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<td><a href="https://misportal.jlab.org/ll/index.jsf?function=view&lessonId=846">Relief Valve System Failure during Unplanned Gas Release at Compressed Natural Gas Fueling Facility - Brookhaven National Laboratory</a></td>
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<h2 style="white-space:nowrap">Statement of Lessons Learned</h2>
<pre>For a copy of the original report, see “Attachments” on Lessons Learned page.
When designing and installing a pressure relief system, the configuration of the inlet and outlet piping is critical to its performance. Inlet and outlet piping, as well as the supporting structures, must be designed to withstand both static and dynamic loads. It is important to verify compatibility of system components according to applicable design and safety codes to avoid, or at least mitigate, flow restrictions and excessive pressure drops which can result in reduced relief capacity and thus damage to the system.
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<h2 style="white-space:nowrap">Discussion of Activities</h2>
<pre>On the days leading to January 6, 2014, unusual weather conditions with high temperature variations caused a large pressure rise inside three storage vessels at the Brookhaven National laboratory (BNL) compressed natural gas (CNG) fueling facility. The pressure increase reached the point where the relief valve on each vessel opened automatically and released gas to the atmosphere. During this event, the valves were damaged and did not reclose as designed. The gas release continued until emergency personnel responded, manually shutting down the system and closing the valves. The discharge piping structure downstream from the relief valves collapsed. (See attached photos.)</pre>
<h2 style="white-space:nowrap">Analysis</h2>
<pre>Failure analysis was performed by the manufacturer of the relief valves. It was found that damage was caused by rapid open/close cycles (chatter). It was found that the isolation valve, between the vessel and the relief valve, was a reduced-port model which produced flow restriction which cause a pressure drop large enough to induce the valve chatter.
The investigation also found that the collapsed discharge piping was self-supporting, which is against prevailing code recommendation, and insufficiently braced to resist the reaction forces generated by the high pressure gas discharge.
Minimum relief valve capacity is determined by industry code based on protection from a fire situation. The relief valve used exceeded the minimum required capacity and was selected and supplied by the pressure vessel company alongside several key piping components. A separate contractor assembled and installed the inlet piping and the discharge system using those components in addition to others custom made for this facility.
Even though a third party provided an independent review of the system and all the individual components were commercially available, high quality and rated for the application, no one realized that they could be combined and assembled in such a way that they rendered the relief system vulnerable to valve chatter and structural damage.
A review of similar CNG filling stations indicates that these issues are common and widespread in the industry. While the selection and sizing of relief devices is done carefully, the importance of the correct design and installation of the complete relief system is frequently overlooked despite specific code requirements.
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<h2 style="white-space:nowrap">Recommended Actions</h2>
<pre>Below are the consequences of the above event. They are provided for information and discussion purposes only.
Make designers, installers and reviewers of relief systems aware that incorrect selection, application or installation of system components can result in valve chatter or reduced relieving capacity.
Require extreme caution at the outlet piping if installed where liquids could form an ice block in below-freezing conditions. "Weather cap" discharge lines and provided a drain hole to prevent liquid collecting in the relief valve body or outlet piping.
When operational testing and validation of a pressure relief system is impractical, require a qualified professional engineer review to ensure compliance with applicable codes.
Brief emergency personnel regarding the potential dangers of isolating relief devices during a release. If the cause of over-pressure during this incident had been a runaway compressor, chemical reaction, or fire, the consequences of closing the relief isolation valves could be catastrophic unless the situation creating the pressure rise was controlled.
Additional important installation information is contained in Paragraph UG-135, Section VIII, Div. 1 of the ASME Boiler and Pressure Vessel Code.
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<h2>Comments</h2>
<h5 style="white-space:nowrap">9/3/2014 9:39:45 AM by Bailey, Mary Jo</h5>
<pre>Submitted to those with current Pressure Safety System training</pre>
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<legend>Summary</legend>
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<td class="label" nowrap>Lesson ID:</td>
<td class="dataval">846</td>
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<tr class="row">
<td class="label" nowrap>Status:</td>
<td class="dataval">OK</td>
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<tr class="row">
<td class="label" nowrap>Doc ID:</td>
<td class="dataval">2014-JLAB-846</td>
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<td class="label" nowrap>Priority:</td>
<td class="dataval">Best Practice</td>
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<td class="label" nowrap>Safety Related:</td>
<td class="dataval">YES</td>
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<td class="label" nowrap>Originator:</td>
<td class="dataval">Bailey, Mary Jo</td>
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<tr class="row">
<td class="label" nowrap>Issued:</td>
<td class="dataval">9/3/2014 9:34:02 AM</td>
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<td class="label" nowrap>Approved By:</td>
<td class="dataval">Bailey, Mary Jo</td>
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<tr class="row">
<td class="label" nowrap>Approved On:</td>
<td class="dataval">9/3/2014 9:39:45 AM</td>
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<td class="label">Source:</td>
<td class="dataval">
DOECRD
</td>
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<tr class="row">
<td class="label" nowrap>Location:</td>
<td class="dataval">BNL</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">M. Cubillo, Safety Engineering Group, 631-344-4049 mcubillo@bnl.gov </td>
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<tr class="row">
<td class="label" nowrap>Queued Emails:</td>
<td class="dataval">0</td>
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<tr class="row">
<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">2 times</td>
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<legend>Attachments</legend>
<a name="attachments"></a>
<ul class="lesson_attribute_listing">
<li><a target="_blank" href="https://misportal.jlab.org/ll/downloadAttachment?attachmentId=3321">M:\wcd\LessonsLearned\Pressure Sys\DOE - Yellow - Relief Valve FailurePic.pdf</a></li>
<li><a target="_blank" href="downloadAttachment?attachmentId=3322">M:\wcd\LessonsLearned\Pressure Sys\DOE - Yellow - Relief Valve Failure.pdf</a></li>
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<legend>Hazard Issues</legend>
<ul class="lesson_attribute_listing">
<li>Pressure Systems</li>
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<legend>Skills</legend>
<ul class="lesson_attribute_listing">
<li>SAF130A: PRESSURE SYSTEMS SAFETY AWARENESS</li>
<li>SAF130B: PRESSURE SYSTEMS SAFETY DESIGN AUTHORITY</li>
<li>SAF130kd: PRESSURE SYSTEMS QUALITY PROCEDURE</li>
</ul>
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<legend>Distribution/Notification</legend>
<ul class="lesson_attribute_listing">
<li>*Division Safety Officers (DSOs)</li>
<li>*Safety Wardens</li>
<li>*DOE Notification</li>
<li>*ESH&Q Liaisons</li>
</ul>
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