[labnetwork] Corrosive exhaust material of construction

[Abbie Gregg]

Thanks for the lead in Julia, 
A few comments. The Teflon lined stainless steel which is flanged/gasketed/bolted or welded is especially important if you are combining potential effluents containing pyrophorics or hydrogen (eg CVD or LPCVD exhaust/purge) in the same duct as the wet hood (acid or base) effluent, because you have the risk of explosion, fire and corrosion in the same exhaust stream. 
Also we have been able to modify the Teflon lined stainless in the field at many jobs, it just takes special skills and a kit from PSP to do a tap in the field for modifications. This material is a long lead item and also quite expensive,  but it has been much safer than any other material. FM prefers it because it is "factory made" rather than wrapped or coated in the field. 
We did use Plasite coated heavy gauge galvanized ductwork in the same application at a couple of Northern CA projects but this was not preferred because the plasite is coated at the fabrication shop and there can be voids, think areas or other quality control problems that are hard to find. It is also heavier. 
If there is no risk of overheating, fire, or explosion and only corrosion resistance needed, the Fiberglass reinforced plastic "field fabricated" duct is good if made by talented fabricators, although any Fire in the facility will also destroy it,  and it makes really awful destructive and corrosive smoke when it burns. PVC has  similar characteristics, and neither of these materials meet the 25/50 flame and smoke spread requirements of some H-5 codes. (depending on IBC year, I believe).  
Best regards, 

Abbie Gregg
President
Abbie Gregg, Inc.
1130 East University Drive, Suite 105
Tempe, Arizona 85281
Phone 480 446-8000 x 107
Cell 480-577-5083
FAX 480-446-8001
email agregg at abbiegregg.com
website www.abbiegregg.com

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-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Aebersold,Julia W.
Sent: Thursday, December 19, 2013 3:57 PM
To: Iulian Codreanu; Fab Network
Subject: Re: [labnetwork] Corrosive exhaust material of construction

Teflon lined stainless steel was designed and implemented for our acid exhaust system.  Our cleanroom has been in place since 2006 and was designed by Abbie Gregg.  She would be a great source for this type of information.

Cheers!

Julia Aebersold, Ph.D. 
MNTC Cleanroom Manager
Shumaker Research Building, Room 233
2210 South Brook Street
University of Louisville
Louisville, KY  40292

502-852-1572
http://louisville.edu/micronano/

-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Iulian Codreanu
Sent: Thursday, December 19, 2013 1:52 PM
To: Fab Network
Subject: [labnetwork] Corrosive exhaust material of construction

Dear Lab Network,

I, once again, seek your wisdom.  Could you please share with me the type of material used for your corrosive exhaust system, how long you had it in operation, if you had any problems with it, and what you would do differently of you were in a position to do so?

Thank you very much for your help.

Iulian

--
iulian Codreanu, Ph.D.
Director of Operations, UD NanoFab
University of Delaware
149 Evans Hall
Newark, DE 19716
302-831-2784


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