Guidebook for the Design of ASME Section VIII Pressure Vessels

Guidebook for the Design of ASME Section VIII Pressure Vessels

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GUIDEBOOK FOR THE DESIGN OF

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Copyright © 2001

The American Society of Mechanical Engineers Three Park Ave., New York, NY 10016 Library of Congress Cataloging-in-Publication Data Farr, James R

Guidebook for the design of ASME Section VHI pressure vessels/by James R Farr, Maan H Jawad.—2™ ed

p cm

Includes bibliographical references and: index

ISBN 0-7918-0172-1

1 Pressure vessels——Design and construction 2 Structural engineering I Jawad, Maan H,

IL Title

TA660 T34 F36 2001 6817.76041——dc21

2001046096

All rights reserved Printed in the United States of America Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher

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INFORMATION CONTAINED IN THIS WORK HAS BEEN OBTAINED BY THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS FROM SOURCES BELIEVED TO BE RELIABLE HOWEVER, NEITHER ASME NOR ITS AUTHORS OR EDITORS GUARANTEE THE ACCURACY OR COMPLETENESS OF ANY INFORMATION PUBLISHED IN THIS WORK NEITHER ASME NOR ITS AUTHORS AND EDITORS SHALL BE

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Cover Photo Courtesy of Nooter Corp

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PREFACE TO

SECOND EDITION

The ASME Boiler and Pressure Vessel Code, Section VIII, is a live and progressive document It strives to contain the latest, safe and economical rules for the design and construction of pressure vessels, pressure vessel components, and heat exchangers A major improvement was made within the last year by changing the design margin on tensile strength from 4.0 to 3.5, This reduction in the margin permits an increase in the allowable stress for many materials with a resulting decrease in minimum required thickness This was the first reduction in this design margin in 50 years and was based upon the many improvements in material properties, design methods, and inspection procedures during that time

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ACKNOWLEDGMENTS

We are indebted to many people and organizations for their help in preparing this book Special thanks are given to the Nooter Corporation, fellow Committee Members, and to former coworkers for their generous support during the preparation of the manuscript We also give thanks to Messrs Greg L Hollinger and George B Komora for helping with the manuscript, and to our editor Ray Ramonas at ASME for having great patience and providing valuable suggestions

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CONTENTS Preface V Acknowledgments vii List of Figures xi List of Tables xvil Chapter 1 Background Information 1 11 Introduction i 12 Allowable Stresses 2

1.3 Joint Efficiency Factors 3

1.4 Brittle Fracture Considerations 9

1.5 Fatigue Reguirements 19

1.6 Pressure Testing of Vessels and Cornponents 22

1.6.1 ASME Code Requirements 22

1.6.2 What Does a Hydrostatic or Pneumatic Pressure Test Do? 22

1.6.3 Pressure Test Requirements for VIH-1 23

1.6.4 Pressure Test Requirements for VIH-2 24

Chapter 2

Cylindrical Shells 27

24 lntroduction 27

2.2 Tensile Forces, VIH-I 27

2.2.1 Thin Cylindrical Shells 27

2.2.2 Thick Cylindrical Shells 33

2.3 Axial Compression 36

2.4 External Pressure 42

2.4.1 Extemal Pressure for Cylinders with Do/t = 10 43 2.4.2 External Pressure for Cylinders with Do/t < 10 46

2.4.3 Empirical Equations AT

24.4 Stiffening Rings 48

24.5 Attachment of Stiffening Ring: 50

25 Cylindrical Shell Equations, VIH-2 53 2.6 Miscellaneous Shels s4 2.6.1 Mitered Cylinders 54 2.6.2 Elliptical Shells 55 Chapter 3 Spherical Shells, Heads, and Transition Sections 57 3.1 Introduction 57

3.2 Spherical Shells and Hemispherical Heads, VIH-I àeeeeerrerrrtrrrerrmrereirerrrerreirrirrrrr 37

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3.4 EHipsoidal Heads, VII-1

3.4.1 Pressure on the Concave Side 3.4.2 Pressure on the Convex Side

3.5 Torispherical Heads, VII-1

3.5.1 Pressure on the Concave Side 3.5.2 Pressure on the Convex Side 3.6 Ellipsoidal and Torispherical Heads, VIIL 3.7 Conical Sections, VIH-1 3.7.1 Intemal Pressure 3.7.2 Extemal Pressure 3.8 Conical Sections, VHI-2 Chapter 4 Flat Plates, Covers, and Flanges 41 Introduction

42 Integral Flat Plates and Covers 4.2.1 Circular Flat Plates and Covers 4.2.2 Noncircular Flat Plates and Covers 43 Bolted Flat Plates, Covers, and Flanges

4.3.1 Gasket Requirements, Bolt Sizing, and Bolt Loadings 44 Flat Plates and Covers With Bolting

44.1 Blind Flanges & Circular Fiat Plates and Covers

44.2 Noncircular Flat Plates and Covers

45 Openings in Flat Plates and Covers

4.5.1 Opening Diameter Does Not Exceed Half the Plate Diameter 4.5.2 Opening Diameter Exceeds Half the Plate Diameter

46 Bolted Flange Connections With Ring Type Gaskets 4.6.1 Standard Flanges

4.6.2 Special Flanges

AT Sphericaly Dished Covers

4.7.1 Definitions and Terminology 4.7.2 Types of Dished Covers

Chapter 5

Openiings che, HH0 HH 1111121011110117011000111T1001En0nnnr.rerrir 3.4 Introduction

52 Code Bases for Acceptability of Opening 5.3 Terms and Definitions cscs

5.4 Reinforced Openings—General Requirements

5.4.1 Replacement Area 5.4.2 Reinforcement Limit

5.5 Reinforced Opening Rules, VHI-1

5.5.1 Openings With Inherent Compensation

5.5.2 Shape and Size of Openings

5.5.3 Area of Reinforcement Required 5.54 Limits of Reinforcement

5.5.5 Area of Reinforcement Available

5.5.6 Openings Exceeding Size Limits of Section 5.5.2.2 5.6 Reinforced Opening Rules, VI-2 .rerereesee 5.6.1 Definilion§ cu eHeiererererrrrrreriee

