Changes Between API STD 521 6th Ed and 5th Ed Cataloged

API STD 521, Pressure-relieving and Depressuring Systems, is perhaps the most thorough published guidelines on how to size relief devices and flare systems.  This paper reviews the differences between the 6^th Edition of API STD 521 (Published in 2014) and the 5^th edition (Published in 2007).  The authors will review changes and highlight several new requirements that are deemed critical to relief systems design.  The paper is based on a comprehensive review of the two documents and is a valuable resource for any engineer or process designer who needs to be knowledgeable of the latest relief systems recommendations.