Reliability Factors and Tightness of Tube-to-Tubesheet Joints

1996 ◽  
Vol 118 (2) ◽  
pp. 137-141 ◽  
Author(s):  
Z. F. Sang ◽  
Y. Z. Zhu ◽  
G. E. O. Widera
Keyword(s):  
Pressure Vessel ◽  
Division 1 ◽  
Asme Code ◽  
Section Viii ◽  
Preliminary Study

The main purpose of this paper is to provide an applicable method to establish reliability factors for expanded tube-to-tubesheet joints. The paper also reports on the results of a preliminary study to validate experimentally the reliability efficiencies listed in Table A-2 of Appendix A of Section VIII, Division 1, of the Boiler and Pressure Vessel Code (ASME, 1986), and tightness of expanded tube-tubesheet joints. A comparison between the actual reliability factors fr determined from testing the damage strength of the joint and calculated according to Appendix A-4 of the ASME Code and those of Table A-2 is carried out. The results are discussed in light of the restrictions inherent in Table A-2. It is confirmed that some existing values of fr are conservative, while others are less so.

Heat Treatment of Fabricated Components and the Effect on Properties of Materials

2019 ◽  
Author(s):  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Heat Treatment ◽  
Pressure Vessel ◽  
Test Specimen ◽  
Stress Relieving ◽  
Division 1 ◽  
Asme Code ◽  
Alloy Steels ◽  
Section Viii ◽  
Properties Of Materials ◽  
Division 2

Abstract Most of the heavy thickness boiler and pressure vessel components require heat treatment — in the form of post weld heat treatment (PWHT) and sometimes coupled with local PWHT. It is also a common practice to apply post heating/ intermediate stress relieving/ dehydrogenation heat treatment in case of alloy steels. The heat treatment applied during the various manufacturing stages of boiler and pressure vessel have varying effects on the type of material that is used in fabrication. It is essential to understand the effect of time and temperature on the properties (like tensile and yield strength/ impact/ hardness, etc.) of the materials that are used for fabrication. Considering the temperature gradients involved during the welding operation a thorough understanding of the time-temperature effect is essential. Heat treatments are generally done at varying time and temperatures depending on the governing thickness and the type of materials. The structural effects on the materials or the properties of the materials tends to vary based on the heat treatment. All boiler and pressure vessel Code require that the properties of the material should be intact and meet the minimum Code specification requirements after all the heat treatment operations are completed. ASME Code(s) like Sec I, Section VIII Division 1 and Division 2 and API recommended practices like API 934 calls for simulation heat treatment of test specimen of the material used in fabrication to ascertain whether the intended material used in construction meets the required properties after all heat treatment operations are completed. The work reported in this paper — “Heat treatment of fabricated components and the effect on properties of materials” is an attempt to review the heat treatment and the effect on the properties of materials that are commonly used in construction of boiler and pressure vessel. For this study, simulation heat treatment for PWHT of test specimen for CS/ LAS plate and forging material was carried out as specified in ASME Section VIII Div 1, Div 2 and API 934-C. The results of heat treatment on material properties are plotted and compared. In conclusion recommendations are made which purchaser/ manufacturer may consider for simulation heat treatment of test specimen.

Code Case 2286 Applied to the Design of Pressure Vessels

2003 ◽  
Author(s):  
Kanhaiya L. Bardia ◽  
Kim Nguyen ◽  
Manfred Lengsfeld ◽  
Donald G. LaBounty ◽  
Bernie Au
Keyword(s):  
Pressure Vessel ◽  
Petrochemical Industry ◽  
External Pressure ◽  
Pressure Vessels ◽  
Compressive Stresses ◽  
Division 1 ◽  
Shell Design ◽  
Asme Code ◽  
Section Viii ◽  
Sample Vessel

Code Case 2286-1 [1] of the ASME Boiler and Pressure Vessel Code [2][3] provides alternate rules for determining the allowable external pressure and compressive stresses for cylinders, cones, spheres, and formed heads in lieu of the rules of Section VIII, Divisions 1 and 2. The authors in this paper present a comparison of the longitudinal and circumferential compressive stresses in pressure vessels based on the methods outlined in Paragraph UG-28 of Division 1, Section VIII of the ASME Code and Code Case 2286-1. The Do/t ratio in this paper is limited to 600 which covers the majority of pressure vessel designs found in the petrochemical industry. A sample vessel shell design is presented applying both the ASME Code, Section VIII, Div. 1 method and that of Code Case 2286-1.

