[labnetwork] Recommendations to reduce lab nitrogen usage

[Carsen Kline]

Hi Ben,

Here at Stanford we just moved to a nitrogen generator in July. We're now filling our 9000 gallon liquid tank every five weeks instead of every five days. So if you can convince the powers that be to pay for it (major savings in operating costs), and if your overhead dollars pay the electricity, it's the greatest thing ever. We've kept our tank in place to keep feeding our branch of purified process nitrogen, and it serves as automatic backup in case the generator shuts down.

Before the generator, we were looking for ways to automate nitrogen cuts to our vacuum pumps during idle times. I inherited a control panel from a fab surplus sale that uses a PLC and solenoid valves to reduce N2 flow after x minutes using a signal tied to the NEMO interlock. I can provide full details or even a partially built panel if you like.

We're using CDA for all of our gas cabinet headcase purges (we were able to justify it with our jurisdiction because there are sprinklers in the cabinets) and acid wet bench headcase purge.

You can also get away purging some of your vacuum pumps using CDA instead of N2. I refer you to a thread on the labnetwork archives:
https://mtl.mit.edu/pipermail/labnetwork/2013-September/001033.html

Or try a search like "Show me threads about using CDA in lieu of N2" on nanobot.chat to go deeper into the Labnetwork archives.

Happy to share more offline if you like.

All the best,

Carsen


Carsen Kline
Lab Operations Manager
Stanford Nanofabrication Facility
650-724-8214
snfexfab.stanford.edu
________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Schmidt, Benjamin Willis <ben.w.schmidt at Vanderbilt.Edu>
Sent: Thursday, September 18, 2025 10:05 AM
To: Labnetwork (labnetwork at mtl.mit.edu) <labnetwork at mtl.mit.edu>
Subject: [labnetwork] Recommendations to reduce lab nitrogen usage

Hello Labnetwork,
In our nanofab at Vanderbilt, we are looking at ways to reduce our nitrogen usage, and I wanted to ask for any recommendations, success stories, or failures that might help in our search.
For background, we use 5N “house” N2 for purging catastrophic scrubbers, point-of-use scrubbers, gas cabinets, VMBs, and some vacuum pumps 24/7.  Additionally, we have on-demand usage at wet chemical hoods and various tools, but the most significant users are the constant-purge items listed above.
Our N2 is supplied from a large tank next to our building that is periodically filled from a truck to provide 5N “house” nitrogen, and then we have a set of purifiers to give us 6N “process” nitrogen for specific tools.  This was part of an original design for flexibility with future lab growth.
We’re already trying to cut back on the on-demand needs and only turning hoods on and off as needed for example, but we don’t really have the same options for the gas delivery and abatement systems.
We’re also looking at ideas such as a hybrid approach like putting the scrubbers onto a nitrogen generator that may not need the same purity requirements, but this is a new area for us.
I can provide specific usage numbers privately if it helps, but we are a nominally 10,000 sqft facility (half under filtration, half service areas).
Thanks for any suggestions!
Ben



Ben W. Schmidt, Ph.D.

Cleanroom Manager
Vanderbilt Institute of Nanoscale Science and Engineering

Vanderbilt University, Nashville, TN

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