pressure vessel design asme guide

1

Overview of Pressure Vessel Design

Instructor’s Guide

2

CONTACT INFORMATION

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You can also find information on these courses and all of ASME, including ASME Professional Development, the Vice President of Professional Development, and other contacts at the ASME Web site......

http://www.asme.org

3


By:

Vincent A. CarucciCarmagen Engineering, Inc.

Copyright © 1999 by

All Rights Reserved

4

TABLE OF CONTENTS

Abstract………………………………………………………………… 5

Introduction…………………………..…………………………………6

Organizing Unit Responsibilities……………………………………..7

Instructor Guidelines and Responsibilities………………………….9

Overview of Pressure Vessel Design Outline/Teaching Plan…………………………………………………………11

Instructor Notes……………………………………………………….13

Appendix A: Reproducible Overheads

Appendix B: Course and Instructor Evaluation Form

Appendix C: Continuing Education Unit (CEU) Submittal Form Course Improvement FormInstructor’s Biography Form

5

ABSTRACT

Pressure vessels are typically designed, fabricated, installed, inspected, and tested in accordance with the ASME Code Section VIII. Section VIII is divided into three separate divisions. This course outlines the main differences among the divisions. It then concentrates on and presents an overview of Division I. This course also discusses several relevant items that are not included in Division I.

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INTRODUCTION

This Overview of Pressure Vessel Design course is part of the ASME International Career Development Series – an educational tool to help engineers and managers succeed in today’s business/engineering world. Each course in this series is a 4-hour (or half-day) self-contained professional development seminar. The course material consists of a participant manual and an instructor’s guide. The participant manual is a self-contained text for students/participants, while the guide (this booklet) provides the instructional material designed to be presented by a local knowledgeable instructor with a minimum of preparation time.

The balance of this instructor’s guide focuses on:

1. Organizing Unit Responsibilities2. Instructor Guidelines and Responsibilities3. Comprehensive teaching materials which may be used “as is” or adapted

to incorporate experiences and perspective of the instructor.

Welcome to the ASME International Career Development Series! We wish you all the best in your presentation, operation and delivery of this course.

11

Suggested Outline/Teaching Plan

Time,min.

MajorInterval

Class Segment Sub-SegmentInterval

Sub-Segment Overheads/Participant

Pages5 Introduction/Logistics

Outline ModuleOV – 1Part. – 65

10 Introduction

5 Module based primarily on theASME Code Section VIII, Division1. Divisions 2 and 3 will be brieflydescribed

OV – 2Part. – 65

10 Main Pressure Vessel Components OV – 3-9Part. – 67

10 Scope of ASME Code Section VIII• Division 1• Division 2• Division 3

OV – 10-13Part. – 75

25 General

5 Structure of Section VIII, Division 1 OV – 14Part. –78

15 Material Selection Factors• Strength• Corrosion Resistance• Resistance to Hydrogen Attack• Fracture Toughness• Fabricability

OV – 15-31Part. – 79

20 Materials ofConstruction

5 Maximum Allowable Stress OV – 32-34Part. – 87

10 Exercise 10 Material Selection Based On FractureToughness

OV – 35-38Part. – 91

10 Break 1010 Design Conditions and Loadings

• Pressure• Temperature• Other Loadings

OV – 39-43 Part. – 92

25 Design for Internal Pressure• Weld Joints• Cylindrical Shells• Heads• Conical SectionsSample Problem

OV – 44-55 Part. - 98

55 Design

20 Design for External Pressure andCompressive Stresses• Cylindrical Shells• Other Components• Sample Problem

OV – 56-65 Part. – 109

12

Suggested Outline/Teaching Plan, continued

Time,min.

Major

Interval

Class Segment Sub-SegmentInterval

Sub-Segment Overheads/Participant

Pages10 - 50 Major Break Lunch or Major Break

15 Exercise 15 Required Thickness for InternalPressure

OV – 66-68Part. - 118

20 Reinforcement of Openings (IncludeSample Problem)

OV – 69-84Part. – 119

10 Flange Rating (Including SampleProblem)

OV – 85-90Part. – 127

15 Flange Design OV – 91-97Part. – 131

50 Design(Cont’d.)

5 Maximum Allowable WorkingPressure (MAWP)

OV – 98Part. – 138

10 Break10 Local Loads OV – 99

Part. – 13920 Other Design

Considerations10 Vessel Internals OV – 100-102

Part. – 14110 Acceptable Welding Details OV – 103-106

Part. – 14320 Fabrication

10 Postweld Heat Treatment(PWHT)Requirements

OV – 107Part. – 146

10 Inspection OV – 108-113Part. – 148

15 Inspection andTesting

5 Pressure Testing OV – 114-115Part. – 152

10 Closure 10 SummaryQuestionnaire (fill in and collect)CEU Form (hand out – individualresponsibility to return)

OV – 116Part. - 155

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Instructor’s Personal Notes

Instructor’s Outline

1. Course discusses pressure vessel design and is introductory in nature.

2. Based on ASME Code Section VIII.

3. Preliminary emphasis is on Division 1 but Divisions 2 and 3 are highlighted.

4. Introduces several items that are not covered in the ASME Code.

Major Learning Points

Course Introduction

1

OVERVIEW OFPRESSURE VESSEL DESIGN

By: Vincent A. CarucciCarmagen Engineering, Inc .

14




1. The objective: Provide a general knowledge of design requirements for pressure vessels.

2. This is not a comprehensive course. It provides sufficient information for management personnel to have an overall understanding of this subject. Individuals having more detailed responsibility will receive a solid starting point to proceed further.

3. Review outline.

4. Establish schedule.

5. Participation is key:

• Questions

• Discussion/interaction


• Establish course objectives.

• Outline course content, a road map.

2

Course Overview

• General

• Materials of Construction

• Design

• Other Design Considerations

• Fabrication

• Inspection and Testing

15




1. Describe what a pressure vessel is.

2. Note that pressure vessels are used in a wide variety of industries. They can be designed for a wide variety of conditions and in a broad range of sizes.


