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Becht Engineering Blog

In this section of the site contributing authors submit interesting articles relating to the various services, industries and research & development efforts of Becht Engineering.

When Should the Rules for Severe Cyclic Conditions (Service) in ASME B31.3 Be Used?

process_piping_ASME_B31
This posting (November 2019) is an update to an October 2013 post which reflects changes to the ASME B31.3 Code relative to severe cyclic service that have occurred since the original post.There has been a fair amount of confusion as to when the rules for severe cyclic conditions in ASME B31.3 should be used, and the rules themselves can be somewhat confusing to apply. In the 2016 edition of ASME B31.3 the definition of when the rules for severe cyclic service are applicable were changed, which may reduce the confusion.  The definition as to when the rules of severe cyclic apply is in the 300.2, Definitions.  Prior to the 2016 edition, it stated that severe cyclic conditions are:Conditions applying to specific piping components or joints in which SE computed in accordance with para. 319.4.4 exceeds 0.8SA (as defined in para. 302.3.5); andThe equivalent number of cycles (N in para. 302.3.5) exceeds...
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Recent Comments
Guest — Rohit Patel

ASME B31.3

Thanks for showing the Rules for Severe Cyclic Conditions (Service) in ASME B31.3 Be Used.
Monday, 16 December 2019 05:48
Guest — Hafiz Ali Alvi

Impact on Wall thickness for C...

Dear Mr. Becht, I would like to ask what could be possible impact of cyclic service for the calculated pipe wall thickness under p... Read More
Saturday, 16 November 2019 23:59
Chuck Becht

Impact on Wall thickness for C...

Designation of a system as being in severe cyclic service does not impact the wall thickness calculations for pressure design. No... Read More
Sunday, 17 November 2019 07:40
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ASME B31.3 - Substantive Changes in the 2018 Edition for Process Piping

B31-3_ASME
In addition to the many clarifications, updated references to codes and standards, updates to basic allowable stresses, and added listed materials, there are several substantive changes to the 2016 Edition of ASME B31.3, Process Piping, which is scheduled to be issued mid-January 2019. These substantive changes are:OwnerAdded specific permission for the owner to designate a representative to carry out selected responsibilities required by this Code, and noted that the owner retains ultimate responsibility for the actions of the representatives.Flange DesignAdded the ASME B&PV Code Section VIII, Division 2, para. 4.16 flange calculation method as an acceptable way to design flanges for B31.3 applications. The Division 2 procedure considers pressure, gasket seating, and externally applied axial forces and net-section bending moments.Stress Intensification and Flexibility FactorsAdded specific references to ASME B31J-2017 as a resource for stress intensification and flexibility factors as an alternate to Appendix D.High Cycle FatigueAdded Appendix W, which describes an alternate method...
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Guest — Sharun Suresh

Flange Design

As per your quote "Added the ASME B&PV Code Section VIII, Division 2, para. 4.16 flange calculation method as an acceptable way to... Read More
Wednesday, 13 November 2019 03:12
Don Frikken

Flange Design

The 2016 edition permitted flange design in accordance with Division 2 for high pressure fluid service only. The 2018 edition adde... Read More
Wednesday, 13 November 2019 08:20
Guest — Bilal Shah

Occasional Allowable per Appen...

Thank you Mr. Frikken for your response. This is very insightful. To clarify my understanding: 1. On using appendix V for calcula... Read More
Friday, 08 November 2019 05:28
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Identifying Gaps in Risk Based Inspection Programs (RBI) That Impact Reliability

heater-tube-bundle
Risk based inspection (RBI) is a powerful tool to identify and manage mechanical integrity risks in fixed equipment and piping but is only one part of a robust reliability program.  RBI informs inspection decision making on where, when and how to inspect most of equipment but is frequently misinterpreted as a “Silver Bullet” that covers all necessary inspection activities in a refinery.  Most RBI programs have significant gaps that can result in costly reliability issues or unjustified maintenance costs. RBI gaps can exist where risk assessments require input from outside of an inspection department or mechanical integrity group.  Examples of these gaps are when failures have process consequences but not mechanical integrity concerns, such as tube leaks in shell and tube heat exchangers and cyclones in an FCC Unit.  Another example is when mechanical integrity is dependent upon other systems functioning per design, such as fired heater tubes.  Quantitative RBI Programs are...
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Reducing Loss of Primary Containment (LOPC's) in a Refinery

cover-LOPCs
Reducing Loss of Primary Containment (LOPC's) or commonly referred to as “leaks” in a refinery is a key factor to improve reliability.  Historically, most refiners reduced the high consequence leaks to avoid major incidents; however, lower consequence related leaks were not given high priority.  Today high reliability is required, and reduction of all leaks is desired due to greater legal and regulatory oversight of the industry.  Approximately 90% of the leaks occur in piping systems.  These leaks typically fall into 3 categories; internal corrosion, flange leaks and external corrosion.  Many refiners have programs in place for internal corrosion and programs for flanged joints; however, many lack comprehensive programs for external corrosion. To fully reduce LOPCs a comprehensive internal and external corrosion management system is necessary.BackgroundMany refineries have had Mechanical Integrity related audits performed during the last decade.  These audits have found many areas for improvements and programs were initiated to address...
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