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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi All,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">At Draper we have two Excimer lasers that use the F2 premix gas and both machines have the premix in a gas cabinet. Yes it cost more upfront but better to be
safe than sorry.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Rick<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Richard H. Morrison<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Principal Member of the Technical Staff<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Draper<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">555 Technology Square<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Cambridge, MA<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">02139-3573<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Work 617-258-3420<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Cell 508-930-3461<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><a href="http://www.draper.com"><span style="color:#0563C1">www.draper.com</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>Sandrine Martin<br>
<b>Sent:</b> Friday, March 03, 2017 2:29 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] Gas cabinet for F2 premix for excimer lasers?<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hello,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">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. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">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. <o:p></o:p></p>
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<p class="MsoNormal">Pure F2 is listed with a LC50 (rat, 1h) at 185ppm. <o:p></o:p></p>
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<p class="MsoNormal">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)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Since the mixture is not toxic and the F2 concentration is <1%, EH&S concludes that a gas cabinet is not required.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">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.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Has anybody gone through similar discussions? <o:p></o:p></p>
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<p class="MsoNormal">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?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks<o:p></o:p></p>
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<p class="MsoNormal">Sandrine<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Sandrine Martin, Ph.D.<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">University of Michigan <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">LNF Managing Director<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">1246D EECS, 1301 Beal Ave<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Ann Arbor, MI 48109<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Cell 734-277-2365<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Fax 734-647-1781<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif"><a href="http://www.lnf.umich.edu/" target="_blank"><span style="color:#1155CC">www.LNF.umich.edu</span></a> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">@LurieNanofab<o:p></o:p></span></p>
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