• Define pressure vessels.

• Identify wide variety of industrial applications.

3

Pressure Vessels• Containers for fluids under pressure

• Used in variety of industries– Petroleum refining– Chemical– Power– Pulp and paper– Food

16




1. Use this and following overheads to describe main pressure vessel components and shapes.

2. Shell is primary component that contains pressure. Curved shape.

3. Vessel always closed by heads.

4. Components typically welded together.

5. Vessel shell may be cylindrical, spherical, or conical.

6. Multiple diameters, thicknesses or materials are possible.

7. Saddle supports used for horizontal drums.

• Spreads load over shell.

• One support fixed, other slides.


Main pressure vessel components and configurations.

4

Horizontal Drum onSaddle Supports

Figure 2.1

Nozzle

ShellA

A

Head

Saddle Support(Fixed)

Saddle Support(Sliding)

Head

Section A-A

17




1. Most heads are curved shape for strength, thinness, economy.

2. Semi-elliptical shape is most common head shape.

3. Small vertical drums typically supported by legs.

• Typically maximum 2:1 ratio of leg length to diameter.

• Number, size, and attachment details depend on loads.


Main pressure vessel components and shapes.

5

Vertical Drum on Leg Supports

Figure 2.2

Head

Shell Nozzle

Head

SupportLeg

18




1. Nozzles used for:

• Piping systems

• Instrument connections

• Manways

• Attaching other equipment

2. Ends typically flanged, may be welded.

3. Sometimes extend into vessel.



6

Tall Vertical Tower

Figure 2.3

Trays

NozzleHead

Shell

Nozzle

Cone

Shell

Nozzle

NozzleSkirtSupport

Head

19




1. Skirt supports typically used for tall vertical vessels:

• Cylindrical shell

• Typically supported from grade

2. General support design (not just for skirts)

• Design for weight, wind, earthquake.

• Pressure not a factor.

• Temperature also a consideration for material selection and thermal expansion.



7

Vertical Reactor

Figure 2.4

InletNozzle

Head

Shell

UpperCatalyst

Bed

Catalyst BedSupport Grid

LowerCatalyst

BedOutletCollector

Head

SupportSkirt

OutletNozzle

20




1. Spherical storage vessels typically supported on legs.

2. Cross-bracing typically used to absorb wind and earthquake loads.



8

Spherical Pressurized Storage Vessel

Figure 2.5

CrossBracing

SupportLeg

Shell

21




1. Vessel size limits for lug supports:

• 1 – 10 ft diameter

• 2:1 to 5:1 height/diameter ratio

2. Vessel located above grade.

3. Lugs bolted to horizontal structure.


Main pressure vessel components and configurations.

9

Vertical Vessel on Lug Supports

Figure 2.6

22




1. Section VIII is most widely used Code.

2. Assures safe design.

3. Three divisions have different emphasis.


Define scope of ASME Code Section VIII.

10

Scope of ASME CodeSection VIII

• Section VIII used worldwide• Objective: Minimum requirements for safe

construction and operation• Division 1, 2, and 3

23




1. Review scope of Division 1.

2. Division 1 not applicable below 15 psig.

3. Additional rules required above 3000 psig.

4. Items that are connected to pressure vessels not covered by Division 1, except for:

• Their effect on pressure part.

• Welded attachment to pressure part.


• Scope of Division 1

• Exclusions from scope

11

Section VIII Division 1• 15 psig < P ≤ 3000 psig• Applies through first connection to pipe• Other exclusions

– Internals (except for attachment weld to vessel)– Fired process heaters– Pressure containers integral with machinery– Piping systems

24




1. Review differences between Divisions 1 and 2.

2. Division 2 allowable membrane stress is higher.

3. Division 2 requires more complex calculations.

4. Division 2 does not permit some design details that are permitted in Division 1.

5. Division 2 requires more stringent material quality control, fabrication, and testing requirements.


Differences between Division 1 and 2.

12

Section VIII, Division 2,Alternative Rules

• Scope identical to Division 1 butrequirements differ– Allowable stress– Stress calculations– Design– Quality control– Fabrication and inspection

• Choice between Divisions 1 and 2 based oneconomics

25




1. Review application of Division 3.

2. Newest Division of Section VIII and has least applicability.

3. After this point, this course only addresses Division 1 requirements when code-specific items are discussed.


Scope of Division 3

13

• Applications over 10,000 psi• Pressure from external source, process

reaction, application of heat, combinationof these

• Does not establish maximum pressurelimits of Division 1 or 2 or minimum limitsfor Division 3.

Division 3, Alternative RulesHigh Pressure Vessels

26




1. Review Division 1 organization

2. Fabrication methods:

• Welded

• Forged

• Brazed

3. Material classes

• Carbon and low-alloy steel

• Non-ferrous metals

• High alloy steel

• Cast iron

• Clad and lined material

• Ductile iron

• Heat treated steels

• Layered construction

• Low-temperature material

4. Highlight several mandatory and nonmandatory appendices.


Basic organizational structure of Division 1.

14

Structure of Section VIII,Division 1

• Subsection A– Part UG applies to all vessels

• Subsection B– Requirements based on fabrication method– Parts UW, UF, UB

• Subsection C– Requirements based on material class– Parts UCS, UNF, UHA, UCI, UCL, UCD, UHT,

ULW, ULT

• Mandatory and Nonmandatory Appendices

27




1. ASME Code does not specify particular materials to use in each application. Owner must do this.

2. ASME Code specifies permittedmaterials and the requirements that these must meet.


Primary factors that influence pressure vessel material selection.

15

Material Selection Factors

• Strength• Corrosion Resistance• Resistance to Hydrogen Attack• Fracture Toughness• Fabricability

28




1. Strength: Material’s ability to withstand imposed loading.

2. Higher strength material → thinner component.

3. Describe properties that are used to define strength.


Material strength and pressure vessel design.

