Silane, properties and hazards of
Stephanie Oberg
Our fab will be beginning the use of 100% silane in a couple of months. Our
Emergency Response Team would like some practical info about the hazards. I
have gleaned the following from various sources.
SILANE
Silicon tetrahydride SiH4
· Colorless gas
· Repulsive odor
· Mildly toxic, not a carcinogen (TWA 9600 ppm)
· Can burst into flame on contact with air, chlorine, or other oxidizers
· Extreme fire and explosion hazard
· Non-corrosive (OK with Viton, stainless steel, brass, etc.)
· Leaks may create silicon dioxide plugs which slow or stop the flow - do not
disturb the plug, instead make permanent repair
· Do not use Halon fire extinguisher (??? why - is Halon an oxidizer???)
My unanswered questions are:
* Should any fire be fought? If so, is this best left to the fire department?
* If a fire can be fought, what type extinguisher?
* Is there any size cylinder of 100% silane which, if ignited, results in a
fightable fire? Or should any fire of any size cylinder be permitted to burn
itself out?
* How does the odor threhold compare with the explosive/pyrophoric level
(which I believe is about 1%)?
* Generally, what precautions above and beyond ordinary toxic gas handling
(cabinets, sensors, automatic shutoffs) should be used?
Please reply to sob...@candescent.com. Thanks for your help
Alan "Uncle Al" Schwartz
Stephanie Oberg <sob...@svc.com> wrote:
>Our fab will be beginning the use of 100% silane in a couple of months. Our
>Emergency Response Team would like some practical info about the hazards.
[snip]
There is one more surprise. Si-H bonds are activated by common
hydrogenation catalysts like the platinum triads including nickel.
Hydrogen embrittlement over time in nickelous alloys might obtain, as
well as more serious oxidation kinetics in the presence of air.
Unsaturated elastomers with catalyst residues (including platinum-cure
silicones) might also be interesting, or at least change their physical
properties over time.
Plan though you will, the only way to do it is to do it. Allow for a
little contingency.
--
Alan "Uncle Al" Schwartz
Uncl...@ix.netcom.com ("zero" before @)
http://www.netprophet.co.nz/uncleal/ (best of + new)
http://www.ultra.net.au/~wisby/uncleal.htm (lots of + new)
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