The Background of ASME Code Case 1828: A Simplified Method of Analyzing Part B Flanges

1978 ◽  
Vol 100 (2) ◽  
pp. 215-219 ◽  
Author(s):  
R. W. Schneider ◽  
E. O. Waters
Keyword(s):  
Pressure Vessel ◽  
Metal Contact ◽  
Analysis And Design ◽  
Division 1 ◽  
Simplified Method ◽  
Asme Code ◽  
Section Viii ◽  
Consistent Basis

The 1974 Edition of ASME Boiler and Pressure Vessel Code Section VIII, Division 1, provides rules for the analysis and design of identical pairs of Part B flanges (flat face flanges in metal-to-metal contact). The theory has been extended on a consistent basis to cover the analysis of a pair of nonidentical Part B flanges but since the resulting procedure is laborious, action to include the rules has been delayed pending further consideration by the cognizant ASME Code Committees. In the interim a simplified method suitable for analyzing both identical and nonidentical pairs of Part B flanges has been developed and is available as ASME Code Case 1828: “A SIMPLIFIED METHOD FOR ANALYZING PART B FLAT FACE FLANGES WITH METAL-TO-METAL CONTACT OUTSIDE THE BOLT CIRCLE.” The purpose of this paper is to describe the simplified method and to derive some of the more important equations which are contained in the Code Case.

The Stress Analysis of a Cylinder With a Partition Plate Subjected to Internal Pressure

1993 ◽  
Vol 115 (3) ◽  
pp. 330-333
Author(s):  
Degui Fan
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Pressure Vessel ◽  
Division 1 ◽  
Asme Code ◽  
Bending Stresses ◽  
Section Viii

This paper presents a method to calculate stresses of a cylinder with a partition plate, whose equations for determining bending stresses of a cylinder and its partition plate are different (less conservative) from those in ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. The paper contains: 1) the derivation of equations for calculating bending stresses of a cylinder and its partition plate; 2) the comparisons between the method in ASME Code VIII-1 and the author’s method, and commentary on the equations for determining bending stresses of a cylinder and its partition plate in ASME Code VIII-1. Also, the recommendation to modify the equations for determining bending stresses of a cylinder and its partition plate in ASME Code VIII-1 has been put forward.

ASME B&PV Code Section VIII Pressure Vessel Design: A Comparison — Division 1 Versus Division 2

2002 ◽  
Author(s):  
Dwight V. Smith
Keyword(s):  
Pressure Vessel ◽  
Pressure Vessels ◽  
Main Design ◽  
Division 1 ◽  
Asme Code ◽  
Section Viii ◽  
Design Requirements ◽  
Division 2

Historically, the ASME B&PV Code, Section VIII, Division 2, Alternative Rules for Construction of Pressure Vessels (Div.2), ASME [1], was usually considered applicable only for large, thick walled pressure vessels. Otherwise, ASME B&PV Code, Section VIII, Division 1, Rules for Construction of Pressure Vessels (Div. 1), ASME [2], was typically applied. A case can also be made for the application of the Div. 2 Code Section for some vessels of lesser thicknesses. Each vessel should be closely evaluated to ensure the appropriate choice of Code Section to apply. This paper discusses some of the differences between the Div. 1 and Div. 2 Code Sections, summarizes some of the main design requirements of Div. 2, and presents a ease for considering its use for design conditions not usually considered by some, to be appropriate for the application of Div. 2 of the ASME Code.

