[labnetwork] Silane quantity

[Dennis Schweiger]

A couple of items that no one has yet mentioned, or at least I haven't seen
them, are;

1) The installation of an RFO (Restrictive Flow Orifice) at the cylinder
connection.  This is just another level of protection/safety, that
minimizes the exposure risk in the event that there is a failure.
Especially in the higher cylinder pressure gases, like Silane, Arsine, and
Phosphine.  These can be either installed at your vendors facility (best
practice, but you have to be confident of the size), or can be installed at
the time of cylinder installation.

2) The use of DISS cylinder connections for all HPM gases, versus the use
of CGA.  The DISS, with it's gasket interface, is by far the best choice
for any HPM gas.

About two years ago we were visited/audited by DHS because of the
combination of gases we had on hand.  It wasn't the pure gases that put us
on the list, but the premixes for the HPM's, the Silane/Phosphine dopants
to be exact.  There were some additional things we had to do to become
"more compliant" (three levels of security on the cylinders, primary key
card access, chain of custody documentation, limiting the number of
individuals that can access cylinders, etc..), all of them were relatively
small changes in our "handling of HPM's, and some we already had in place.

DennisSchweiger
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?

On Wed, Jan 7, 2015 at 4:24 PM, Matthieu Nannini, Dr. <
matthieu.nannini at mcgill.ca> wrote:

>  Bob:
>
>  Fully agreed. Most large spectacular accidents that scare the hell of
> EHS dept. (at least mine) when they google « silane safety » are from large
> PV solar factories where bottle changes occur much more often that in our
> academic fabs. As such, danger there might be underestimated. So smaller
> quantities leading to more bottle changes might very well be less secure.
>
>
>  Matthieu
>
>
>  Le 2015-01-07 à 14:32, Bob Hamilton <roberthamilton at berkeley.edu> a
> écrit :
>
>  Fab Colleagues,
>
> I'll add, as a general policy about gas cylinder safety, given modern gas
> cabinets, toxic gas monitoring systems and orbitally-welded distribution
> the most likely time for a corrosive, pyrophoric or toxic gas incident to
> occur is during a cylinder change-out.
>
> My statement draws on presentations by Eugene Ngai who is often described
> as the "silane guru". Retired chemical eningeer Eugene Ngai has done an
> excellent job of documenting silane incidents and safety practices.
>
> Arguing for smaller quantities of dangerous gases is in many cases an
> argument for less safety.
>
> Bob Hamilton
>
> --
> Robert Hamilton
> University of California at Berkeley
> Marvell NanoLab
> Equipment Eng. Mgr.
> Room 520 Sutardja Dai Hall
> Berkeley, CA 94720-1754bob at eecs.berkeley.edu
> Phone: 510-809-8600
> Mobile: 510-325-7557 (Emergencies only poor cell phone service in lab)e-mail preferred
>
>
>
> On 1/7/2015 9:04 AM, Dennis Schweiger wrote:
>
> Matthie,
>
>  good morning.  Here at UofMichigan, we have two cylinders on-line, both
> are about 40 cubic feet.  We also have a single spare cylinder in storage.
> Our current cadence for change-out is about every 8 months.  It can vary
> +/- 2 months with usage.
>
>  Dennis Schweiger
> University of Michigan/LNF
>
> 734.647.2055 Ofc
>
> On Tue, Jan 6, 2015 at 4:30 PM, Matthieu Nannini, Dr. <
> matthieu.nannini at mcgill.ca> wrote:
>
>> Dear colleagues,
>>
>> first of all, happy new year to all of you ! May the force be with you
>> all !
>>
>> My EHS dept. would like to compare quantity of silane on site in
>> different labs. So, if you can spare 30s to answer those 2 questions then
>> you can go chasing the student that left the evaporator at atmosphere
>> during christmas:
>> - how much silane do you use yearly ?
>> - what is the cylinder volume you have ?
>>
>> cheers
>>
>> Matthieu
>> McGill Nanotools
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>
>
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