5.6.2 Openings Not Requiring Reinforcement Calculations 5.6.3 Shape and Size of Openings

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5.6.7 Strength of Reinforcement Metal 5.6.8 Altemative Rules for Nozzle Design 57 Ligament Efficiency Rules, VIII-1 Chapter 6 Special Components, VHI-1 6.1 Introducton

6.2 Braced and Stayed Construction

6.2.1 Braced and Stayed Surfaces

6.2.2 Stays and Staybolts

6.3 Jacketed Vessels

6.3.1 Types of Jacketed Vessels

63.2 Design of Closure: Member for Jacket to Vessel 6.3.3 Design of Openings in Jacketed Vessels

6.4 Half-Pipe lackebs eeeieerrierre

6.4.1 Maximum Allowable Internal Pressure in Half-Pipe Jacket 6.4.2 Minimum Thickness of Half-Pipe Jacket

6.5 Vessels of Noncircular Cross Seclon

6.5.1 Types of Vessels 6.5.2 Basis for Allowable Stresses

6.5.3 Openings in Vessels of Noncircular Cross Section

6.5.4 Vessels of Rectangular Cross Section Chapter 7 Design of Heat Exchangers 71 Introduction 72 Tubesheet Design in U-Tube Exchangers 7.2.1 Nomenclattre esreiierrrrrrrrerree 7.2.2 Design Equations for Simply Supported Tubesheets 7.2.3 Design Equations for Integral Construction

72.4 Design Equations for Integral Construction With Tubesheet Extended as a Flange 73 Fixed TubesheefS c chai 7.3.1 Nomenclature 7.3.2 Design Equations 1.4 Expansion Joints Chapter 8 Analysis of Components in VIIE-2 8.1 Introduction 8.2 Stress Categories 8.3 Stress Concentration 8.4 Combinations of Stresses 8.5 Fatigue Evaluation : On úÁẶÁố cac nh Appendices

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Figure Number 1.1 1.2 BII 13 B12 14 15 1.6 17 21 2.2 23 24 2.5 E2.8 2.6 27 £2.13 2.8 2.9 2.10 3.1 E3.4 3.2 3.3 3.4 35 3.6 3.7 E311 £3.12 £3.13 3.8 3.9 3.10 3.11 3.12 41 42 LIST OF FIGURES Welded Joint Categories (ASME VIII-1) Category C Weld Some Governing Thickness Details Used for Toughness (ASME VHI-1) Charpy Impact-Test Requirements for Full Size Specimens for Carbon and Low Alloy Steels

With Tensile Strength of Less Than 95 ksi (ASME VII-1) Reduction of MDMT Without Impact Testing (ASME VIII-1)

Fatigue Curves for Carbon, Low Alloy, Series 4XX, High Alloy Steels, and High Tensile Steels

for Temperatures Not Exceeding 700°F (ASME VII-2) Chart for Carbon and Low Alloy Steels With Yield Stress of 30 ksi and Over, and Types 405 & 410 Stainless Steels

C Factor as a Function of R/T (Jawad, 1994)

Geometric Chart for Cylindrical Vessels Under External Pressure (Jawad and Farr, 1989) Some Lines of Support of Cylindrical Shells Under External Pressure (ASME VIH-1) Some Details for Attaching Stiffener Rings (ASME VHI-1} Mitered Bend Elliptical Cylinder

Inherent Reinforcement for Large End of Cone-to-Cylinder Junction (ASME VIl-2) Values of QO for Large End of Cone-to-Cylinder Junction (ASME VII-2)

Inherent Reinforcement for Small End of Cone-to-Cylinder Junction (ASME VII-2) Values of Q for Small End of Cone-to-Cylinder Junction (ASME VHI-2)

Some Acceptable Types of Unstayed Flat Heads and Covers

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EAS E46 E47 43 E48 3.1 5.2 5.3 ES.1 E52 5.3.1 E5.3.2 E54 5.4.1 54,2 5.5 5.6 ES.5 E56 E5.7 6.1 62 643 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 E6.8 71 72 73 7.4 T5 7.6 7.7 7.8 79 7.10 71 7.12 E8 8.1 E84 8.2

Ring Flange Sample Calculation Sheet

Welding Neck Flange Sample Calculation Sheet Reverse Welding Neck Flange Sample Calculation Sheet Spherically Dished Covers With Bolting Flanges (ASME VIH-1) Example Problem of Spherically Dished Cover, Div 1

Reinforcement Limits Parallel to Shell Surface

Chart for Determining Value of F for Angle 8

Determination of Special Limits for Setting 1, for Use in Reinforcement Calculations Example Problem of Nozzle Reinforcement in Ellipsoidal Head, Div 1

Example Problem of Nozzle Reinforcement of 12 in X 16 in Manway Opening, Div 1

Example Problem of Nozzle Reinforcement of Hillside Nozzle, Div 1 Example Problem of Nozzle Reinforcement of Hillside Nozzle, Div 1 Example Problem of Nozzle Reinforcement With Corrosion Allowance, Div I

Nozzle Nomenclature and Dimensions (Depicts General Configurations Only) Limits of Reinforcing Zone for Alternative Nozzle Design

Example Problem of Nozzle Reinforcement in Ellipsoidal Head, Div 2

Example Problem of Nozzle Reinforcement of 12 in X 16 in Manway Opening, Div 2

Example Problem of Nozzle Reinforcement of Series of Openings, Div 1 Typical Forms o£ Welded Staybolts eireeier Typical Welded Stay for Jacketed Vessel

Some Acceptable Types of Jacketed Vessel Some Acceptable Types of Closure Details Some Acceptable Types of Penetration Details Spiral Jackets, Half-Pipe and Other Shapes Factor K for NPS 2 Pipe Jacket

