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<td><a href="https://misportal.jlab.org/ll/index.jsf?function=view&lessonId=945">Unsecured Ferrous Metal in a High Magnetic Field</a></td>
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<h2 style="white-space:nowrap">Statement of Lessons Learned</h2>
<pre>This event serves as a reminder to double check fasteners for tightness and add a second level of restraint (as needed) to ensure material is not pulled into the magnetic field(s).
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<h2 style="white-space:nowrap">Discussion of Activities</h2>
<pre>On April 11th, 2016 an access was made to the Hall to determine why several high voltage cards on the Central Drift Chamber (CDC) had stopped working. It was discovered that a bracket securing one of the cooling ducts for the CDC had worked loose from its' mount and had been drawn into the bore of the Solenoid by the magnetic field. At this point the magnet was ramped down, the bracket was removed, and the Hall taken back to beam permit to continue running until the next morning when the beam was schedule to be taken away.</pre>
<h2 style="white-space:nowrap">Analysis</h2>
<pre>On April 12th the Hall went back to Controlled Access and an assessment of the incident was done. It was determined that the combination of the vibration from the air flow in the duct in combination with the magnetic force pulling on the rigid galvanized tin duct work had pulled the bracket off of its' Uni-Strut mount. The equipment damaged was one low voltage cable, one high voltage board, and one pre-amp board. The cost estimate of the replacement parts is less than $300.</pre>
<h2 style="white-space:nowrap">Recommended Actions</h2>
<pre>The Hall Leader and Lead Engineer agreed on a two step approach to correct the cause of the incident.
Step one: is to remove the hazard and take any necessary steps to prevent this or similar incidents. To accomplish this step the two rigid vertical runs of the duct work were replaced with non-magnetic flex hose and secured with plastic anchors instead of the ferrous metallic brackets. Next, all of the fasteners inside the 600 Gauss field were checked for tightness and ¿torque striped¿ to both indicate they were checked and for future visual examination. Lastly, plastic tie wraps were added to the ends of the other Uni-Strut bars to prevent these other brackets from sliding out of their supports.
Step two: is to replace the temporary tie wraps at the ends of the Uni-Strut rails with more permanent stops. Additionally, the steel bracket foot supporting the vertical aluminum stand to which the duct work is secured will be replaced with an aluminum one. Also, other ferrous fasteners inside the 600 Gauss field will be looked at to determine if they need to be replaced with stainless steel fasteners.
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<h2 style="white-space:nowrap">JLab Preventive Measures</h2>
<pre>Operation of magnets requires an OSP if the magnet owner has determined that the risk code is >2. An OSP guideline for magnets is provided in ESH Manual Chapter 6420-T2. This guideline is provided to assist owners in identifying hazards associated magnet operations and write operation instructions including ferromagnetic object and tool sweep procedures.</pre>
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<h2>Comments</h2>
<h5 style="white-space:nowrap">4/22/2016 8:37:55 AM by Johnson, Tina</h5>
<pre>SME has reviewed and provided appropriate preventative measures. Please read and share within your work groups.</pre>
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<legend>Summary</legend>
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<td class="label" nowrap>Lesson ID:</td>
<td class="dataval">945</td>
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<td class="label" nowrap>Status:</td>
<td class="dataval">OK</td>
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<td class="label" nowrap>Doc ID:</td>
<td class="dataval">2016-JLAB-945</td>
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<td class="label" nowrap>Priority:</td>
<td class="dataval">Info</td>
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<td class="label" nowrap>Safety Related:</td>
<td class="dataval">NO</td>
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<td class="label" nowrap>Originator:</td>
<td class="dataval">Johnson, Tina</td>
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<tr class="row">
<td class="label" nowrap>Issued:</td>
<td class="dataval">4/18/2016 3:40:29 PM</td>
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<td class="label" nowrap>Approved By:</td>
<td class="dataval">Johnson, Tina</td>
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<td class="label" nowrap>Approved On:</td>
<td class="dataval">4/22/2016 8:37:55 AM</td>
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<td class="label">Source:</td>
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TJNAF Other
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<td class="label" nowrap>Location:</td>
<td class="dataval">TJNAF</td>
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<td class="label" nowrap>Cost Savings:</td>
<td class="dataval"></td>
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<td class="label" nowrap>Contact:</td>
<td class="dataval">Tom Carsten</td>
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<td class="label" nowrap>Queued Emails:</td>
<td class="dataval">0</td>
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<td class="label" nowrap>Sent Emails:</td>
<td class="dataval">0</td>
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<td class="label" nowrap>Viewings:</td>
<td class="dataval">183 times</td>
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<legend>Hazard Issues</legend>
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<li>Static Magnetic Fields >5G: Fringe, High, & Quench Effect</li>
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<legend>Skills</legend>
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<legend>Distribution/Notification</legend>
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<li>*Division Safety Officers (DSOs)</li>
<li>*Safety Wardens</li>
<li>*DOE Notification</li>
<li>*ESH&Q Liaisons</li>
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