From: Don Abramowitz <dabramow**At_Symbol_Here**BRYNMAWR.EDU>
Subject: Re: [DCHAS-L] Overspray from screen print cleaning
Date: January 27, 2012 11:33:33 PM EST
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: <FAA5E76A77B37C43BB4A038C8A1D6B652D7AC07F**At_Symbol_Here**>

Assuming the overspray is simply a nuisance and local exhaust is truly unnecessary, perhaps you could place particulate filters over the return air intakes.  This could be as crude as taping air handler, furnace, or paint booth overspray filters over the openings, or having metal filter holders installed over the intake to make filter changes easy.  Could even add magnehelic guages to monitor the differential pressure to know when it's time to change the filters.   This should keep the material out of the system, as long as there are no volatiles involved that would be a concern if they passed through or  evaporated off the filters and were drawn into the system.


Donald Abramowitz, CIH
Environmental Health & Safety Officer
Bryn Mawr College
Bryn Mawr, PA

Please excuse the cross-postings - I need to cast a wide net.


Our Design department has moved into new digs in a renovated older building (early 1960's vintage).  It has a return air system with openable windows.


In the screen printing shop, they treat the screens with an emulsion and various inks to form the image.  After they develop the image and use the screen, the dried ink and emulsion need to be removed from the screen.  They use a stripper and power washer to clean the screens.  The cleaning process occurs in the shop in a large, stainless steel sink, installed against one wall in the shop.  The sink is fitted with a solids trap.  All of the emulsions, inks and strippers are water-based, don't have any hazardous materials in them and are allowed to go down the drain.


But the cleaning process puts water spray and particulate into the air - in a return air building - and my shop manager is concerned about occupant exposure and contamination of the supply air from the overspray.  Adding exhaust ventilation isn't possible, for a variety of reasons.  Cleaning the screens outside isn't possible either, as there are strict storm drain rules in California.  There haven't been any complaints yet but they just moved into the space last quarter.


Any ideas?  I'm fresh out.






Debbie M. Decker, Campus Chemical Safety Officer
Environmental Health and Safety
University of California, Davis
1 Shields Ave.
Davis, CA  95616
(530)754-7964/(530)681-1799 (cell)

(530)752-4527 (FAX)
Co-Conspirator to Make the World A
Better Place -- Visit and join the conspiracy



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