Investigation of Nozzle on Knuckle Region of Dished Head

2021 ◽  
Author(s):  
Sujay S. Pathre ◽  
Ameya M. Mathkar ◽  
Shyam Gopalakrishnan
Keyword(s):  
Stress Pattern ◽  
Design Specification ◽  
Specific Location ◽  
Bending Effect ◽  
Division 1 ◽  
User Design ◽  
Asme Code ◽  
Section Viii ◽  
Design Requirements ◽  
Induced Stresses

Abstract ASME Code Section VIII Division 1 [1] provides rules for the shape of openings, size of openings, strength and design of openings, however, the existing rules do not provide any restrictions on the specific location of the nozzle on the dished head knuckle region. Many corporate guidelines/ user design requirements meant for pressure vessel design and specification suggest avoiding placement of any type of nozzle in the knuckle area of a dished head and generally state in their design specification to limit the placement of a nozzle including its reinforcement within the crown area. This applies to Torispherical and Ellipsoidal dished heads. Code [1] rule UG-37(a) provides the benefit in reinforcement by reducing the required thickness (tr) of the dished head when the nozzle is in the spherical portion of the dished head for the Ellipsoidal and Torispherical dished head. High stresses occur in the knuckle region of the dished head due to the edge bending effect caused as the cylinder and head try to deform in different directions. For various reasons the user design requirements insist on placing the nozzle in the knuckle region, further compounding the complexity of the stress pattern in the knuckle area. The work carried out in this paper was an attempt to check whether it is safe to locate a nozzle in the knuckle region of the dished head since the knuckle portion is generally subjected to higher stresses in comparison to the crown portion of a dished head and the Code [1] and [2] does not impose any restrictions for the placement of nozzles in the knuckle region. Also, in this paper an attempt was made to evaluate the induced stresses when equivalent sizes of nozzles are placed in the crown as well as the knuckle portion of the dished head.

The Applicability of the ASME Boiler and Pressure Vessel Code, Section XII, Transport Tanks, for Use in U.S. Federal Maritime Regulations

2010 ◽  
Author(s):  
Allen Selz ◽  
Daniel R. Sharp
Keyword(s):  
Pressure Vessel ◽  
Road Transport ◽  
Pressure Vessels ◽  
Department Of Transportation ◽  
The Road ◽  
Dangerous Goods ◽  
Division 1 ◽  
The Us ◽  
Section Viii ◽  
Marine Applications

Developed at the request of the US Department of Transportation, Section XII-Transport Tanks, of the ASME Boiler and Pressure Vessel Code addresses rules for the construction and continued service of pressure vessels for the transportation of dangerous goods by road, air, rail, or water. The standard is intended to replace most of the vessel design rules and be referenced in the federal hazardous material regulations, Title 49 of the Code of Federal Regulations (CFR). While the majority of the current rules focus on over-the-road transport, there are rules for portable tanks which can be used in marine applications for the transport of liquefied gases, and for ton tanks used for rail and barge shipping of chlorine and other compressed gases. Rules for non-cryogenic portable tanks are currently provided in Section VIII, Division 2, but will be moved into Section XII. These portable tank requirements should also replace the existing references to the outmoded 1989 edition of ASME Section VIII, Division 1 cited in Title 46 of the CFR. Paper published with permission.

A Study of the Conservatism in ASME BPVC Section VIII Division 2 Opening Design for External Pressure

2019 ◽  
Author(s):  
Barry Millet ◽  
Kaveh Ebrahimi ◽  
James Lu ◽  
Kenneth Kirkpatrick ◽  
Bryan Mosher
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
External Pressure ◽  
The Other ◽  
Finite Element Analyses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
Division 2

Abstract In the ASME Boiler and Pressure Vessel Code, nozzle reinforcement rules for nozzles attached to shells under external pressure differ from the rules for internal pressure. ASME BPVC Section I, Section VIII Division 1 and Section VIII Division 2 (Pre-2007 Edition) reinforcement rules for external pressure are less stringent than those for internal pressure. The reinforcement rules for external pressure published since the 2007 Edition of ASME BPVC Section VIII Division 2 are more stringent than those for internal pressure. The previous rule only required reinforcement for external pressure to be one-half of the reinforcement required for internal pressure. In the current BPVC Code the required reinforcement is inversely proportional to the allowable compressive stress for the shell under external pressure. Therefore as the allowable drops, the required reinforcement increases. Understandably, the rules for external pressure differ in these two Divisions, but the amount of required reinforcement can be significantly larger. This paper will examine the possible conservatism in the current Division 2 rules as compared to the other Divisions of the BPVC Code and the EN 13445-3. The paper will review the background of each method and provide finite element analyses of several selected nozzles and geometries.