16

Strength

• Determines required component thickness• Overall strength determined by:

– Yield Strength– Ultimate Tensile Strength– Creep Strength– Rupture Strength

29




1. Corrosion is thinning of metal.

2. Adding extra component thickness (i.e., corrosion allowance) is most common method to address corrosion.

3. Alloy materials are used in services where corrosion allowance would be unreasonably high if carbon steel were used.


Importance of corrosion resistance in materials selection.

17

Corrosion Resistance

• Deterioration of metal by chemical action• Most important factor to consider

• Corrosion allowance supplies additionalthickness

• Alloying elements provide additionalresistance to corrosion

30




1. Low-temperature H2 attack can cause cracking.

2. Higher temperature H2 attack causes through-thickness strength loss and is irreversible.

3. H2 attack is a function of H2 partial pressure and design temperature.

• Increased alloy content (i.e., Cr) increases H2 attack resistance.

• Reference API-941 for “Nelson Curves.”


Hydrogen attack can damage carbon and low-alloy steel.

18

Resistance toHydrogen Attack

• At 300 - 400°F, monatomic hydrogenforms molecular hydrogen in voids

• Pressure buildup can cause steel to crack• Above 600°F, hydrogen attack causes

irreparable damage through componentthickness

31




1. Describe brittle fracture as equivalent to dropping a piece of glass.

2. Material selection must ensure that brittle fracture will not occur.


Brittle fracture and its consequences.

19

Brittle Fractureand Fracture Toughness

• Fracture toughness: Ability of material towithstand conditions that could causebrittle fracture

• Brittle fracture– Typically at “low” temperature– Can occur below design pressure– No yielding before complete failure

32




1. A brittle fracture will occur the first time the appropriate conditions occur.

2. Brittle fracture occurs without warning and is catastrophic.


Three conditions that are required for a brittle fracture to occur.

20

Brittle Fracture andFracture Toughness, cont’d

• Conditions required for brittle fracture– High enough stress for crack initiation and

growth– Low enough material fracture toughness at

temperature– Critical size defect to act as stress

concentration

33




1. Describe influence of material and temperature factors on fracture toughness.

2. Other factors increase brittle fracture risk.


Primary factors that influence material fracture toughness.

21

Factors That InfluenceFracture Toughness

• Fracture toughness varies with:- Temperature- Type and chemistry of steel- Manufacturing and fabrication processes

• Other factors that influence fracturetoughness:- Arc strikes, especially if over repaired area- Stress raisers or scratches in cold formed thick

plate

34




1. Charpy V-Notch test is most widely used measure of material fracture toughness.

2. Describe test set-up.


Charpy V-Notch testing.

22

Charpy V-Notch Test Setup

Starting PositionHammer

Scale

Pointer

End of swing

Anvil

Specimen

h'

h'

35




1. ASME Code contains brittle fracture evaluation procedure.

2. Review components to be included -only items that relate to structural integrity of pressure-containing shell.


Components to consider is ASME Code brittle fracture evaluation.

23

ASME Code andBrittle Fracture Evaluation

– Shells– Manways– Heads– Reinforcing pads– Backing strips

that remain inplace

– Nozzles– Tubesheets– Flanges– Flat cover plates– Attachments essential

to structural integritythat are welded topressure parts

• Components to consider

36




1. Describe the distinction between MDMT and CET.

• MDMT is a materialproperty.

• CET is an environmental factor.

2. Important to understand this distinction.


Two temperatures to be considered in brittle fracture evaluation.

24

Temperatures to Consider

• Minimum Design Metal Temperature(MDMT)– Lowest temperature at which component has

adequate fracture toughness

• Critical Exposure Temperature (CET)– Minimum temperature at which significant

membrane stress will occur

37




1. Outline ASME procedure.

2. Details described in following overheads.


Simplified ASME brittle fracture evaluation procedure.

25

Simplified ASMEEvaluation Approach

• Material specifications classified intoMaterial Groups A through D

• Impact test exemption curves– For each Material Group– Acceptable MDMT vs. thickness where impact

testing not required

• If combination of Material Group andthickness not exempt, then must impact testat CET

38




1. Materials are grouped based on common fracture toughness properties.

2. Groups A through D move from worst to best fracture toughness.

3. Point out several common materials.

• SA-516 Gr. 65 and 70 are Curve B if not normalized.

• Most pipe, fittings and forgings are Curve B.


Material group classifications for brittle fracture evaluations.

26

Material Groups

Table 3.1 (Excerpt)

MATERIALGROUP APPLICABLE MATERIALS

Curve A • A l l c a r b o n a n d l o w a l l o y s t e e l p l a t e s , s t r u c t u r a l s h a p e s , a n d b a r s n o tl i s t ed in Curves B , C & D

• S A - 2 1 6 G r . W C B & W C C , S A - 2 1 7 G r . W C 6 , i f n o r m a l i z e d a n d t e m p e r e do r w a t e r - q u e n c h e d a n d t e m p e r e d

Curve B • S A - 2 1 6 G r . W C A , i f n o r m a l i z e d a n d t e m p e r e d o r w a t e r - q u e n c h e d a n dt e m p e r e d

• S A - 2 1 6 G r . W C B & W C C f o r m a x i m u m t h i c k n e s s o f 2 i n . , i f p r o d u c e dt o f i n e g r a i n p r a c t i c e a n d w a t e r - q u e n c h e d a n d t e m p e r e d

• S A - 2 8 5 G r . A & B

• SA-414 Gr . A• S A - 5 1 5 G r . 6 0• S A - 5 1 6 G r . 6 5 & 7 0 , i f n o t n o r m a l i z e d• E x c e p t f o r c a s t s t e e l s , a l l m a t e r i a l s o f C u r v e A i f p r o d u c e d t o f i n e

g r a i n p r a c t i c e a n d n o r m a l i z e d w h i c h a r e n o t i n c l u d e d i n C u r v e s C & D

• A l l p i p e , f i t t i n g s , f o r g i n g , a n d t u b i n g w h i c h a r e n o t i n c l u d e d i n C u r v e sC & D

39




1. Identify other common materials.

• SA-516 Gr. 55 and 60 are Curve C if not normalized.

