[labnetwork] final filter on makeup air units

[Nibarger, John]

We have a new (< 2 years old) HDR designed ISO 5 cleanroom here in NIST
Boulder that has the following filter sequence in the make-up air unit
(MAU):
MERV 7 (30%)
MERV 13 (85%)
Carbon Filter
MERV 7 (35%)
Conditioning (preheat coil, humidifier, cooling coils, fans, reheat coil)
HEPA Filter

This air is pushed to a mechanical space with recirculation units for each
bay. Without the final HEPA's in the MAU the cleanroom ceiling HEPA's will
load up comparatively sooner. At least in our configuration it will be
much easier to replace the MAU HEPA's over the ceiling HEPA's.
Cheers,
John

John P. Nibarger, Ph.D.
Manager, Boulder Micro-Fabrication Facility
National Institute of Standards and Technology
325 Broadway, MS 817.03
Boulder, CO  80305
303-497-4575 (phone)
303-497-3042 (fax)
john.nibarger at nist.gov





On 6/4/13 7:25 AM, "Iulian Codreanu" <codreanu at udel.edu> wrote:

>Dear Colleagues,
>
>I am trying to convince some folks that having filters placed on the
>discharge side of a cleanroom makeup air unit (MAU) is not only a good
>idea but a must.    I only have a MERV 8 and a MERV 14 on the intake
>side and I am pushing for HEPA filtration on the discharge side; your
>input carries a lot of weight and I hope you can help.
>
>My cleanroom is "two stories tall"; the makeup air discharges into the
>mechanical space (it houses the recirculating air units that push the
>air into the bay plenum boxes) that is above the the bay and chase
>cleanroom (no raised floor, sidewall air return).
>
>Can you please share your MAU filter configuration; it would be helpful
>to list all the filters in the unit and where they are located.
>
>Thank you very much.
>
>Iulian
>
>-- 
>iulian Codreanu, Ph.D.
>Director of Operations, UD Nanofab
>149 Evans Hall
>Newark, DE 19716
>302-831-2784
>
>
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