A Study of Axial Compression in the ASME B&PV Code for Pipe Supports and Restraints

2016 ◽  
Author(s):  
Phillip E. Wiseman ◽  
Zara Z. Hoch
Keyword(s):  
Axial Compression ◽  
Pressure Vessel ◽  
Slenderness Ratio ◽  
Elastic Buckling ◽  
Allowable Stress ◽  
Linear Elastic ◽  
Division 1 ◽  
Asme Code ◽  
American Society ◽  
Allowable Stress Design

Axial compression allowable stress for pipe supports and restraints based on linear elastic analysis is detailed in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NF. The axial compression design by analysis equations within NF-3300 are replicated from the American Institute of Steel Construction (AISC) using the Allowable Stress Design (ASD) Method which were first published in the ASME Code in 1973. Although the ASME Boiler and Pressure Vessel Code is an international code, these equations are not familiar to many users outside the American Industry. For those unfamiliar with the allowable stress equations, the equations do not simply address the elastic buckling of a support or restraint which may occur when the slenderness ratio of the pipe support or restraint is relatively large, however, the allowable stress equations address each aspect of stability which encompasses the phenomena of elastic buckling and yielding of a pipe support or restraint. As a result, discussion of the axial compression allowable stresses provides much insight of how the equations have evolved over the last forty years and how they could be refined.

Evaluation of ASME Pressure Vessel Code Prohibitions on Rod and Bar Stock and Potential Remedies

2014 ◽  
Author(s):  
John J. Aumuller ◽  
Vincent A. Carucci
Keyword(s):  
Pressure Vessels ◽  
Early 20Th Century ◽  
Economic Disadvantage ◽  
User Experiences ◽  
The Public ◽  
Division 1 ◽  
Asme Code ◽  
Billet Material ◽  
Section Viii ◽  
Division 2

The ASME Codes and referenced standards provide industry and the public the necessary rules and guidance for the design, fabrication, inspection and pressure testing of pressure equipment. Codes and standards evolve as the underlying technologies, analytical capabilities, materials and joining methods or experiences of designers improve; sometimes competitive pressures may be a consideration. As an illustration, the design margin for unfired pressure vessels has decreased from 5:1 in the earliest ASME Code edition of the early 20th century to the present day margin of 3.5:1 in Section VIII Division 1. Design by analysis methods allow designers to use a 2.4:1 margin for Section VIII Division 2 pressure vessels. Code prohibitions are meant to prevent unsafe use of materials, design methods or fabrication details. Codes also allow the use of designs that have proven themselves in service in so much as they are consistent with mandatory requirements and prohibitions of the Codes. The Codes advise users that not all aspects of construction activities are addressed and these should not be considered prohibited. Where prohibitions are specified, it may not be readily apparent why these prohibitions are specified. The use of “forged bar stock” is an example where use in pressure vessels and for certain components is prohibited by Codes and standards. This paper examines the possible motive for applying this prohibition and whether there is continued technical merit in this prohibition, as presently defined. A potential reason for relaxing this prohibition is that current manufacturing quality and inspection methods may render a general prohibition overly conservative. A recommendation is made to better define the prohibition using a more measurable approach so that higher quality forged billets may be used for a wider range and size of pressure components. Jurisdictions with a regulatory authority may find that the authority is rigorous and literal in applying Code provisions and prohibitions can be particularly difficult to accept when the underlying engineering principles are opaque. This puts designers and users in these jurisdictions at a technical and economic disadvantage. This paper reviews the possible engineering considerations motivating these Code and standard prohibitions and proposes modifications to allow wider Code use of “high quality” forged billet material to reflect some user experiences.

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