[labnetwork] Gas cabinet for F2 premix for excimer lasers?

[Sandrine Martin]

Hello,

There are a few individual labs here at the University of Michigan that
have excimer lasers and use F2 premix gases with 0.1 or 0.2% F2. So far,
these gases have been installed in gas cabinets. We are now involved in a
new installation and are getting some push back about the need for a gas
cabinet.

The argument is made using the Compressed Gas Assoc Pamphlet P-20 Standard
for Classification of Toxic Gas Mixtures (2009) that apparently states
that, if the LC50 value is over 5,000ppm, the gas mixture is not considered
toxic.
Pure F2 is listed with a LC50 (rat, 1h) at 185ppm.
At 0.2% F2, the calculated LC50 is then 92,500ppm, well above the 5,000ppm
threshold and the premix is no longer considered a toxic gas. (it also has
an NFPA rating of  "1" in health on the MSDS)

Since the mixture is not toxic and the F2 concentration is <1%, EH&S
concludes that a gas cabinet is not required.

However, considering that the F2 PEL is 0.1ppm and IDLH 25ppm, it still
seems that a gas cabinet would be the safest option and the best solution.

Has anybody gone through similar discussions?
If you have a lab with a fluorine premix gas, is it in a gas cabinet? If
not, what type of space is it in, and what kind of ventilation and gas
detection are in place?

Thanks
Sandrine


-- 

Sandrine Martin, Ph.D.

University of Michigan

LNF Managing Director

1246D EECS, 1301 Beal Ave

Ann Arbor, MI 48109

Cell 734-277-2365

Fax 734-647-1781

www.LNF.umich.edu <http://www.lnf.umich.edu/>

@LurieNanofab
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