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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I agree with Dennis’ logic. A gas cabinet or exhausted enclosure is the preferred installation. However, installing the gas cylinder in, say 10’x10’x10’ room could work if we treat the room as an exhausted enclosure with proper safeguards. This includes proper exhaust and make up air distribution to minimize dead zones within the room. <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'>Perhaps the cylinder could be installed in 4’Wx3’Lx8’H closet which is closer to a gas cabinet size. Keep in mind that such a closet will have to be designed and built with similar features as a gas cabinet. This includes automatic door closure; air intake louvers at the bottom of the door; proper exhaust flow rate to ensure less than 1/2PEL in the event of a leak since for personnel protection; gas monitoring sensor; and interlocking the access door with the gas monitoring system. The cost of building such a closet will far exceed the cost of a gas cabinet or exhausted enclosure.<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'>Regards<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'>Rizik Michael, PE<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Principal<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Integrated Engineering Services<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Office: 1-408 261 3500, Ext. 201<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Cell: 1-408 718 0927<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><a name="_MailEndCompose"><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></a></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On Behalf Of </b>Dennis Grimard<br><b>Sent:</b> Saturday, March 4, 2017 8:12 AM<br><b>To:</b> Noah Clay<br><b>Cc:</b> labnetwork@mtl.mit.edu<br><b>Subject:</b> Re: [labnetwork] Gas cabinet for F2 premix for excimer lasers?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>I could not agree more with Noah.<o:p></o:p></p></div><div id=AppleMailSignature><p class=MsoNormal><o:p> </o:p></p></div><div id=AppleMailSignature><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>My take on this:<o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>1. Let’s say you have the bottle in a smallish room … say 10x10x10 or 1,000 CF.</span><o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>2. Let’s say you leak 1 CF … that is a dilution of 1,000X</span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>3. 0.2 % F2 in whatever is 2,000 PPM …</span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>4. Assuming perfect and uniform dissipation throughout the room … the room concentration would be 2 ppm.</span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>5. That is 20X the PEL which is a legally enforceable exposure limit … independent of a non-binding CGA recommendation.</span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'> </span><o:p></o:p></p><p class=MsoListParagraph style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span style='color:black'>6. At 2 ppm you would be right at the odor threshold … so you would have a poor warning property to the leak</span><o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:black'>Of course my logic could be wrong, my math could be wrong and the amount of the leak could be less … or more … you should verify for yourself.</span><o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:black'>Finally, if you did have a leak and the people were not able to detect the leak until they began to experience the effects of F2 exposure … what do you tell them? The CGA P-20 pamphlet said it was ok? As Noah says ... pitchforks might be the least of your worries.</span><o:p></o:p></p><p class=MsoNormal><span style='color:black'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:black'>Put it in the gas cabinet …. Or a vented enclosure with detection. At the very, very, least, place a vent in the room with a detection point in the vent to actively sweep up (constantly sample) a possible leak that could occur. I would smoke the room to make sure that any point in the room eventually ends up in that vent at some point in time.</span><o:p></o:p></p></blockquote></blockquote></blockquote><div id=AppleMailSignature><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>D<br><br><b>Dennis S Grimard, Ph.D.</b> <o:p></o:p></p><div><p class=MsoNormal>Associate Director of Operations<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><b>MIT.nano</b><o:p></o:p></p></div><div><p class=MsoNormal><b>School of Engineering</b><o:p></o:p></p></div><div><p class=MsoNormal>Massachusetts Institute of Technology<o:p></o:p></p></div><div><p class=MsoNormal>60 Vassar Street, Bldg 39-559<o:p></o:p></p></div><div><p class=MsoNormal>Cambridge, MA 02149<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>C: (734) 368-7172<o:p></o:p></p></div><div><p class=MsoNormal>EM: <a href="mailto:dgrimard@mit.edu">dgrimard@mit.edu</a><o:p></o:p></p></div></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Mar 4, 2017, at 9:04 AM, Noah Clay <<a href="mailto:nclay@upenn.edu">nclay@upenn.edu</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal>Hi Sandrine,<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>We have a 193nm excimer laser micromachining system in our cleanroom and went through a similar exercise. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>We concluded that even though OSHA or NIOSH limits would indicate that a gas cabinet is unnecessary, that housing the ArF cylinders in an exhausted enclosure is a safer/better option. Since the laser requires frequent purges/refills, placing the cylinder near the cabinet is a must - therefore, it needed to be placed in an adjacent service chase. And so, we reasoned that:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>1. Housing F2 gases directly in the recirc path (no gas cabinet) was not an option.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>2. Shutting down the gas with with a TGMS interlock was required since<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>3. We perceived inherent difficulty in diluting a full cylinder release, as might be the case with a standard gas panel that could not be shut down by our TGMS.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>4. Our researchers would be wielding pitchforks if they were exposed to high levels of F2, even if we explained it was permissible.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I hope this helps.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Best,<o:p></o:p></p></div><div><p class=MsoNormal>Noah<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Noah Clay <o:p></o:p></p><div><p class=MsoNormal>Director, Quattrone Nanofabrication Facility<o:p></o:p></p></div><div><p class=MsoNormal>University of Pennsylvania <o:p></o:p></p></div></div></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Mar 3, 2017, at 14:28, Sandrine Martin <<a href="mailto:sandrine@umich.edu">sandrine@umich.edu</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal>Hello, <o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><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></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><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></div><div><p class=MsoNormal>Pure F2 is listed with a LC50 (rat, 1h) at 185ppm. <o:p></o:p></p></div><div><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></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><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></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><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></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Has anybody gone through similar discussions? <o:p></o:p></p></div><div><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></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Thanks<o:p></o:p></p></div><div><p class=MsoNormal>Sandrine<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>-- <o:p></o:p></p></div><div><div><div><div><div><div><div><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></div></div></div></div></div></div></div></div></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><a href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></div></blockquote></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>_______________________________________________<br>labnetwork mailing list<br><a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br><a href="https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork</a><o:p></o:p></p></div></blockquote></div></body></html>