[labnetwork] [EXTERNAL] MAU Steam Coil

[Morrison, Richard H., Jr]

HI Everyone,

We have replaced our coil 2 times in 12 years, the last one had the cleanroom down for 2 days, we did it over a weekend to minimize the work. We purchased the new coil ourselves and hired a mechanical contractor to install, our was on the roof so it need to be craned up and the old one craned out. The issue we have is with vibration so we used a flexible coupling to dampen the vibration this time, we also upgraded the steam generator and replace the humidifier in the duct work all at the same time.

Since 2012 install the weather has become very cold and dry in the winter time in Cambridge and we could not keep the RH in spec, so we increased the steam generator output from 6" to 8" and used a larger dispersion coil in the duct work and now we meet spec on the coldest/driest day. Because the summers are hotter and more humid we just increased the chilled water by adding a pump. So over 12 years we had to upgrade the chilled water and stream generator to maintain RH during the winter and summer.

Beware to those building new cleanrooms the old rules of thumb for RH control do not always work due to climate change.

Rick


Richard Morrison
DMTS
Draper Laboratory
555 Technology Square
Cambridge Ma  02139
Office: 617-258-3420
Cell: 508-930-3461



-----Original Message-----
From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Mark Weiler
Sent: Wednesday, January 4, 2023 1:30 PM
To: labnetwork at mtl.mit.edu
Subject: [EXTERNAL] [labnetwork] MAU Steam Coil

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Hello Everyone…

I am writing to ask whether any of you have ever had to replace a steam coil of the Make-up Air Units (MAU’s) of your cleanrooms, and what you, your facilities team, or the product vendor did to solve the problem.  Are there any cost-effective solutions with minimal downtime?  We have completed three repairs of our coil since starting here in 2016…(replacing likely requires a Cleanroom shutdown and the construction of a bypass), and currently have another leak.

I’m really interested to know if this has happened anywhere else… are we an outlier?

Best regards,

Mark



Mark Weiler
Manager, Equipment & Facilities
Bertucci Nanotechnology Laboratory
Eden Hall Nanofabrication Cleanroom
Carnegie Mellon University
P:      412-268-2471
F:      412-268-3497
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