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>From UC Berkeley:<br>
<br>
low level - email and txt alarm to staff<br>
high level - seal gases, annunciate local alarm, evac lab<br>
high level persistent (>60sec) - link to building fire alarm
activated, annunciate<br>
building fire alarm, evac entire building<br>
<br>
Bill<br>
<br>
<small>Bill Flounders, Ph.D.<br>
Executive Director<br>
Berkeley Marvell Nanofabrication Laboratory<br>
520 Sutardja Dai Hall Mail Code 1754<br>
Berkeley, CA 94720<br>
<br>
Office: 510-809-8600<br>
<a class="moz-txt-link-freetext" href="http://nanolab.berkeley.edu/">http://nanolab.berkeley.edu/</a></small><br>
<br>
<br>
<br>
<br>
Ian Harvey wrote:
<blockquote cite="mid:A6EB11E4-E522-4870-9BE8-97C272E77DC0@eng.utah.edu"
type="cite">Dear Labnetwork,
<div><br>
</div>
<div><b>Question:</b><br>
How to prevent spurious gas/silane alarms (e.g., from cylinder change
burps) from unnecessarily evacuating an entire building? <br>
<br>
<b>Background:</b><br>
We recently had a very brief burst/decay of silane associated with the
removal of the dust cap in preparation for installing a new silane
cylinder. The burst was captured by our gas alarm as a single "spike"
that exceeded the level-2 alarm threshold (10 PPM) for 3 seconds and
decayed back to below level 1 (5 PPM) after 12 seconds (peak was 19
PPM). However, the fire alarm was triggered, the entire engineering
building was evacuated for 20 minutes, and six fire trucks showed up.<br>
<br>
This cylinder was 13 months old, 1 month past its expiration date. The
cylinder was chained and strapped into position inside the gas cabinet
when the dust cap was removed. At present, we feel it is best to
evacuate the building, since our old lab is in a B-class occupancy
area. However, in our new facility, our silane will be behind a 2 hr
firewall in a special gas room, attached to the single-story fab wing
and 50 yards from (but still attached to) the multi-story research
tower. We are looking for more robust system-level solutions limiting
unnecessary evacuation of the research tower in our new facility.<br>
<br>
<b>Approaches:</b> Aside from procedural approaches like "Don't use
expired cylinders", and "Open dust caps very slowly", has anyone
attempted to use alarm logic in their HPM system, such as:
"<<If>> the alarm originates in the gas box
<<and>> room air sensor is below threshold... or
variations on timing between sense and decay to stage the triggering of
different alarm levels??</div>
<div><br>
</div>
<div>How do others handle this situation in your respective labs?</div>
<div><br>
Thank you in advance for your inputs!<br>
<br>
--Ian<br>
</div>
<br>
<div><span class="Apple-style-span"
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class="Apple-style-span"
style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;">
<div style="word-wrap: break-word;">
<div>********************************************<br>
Ian R. Harvey, Ph.D.<br>
Associate Director, Utah nanofab<br>
College of Engineering / University of Utah</div>
<div><br>
</div>
<div>Research Associate Professor<br>
Department of Mechanical Engineering</div>
<div>Adjunct Associate Professor</div>
<div>Department of Electrical & Computer Engineering<br>
2232 MEB<br>
<br>
mail to suite 2110 MEB, 50 S. Central Campus Drive<br>
Salt Lake City, Utah 84112-9011<br>
801/585-6162 (voicemail)<br>
801/581-5676 (lab main number)<br>
<a moz-do-not-send="true" href="http://www.nanofab.utah.edu">www.nanofab.utah.edu</a><br>
</div>
</div>
</span></span></div>
<br>
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