Factor K for NPS 3 Pipe Jacket

Factor K for NPS 4 Pipe Jacket Vessels of Rectangular Cross Section

Vessels of Rectangular Cross Section With Stay Plates

Vessels of Obround Cross Section With and Without Stay Plates and Vessels of Circular Cross Section With a Stay Plate

Plate With Constant-Diameter Openings of Same or Different Diameter

Plate With Multidiameter Openings

Example Problem of Noncircular Vessel, Div 1

Various Heat-Exchanger Configurations (TEMA, 1999) Some Typical Tubesheet Details for U-Tubes (ASME, 2001) Tubesheet Geometry

Effective Poisson’s Ratio and Modulus of Elasticity (ASME, 2001) Chart for Determining À (ASME, 2001) Hee Fixiy Factor, # (ASME, 2001) ch rrreruên Some Typical Details for Fixed Tubesheet Heat Exchangers (ASME, 1995) Za, Z, and Zp, versus X, (ASME, 2001)

Values of Q; Between 0.0 and 0.8 Values of Q; Between 0.8 and 0.0 Beliows-Type Expansion Joints Flanged and Flued Expansion Joints

Linearizing Stress Distribution

Model of a Finite Element Layout in a Flat Head-to-Shell Junction

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Cl 255 C2 256 C3 257 C4 258 C5 259 có 260 C7 261 C8 262 c9 263 C.10 264 Cll 265 C12 266 c15 267 C14 268 C15 269 C.16 270 C17 271 C.18 272 CA9 273 C.20.E 274

DA D.1-—Ring Flange With Ring-Type 277

D.2 Fig D.2—Slip-On or Lap-Joint Flange With Ring-Type Gasket 278 D3 Fig D.3-—Welding Neck Flange With Ring-Type Gasket 279

D4 Fig D.4—-Reverse Welding Neck Flange With Ring-Type Gasket 280

D5 Fig D.5—Slip-On Flange With Full-Face Gasket 281

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Table Number 11 12 1.3 14 15 Ell 1.6 17 24 31 3.2 3.4 E3.14 6.1 6.2 6.3 8.1 82 8.3 84 8.5 8.6 E84 BỊ B2 B43 B4 B.5 List OF TABLES

Criteria for Establishing Allowable Stress Values for VIII-1 (ASME H-D) Criteria for Establishing Design Stress Infensity Values for VII-2 (ASME H-D) Stress Values for SA-515 and SA-516 Materials

Aliowable Stress Values for Welded Connections

Maximum Allowable Efficiencies for Arc- and Gas-Welded Joints Stress Categories

Assignment of Materials to Curves (ASME VHI-1)

Minimum Design Metal Temperatures in High Alloy Steels Without Impact Testing Tabular Values for Fig 2.4

Factor Ko for an Ellipsoidal Head With Pressure on the Convex Side Values of A for Junctions at the Large Cylinder Due to Internal Pressure Values of A for Junctions at the Small Cylinder Due to Internal Pressure

Values of A for Junctions at the Large Cylinder Due to External Pressure

AIlowable Stress and Pressure Data eeeieeirere Example of Pressure Used for Đesign of Componenls

Closure Detail Requirements for Various Types of Jacket Closures

Penetration Detail Requirements Primary Stress Category

Structural Discontinuity

Thermal Stress

Stress Categories and Their Limits (ASME VIN-2) Classification of Stresses (ASME VHI-2)

Some Stress Concentration Factors Used in Fatigue

Summary of Finite Element Output Carbon Steel Plate .à.oeeirere

Chrome-Moly Steel Plate Specifications, SA-387

Chrome-Moly Steel Forging Specifications, SA-182

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1

BACKGROUND INFORMATION

1.1 INTRODUCTION

In this chapter some general concepts and criteria pertaining to Section VIE are discussed These include allowable stress, factors of safety, joint efficiency factors, brittle fracture, fatigue, and pressure testing Detailed design and analysis rules for individual components are discussed in subsequent chapters

Since frequent reference will be made to ASME Section VII Divisions 1 and 2, the following designation will be used from here on to facilitate such references ASME Section VII, Division 1 Code will be designated by VIH-1 Similarly, VIII-2 will designate the ASME Section VHI, Division 2 Code Other ASME code sections such as Section II Part D will be referred to as II-D Equations and paragraphs referenced in each of these divisions will be called out as they appear in their respective Code Divisions Many design rules in VIII-1 and VIII-2 are identical These include flange design and external pressure

requirements In such cases, the rules of VIIJ-1 will be discussed with a statement indicating that the rules

of VIH-2 are the same Appendix A at the end of this book lists the paragraph numbers in VHI-1 that pertain to various components of pressure vessels

Section VIL requires the fabricator of the equipment to be responsible for its design Paragraphs UG- 22 in VU-1 and AD-110 in VUI-2 are given to assist the designer in considering the most commonly encountered loads They include pressure, wind forces, equipment loads, and thermal considerations When the designer takes exceptions to these loads either because they are not applicable or they are unknown, then such exceptions must be stated in the calculations, Similarly, any additional loading conditions considered by the designer that are not mentioned in the Code must be documented in the design calculations Paragraphs U-2(a) and U-2(b) of VII-1 give guidance for some design requirements VIH-2, paragraph AD-110 and the User’s Design Specifications mentioned in AG-301 provide the loading conditions to be used by the manufacturer

Many design rules in VII-1 and VIJI-2 are included in the Appendices of these codes These rules are for specific products or configurations Rules that have been substantiated by experience and used by industry over a long period of time are in the Mandatory Appendices New rules or rules that have limited applications are placed in the Non-Mandatory Appendices Non-Mandatory rules may eventually be transferred to the Mandatory section of the Code after a period of use and verification of their safety and practicality However, guidance-type appendices will remain in the Non-Mandatory section of the Code The rules in VIIL-1 do not cover all applications and configurations When rules are not available, Paragraphs U-2(d), U-2(g), and UG-101 must be used Paragraph U-2(g) permits the engineer to design components in the absence of rules in VIII-1 Paragraph UG-101 is for allowing proof testing to establish maximum allowable working pressure for components In VII-2 there are no rules similar to those in UG-101, since VII-2 permits design by analysis as part of its requirements This is detailed in Paragraphs

