[labnetwork] gas cylinder tracking

Wed Feb 28 13:11:17 EST 2024

Hi Dennis,

Thanks for bringing up this topic.  We have struggled with this over the
years in part due to the way cylinders are managed through central
university systems and by our gas vendor.  The current system creates a lot
of inaccuracy, so we too would like to find a better solution.  Here are
our answers to your questions:

   1. What is the oldest gas cylinder you have installed in your facility?
   2. How do you track the cylinders being used by your facility?
   3. How do you handle gases with potential expiration dates, and what is
   the typical duration these gases are kept in use in your facility?  I'm
   particularly interested in the reactive HPM materials that have a
   tendency to volatilize with moisture.
   4. How many different suppliers are you getting your gas cylinders from?
   5. How many individuals in your facility change out gas cylinders?  Is
   that number the same for both inert and HPM materials?
   6. Are you using CGA or DISS cylinder connections on your HPM gases?
   7. How do you address the extremely low use gases that you have to have,
   but usage is borderline "maybe we should remove this gas capability".

Our Answers:

   1. Currently, the oldest cylinders are ~8yrs.  These cylinders are inert
   gas cylinders installed in low use applications.  I should also note that
   we do monitor hydrostatic testing dates.  As cylinders must be
   hydrostatically tested every 10yrs, those cylinders approaching the cutoff
   date will be swapped (the ones at ~8yrs old will be removed in the coming
   months for example).
   2. In the past, we have used basic logs, where inventory is kept in a
   master database and updated as cylinders are swapped in and out.  However,
   records are not always accurate and audits are required.
   3. In many cases, we run our cylinders past the listed expiration date.
   The date listed is typically a guarantee of quality and not safety
   related.  We have also consulted with our EHS group on this, as well as gas
   manufacturers, and in most cases, we do not see any degradation in
   processes that would warrant more frequent changes.  That said, we are more
   strict with HPMs, especially corrosives where attack or degradation of the
   cylinder may occur.  We swap those out every 3 years on average (assuming
   they have not been used up sooner).
   4. Our campus maintains a master agreement with one gas supplier, so the
   vast majority of cylinders come from one vendor.  However, we are allowed
   to order specialty gases from other suppliers, and at the moment, we
   utilize that approach for only 2 cylinders.
   5. Up to 5 individuals change out gas cylinders right now, but only 3
   people are involved in changing HPMs (in 2 person teams).  We also have a
   member of EHS on standby when changing silane.
   6. The vast majority of our panels are designed for DISS.  However, we
   do use CGA in some applications.  All HPMs are DISS.  Most electronic gases
   are DISS as well.  In other cases, we have used CGA to DISS adapters to get
   around long lead time issues for DISS cylinders on gases that are more
   frequently used (Ar or N2 for instance).
   7. Depending on the definition of "low use," we are fortunate enough to
   have only 1 or 2 of such gases if any.  In one case, we were able to find a
   lecture bottle solution.  In other cases, we will support the use of that
   gas assuming we can establish a chargeback rate sufficient enough to cover
   any waste gas (i.e. gas not used before bottle swap is required) and
   infrastructure needed to support that gas.  That said, we must also look at
   the tool in that application to ensure it is worth having in the fab from a
   budgetary standpoint.

Hope that helps.  I would also be interested in knowing what others are
doing, as we have long discussed improvements to tracking cylinders.

Best Regards,

Matt

On Fri, Feb 23, 2024 at 8:01 AM Dennis Schweiger <schweig at umich.edu> wrote:

> Good morning all,
>
> As I finish up our yearly gas cylinder audit, I'm thinking there has to be
> a better way to track all of the cylinders we have in the fab so that we
> can easily verify what is on site, and cross reference tha number against
> our demurrage charges.  I would be interested in your input on the
> following issues from your facility's operation;
>
>    1. What is the oldest gas cylinder you have installed in your facility?
>    2. How do you track the cylinders being used by your facility?
>    3. How do you handle gases with potential expiration dates, and what
>    is the typical duration these gases are kept in use in your facility?  I'm
>    particularly interested in the reactive HPM materials that have a
>    tendency to volatilize with moisture.
>    4. How many different suppliers are you getting your gas cylinders
>    from?
>    5. How many individuals in your facility change out gas cylinders?  Is
>    that number the same for both inert and HPM materials?
>    6. Are you using CGA or DISS cylinder connections on your HPM gases?
>    7. How do you address the extremely low use gases that you have to
>    have, but usage is borderline "maybe we should remove this gas capability".
>
> Here are the answers for our facility;
>
>    1. We have some inert cylinders (Nitrogen, Argon) that are over 4,200
>    days on site.
>    2. A couple of our former employees set us up with a scanning program
>    that allows us to use our cell phone to scan the cylinder bar code (or
>    manually enter the cylinder serial number) of each and every cylinder that
>    comes into our facility.  We have also assigned every cylinder position in
>    our facility a unique and identifiable location number that is scanned as
>    part of that tracking system.  When a cylinder moves within the facility,
>    its location is updated, as well as its status (received, full, returned).
>    There are still some issues with tracking (hence the yearly audit), and I'm
>    trying to get our cylinder vendors to provide more information on both
>    their packing lists, and their invoices for both the gas charges, and
>    cylinder rentals.
>    3. Our current goal is to "right size" the cylinder fills so that we
>    change out the HPM gas cylinders every 18 months.  This right sizing also
>    helps to reduce our exposure risk in the event we would have a
>    catastrophic failure.  We have not had one yet, but just in case.
>    4. We currently have three different vendors that provide gas
>    cylinders for our facility.  I'm trying to reduce that to two to keep the
>    demurrage invoicing easier to manage.
>    5. All of our staff have been trained to change out inert cylinders,
>    however of the 12-14 people, only about four do it more frequently than
>    once a year.  There are only two of us that change out the HPM gases.
>    6. All of our inert gases are CGA, and all of our HPM products (except
>    for H2, CH4, and C2H2) are using DISS cylinder connections.
>    7. Currently, we revisit all of these at least once a year, and
>    evaluate the capability/profitability of having that gas available.
>
> Thank you for taking the time to respond, and sharing your practices.
>
> Dennis Schweiger
> Facilities Manager
> University of Michigan/LNF
>
> 734.647.2055 Ofc
>
> "People can be divided into 3 groups - those that make things happen,
> those that watch things happen, and those that wonder what happened."
> Within which group do you belong?
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-- 

--
Matthew T. Moneck, Ph.D
Executive Director, Claire & John Bertucci Nanotechnology Laboratory
Electrical & Computer Engineering | Carnegie Mellon University
5000 Forbes Avenue, Pittsburgh, PA 15213-3890
Phone: 412-268-5430
ece.cmu.edu
nanofab.ece.cmu.edu
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