• SA-516 (all grades) is Curve D if normalized.

2. Highlight points.

• Lower strength grades of same specification have better fracture toughness.

• Normalization improves fracture toughness.


Material group classifications for brittle fracture evaluations.

27

Material Groups, cont’d

Table 3.1 (Excerpt)

MATERIALGROUP APPLICABLE MATERIALS

Curve C • S A - 1 8 2 G r . 2 1 & 2 2 , i f n o r m a l i z e d a n d t e m p e r e d• SA-302 Gr . C & D

• S A - 3 3 6 G r . F 2 1 & F 2 2 , i f n o r m a l i z e d a n d t e m p e r e d

• S A - 3 8 7 G r . 2 1 & 2 2 , i f n o r m a l i z e d a n d t e m p e r e d

• S A - 5 1 6 G r . 5 5 & 6 0 , i f n o t n o r m a l i z e d• SA-533 Gr . B & C

• SA-662 Gr . A

• A l l m a t e r i a l o f C u r v e B i f p r o d u c e d t o f i n e g r a i n p r a c t i c e a n d n o r m a l i z e d w h i c h a r e n o t i n c l u d e d i n C u r v e D

Curve D • S A - 2 0 3 • SA-537 Cl . 1 , 2 & 3

• SA-508 Cl . 1 • S A - 6 1 2 , i f n o r m a l i z e d

• S A - 5 1 6 , i f n o r m a l i z e d • S A - 6 6 2 , i f n o r m a l i z e d

• SA-524 Cl . 1 & 2 • S A - 7 3 8 G r . A

Bol t ing • S e e F i g u r e U C S - 6 6 o f t h e A S M E C o d e S e c t i o n V I I I , D i v . 1 , f o r i m p a c t

and Nu t s t e s t e x e m p t i o n t e m p e r a t u r e s f o r s p e c i f i e d m a t e r i a l s p e c i f i c a t i o n s

40




1. Describe relationship between Material Group, component thickness, and MDMT.

2. Impact testing not required if point is at or below curve (i.e., OK if MDMT ≤CET).

3. Example: 1.5 in. thick Group B material does not require impact testing if CET ≥ 50°F.

4. If not exempt, must impact test material at CET.

5. “Exemption” means there is enough experience that material has adequate fracture toughness without need for further testing.


Impact test exemption curves.

28

Impact Test Exemption Curvesfor Carbon and Low-Alloy Steel

Figure 3.1

Nominal Thickness, in.

(Limited to 4 in. for Welded Construction)

0.394 1 2 3 4 5

140

120

100

8 0

6 0

4 0

2 0

0

-20

-40

-55-60

-80

Min

imum

Des

ign

Met

al T

empe

ratu

re,

F

Impact testing required

D

C

BA

41




1. Review additional requirements.

2. Note that most flanges will not require impact testing.


Additional impact test requirements.

29

Additional ASME Code ImpactTest Requirements

• Required for welded construction over 4 in.thick, or nonwelded construction over 6 in.thick, if MDMT < 120°F

• Not required for flanges if temperature≥ -20°F

• Required if SMYS > 65 ksi unlessspecifically exempt

42




1. Review additional requirements.

2. PWHT reduces MDMT by 30°F provided PWHT not required by Code and resulting MDMT ≥ -55°F.

3. Can take MDMT credit if component thickness greater than needed (i.e., calculated stress < allowable stress).


Additional impact test requirements.

30

Additional ASME CodeImpact Test

Requirements, cont’d• Not required for impact tested low

temperature steel specifications– May use at impact test temperature

• 30°F MDMT reduction if PWHT P-1 steeland not required by code

• MDMT reduction if calculated stress <allowable stress

43




Describe fabricability.


Definition of fabricability.

31

Fabricability

• Ease of construction• Any required special fabrication practices• Material must be weldable

44




1. Discuss the use of allowable stress in determining vessel component design.

2. Section II, Part D, Appendix I contains allowable stress criteria for materials other than bolting.

3. Section II, Part D contains allowable stress tables.


• Description of allowable stress.

• ASME Code allowable stress tables

32

Maximum Allowable Stress• Stress: Force per unit area that resists loads

induced by external forces• Pressure vessel components designed to

keep stress within safe operational limits• Maximum allowable stress:

– Includes safety margin– Varies with temperature and material

• ASME maximum allowable stress tables forpermitted material specifications

45




1. Describe information contained in first section of table.

2. Information is grouped by material chemistry and material form.


ASME Code allowable stress tables.

33

Maximum AllowableStress, cont’d

ALLOWABLE STRESS IN TENSION FOR CARBON ANDLOW-ALLOY STEEL

Spec No. Grade NominalComposition

P-No. Group No. Min. Yield(ksi)

Min. Tensile(ksi)

Carbon Steel Plates and SheetsSA-515 55 C-Si 1 1 30 55

60 C-Si 1 1 32 6065 C-Si 1 1 35 6570 C-Si 1 2 38 70

SA-516 55 C-Si 1 1 30 5560 C-Mn-Si 1 1 32 6065 C-Mn-Si 1 1 35 6570 C-Mn-Si 1 2 38 70

Plate - Low Alloy SteelsSA-387 2 Cl.1 1/2Cr-1/2Mo 3 1 33 55

2 Cl.2 1/2Cr-1/2Mo 3 2 45 7012 Cl.1 1Cr-1/2Mo 4 1 33 5512 Cl.2 1Cr-1/2Mo 4 1 40 6511 Cl.1 1 1/4Cr-1/2Mo-Si 4 1 35 6011 Cl.2 1 1/4Cr-1/2Mo-Si 4 1 45 7522 Cl.1 2 1/4Cr-1Mo 5 1 30 6022 Cl.2 2 1/4Cr-1Mo 5 1 45 75

ASME Maximum Allowable Stress (Table 1A Excerpt)Figure 3.2

46




1. Review allowable stress vs. design temperature.

2. Most ferritic materials have a constant allowable stress at temperatures through 650°F.


ASME Code allowable stress tables.