AD-100(b), AD-140, AD-150, and AD-160 of VIT-2

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1.2 ALLOWABLE STRESSES

The criteria for establishing allowable stress in VIU-1 are detailed in Appendix P of VIII-1 and Appendix 1 of TI-D and are summarized in Table 1.1 The allowable stress at design temperature for most materials is the lessor of 1/3.5 the minimum effective tensile strength or 2/3 the minimum yield stress of the material for temperatures below the creep and rupture values The controlling allowable stress for most bolts is 1/5 the tensile strength The minimum effective tensile stress at elevated temperatures is obtained from the actual tensile stress curve with some adjustments The tensile stress value obtained from the actual curve at a given temperature is multiplied by the lessor of 1.0 or the ratio of the minimum tensile stress at room temperature obtained from ASTM Specification for the given material to the actual tensile stress at room temperature obtained from the tensile strength curve This quantity is then multiplied by the factor 1.1 The effective tensile stress 1s then equal-to-the lessor of this quantity or:the minimum tensile ‘stress-at: room temperature given in ASTM This procedure is illustrated in example 4.1 of Jawad and Farr (reference 14, found at back of book)

The 1.1 factor discussed above is a constant established by the ASME Code Committee It is based on engineering judgment that takes into consideration many factors Some of these include increase in tensile strength for most carbon and Jow alloy steels between room and elevated temperature; the desire to maintain a constant allowable stress level between room temperature and 500°F or higher for carbon steels; and the adjustment of minimum strength data to average data Above approximately 500°F or higher the allowable stress for carbon steels is controlled by creep-rupture rather than tensile-yield criteria Some materials may not exhibit such an increase in tensile stress, but the criterion for 1.1 is still applicable to practically all materials in VIU-1

Table 1.1 also gives additional criteria for creep and rupture at elevated temperatures The criteria are

based on creep at a specified strain and rupture at 100,000 hours The 100,000 hours criterion for rupture corresponds to about eleven years of continual use However, VIII-1 does not limit the operating life of the equipment to any specific number of hours,

The allowable stress criteria in VUHI-2 are given in II-D of the ASME Code The allowable stress at the design temperature for most materials is the smaller of 1/3 the tensile strength or 2/3 the yield stress The design temperature for all materials in VIU-2 is kept below the creep and rupture values Table 1.2 summarizes the allowable stress criteria in VII-2

A sample of the allowable stress Tables listed in Section IL-D of the ASME Code is shown in Table 1.3 It lists the chemical composition of the material, its product form, specification number, grade, Unified Nambering System (UNS), size, and temper This information, with very few exceptions, is identical to that given in ASTM for the material The Table also lists the P and Group numbers of the material The P numbers are used to cross reference the material to corresponding welding processes and procedures listed in Section LX, ‘‘Welding and Brazing Qualifications,’’ of the ASME Code The Table also lists the minimum yield and tensile strengths of the material at room temperature, maximum applicable temperature limit, External Pressure Chart reference, any applicable notes, and the stress values at various temperatures The designer may interpolate between listed stress values, but is not permitted to extrapolate beyond the published values

Stress values for components in shear and bearing are given in various parts of VIII-1, VIII-2, as well as II-D Paragraph UW-15 of VII-1 and AD-132 of VIII-2 lists the majority of these values A summary of the allowable stress values for connections is shown in Table 1.4

Some material designations in ASTM as well as the ASME Code have been changed in the last 20 years The change is necessitated by the introduction of subclasses of the same material or improved properties Appendix B shows a cross reference between older and newer designations of some common materials

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TABLE 1.1 CRITERIA FOR ESTABLISHING ALLOWABLE STRESS VALUES FOR VIlI-1 (ASME II-D) Below Room

Temperature Room Temperature and Above

Tensile Yield Tensile Yield Stress Creep

Product/Material | Strength| Strength Strength Strength Rupture Rate Wrought orcast =| Sy 4% Sy Sy 13 5 % Sy 3⁄4 §yRy Fan Se ag 08S cain 1.0%

ferrous and 35 35 3A TỰ ar 0.9SyRy

nonferrous tNote t1

Welded pipe or 0.85 |[%x 0855, 10.85 5 | (2.2 0.85) % x 0.05Sy |#4 x0.855y8y (Fug ¥ 985)Sa nq | (0.8 X 0.85)Semin | 0-855 tube, ferrous and 73.5 °F 3g 3m TIẾT or 0.9 x 0.885/Êy

nonferrous {Note (97

NOTE:

(LY Two’ sets of ‘Allowable stress: values may be provided In Table-2A-for-austenitic.materials and.in Table 1B for specific nonferrous alloys ‘The lower values are not specifically identified by a footnote, These Jower values do not exceed two-thirds of the minimum yield strength at temperature The higher alternative allowable stresses are identified by a footnote Thase higher stresses may exceed two-thirds but do nat exceed 90% of the minimum yield sirength at temperature The higher values should be used only where slightly higher deformation ts

not in itself objectionable These higher stresses are not recommended for the design of flanges or for other strain sensitive applications

Nomenclature

R, = ratio of the average temperature dependent trend curve value of tensile strength to the room temperature tensile strength Ry = ratio of the average temperature dependent trend curve value of yield strength to the room temperature yield strength

Sra = average stress to cause rupture at the end of 100,000 hr Srmn = minimum stress to cause rupture at the end of 100,000 hr

Sc = average stress to produce a creep rate of 0.01%/1000 hr

S, = specified minimum tensile strength at room temperature, ksi Sy = specified minimum yield strength at room temperature

TABLE 1.2

CRITERIA FOR ESTABLISHING DESIGN STRESS INTENSITY VALUES FOR VIII-2

(ASME ILD)

