Session: DA-01-04 Design and Analysis of Pressure Vessels and Components-4

Paper Number: 122532

122532 - Large Openings on Cylindrical Shells Subject to Axial Compression 

Vertical vessels experience axial compression due to equipment dead weight, vessel contents and environmental loads. ASME Boiler and Pressure Vessel Code Section VIII Division 2, Paragraph 4.5.17 provides rules for reinforcement of openings in cylindrical and conical vessels subject to axial compression. The rules outlined in the Code only apply to openings not exceeding 25% of the vessel diameter or 80% of the stiffening ring spacing. Openings exceeding these limits are required to be designed by analysis per Section VIII Division 2, Part 5. The rules in Section VIII Division 2 Code are quite restrictive for vessel manufacturers as a vessel smaller than 8’-0” in diameter with a 24” inner diameter manway would require a specialized buckling analysis per the rules in Part 5 of the Code for which the majority of fabricators would require an outside consultant to perform, resulting in higher engineering costs for small diameter Division 2 vessels. Pressure vessels designed to Section VIII Division 1 Code, European Standards EN 13445 and British Standard PD 5500 do not require calculations for opening reinforcement due to axial compression. Therefore, with the lack of evidence regarding buckling failures from openings not designed for axial compression, and the knowledge that most vessel opening reinforcements are governed by pressure loading, along with the recognition of the additional engineering burden being placed on vessel fabricators, this paper will examine the effects of reinforcement for openings greater than the 25% limit established in Division 2 Code and propose a new opening size limit of 50% of vessel diameter based on detailed bucking analysis results of cylindrical shells with different opening sizes.

Presenting Author: James Lu Fluor Corporation

Presenting Author Biography: James Lu is a Fluor fellow, Subject Matter Expert for pressure vessels and vessel design softwares, and a technical director at Fluor’s Houston office. Dr. Lu has more than 25 years of experience in design, analysis, and fabrication of pressure vessels. His expertise includes heavy wall reactors for high pressure service, tubular reactors, coke drums, process columns, and other large and complex pressure equipment.
Dr. Lu has extensive knowledge of ASME Boiler and Pressure Vessel Code, Section VIII, Div 1 & 2. He is a Code Committee member of Subgroup on Fabrication and Examination (ASME BPV VIII). He is also a member of API-934 Committees. Dr. Lu has published several technical papers on pressure vessel design, fabrication and examination; and has made presentations at ASME Pressure Vessel and Piping (PVP) and other conferences.
Dr. Lu received his bachelor’s and master’s degrees in mechanical engineering from Shanghai Jiaotong University in China, his PhD in mechanical engineering from the University of Houston. He is a registered professional engineer in Texas since 2000.

Authors:

James Lu Fluor Corporation
Barry Millet Fluor Corporation
Kenneth Kirkpatrick Fluor Corporation
Bryan Mosher Fluor Corporation
Jacob Hundl Fluor Corporation