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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.

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: Owner Added 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 Design Added 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 Factors Added specific references to ASME B31J-2017 as a resource for stress intensification and flexibility factors as an alternate to Appendix D. High Cycle Fatigue...
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Rigging Points Of Attachment - A Critical Element of Heavy Lift

cover-image Rigging Points In Heavy Lifts Are Critical
Review of rigging attachments to the equipment being lifted have prevented lift failures.  When planning major crane lifts we are very careful about confirming the crane foundation, rigging stability/capacity, and crane capacity. Are we taking enough time to analyze the points of attachment for the rigging? Becht Engineering Heavy Lift Division says “NO”. Our experience is that reviews of rigging points of attachment have identified critical flaws that may have resulted in dropped loads. In industry today, the load/vessel designers typically design the lifting lugs and trunnions at the same time. It is our experience that the owners of the equipment and the crane contractors are assuming these devices are properly designed and rated. It is a common practice that the crane contractor assumes responsibility for rigging above the points of attachment. Generally, the consensus is that trunnions and lift lugs are designed by others and they should be right. That...
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Basics of Design By Analysis in ASME Section VIII, Division 2

fea-pressure-vessel-nozzl_20181115-174743_1
How hard can it be?  I’ve heard from several (unnamed) analysts that because they have access to an FEA program and have successfully applied FEA in other fields, that FEA for pressure vessels should be a snap.  What is it about FEA for pressure vessels that makes it unique? I was recently discussing with another blogger regarding some distinctive aspects of performing Design By Analysis for pressure vessels.  We generated several questions, and so I decided to post this in a Question & Answer format. When do I have to use FEA in my pressure vessel design? The short answer here is that for most situations, you probably should not be using FEA to design your pressure vessel.  The rules for designing pressure vessels in ASME Section VIII, Division 1 and ASME Section VIII, Division 2 have a long history of successful application.  So, wherever possible, I would recommend that you...
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How To Quantify And Evaluate Oil Storage Tank Annular Plate Corrosion

annular_plates_cover-imag_20181008-172036_1 Failure of Oil Storage Tank Annular Plate
In the past ten years, there have been a few oil storage tank annular plate failures due to soil side corrosion and fatigue loading (filling and emptying) which has led to large spills. The corrosion tends to be localized in a groove fashion and the size of the flaw could vary from 3 feet to 12 feet in the circumferential direction. The location of the corrosion is also where the highest bending stress will occur during filling and emptying of tanks. See Figures 1 and 2 for the location of the failure on the annular plate.   Since the location of failure is under the tank, the corrosion flaws cannot be detected easily from the outside of the tank. It can only be detected if an internal inspection is done which would require the tank to be emptied and cleaned and this is very expensive. However, with UT shear wave technology...
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