34

Maximum AllowableStress, cont’d

ALLOWABLE STRESS IN TENSION FOR CARBON AND LOW ALLOY STEELMax Allowable Stress, ksi (Multiply by 1,000 to Obtain psi)

for Metal Temperature, °F, Not Exceeding

650 700 750 800 850 900 950 1000 1050 1100 1150 1200SpecNo.

Carbon Steel Plates and Sheets13.8 13.3 12.1 10.2 8.4 6.5 4.5 2.5 -- -- - - - - SA-51515.0 14.4 13.0 10.8 8.7 6.5 4.5 2.5 -- -- - - - - SA-51516.3 15.5 13.9 11.4 9.0 6.5 4.5 2.5 -- -- - - - - SA-51517.5 16.6 14.8 12.0 9.3 6.5 4.5 2.5 -- -- - - - - SA-515

13.8 13.3 12.1 10.2 8.4 6.5 4.5 2.5 -- -- - - - - SA-51615.0 14.4 13.0 10.8 8.7 6.5 4.5 2.5 -- -- - - - - SA-51616.3 15.5 13.9 11.4 9.0 6.5 4.5 2.5 -- -- - - - - SA-51617.5 16.6 14.8 12.0 9.3 6.5 4.5 2.5 -- -- - - - - SA-516

Plate-Low Alloy Steels (Cont'd)13.8 13.8 13.8 13.8 13.8 13.3 9.2 5.9 -- -- - - - - SA-38717.5 17.5 17.5 17.5 17.5 16.9 9.2 5.9 -- -- - - - - SA-38713.8 13.8 13.8 13.8 13.4 12.9 11.3 7.2 4.5 2.8 1.8 1.1 SA-38716.3 16.3 16.3 16.3 15.8 15.2 11.3 7.2 4.5 2.8 1.8 1.1 SA-38715.0 15.0 15.0 15.0 14.6 13.7 9.3 6.3 4.2 2.8 1.9 1.2 SA-38718.8 18.8 18.8 18.8 18.3 13.7 9.3 6.3 4.2 2.8 1.9 1.2 SA-38715.0 15.0 15.0 15.0 14.4 13.6 10.8 8.0 5.7 3.8 2.4 1.4 SA-38717.7 17.2 17.2 16.9 16.4 15.8 11.4 7.8 5.1 3.2 2.0 1.2 SA-387

ASME Maximum Allowable Stress (Excerpt), cont'dFigure 3.2, cont'd

47




1. This independent Exercise gives the Participants practice in material selection based on fracture toughness.

2. Review the given information together.

3. Allow approximately 10 minutes for the Participants to solve the problem. Then review the solution with them.


Participant Exercise 1 covering fracture toughness.

35

Material Selection Basedon Fracture Toughness

Exercise 1

• New horizontal vessel• CET = - 2°F• Shell and heads: SA-516 Gr. 70• Heads hemispherical: ½ in. thick• Cylindrical shell: 1.0 in. thick• No impact testing specified• Is this correct?• If not correct, what should be done?

48




1. Review difference between normalized and non-normalized material with respect to fracture toughness.

2. Review MDMT determination in each case.

3. Note difference between MDMT and CET in each case.


Solution to Participant Exercise.

36

Exercise 1 - Solution• Must assume SA-516 Gr. 70 not normalized.

Therefore, Curve B material (Ref. Table 3.1).• Refer to Curve B in Figure 3.1.

– ½ in. thick plate for heads: MDMT = -7°F– ½ in. thick plate exempt from impact testing since

MDMT < CET

• 1 in. shell plate: MDMT = +31°F– Not exempt from impact testing

49




1. Review possible solutions for the 1 in. plate.


Solution to Participant Exercise.

37

Exercise 1 - Solution, cont’d

• One approach to correct: Impact test 1 in. plateat -2°F. If passes, material acceptable.

• Another approach: Order 1 in. plate normalized– Table 3.1: normalized SA-516 is Curve D material– Figure 3.1: 1 in. thick Curve D, MDMT = -30°F– Normalized 1 in. thick plate exempt from impact testing

50




1. Review rationale for which option to select.


Solution to Participant Exercise 1.

38

Exercise 1 - Solution, cont’d

• Choice of option based on cost, materialavailability, whether likely that 1 in. thick non-normalized plate would pass impact testing

51




1. Review conditions to be considered.

2. Worst case operating scenario determines mechanical design.


Design conditions and loadings to be considered in pressure vessel mechanical design.

39

Design Conditionsand Loadings

• Determine vessel mechanical design• Design pressure and temperature, other

loadings• Possibly multiple operating scenarios to

consider• Consider startup, normal operation,

anticipated deviations, shutdown

52




1. May have internal of external pressure, or both at different times.

2. Must have margin between maximum operating pressure at top of vessel and design pressure.

3. Hydrostatic pressure of operating liquid (if present) must be considered at corresponding vessel elevation.


Design pressure as a mechanical design condition.

40

Design PressurePT = Design Pressure at

Top of Vessel

PBH

= Design Pressure ofBottom Head

H = Height of Liquid

= Weight Density of Liquid in Vessel

γ

Figure 4.1

53




1. Margin required between operating temperature and design temperature.

2. Maximum design temperature needed to determine allowable stress and thermal expansion considerations.

3. CET needed for material selection considering brittle fracture.

4. There may be a wide temperature variation between the bottom and top of a tall tower.


Design temperature as a mechanical design condition.

41

Temperature Zonesin Tall Vessels

Support Skirt

Grade

Section 2(T-X)

Section 3(T-Y)

Section 4(T-Z)

Section 1(T) F

Figure 4.2

54




1. Highlight other loads that must be considered in the mechanical design.

2. These other loads may govern the mechanical design in local areas.


Loadings other than pressure and temperature must also be considered.

