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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>In my experience, the major reason for changing HEPA or ULPA filters – unless there is an “incident” – is the failure of the seal between the T-bar ceiling grid and the filter housing. If you are using a gel-track system, this is generally a non-issue.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The only warning is that if you are using a closed cell (or worse, open cell) gasket material and it fails, you may not catch the failure with a particle counter. The particles given off and allowed through are often far bigger than a particle counter can detect. A bright-light inspection is the primary method for finding these large particles. You need to get on a ladder and inspect the top of the T-bar downstream of the seal. The other approach is to pull a filter module and inspect the gasket directly. Unless there is chemical usage in the area, the gaskets should “dry out” at about the same rate. Most neoprene seals (closed cell) should last more than 15 years; I’ve had some last more than 20.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>John<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>John R. Weaver<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>Facility Manager<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>Birck Nanotechnology Center<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>Purdue University<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>(765) 494-5494<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;color:#1F497D'>jrweaver@purdue.edu<o:p></o:p></span></i></b></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Flückiger Philippe<br><b>Sent:</b> Tuesday, September 25, 2012 4:22 AM<br><b>To:</b> Dennis Grimard; labnetwork@mtl.mit.edu<br><b>Subject:</b> Re: [labnetwork] HEPA Filters<o:p></o:p></span></p></div></div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Denis,<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Let me mention that EPFL is running with the original HEPA filters since 14 years (1998) and still reach the class 100 specifications.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>EPFL has no plan to change the HEPA filters. Only some pre-filters might be occasionally changed for example after construction work in the area.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Anyway, back to your question facilities would pay for this.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>With my very best regards,<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Philippe<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dr Philippe Flückiger<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Director of Operations<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://cmi.epfl.ch/">http://cmi.epfl.ch/</a><o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Phone +41 21 693 6695</span></i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><b><span lang=FR style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span lang=FR style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a> [<a href="mailto:labnetwork-bounces@mtl.mit.edu">mailto:labnetwork-bounces@mtl.mit.edu</a>] <b>De la part de</b> Dennis Grimard<br><b>Envoyé :</b> vendredi 21 septembre 2012 00:17<br><b>À :</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><b>Objet :</b> [labnetwork] HEPA Filters<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>All:<o:p></o:p></span></p><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>Do any of you have to pay for the replacement of your HEPA filters in your cleanrooms?<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>Thanks ...<br clear=all><o:p></o:p></span></p><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p></div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>-- <br>Dennis S Grimard, Ph.D<o:p></o:p></span></p><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>Managing Director, Lurie Nanofabrication Facility<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>University of Michigan<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>1246D EECS Building<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>1301 Beal Avenue<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>Ann Arbor, MI 48109-2122<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>(734) 368-7172 (Cell)<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH>(734) 647-1781 (Fax)<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><a href="http://www.lnf.umich.edu" target="_blank">http://www.lnf.umich.edu</a><o:p></o:p></span></p></div><p class=MsoNormal style='margin-left:.5in'><span lang=FR-CH><o:p> </o:p></span></p></div></div></body></html>