[labnetwork] HEPA/ULPA Filter Experience?

[Dennis Schweiger]

Ron,

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.

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.

I'd be happy to discuss this more with you.  Feel free to give me a call,
or shoot me an email.

Dennis Schweiger
Facilities Supervisor
University of Michigan/LNF

734.647.2055 Ofc

"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?


On Tue, Jan 25, 2022 at 7:59 PM Reger, Ronald K <rreger at purdue.edu> wrote:

> Dear Colleagues,
>
> 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.
>
> 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?
>
> 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.
>
> Thanks very much for your information.
>
>
> Ron
>
> *Ron Reger*
> *Engineering Manager*
> Birck Nanotechnology Center | Room 2289 |
> *Office:*  765.494.6667 | *Email:* *rreger at purdue.edu* <rreger at purdue.edu>
> Wiki:  *https://wiki.itap.purdue.edu/display/BNCWiki*
> <https://wiki.itap.purdue.edu/display/BNCWiki>
> iLabs:  *https://purdue.ilabsolutions.com/homepage/*
> <https://purdue.ilabsolutions.com/homepage/>
>
>
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