42

Additional Loadings

• Weight of vessel and normal contentsunder operating or test conditions

• Superimposed static reactions from weightof attached items (e.g., motors, machinery,other vessels, piping, linings, insulation)

• Loads at attached internal components orvessel supports

• Wind, snow, seismic reactions

55




1. Review these additional other loads.


Additional other loadings to consider.

43

Additional Loadings, cont’d• Cyclic and dynamic reactions caused by

pressure or thermal variations, equipmentmounted on vessel, and mechanical loadings

• Test pressure combined with hydrostaticweight

• Impact reactions (e.g., from fluid shock)• Temperature gradients within vessel

component and differential thermalexpansion between vessel components

56




1. Review the ASME Code Weld Joint Categories.

2. Only specific weld types may be used in each category.


ASME Code defines welded joints by category.

44

Weld Joint Categories

B AC

D

D B

C

A

B

A

BD

D CA

A

C

AC

C

BD

Figure 4.3

57




1. Review the different weld types.

2. Limited applications for Types 3 through 6.


ASME Code defines specific weld types that may be used.

45

Weld Types1

2

3

4

5

6

Butt joints as attained by double-welding or by othermeans which will obtain the same quality of depositedweld metal on the inside and outside weld surface.

Backing strip, if used, shall be removed aftercompletion of weld.

Single-welded butt joint with backing strip whichremains in place after welding.

For circumferentialjoint only

Single-welded butt joint without backing strip.

Double-full fillet lap joint.

Single-full fillet lap joint with plug welds.

Single-full fillet lap joint without plug welds.

Figure 4.4

58




1. Weld joint efficiency, E, is a measure of weld quality and accounts for stress concentrations.

2. E is needed in component thickness calculations.

3. Review information in table.

4. Note that corrosion allowance was previously discussed.


Weld joint efficiency vs. Joint Type, Category, Radiographic Examination.

46

Weld Joint Efficiencies

JointType

Acceptable Joint Categories Degree ofRadiographic Examination

Full Spot None

1 A, B, C, D 1.00 0.85 0.70

2 A, B, C, D (See ASME Code for limitations) 0.90 0.80 0.65

3 A, B, C NA NA 0.60

4 A, B, C (See ASME Code for limitations) NA NA 0.55

5 B, C (See ASME Code for limitations) NA NA 0.50

6 A, B, (See ASME Code for limitations) NA NA 0.45

Figure 4.5

59




1. Circumferential stress governs minimum required component thickness in most cases.

2. Longitudinal stress may govern local thickness in some cases (e.g., under wind or earthquake loads).

3. Review ASME Code equations for internal pressure design.

• May calculate required thickness, permitted pressure, component stress.

• Must account for corrosion allowance.


ASME Code equations for various components under internal pressure.

47

Summary Of ASMECode Equations

PartThickness,

tp , in.Pressure,

P, psiStress,S, psi

Cylindrical shell P6.0SEPr

1 − t6.0rtSE1

+

( )1tE

t6.0rP +

Spherical shell P2.0SE2Pr

1 − t2.0rSEt2

+( )

tE2t2.0rP +

2:1Semi - Elliptical

headP2.0SE2

PD− t2.0D

SEt2+

( )tE2

t2.0DP +

Torispherical headwith 6% knuckle

P1.0SEPL885.0

− t1.0L885.0SEt

+( )

tEt1.0L885.0P +

Conical Section(α = 30°) ( )P6.0SEcos2

PD−α α+

αcost2.1D

cosSEt2 ( )α

α+costE2

cost2.1DP

Figure 4.6

60




1. Review the different head types.

2. The 2:l semi-elliptical head is the most common.


Different types of closure heads may be used.

48

Typical Formed Closure Headst

sf

ID

Flanged

t

sf

R

ID

Hemispherical

sf

t

h

Flanged and Dished(torispherical)

t

sf

h

Elliptical

tα

IDConical Toriconical

I Dr

sf

tα

Figure 4.7

61




1. Required thickness of a hemispherical head is about half that of the connected cylindrical shell.

2. Must have a tapered thickness transition in the head to end up matching the shell thickness.


Thickness transition at a hemispherical head.

49

HemisphericalHead to Shell Transition

Length of required taper, l,may include the width

of the weld

y y

tsts

Tangent Line

th th

y3l ≥y3l ≥

Thi

nner

Par

t

Thi

nner

Par

t

Figure 4.8

62




1. Sample Problem 1 illustrates calculation of required shell and head thicknesses for internal pressure.

2. Review the given information.

3. Review the problem solution with the Participants.


Sample Problem to illustrate calculation of required thickness for internal pressure.

50

Sample Problem 1Hemispherical

4' - 0"

60' - 0"

10' - 0"

6' - 0"30' - 0"

2:1 Semi-Elliptical

DESIGN INFORMATIONDesign Pressure = 250 psigDesign Temperature = 700° FShell and Head Material is SA-515 Gr. 60Corrosion Allowance = 0.125"Both Heads are SeamlessShell and Cone Welds are Double Welded and will be Spot RadiographedThe Vessel is in All Vapor ServiceCylinder Dimensions Shown are Inside Diameters

Figure 4 .9

63




1. Review the relevant equation for a cylindrical shell.

2. Note the sources used for the various parameters.


Sample Problem 1 solution.

51

Sample Problem 1 - Solution

• Required thickness for internal pressure of cylindricalshell (Figure 4.6):

• Welds spot radiographed, E = 0.85 (Figure 4.5)

• S = 14,400 psi for SA- 515/Gr. 60 at 700°F (Figure 3.2)

• P = 250 psig

P6.0SEPrt

1p −

=

64




1. The corrosion allowance must be added to obtain the inside radius.

2. The corrosion allowance must be added to the calculated thickness.



52

Sample Problem 1Solution, cont’d

• For 6 ft. - 0 in. shell

r = 0.5D + C = 0.5 × 72 + 0.125 = 36.125 in.

