Bolted Flange Design and Stress Analysis (ASME/ANSI)

Introduction

 This hands-on, highly-interactive course includes practical sessions and exercises. Theory learned will be applied using our state-of-the-art simulators. In this course, we shall be analyzing the riveted and bolted joints used in the oil refineries for the jointing of pipes & plates, for the blinding of pipes, pressure vessels, and heat exchangers.

The selection of pipe flanges is well documented in the ASME code and is fairly straight forward when pressures and temperatures are known. The use of the code makes the specific selection of components such as flanged valves, meters, pumps, and compressors also fairly straight forward in most instances. As a piping designer or engineer, it is, however, essential to have an understanding of the flange joint make-up as a unit. To this end, it is essential to understand the meaning of bolt preload and its importance in the flange joint, when considering external loadings due to (1) internal pressure, (2) cyclic conditions- leading to possible fatigue, (3) the effect of temperature, (4) shear and bending loads, and (5) vibration.

Material selection will also be discussed. Once materials have been selected for flanges, bolts, and gasket, for a particular joint, the engineer should be able to specify and/ or calculate initial torque requirements and to ensure that the joint will not fail or leak.

The aspect of fatigue loadings will be covered, however, in practice, the cyclic conditions encountered can be extremely difficult to estimate. An example of a pipeline in Alaska will be discussed in this regard. Sometimes, at best, a designer/ engineer can only make assumptions (and judgments based on experience), regarding expected vibration.

Accurate bending and shear loads on flange joints can sometimes only be established from a pipe stress analysis program. Only in special instances will a full finite element analysis have to be carried out for a critical joint. This is best left to the specialists and in this course, no attempt will be made to teach the participants the FEA techniques (e.g. Nuclear Specials). However, research will be discussed to illustrate the process and to give the participants some understanding of FEA techniques when applied to a flange joint. When a flange joint is subjected to critical high temperatures and pressures it is always recommended to give the design to a specialist who has the necessary software available. Circular flat plates will be analyzed and compared to blind flanges, and pressure vessel heat exchanger applications. 

Objectives

Upon the successful completion of this course, each participant will be able to:-

• Apply a comprehensive knowledge and techniques on the bolted flange and gasket design and stress analysis in accordance with ASME/ANSI Standards
• Identify the different types of flanges and gaskets used in the industry and become familiar with their applications
• Enumerate the system components of flange joint and analyze torque equations, stiffness of members, pretensioning, bolt strength, external loads and torques versus tension
• Determine the various torque requirements needed and compare theory versus manufacturer/contractor recommendations
• Analyze a joint in shear and explain fatigue loading and the effect of temperature
• Determine the system components of gaskets and their effect in the flange joint
• Employ the selection process of flanges and ratings and identify the parameters that can cause flange leakage
• Distinguish blind end flange design for both pipelines and pressure vessels
• Use ASME/ANSI charts, bolting charts and torque charts in the selection of flange components
• Recognize why FEA techniques are necessary for critical flange design applications
• Identify some of the software packages available for specific locations

Training Methodology

The course will be conducted along with workshop principles with formal lectures and interactive worked examples and with an active contribution by all delegates during workshops and discussions and teamwork. Real-life examples will be selected to illustrate the procedure for control of good performance of gas turbines. The emphasis will be on the explanation of technical phenomena and providing answers to problems that are encountered in everyday industrial practice. There will be ample opportunities for problem solving and workshops with active open discussion and sharing professional experiences on the operation, maintenance and troubleshooting. All course materials will be provided.

Who Should Attend?

This course provides systematic techniques and methodologies on bolted flange, gasket design and stress analysis for engineers involved in the design, construction or maintenance of pressurized equipment utilizing flanged joints for the petroleum, refining, chemical, power and process industries.

Course Outline

Day 1:

• Introduction & Course Overview
• Types of Flanges and Gaskets Used in the Industry
• Power Screws–Basic Theory Summary Torque Equations
• Stiffness of Members
• Pretensioning
• Bolt Strength
• External Loads
• Torque vs. Tension
• Bolt Strength and Preload–Theory and Examples

Day 2:

• Gaskets and their Effect in the Flange Joint
• Flange Joints in Shear and Examples Fatigue Revision
• The Effect of Temperature
• Fatigue Loading of Tension Joints and Examples
• Selection of Flanges and Ratings

Day 3:

• Bolted Joints in Shear
• Application in Pressure Vessels–Circular Flat Plate Theory and Examples
• Use of ASME/ANSI Charts, Bolting Charts and Torque Charts vs. Tension
• Causes of Flange Leakage

Day 4:

• Special Cases of Flange Design
• Introduction to Finite Element (FE) Analysis of a Flange Joint Under the Combined Effect of Preload, Pipe Internal Pressure and Temperature
• Introduction to Finite Element (FE) Analysis of a Flange Joint Under the Combined Effect of Preload, Pipe Internal Pressure and Temperature

Day 5:

• Why Joints Fail
• Discussion around Various Aspects
• Standard Procedures for the Assembly of Flange Joints
• Practical Question Time
• Worked Examples