[labnetwork] Combined or separate exhaust?

[Iulian Codreanu]

Hi Travis,

In the two cleanrooms I helped build I had a number of exhaust systems:
-Two for the cleanroom itself
-One for the gas room
-One for the gas bunker.

Each exhaust system has at least two fans for capacity and n+1 redundancy.

Folks use different names for the two exhaust systems typically used for 
the tools and hoods in cleanroom but a simple way to look at it is by 
focusing on the fume hoods:
-One is for corrosives; typically teflon-coated SS but I have plastic 
too (not my favorite)
-One is for solvents; typically SS but I have seen galvanized steel too 
(not my favorite)

When hooking up tools to the exhaust system you decide based on what 
kind of gases those tools will process; e.g. an evaporator ties to the 
solvent exhaust and a PECVD to the corrosive exhaust.

You have to keep in mind your local  codes and the input of the 
authority having jurisdiction. EHS may be a good resource to support 
your efforts to perhaps go above the minimum requirements; when 
designing/building those labs my mindset was that I was going to live 
with them until I retired. We all know that it's easier/cheaper to put 
things in place when you build new rather than adding them later.

Good luck!


iulian Codreanu, Ph.D.
Director, Nanofabrication Facility
University of Delaware
Harker ISE Lab, Room 163
221 Academy Street
Newark, DE 19716
302-831-2784
https://udnf.udel.edu

On 2/24/2025 9:23 PM, Massey, Travis wrote:
>
> Hi all,
>
> LLNL is planning a significant cleanroom expansion, and the question 
> arose whether we /need/ separate exhaust for hoods and tools/gases, or 
> if they can be combined into a single shared exhaust.  Or do you have 
> a single exhaust with 2+ exhaust fans pulling simultaneously, so 
> there’s always /some /exhaust air moving if one fan is down?  The 
> conventional wisdom around here has its share of holes, so I’m out to 
> learn from the broader nanofab cleanroom community.  How are your 
> cleanrooms’ exhaust systems are configured, especially if you’ve had 
> to go down this cleanroom design rabbit hole?
>
> I’m also broadly open /any/ other lessons learned regarding 
> provisioning exhaust or other utilities – whatever you feel like 
> sharing.  Too much information during the design phase is far better 
> than too little.
>
>
> Thanks,
>
> Travis Massey
>
> Center for Micro and Nano Technology (CMNT)
>
> Lawrence Livermore National Laboratory (LLNL)
>
>
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