= 0.747 in.

t = tp + c = 0.747 + 0.125

t = 0.872 in., including corrosion allowance

2506.085.0400,14125.36250

P6.0SEPr

t1

p ×−××

=−

=

65




1. The calculation is repeated for the other cylindrical shell section.



53


• For 4 ft. - 0 in. shell

r = 0.5 × 48 + 0.125 = 24.125 in.

= 0.499 in.

t = 0.499 + 0.125


2506.085.0400,14125.24250

tp ×−××

=

66




1. Review the relevant equation for a hemispherical head.

2. Note the sources for the relevant parameters and how corrosion allowance is accounted for.



54


Both heads are seamless, E = 1.0.Top Head - Hemispherical (Figure 4.6)

r = 24 + 0.125 = 24.125 in.

= 0.21 in.

t = tp + c = 0.21 + 0.125


2502.01400,142125.24250

P2.0SE2Pr

t1

p ×−×××

=−

=

67




1. Review the relevant equation for a semi-elliptical head.

2. Note the sources for the relevant parameters and how corrosion allowance is accounted for.



55


• Bottom Head - 2:1 Semi-Elliptical (Figure 4.6)

D = 72 + 2 × 0.125 = 72.25 in.

t = 0.628 + 0.125


in. 0.628 2502.01400,142

25.72250P2.0SE2

PDtp =

×−×××

=−

=

68




1. Buckling of a shell under external pressure or compressive forces is analogous to column buckling under a compressive force.

2. Addition of stiffener rings reduces effective buckling length.


Different procedures are used to design for external pressure or compressive loads.

56

Design For ExternalPressure and Compressive

Stresses• Compressive forces caused by dead

weight, wind, earthquake, internal vacuum• Can cause elastic instability (buckling)• Vessel must have adequate stiffness

– Extra thickness– Circumferential stiffening rings

69




1. Highlight the main parameters that affect buckling strength.

2. ASME Code has design procedure for each type of shell or head.


Parameters that affect compressive strength.

57

Design ForExternal Pressure and

Compressive Stresses, cont’d

– Material– Diameter– Unstiffened length

– Temperature– Thickness

• ASME procedures for cylindrical shells,heads, conical sections. Function of:

70




1. Stiffener rings reduce the buckling length of a shell and may be either inside or outside.

2. Stiffener rings are not used for heads.


Use and location of stiffener rings.

58

Stiffener Rings

LLLLL

LLLLL

Moment Axis of Ring

h/3

h/3

h = Depth of Head

Figure 4.10

71




1. Sample Problem 2 illustrates procedure for calculation of required cylindrical shell thickness for external pressure.

2. The problem does not cover all aspects of the general procedure since it is geometry-specific.


4. Review the problem solution with the participants.


Sample Problem to illustrate calculation of required cylindrical shell thickness for external pressure.

59

Sample Problem 2

2:1 Semi-Elliptical(Typical)

150' - 0"

4' - 0"

DESIGN INFORMATIONDesign Pressure = Full VacuumDesign Temperature = 500° FShell and Head Material is SA-285 Gr. B, Yield Stress = 27 ksiCorrosion Allowance = 0.0625"Cylinder Dimension Shown is Inside Diameter

Figure 4.11

72




1. Corroded shell diameter and thickness are used in the calculations.

2. The unstiffened length of the shell must include part of the head depth.



60

Sample Problem 2 - Solution• Calculate L and Do of cylindrical shell.

L = Tangent Length + 2 × 1/3 (Head Depth)L = 150 × 12 + 2/3 × (48/4) = 1,808 in.Do = 48 + 2 × 7/16 = 48.875 in.

• Determine L/Do and Do/tAccount for corrosion allowance:

t = 7/16 – 1/16 = 6/16 = 0.375 in.Do/t = 48.875 / 0.375 = 130L/Do = 1808 / 48.875 = 37

73




1. Factor A is determined based only on geometry.

2. Note the source of Factor A.



61


• Determine A.• Use Figure 4.12, Do/t, and L/Do.

Note: If L/Do > 50, use L/Do = 50. For L/Do < 0.05, useL/Do = 0.05

74




1. Note how Factor A is determined from these curves.

2. After determine Factor A, go to applicable material chart.



62


Factor AFigure 4.12

2

3

4

5

6 7

8 9

50

.0

40

.0

35

.0

30.0

25.0

20.0

18.0

16.0

14.0

12.0

10.0 9.0

8.0

7.0

6.0

5.0

4.0

3.5

3.0

2.5 2.0

1.8

1.6

1.4

1.2

.00

00

1

.

00

01

Length + Outside Diameter = L/Do

D o/t =

400

Do/t = 100

Do/t = 125

Do/t = 150

Do/t = 200

Do/t = 250

Do/t = 300 D o/t = 500

D o/t =

600

D o/t =

800

D o/t =

1,000

Do/t = 130

L/Do = 37

A = 0.000065

75




1. Different material charts are used for different material types. This is chart used for most carbon and low-alloy steels.

2. If A is under curves:

• Move up to intersect with temperature line.

• Move right to get B.

• B is then used to calculate allowable external pressure.

3. Since A is to left of curves in our case, must use alternate procedure.



63


Factor BFigure 4.13

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9

20,00018,00016,000

14,000

12,000

10,000

9,0008,000

7,000

6,000

5,000

4,000

3,500

3,000

2,500

2,000

.00001 .0001 .001 .01 .1

FACTOR A

FA

CTO

R B

GENERAL NOTE: See Table CS-1 for tabular valuesup to 300°F

900°F

500°F

700°F

800°F

E=29.0 x 106

E=27.0 x 106

E=24.5 x 106

E=22.8 x 106

E=20.8 x 106

A=0.000065

76




1. Pa is calculated using indicated equation because A is not under curves.

2. Must use E from curves at design temperature.



64


• Calculate maximum allowable external pressure

Where:

E = Young's modulus of elasticity

E = 27 × 106 psi (Figure 4.13) at T = 500°F

Pa = 9 psi

)t/D(3AE2

Po

a =

77




1. Since Pa < 15 psi, must either increase shell thickness or add stiffeners to decrease L.

2. Problem illustrates results if increase thickness.

3. Choice of whether to increase thickness or add stiffeners depends on cost.



65


Since Pa < 15 psi, 7/16 in. thickness not sufficient

• Assume new thickness = 9/16 in.,corroded thickness L = 1/2 in.

