<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Microsoft PhagsPa";
panose-1:2 11 5 2 4 2 4 2 2 3;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.EmailStyle23
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal">Depending on your air handler design, you may be able to track HEPA life by monitoring amperage draw from the VFD’s if you have it set at a closed loop ACPH setup. All acronyms aside, if you require something like 200 air changes per hour,
you could baseline the air handler fan current and check it periodically.<o:p></o:p></p>
<p class="MsoNormal">Some older clean rooms simply use the fan speed determined at the design phase, and let the HEPA’s do their thing. This simple setup is easy to baseline and monitor as well. Our facility has a closed loop Variable frequency drive system
coupled with particle counters in every chase to allow the room’s particle count to dictate how much air is pushed through the filters. Our system would be difficult to monitor if we didn’t have speed vs. amperage data since the speeds are constantly changing
depending on the activity in the clean room.<o:p></o:p></p>
<p class="MsoNormal">Makeup air amounts are not part of this equation since the makeup air is mixed with the circulated air and gets filtered with it. The amperage draw will tell if the filters are starting to load up. Most fabs have a HEPA life of decades
is the pre-filters are changed often and the system is sealed as Deon Collins has mentioned.<o:p></o:p></p>
<p class="MsoNormal">Equipment Dood<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><span style="font-size:14.0pt">Steve Paolini<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Principal Equipment Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Harvard University Center for Nanoscale Systems<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">11 Oxford St.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">Cambridge, MA 02138<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">617- 496- 9816<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">spaolini@cns.fas.harvard.edu<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">www.cns.fas.harvard.edu</span><span style="font-size:14.0pt"><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> <b>
On Behalf Of </b>Collins, Deon<br>
<b>Sent:</b> Wednesday, February 16, 2022 2:45 PM<br>
<b>To:</b> Reger, Ronald K <rreger@purdue.edu>; labnetwork@mtl.mit.edu<br>
<b>Subject:</b> Re: [labnetwork] HEPA/ULPA Filter Experience?<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Deon Collins from Holonyak lab University of Illinois<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Our facility has replaced HEPA filters lab independent as well as the entire cleanroom once. Our HEPA’s filter are molded into the supply side(ceiling) with no temporary seals. The filters are bolted into the ceiling as well as caulked
into the structure itself, so replacement is labor intensive. <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Do you have any particle count trends to go by? Do you have any Magnehelic trends to go by? If you are seeing a high delta between the two in conjunction with high particle counts it is time.
<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">If your maintenance group has done a good job of maintaining the pre filters HEPA filters will see prolonged life. If the pre filters have been ignored the HEPA filters will suffer.
<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">As mentioned below your ductwork integrity has a profound effect on your system. You could see an individual lab with excellent results while the lab adjacent is suspect.
<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<div>
<p class="MsoNormal"><b><span style="color:#002060;text-transform:uppercase">Deon D. Collins</span></b><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#002060"><br>
<i>FACILITY MANAGER</i><br>
Holonyak Lab</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#002060">University of Illinois at Urbana-Champaign</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">208 N Wright St Rm. 248 | 2250</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">Urbana, IL 61801</span><span style="color:#1F497D"><br>
</span><span style="color:#13294B">217-300-7531 | </span><a href="mailto:deonc69@illinois.edu"><span style="color:#0563C1">deonc69@illinois.edu</span></a><span style="color:#1F497D"><br>
<br>
<br>
</span><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__illinois.edu_&d=DwMFAg&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=-RHm3HKnxd6ImetSeUzpIQlNl_jbT3aGspPMKfITwjmnVh-Yrkb0gSpgGcFkv_pn&s=_NhNKAtnOJx23DzwGAr8LXXbG6r9uuTMvXNak2vgrIk&e="><span style="color:#1F497D;text-decoration:none"><img border="0" width="119" height="21" style="width:1.2395in;height:.2187in" id="Picture_x0020_1" src="cid:image001.png@01D82352.AF3053A0" alt="https://webtools.illinois.edu/webservices/js/ds/signature_logo.png"></span></a><span style="color:#1F497D"><br>
<br>
</span><i><span style="color:#666666">Under the Illinois Freedom of Information Act any written communication to or from university employees regarding university business is a public record and may be subject to public disclosure.
</span></i><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;color:#A3238B">Life is not about watching other people live it. It’s about you living your own!</span></b><o:p></o:p></p>
</div>
<p class="MsoNormal"> <o:p></o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> labnetwork <<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>>
<b>On Behalf Of </b>Reger, Ronald K<br>
<b>Sent:</b> Tuesday, January 25, 2022 2:30 PM<br>
<b>To:</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> [labnetwork] HEPA/ULPA Filter Experience?<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"> <o:p></o:p></p>
<div>
<p class="MsoNormal">Dear Colleagues,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">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. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">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?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">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.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Thanks very much for your information.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Ron <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><b><span style="font-size:14.0pt;font-family:"Microsoft PhagsPa",sans-serif;color:#1F497D">Ron Reger</span></b><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><i><span style="font-size:10.0pt;color:#1F497D">Engineering Manager</span></i><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:9.0pt;color:#1F497D">Birck Nanotechnology Center | Room 2289 |</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><b><span style="font-size:9.0pt;color:#1F497D">Office:</span></b><span style="font-size:9.0pt;color:#1F497D">
</span><span style="font-size:9.0pt;color:#0070C0">765.494.6667 </span><span style="font-size:9.0pt;color:#1F497D">|
<b>Email:</b> </span><a href="mailto:rreger@purdue.edu"><span style="font-size:9.0pt;color:#0070C0">rreger@purdue.edu</span></a><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">Wiki: </span><a href="https://urldefense.com/v3/__https:/wiki.itap.purdue.edu/display/BNCWiki__;!!DZ3fjg!tb4iR8LU2kJlfRYxlQU2GDoyqa8qNXp4qL2wUDjm03kOYCsscAsB6w3yW8Gyi-BBzBY$"><span style="color:#0070C0">https://wiki.itap.purdue.edu/display/BNCWiki</span></a><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#1F497D">iLabs: </span><a href="https://urldefense.com/v3/__https:/purdue.ilabsolutions.com/homepage/__;!!DZ3fjg!tb4iR8LU2kJlfRYxlQU2GDoyqa8qNXp4qL2wUDjm03kOYCsscAsB6w3yW8Gypg92QoA$"><span style="color:#0563C1">https://purdue.ilabsolutions.com/homepage/</span></a><b><span style="font-size:12.0pt;color:#1F497D">
</span></b><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
</div>
</body>
</html>