Product/Material Tensile Strength Yield Strength

Wrought or cast, ferrous and nonferrous WY Sr Al Sek ¥%, Sy % SyRy or 3 nr 0.95 )Ry LNate (1)3 Welded pipe or tube, ferrous and nonferrous 0.85 Sy (11 x 0.85) SR 0.85 Sy 0.85 SyRy or 3 3 1.5 15 (0.9 x 0.85) SyRy ENote (21 NOTE:

{1) Two sets of allowable stress values may be provided In Table 1A for austenitic materials and in Table 28 for specific nonferrous afloys The {ower values are not specifically identified by a footnote These lower values do not exceed two-thirds of the minimum yield strength at temperature The higher alternative allowable stresses are identified by a footnote These higher stresses may exceed two-thirds but do not exceed 90% of the minimum yield strength at temperature The higher values should be used only where slightly higher deformation is not in Hself objectionable These higher stresses are not recommended for the design of flanges or for other strain sensitive applications

13 JOINT EFFICIENCY FACTORS

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TABLE 1.3 STRESS VALUES FOR SA-515 AND SA-516 MATERIALS Alloy Class/

Line Nominal Product Spec Desig./ Cond/ Size/ Group

No Composition Form No Type/Grade UNS No Temper Thick, in P-No No

28 cs Plate SA-515 70 «03101 1 2

29 cs Plate SA-516 70 K02700 1 2

Min Min Applic & max Temp Limits External

Tensile Yield (NP = Not Permitted) Pressure

Line Strength Stress (SPT = Supports only) Chart

No ksi ksi | ul Vili-t No Notes 28 70 38 1000 700 1000 CcS-2 G10, S1, T2 2g 70 38 850 700 1000 GS2 G10, S1, T2 Maximum Altowable Stress, ksi, for Metal Temperature, °F, Not Exceeding Line No —20 to 100 150 200 300 400 500 600 650 700 760 800 850 900 28 20.0 20.0 20.0 20.0 20.0 20.0 19.4 18.8 18.4 14.8 12.0 9.3 6.7 29 20.0 20.0 20.0 20.0 20.0 20.0 19.4 18.8 18.1 14.8 12.0 9.3 6.7 Note:

G10, $1, T2 are described in #-D and pertain to metallurgical information

factors of safety, depending on the degree of radiographic examination of the main vessel joints As an example, fully radiographed longitudinal butt-welded joints in cylindrical shells have a Joint Efficiency Factor, £, of 1.0 This factor corresponds to a safety factor of 3.5 in the parent material Nonradiographed longitudinal butt-welded joints have an E value of 0.70 This reduction in Joint Efficiency Factor corresponds to a factor of safety of 5.0 in the plates This higher factor of safety due to a nonradiographed joint results in a 43% increase in the required thickness over that of a fully radiographed joint

ASME VIII-1 identifies four joint categories that require E factors They are Categories A, B, C, and D as shown in Fig 1.1 Category A joints consist mainly of longitudinal joints as well as circumferential joints between hemispherical heads and shells Category B joints are the circumferential joints between various components as shown in Fig 1.1, with the exception of circumferential joints between hemispherical heads and shells The attachment of flanges to shells or heads is a Category C joint The attachment of nozzle necks to heads, shells, and transition sections is categorized as a Category D joint

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TABLE 1.4 ALLOWABLE STRESS VALUES FOR WELDED CONNECTIONS Vill-4

Component Type of Stress Stress Value Reference

Fillet weld tension 0.55S* UW-18(d)

Fillet weld shear 0.498 UW-15(c)

Groove weld tension 0.748 UW-15(c)

Groove weld shear 0.60S UW-15(c)

Nozzle neck shear 09/706 UG-4B(c)

Dowel bolts shear 0.808 H-Ð

Any location bearing 1.808 II-Ð

*S = allowable stress for Vitl-4 construction

VỊi-2

Component Type of Siress Stress Value Reference

Fillet weld tension 0.5S,," AD-920

Fillet weld shear 0.5Sn AD-920

Groove weld tension 0.758, AD-920

Groove weld shear 0.755, AD-920

Nozzle neck shear 0.6S,, AD-132.2

Any location bearing &, AD-132.1

*S,, = stress intensity values for VIH-2 construction â đ mm £ : C () (4 |.® A) | (A Ce Là À Š 8 B ® FIG 1.1 WELDED JOINT CATEGORIES (ASME Vill-1)

The type of construction and joint efficiency associated with each of joints A, B, C, and D is given in Table 1.5 The categories refer to a location within a vessel rather than detail of construction Thus, a Category C weld, which identifies the attachment of a flange to a shell, can be either fillet, comer, or butt welded, as illustrated in Fig 1.2 The Joint Efficiency Factors apply only to the butt-welded joint in sketch (c) The factors do not apply to sketches (a) and (b) since they are not butt welded

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TABLE 1.5 MAXIMUM ALLOWABLE JOINT EFFICIENCIES'® FOR ARC- AND GAS-WELDED JOINTS Degree of Radiographic Examination

Type Joint doint a b ở

No Description Limitations Category Full? Spot? None

) Butt joints as attained by None A,B, C&D 1.0 0.85 0.70

double-welding or by other

means which wil! obtain the

same quality of deposited

weld metal on the inside and outside weld’ surfaces to agree with the requirements

of UW-35 Welds using metal

backing strips which remain in place are excluded

(2) Single-welded butt joint with (a) None except as shown in A,B, C&D 0.90 0.80 0.65 backing strip other than {b} below

those included under (1) (0) Circumferential butt joints A,B&C 090 080 065

with one plate offset, see

UW-13(¢) and Fig UW- 18.1(k)

@® Single-weided butt joint without — Circumferential butt joints only, A,B&C NA NA 0.60 use of backing strip not over 5/8 in thick and not

over 24 in outside diameter

(4 Doubie full fillet fap joint Longitudinal joints not over A NA NA 0.55

9/8 in thick

Circumferential joints not over Bac NA NA 0.55 5/8 in, thick

{5} Single full fillet lap joints with (a) Circurnferential joints‘ for B NA NA 0.50 plug welds conforming to attachment of heads not over

