[labnetwork] HEPA/ULPA Filter Experience?

[Mary Tang]

Hi all -

Cleanroom filters dating from the original build in 1986 at SNF were 
replaced in 2012.  There were two unanticipated benefits. First, the 
sound levels dropped -- a lot of people wondered if the laminar flow was 
really on. It certainly made for a more pleasant work environment.  
Second, the electrical use in the building dropped.  It's hard to tell 
exactly what was attributable to the HEPA changeout because we also 
reduced some flow rates as well, but initial estimates were around 12% 
total reduction in electrical energy use versus before the project.

So, there may be additional reasons for replacing HEPA filters, 
including the possibility that energy conservation programs may help 
with project costs.

Mary


-- 

Mary X. Tang, Ph.D.
Managing Director
Stanford Nanofabrication Facility
Paul G. Allen Building
420 Via Palou Mall
Stanford, CA 94305
https://snf.stanford.edu
mtang at stanford.edu

On 2/16/2022 11:44 AM, Collins, Deon wrote:
>
> Deon Collins from Holonyak lab University of Illinois
>
> 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.
>
> 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.
>
> 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.
>
> 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.
>
> *Deon D. Collins*
>
>
> /FACILITY MANAGER/
> Holonyak Lab
>
> University of Illinois at Urbana-Champaign
> 208 N Wright St Rm. 248 | 2250
> Urbana, IL 61801
> 217-300-7531 | deonc69 at illinois.edu <mailto:deonc69 at illinois.edu>
>
>
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>
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> *On Behalf Of 
> *Reger, Ronald K
> *Sent:* Tuesday, January 25, 2022 2:30 PM
> *To:* labnetwork at mtl.mit.edu
> *Subject:* [labnetwork] HEPA/ULPA Filter Experience?
>
> 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 
> <mailto:rreger at purdue.edu>
>
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