>
Organization: Reactives Managment Corporation
Subject: Re: Perchloric Acid Fume Hood Decommissioning
In-Reply-To: <AANLkTikDb29VaYu64Dr7zcLwmDdWsai5z7mUqMvlITUl**At_Symbol_Here**>

Professional experience since 1981 includes responding to two perchloric acid hoods that underwent an exothermic event.  In both cases, the damage to instruments on the floor involved and the floors below were in the five figures.  We have used an ion specific electrode to detect perchloric acid / misc. perchlorates in old systems that measured in the per cent range – certainly enough to provide a highly oxidizing environment, especially when in contact with most organic solvents.  Another problem with old systems is the corrosion in the ducts and fan.  In one case, most of the remaining duct work was multiple layers of paint with traces of the original metal duct remaining.  In other words, even if there are “acceptable” levels of perchlorates, the ventilation system is simply too corroded to be of any use as a working fume hood.  Be careful of renovations – one auxiliary (make-up air) system was remodeled by connecting the make-up air duct to the ventilation system.  That certainly seems to comply with recycling concepts, but in a very bad way.  The lab personnel complained of noxious odors and poor air flow.  After several months of bitch complaining, the suspended tile ceiling was removed, allowing everyone to see the auxiliary duct connected to the exhaust duct.  The second renovation is always more expensive and more disruptive than the first one.  Money talks, but cheap does not equal acceptable.

George Walton

Reactives Management Corporation

Chesapeake, VA


From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of Wendy Campbell
Sent: Tuesday, July 13, 2010 11:53 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Perchloric Acid Fume Hood Decommissioning

Just FYI for those who are interested: at this point, the decommissioning and removal project for the perchloric acid hood has been halted due to budget concerns.  The hood will be left in place, and the department wants to use it as a regular fume hood. 

I'm still pushing to have it, at the very least, scoped and washed down thoroughly before they do so, and then have a very large sign permanently attached to the hood indicating it's new status as a "regular" fume hood. 

Thoughts, comments, concerns, experiences are welcome.


On Thu, Apr 15, 2010 at 11:38 AM, Wendy Campbell <wendycampbell**At_Symbol_Here** > wrote:

We are in the process of remodeling a building, which currently houses an old perchloric acid fume hood.  I'm still tracking down how old it is, but I'm fairly sure it's at least 30 years of age.  As part of the remodel, the perc hood is to be removed.  There are several issues here. 

Wendy Campbell, ASP
Occupational Health and Safety Officer
Environmental Health and Safety
Boise State University

1910 University Drive
Boise, Idaho 83725-1826
Office: (208) 426-3303
Fax:  (208) 426-3343

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