UW-17 24 in outside diameter to shells not over 1/2 in thick

{b) Circumferential joints for the

attachment to shells of c NA NA 0.50

jackets not over 5/8 in in

nominal thickness where the distance from the center of the plug weld to the edge of

the plate is not jess than

1-1/2 times the diameter of

the hole for the plug

(6) Single full fillet lap joints (a) For the attachment of A&B NA NA 0.45 without plug welds heads convex to pressure to

shelis not over 5/8 in required thickness Only with use of filet weld on inside of

shells, or

(b) For attachment of heads A&B NA NA 0.45

having pressure on either

side To shells not over 24 in inside diameter and not over 1/4 in required thickness with fillet weld on outside of head flange only Notes:

(1) The singie factor shown for each combination of joint category and degree of radiographic examination replaces both the stress

reduction factor and the joint efficiency factor considerations previously used in this Division

(2) See UW-12(a) and UW-57

(3) See UW-12(b} and UW-52

(4) Joints attaching hemispherical heads to shells are excluded

(5) E = 1.0 for butt joints in compression

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Example 1.1 Problem

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bar The shell side is not radiographed The longitudinal and circumferential seams m and 1 are single-

welded butt joints with backup bars The jacket longitudinal seam, n, is a single-welded butt joint without backup bar Solution The joint categories of the various joints can be tabulated as given in Table E1.1: TABLE E1.1 STRESS CATEGORIES

Joint Location Category Joint Efficiency

(ay Channelo-flange connection Cc Does not apply

(b) Longitudinal channel seam A 0.80

{c) Channei-to-tubesheet weld Cc Does not apply

{d) Nozzle-to-channel weid D Does not apply

(e) Flange-to-nozzie neck Cc Does not apply

(f) Pass partition-to-tubesheet weid None Does not apply See also UW-15(c) and

UW-18(d) of VIH-1

{g) Tube-to-tubesheet weld None Does not apply See also UW-20 of VIll-1 (h) Shell-to-tubesheet weld Cc Does not apply

@ Jacket bar-to-inner-shell weld None Does not apply 0) Jacket to bar-io-outer-shell weld None Does not apply

(k) Nozzie-to-jacket weld D Does not apply

@ Longitudinal shell seam A 0.65

(m) Head-to-shell seam B 0.65

{n) Longitudinal jacket seam A 0.60

(o) Skirt-to-head seam None Does not apply

1.4 BRITTLE FRACTURE CONSIDERATIONS

Both VII-1 and VII-2 require the designer to consider brittle fracture rules as part of the material and design selection The rules for carbon steels are extensive and are discussed first VII-1 has two options regarding toughness requirements for carbon steels The first is given in Paragraph UG-20(f) and allows the designer to exempt the material of construction from impact testing when all of the following criteria

are met:

The material is limited to P-No 1, Gr No 1 or 2

Maximum thickness of 1/2 in for materials listed in Curve A in Table 1.6

Maximum thickness of 1 in for materials listed in Curves B, C, and D of Table 1.6 The completed vessel shall be hydrostatically tested per UG-99(), (), or 27-3, Design temperature is between — 20°F and 650°F

Thermal, mechanical shock, and cyclical loadings do not control the design Dawa

WN

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TABLE 1.6

ASSIGNMENT OF MATERIALS TO CURVES (ASME VIII-1)

GENERAL NOTES ON ASSIGNMENT OF MATERIALS TO CURVES:

(a) Curve A applies to:

(1) ail carbon and all tow alloy steel plates, structural shapes, and bars not listed in Curves B, C, and D below; (2) $A-216 Grades WCB and WCC Hf sormatized and tempered or water-quenched and tempered; SA-217 Grade WC6 If

normalized and tempered or water-quenched and tempered,

tb) Curve B applies to:

(2) SA-216 Grade WCA if normalized and tempered or water-quenched and tempered

SA-216 Grades WCB and WCC for thicknesses not exceeding 2 In, if produced to fine grain practice and water-quenched and tempered

SA-217 Grade WC9 if normalized and tempered

SA-285 Grades A and B

SA-414 Grade A SA-525 Grade 60

SA-5Sl6 Grades 65 and 70 if not normalized

SAcb12-4f.not-normailzed SA-662 Grade B if not normalized;

except for cast steels, all materials of Curve A if produced to fine grain practice and normalized which are not listed In Curves € and D below;

(2) all pipe, fittings, forgings and tubing not listed for Curves € and D below;

{4) parts permitted under UG-21 shall be included in Curve B even when fabricated from plate that otherwise would be assigned to

a different curve ;

Curve © :

(3) SA-182 Grades 21 and 22 if normalized and tempered

SA-302 Grades C and D

SA-336 F21 and F22 Hf normalized and tempered SA-387 Grades 21 and 22 if normalized and tempered

SA-516 Grades 55 and 60 If not normalized $A-533 Grades B and € SA-662 Grade A; (2) all material of Curve B if produced to fine grain practice and normalized and not listed for Curve D below, Curve D SA-203 SA-508 Grade 1 SA-516 if normalized SA-524 Classes 1 and 2 SA-537 Classes 1, 2, and 3 SA-612 if normalized SA-662 if normalized SA-738 Grade A $A-738 Grade A with Ca and V deliberately added in accordance with the provisions of the material specification, not colder than 20°F (~29°C)

SA-738 Grade B not colder than ~20°F {~29°C}

(e} For bolting and nuts, the following impact test exemption temperature shall apply: (2 te td: Bolting Impact Test Spec No Grade Exemption Temperature, °F SA-193 B5 ~20 SA-193 B? (2% in dia and under) -55

