1. Subcommittee On Pressure Relief Systems API CRE Update Clark Shepard Spring 2010

2. 1 Standard/RPTitleCurrent Edition Date Notes or Comments Expected Publication Date Std 520 Part 1Sizing, Selection, and Installation of Pressure- relieving Devices in Refineries Part I—Sizing and Selection 8th Edition, December 2008 Work items beginning in Spring 2010 9th Edition 2013 RP 520 Part 2Sizing, Selection, and Installation of Pressure- relieving Devices in Refineries Part II— Installation 5th Edition, August 2003 Ballot 1Q106th Edition 2010 Std 521 (ISO 23251) Pressure-relieving and Depressuring Systems 5th Edition, January 2007 Ballot August 2011 (DIS) 6th Edition November 2012 (FDIS) Std 526Flanged Steel Pressure Relief Valves 6th Edition, May 2009 7th Edition 2Q14 Std 527Seat Tightness of Pressure Relief Valves 3rd Edition, July 1991 Re-affirmed July 2007 2012 Std 2000 (ISO 28300) Venting Atmospheric and Low-Pressure Storage Tanks Nonrefrigerated and Refrigerated 6th Edition, November 2009 (API adopt back); ISO release 2008 DIS June 2011December 2012

3. Standard/RPIssuesCost/Reliability Issues Std 520 Part ITask Force focused on RP 520 Part II None identified RP 520 Part IIWork on inlet pressure drop section Potential Cost Improvement - Potential revision and inclusion of 5% into inlet pressure drop criteria Std 521 (ISO 23251) Challenge to heat flux equations Potential Additional Cost – Work nearing completion where detailed equations based on CFD and test data can be used to validate existing simple methodology Std 526/527No issuesNone identified Std 2000 (ISO 28300) 1. In/Out Breathing – Working with SCAST with regards to equation revisions 2. Documenting the basis of the heat flux equations for sizing emergency venting 3. Deflagration venting 1. Potential Additional Cost – Clarifying text when to use equations in Annex A (past API 2000 equations) 2. Cost neutral - Work continues on heat flux basis 3. Potential Additional Cost – Working with SCAST to define when frangible roofs can be acceptable for venting vapors during internal deflagration

4. Projects 1.PERF 99-05 PRV Stability Project evaluating multiple factors that could lead to instability (chattering) including inlet pressure drop –Plans to complete during 4Q10 –Data reviewed this week appeared random although not all test information has been analyzed 2.Heat Recovery Steam Generators (Waste Heat Boiler) in Sulfur Recovery Units –Breakout team – PRS working with HTE and Sulfur Expert –Focus is on pressure relief requirements to address tube failure