[labnetwork] Wet Process Station Exhaust Requirements

[Nicholas Menounos]

For wet benches (sashless) at MIT.nano we designed around 100 FPM capture velocity from a vertical plane of the face shield with an “unoccupied mode” which ramps down to 80 FPM (all heaters off, all covers on, lights off, no process running).

The ASHRAE 110 ejector was placed 6” behind that plane. Our specification called for lip exhaust (which we have), but with no performance criteria or as-installed testing.

Bad sketch below:

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Nick Menounos, PE
MIT.nano - Associate Director of Infrastructure
Cell: (508) 932-0938<tel:+15089320938>

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Hope Fa-Kaji
Sent: Tuesday, July 7, 2026 1:08 AM
To: Network Fab <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Wet Process Station Exhaust Requirements

Apologies for the typo--below should read FPM not CFM.

On Mon, Jul 6, 2026 at 10:44 AM Hope Fa-Kaji <hfakaji at lbl.gov<mailto:hfakaji at lbl.gov>> wrote:
Hello all,

What standards are your facilities are using for wet bench exhaust and where on the bench are your exhaust measurements are taken? We are particularly interested in the case of wet stations without a sash located inside cleanrooms with vertical air flow.

The consensus from the 2012 thread discussing this topic<https://mtl.mit.edu/pipermail/labnetwork/2012-April/000426.html> was a minimum face velocity of 80-100 CFM (following ANSI Z9.5 or similar requirements for fume hoods).

Is anyone using a different minimum velocity? Alternatively, is anyone measuring the capture velocity around the deck openings (i.e. above the baths) instead of the front plane of the bench?

I found an old Intel supplier document advising both of these modifications but am curious if anyone has them in practice.

[cid:image001.png at 01DD0DF7.D66E9F00]

Thank you!
--
All the best,

Hope Fa-Kaji
Semiconductor Equipment Engineer
MicroSystems Laboratory
[https://ci3.googleusercontent.com/mail-sig/AIorK4yBx1QCkq_DPrtgR5B_lqZ1t-Y52u9Nq4qfhFi5qkDXBdbcb8OmcM5Is87_HYBHrwehwut24-Put5a8]
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