(Over 2% in to 7 in, incl.) „0 SA-93 B7M ~55 SA-193 B16 -20 SA-307 B ~20 SA-320 7, L7A, L?M, L43 lmpact tested SA-325 1,2 ~20 SA-354 BC o SA-354 B0 +20 SA-449 v ~20 SA-540 B23/24 +10 Nats Impact Test Spec No Grade Exemption Temperature, °F SA-194 2, 2H, 2HM, 3, 4, 7, 7M, -5 and 16 SA-540 B23/824 55

(f) When po class or grade is shown, ail classes or grades are included {g) The fotlowing shali apply to ali materiat assignment notes

(1) Cooling rates faster than those obtained by cooling in air, followed by tempering, as permitted by the material specification, are considered to be equivalent to normalizing or normatizing and tempering heat treatments,

(2) Fine grain practice is defined as the procedure necessary to obtain a fine austenitic grain size as described in SA-20

NOTES:

{1) Tabular values for this Figure are provided in Table UCS-66

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steel ot those with carbon steel operating beyond the scope of Paragraph UG-20(£) require an evaluation for brittle fracture in accordance with the rules of UCS-66 The procedure consists of

1 Determining the governing thickness in accordance with Fig 1.3

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AB ta ta Pressure part Pressure part tgt = thinner of ty or tg : (ff Welded Attachments as Defined in UCS-66(a) FIG 1.3 (CONT'D)

3 The temperature obtained from Fig 1.4 may be reduced in accordance with Fig 1.6 if the component operates at a reduced stress This is detailed in Paragraph UCS-66(b) of VHI-1 At a ratio of 0.35 in Fig 1.6, the permitted temperature reduction drops abruptly At this ratio, the stress in a component is about 6000 psi At this stress level, experience has shown

that brittle fracture does not occur regardless of temperature level

4, The rules in VIIL-1 also allow a 30°F reduction in température below that obtained from Fig 1.4 when the component is post-weld heat treated but is not otherwise required to be post-weld heat treated by VIII-1 rules

The toughness rules for ferritic steels with tensile properties enhanced by heat treatment are given in Paragraph UHT-6 of VIH-I The rules require such steels to be impact tested regardless of temperature The measured lateral expansion as defined by ASTM E-23 shall be above 0.015 in

The toughness rules for high alloy steels are given in Paragraph UHA-51 of VII-1 The permissible Minimum Design Metal Temperature for base material is summarized in Table 1.7, Similar data are given in VIII-1 for the weld material and weld qualifications Thermally heated stainless steels may require impact testing per the requirements of UHA-5i(c)

The rules for toughness in VII-2 are different than those in VIII-1 However, the concepts of exemption curves and Charpy impact levels are similar in VIII-2 and VIU-1 The toughness requirements for carbon and low alloy steels are given in Paragraph AM-218 of VIII-2 High alloy steels are covered in Paragraph

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Example 1.2

Problem

Determine the Minimum Design Metal Temperature, MDMT, for the reactor shown in Fig E1.2 Let the shell, head, pad, and ring material be SA-516 Gr 70 material Flange and cover material is SA-105 Pipe material is SA-106 The required shell thickness is 1.75 in., and the required head thickness is 0.86 in The required nozzle neck thickness is 0.08 in Assume a joint efficiency of 1.0 and no corrosion allowance

Solution

Shell

SA-516 specifications require the material to.be normalized when the thickness exceeds 1.5 in Thus, from Table 1.6, Curve D is to be used for normalized SA-516 Gr 70 material Using Fig 1.4 and a governing thickness of 2.0 in., we get a minimum temperature of ~5°F The ratio of required thickness to actual thickness is 1.75/2.0 = 0.88 Using Fig 1.6 for this ratio, we obtain 12°F Hence, MDMT = —5 — 12

= —17°F

Head

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| | 140 † | 120 | a ị — 100 | „1 Lene s0 | ˆ s ue a # | / L] Ễ 60 | 4 +” —_ Ễ | / — Cee | ” Pools 4 — 5 | ƒ ⁄ 1 | ee a é 20 ⁄ sa Lan” _ Š so { a | M Z - tA lỆ ⁄ -40 Ị 7 (eo =¬1 E †+-Y-+ -— —-=—_—=— | impact testing required J -80 0.394 1 2 3 4 5

Nominai Thickness, in (Limited to 4 in for Welded Construction}

FIG 1.4

IMPACT-TEST EXEMPTION CURVES (ASME VII-1)

Stiffener

For a 0.75-in stiffener, Curve B of Table 1.6 is to be used Using Fig 1.4 and a governing thickness of 0.75 in., we obtain a minimum temperature of 15°F Since stresses cannot be established from VIIl-1 rules,

the MDMT = 15°F

Pad

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II 0,394 in 50 Minimum specified 40 yield strength > 66 ksi 5 +? Ệ 3 9 Ễ so 56 ksi > 5 § wf ea 5O ksi § +4 -> 5 Ly ”, Lư” sisi | 2 : # 20 La Mo > < 38 ksi ° > a 15 16 PL td te ——_— ene tie inf sami ene sere mee foment afer 9 1.0 2.0 73.0 Maximum Nominal Thickness of Material or Weld, in GENERAL NOTES:

{a} Interpolation between yield strengths shown is permitted,

{b) The minimum impact energy for one specimen shall not be less than 2/3 of the average energy required for three specimens

{c} Materials produced and impact tested in accordance with SA-320, SA-333, SA-334, SA-350, SA-352, SA-420 and SA-765 do not have to satisfy these energy values They are acceptable for use at minimum design metal temperatyre not colder than the test temperature when the energy vatues required by the applicable

specification are satisfied

id) For materials having a specified minimum tensile strength of 95 ksi or more, see UG-84(61(41(b)

FIG 1.5

CHARPY IMPACT-TEST REQUIREMENTS FOR FULL SIZE SPECIMENS FOR CARBON AND LOW ALLOY STEELS WITH TENSILE STRENGTH OF LESS THAN 95 ksi

