<div dir="ltr"><div class="gmail_default" style="font-family:arial,sans-serif">Ron,</div><div class="gmail_default" style="font-family:arial,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,sans-serif">Good morning. Here at the University of Michigan/LNF we just replaced our HEPA filters in May of 2017. This was the second replacement for the cleanroom that was built in 1986. The first set of filters got changed out back in 1996/1997, so roughly 10 years. The second set we let go a little longer as they fell off of everyone's radar, and we ended up at about 20 years of life. We were starting to see a lot of contamination on the back sides of the HEPA filters whenever we had to remove one to change a ballast for the T-8 lamps. When we did the replacement in 2017, we completely relamped the 1986 portion of the cleanroom to LED, and even added some lighting in the bays where it had always been a little on the dark side.</div><div class="gmail_default" style="font-family:arial,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,sans-serif">My guess is, depending on what you have for ductwork ahead of your HEPAs (is the insulation on the inside or outside of the ductwork), will be a big determinant in what you can expect for the lifetime of your HEPAs. For some reason, back in 1986, it was "good design practice" to put the insulation on the inside of the ductwork, now 40 years later, we're seeing increased degradation of that insulation material, and it's filling up our new Hepas. There's a project on our books to replace all of that ductwork, and CRAC fans, but it has a $5 million dollar price tag.... in addition to the impact of closing portions of the lab.</div><div class="gmail_default" style="font-family:arial,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,sans-serif">I'd be happy to discuss this more with you. Feel free to give me a call, or shoot me an email.</div><div class="gmail_default" style="font-family:arial,sans-serif"><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div>Dennis<span class="gmail_default" style="font-family:arial,sans-serif"> Schweiger</span></div><div><span class="gmail_default" style="font-family:arial,sans-serif">Facilities Supervisor</span></div><div><span class="gmail_default" style="font-family:arial,sans-serif">University of Michigan/LNF</span></div><div> </div><div>734.647.2055 Ofc</div><div> </div><div>"People can be divided into 3 groups - those that make things happen, those that watch things happen, and those that wonder what happened." Within which group do you belong?</div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jan 25, 2022 at 7:59 PM Reger, Ronald K <<a href="mailto:rreger@purdue.edu">rreger@purdue.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div>Dear Colleagues,</div>
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<div>The cleanroom here at the Purdue Birck Nanotechnology Center is in its 17th year, and we're starting to see increased frequency on some typical and expected maintenance items. And while we haven't had any catastrophic failures yet in our HEPA & UPLA filters
we are wondering when they may need some serious attention/replacement. All along we've had to replace an occasional filter panel due to some deterioration of a seal or maybe an inadvertent puncture, but we haven't had any wholesale replacement of complete
banks or bays yet. </div>
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<div>We're wondering what other nanofabs have experienced in terms of HEPA/ULPA filter replacements? Is there a target date (~ 20 years, 25 years?) at which filters fail and entire bays are replaced? Are seals degrading at a certain time as shown with increasing
particle counts? Have different nanofabs experienced vastly different durations for the quality of filtration?</div>
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<div>Any insight into filter degradation & replacement experience would be greatly appreciated as we plan for the next few years of maintenance items in our fab.</div>
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<div>Thanks very much for your information.</div>
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<div>Ron </div>
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<div><font face="Microsoft PhagsPa" size="4" color="#1F497D"><span style="font-size:14pt"><b>Ron Reger</b></span></font></div>
<div><font size="2" color="#1F497D"><span style="font-size:10pt"><i>Engineering Manager</i></span></font></div>
<div><font size="2" color="#1F497D"><span style="font-size:9pt">Birck Nanotechnology Center | Room 2289 |</span></font></div>
<div><font size="2" color="#1F497D"><span style="font-size:9pt"><b>Office:</b><font face="Calibri"> </font> <font color="#0070C0">765.494.6667 </font>| <b>Email:</b> <a href="mailto:rreger@purdue.edu" target="_blank"><font color="#0070C0"><u>rreger@purdue.edu</u></font></a></span></font></div>
<div><font color="#1F497D">Wiki: <a href="https://wiki.itap.purdue.edu/display/BNCWiki" target="_blank"><font color="#0070C0"><u>https://wiki.itap.purdue.edu/display/BNCWiki</u></font></a></font></div>
<div><font color="#1F497D">iLabs: <a href="https://purdue.ilabsolutions.com/homepage/" target="_blank"><font color="#0563C1"><u>https://purdue.ilabsolutions.com/homepage/</u></font></a><font size="3"><span style="font-size:12pt"><b> </b></span></font></font></div>
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