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1.00 0.80 0.60 ` 0.40 ie 0.35 a See UCS-66(b)(3) when ratios are 0.35 and smaller 0.20 Ratio: tp-E* / (f,—c); See Nomenclature for Alternative Ratio 0.00 9 20 40 60 80 100 120 140 °F [See UCS-66(b)]

Nomenclature (Note references to General Notes of Fig UCS-66.2.)

tp = required thickness of the component under consideration in the corroded condition for all applicable loadings [General Note (2}], based on the

applicable joint efficiency E [General Note (3)1, in

tq = nominal thickness of the component under consideration before corrosion allowance is deducted, in

¢ = corrosion allowance, in

E* = as defined in General Note (3)

Alternative Ratio S* E* divided by the product of the maximum allowable stress value from Table UCS-23 times E, where S* is the applied general

primary membrane tensile stress and £ and E* are as defined in General Note (3)

FIG 1.6

REDUCTION OF MDMT WITHOUT IMPACT TESTING (ASME VIII-1)

Nozzle Neck

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TABLE 1.7 MINIMUM DESIGN METAL TEMPERATURES IN HIGH ALLOY STEELS WITHOUT IMPACT TESTING Base Material | Austenitic chromium-nicke! stainless steel ts material 304, 304L, 316, S16L, 321, 347 IsC<0.1% [-320°F| | ssr Austenitic chromium- manganese-nickel stainless steel (200 series) IBC < 0.1% Yes No |-820°F ~58°F | 1s material ® Austenitic ferritic duplex stee! with t< 3/8 in @ Ferritic chromium stainless steel with t< 1/8 in

@ Martensitic chromium stainiess steel with t< 1/4 in Yes No Impact test Other materiais and/or thickness impact fest Flange Since the flange is ANSI B16.5, it is good to ~ 20°F Cover From Fig 1.3(c), the controlling cover thickness is 2.5/4 = 0.625 in Curve B applies for this material, and the MDMT = S°F

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L5 FATIGUE REQUIREMENTS

Presently, VIH-1 does not list any rules for fatigue evaluation of components When fatigue evaluation of a component is required in accordance with UG-22 or U-2(g) of VIT-1, the general practice is to use the VIIL-2 fatigue criteria as a guidance up to the temperature limits of VIII-2 At temperatures higher than those given in VHI-2, the rules of HI-H are followed for general guidance Other fatigue criteria, such as those given in other international codes and ASME B31.3, may also be considered as long as the requirements of U-2(g) of VITL-1 are met

VIH-2 contains detailed rules regarding fatigue Paragraph AD-160 gives criteria regarding the need for fatigue analysis The first criterion is listed in Paragraph AD-160.1 and is based on experience Vessels that have operated satisfactorily in a certain environment may be cited as the basis for constructing similar vessels operating under similar conditions without the need for fatigue analysis

The second criterion for vessel components is based on the rule that fatigue analysis i8 not required if all of Condition A or all of Condition B is satisfied, as noted below

Condition A

Fatigue analysis is not required for materials with a tensile strength of less than 80 ksi when the total number of cycles in (a) through (d) below is less than 1000

a The design number of full range pressure cycles including startup and shutdown

b, The number of pressure cycles in which the pressure fluctuation exceeds 20% of the design pressure

c Number of changes in metal temperature between two adjacent points These changes are multiplied by a factor obtained from the following chart in order to transform them to equivalent cycle number

Metal Temperature Differential, °F Factor 50 or less 9 51 to 100 1 101 to 150 2 151 to 250 4 251 to 350 8 351 to 450 12 Higher than 450 20

d Number of temperature cycles in components that have two different materials where a difference in the value (a, ~ o)AT exceeds 0.00034 Where, « is the coefficient of thermal expansion and AT is the difference in temperature

Condition B

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a The number of full range pressure cycles, including startup and shutdown, is less than the number of cycles determined from the appropriate fatigue chart, Fig 1.7, with an 5, value equal to 3 times the allowable design stress value, S,,

b, The range of pressure fluctuation cycles during operation does not exceed P(/3)(5,/5n), where P is the design pressure, S, is the stress obtained from the fatigue curve for the number of significant pressure cycles, and S,, is the allowable stress Significant pressure cycles are defined as those that exceed the quantity P(1/3)(8/S,,) S is defined as

S = S, taken at 10° cycles when the pressure cycles are = 10%

§ = §, taken at actual number of cycles when the pressure cycles are >10°,

c The temperature difference between adjacent points during startup and shutdown does not exceed S,/(2Ew), where S, is the value obtained from the applicable design fatigue curve for.the.total specified number.of startup and shutdown cycles

d The temperature difference between adjacent points during operation does not exceed S,/QEa), where S, is the value obtained from the applicable design fatigue curve for the total number of significant fluctuations Significant fluctuations is defined as those exceeding the quantity S/(2Ea), where S is as defined in (b) above Adjacent points are defined in AD-

160.2, Condition A, Paragraph (c) of VIM-2

e Range of significant temperature fluctuation in components that have materials with different coefficient of expansion or modulus of elasticity and that do not exceed the quantity 9,/[2ŒE œ — Ea; o¿)], where o is the coefficient of thermal expansion and E is the modulus of elasticity Significant temperature fluctuation is that which exceeds the value S/(2(E, œ¡

— EF, o)], where S is as defined in (b) above

f Range of mechanical loads does not result in stress intensities whose range exceeds the S, value obtained from the fatigue chart

NOTES: {1) E = 30 x 10 pai {2) interpolate for UTS 80-115 ksi,

(3} Table §-116.3 containg tabulated values and a formuta for ar accurate interpolation of these curves T TTTIIT For UTS < BO ksi É Values of Sg, Pi a 108 = =< - ÔNG - TS —, For UTS 115-130 kei lR — — F ~ ¬~— m———_| B ¬ ——_ ~~ tot Lot bo 1 L2 a1 LẮ LLL Ha AAU 10 10? 103 108 108 108 Number of Cycles ‘FIG 1.7