A = 0.000114

75.975.0875.48

tDo == )beforeas(37

DL

o=

psi7.1533.1303

1027000114.02P

6

a =×

×××=

78




1. This independent Exercise gives the Participants practice in determining required vessel thicknesses for internal pressure.

2. Review the given information together.

3. Allow approximately 15 minutes for the Participants to solve the problem. Then review the solution with them.

4. Note that this Exercise may be skipped and assigned as homework if available class time is an issue.


Participant Exercise 2 covering required thickness for internal pressure.

66

• Inside Diameter - 10’ - 6”• Design Pressure - 650 psig• Design Temperature - 750°F• Shell & Head Material - SA-516 Gr. 70• Corrosion Allowance - 0.125 in.• 2:1 Semi-Elliptical heads, seamless• 100% radiography• Vessel in vapor service

Exercise 2 - RequiredThickness for Internal Pressure

79




1. Note the relevant equation for the cylindrical shell and the appropriate parameters.

2. Note how corrosion allowance is accounted for.


Exercise 2 solution.

67

Exercise 2 - Solution• For shell

P = 650 psigr = 0.5 × D + CA

= (0.5 × 126) + 0.125 = 63.125 in.• S = 16,600 psi, Figure 3.3 for SA-516 Gr. 70 • E = 1.0, Figure 4.8 for 100% radiography

P6.0SEPr

t1

p −=

.in53.2)6506.0()0.1600,16(

125.63650tp =

×−××

=

80




1. Note the relevant equation for the heads and the appropriate parameters.

2. Note how corrosion allowance is accounted for.


Exercise 2 solution.

68

Exercise 2 - Solution, cont’dAdd corrosion allowance

tp = 2.53 + 0.125 = 2.655 in.

• For the heads

Add corrosion allowance

tp = 2.23 + 0.125 = 2.355 in.

P2.0SE2PD

tp −=

.in23.2)6502.0()600,162(

250.0)9.0126(650tp =

×−×+×

=

81




1. Simplified ASME rules do not require stress calculations. Use “area replacement” approach.

2. Metal removed must be replaced by equivalent metal.


Openings must be reinforced to account for metal removed.

69

Reinforcement of Openings

• Simplified ASME rules - Area replacement• Metal used to replace that removed:

- Must be equivalent in metal area - Must be adjacent to opening

82




1. Review cross-sectional view of region and associated nomenclature.

2. Note the different areas involved in the calculations and the “reinforcement zone” in the nozzle and shell.


Region near opening and nomenclature.

70

Cross Sectional View ofNozzle Opening

Dp

t nR n

t rn

t r

c

hd

te

d or R n + tn + t

Use larger value

t

2.5t or 2.5t nUse smaller value

2.5t or 2.5t n + teUse smaller value

d or R n + tn + t

Use larger value

For nozzle wall abuttingthe vessel wall

For nozzle wall insertedthrough the vessel wall

Figure 4.14

83




1. Note the different nozzle design details that may be used.

2. The actual detail used in each case depends on the design conditions and the needed reinforcement.


Typical nozzle configurations.

71

Nozzle Design Configurations

(a)Full Penetration Weld

With Integral Reinforcement (a-1) (a-2) (a-3)

Separate Reinforcement Plates Added

(b) (c) (d) (e)

Full Penetration Welds to Which Separate Reinforcement Plates May be Added

(f-1) (f-3)

(f-2)(f-4) (g)

Self - Reinforced Nozzles

Figure 4.15

84




1. The method used to provide additional reinforcement depends on the particular situation.

2. The ASME Code specifies circumstances where nozzle reinforcement evaluation is not needed. The opening is considered to be “inherently” reinforced in these cases.


Requirements for additional reinforcement.

72

Additional Reinforcement• Necessary if insufficient excess thickness• Must be located within reinforcement zone• Allowable stress of reinforcement pad

should be ≥ that of shell or head

• Additional reinforcement sources– Pad– Additional thickness in shell or lower part of

nozzle

85




1. Sample Problem 3 illustrates evaluation of an opening for adequate reinforcement.




Sample Problem to illustrate evaluation of nozzle reinforcement.

73

Sample Problem 3

NPS 8 Nozzle(8.625" OD)0.5" Thick

0.5625" Thick Shell, 48" Inside Diameter

DESIGN INFORMATIONDesign Pressure = 300 psigDesign Temperature = 200° FShell Material is SA-516 Gr. 60Nozzle Material is SA-53 Gr. B, SeamlessCorrosion Allowance = 0.0625"Vessel is 100% RadiographedNozzle does not pass through Vessel Weld Seam

Figure 4.16

86




1. Required replacement area is based on the cross-sectional area removed.

2. Calculated using the required shell thickness, not the actual.



74

Sample Problem 3 - Solution• Calculate required reinforcement area, A

A = dtrF

Where:

d =Finished diameter of circular opening, orfinished dimension of nonradial opening inplane under consideration, in.

tr = Minimum required thickness of shell usingE = 1.0, in.

F = Correction factor, normally 1.0

87




1. Corrosion allowance is accounted for.

2. tr is calculated using the appropriate shell equation.



75

Sample Problem 3 -Solution, cont’d

• Calculate diameter, d.d = Diameter of Opening – 2 (Thickness +

Corrosion Allowance)

d = 8.625 – 1.0 + .125 = 7.750 in.

• Calculate required shell thickness, t r (Figure 4.6)

tr = 0.487 in.

• Assume F = 1.0

88




1. Required area is calculated using the previously calculated parameters.

2. Two equations must be checked to determine the reinforcement area available in the shell.



76


• Calculate A

A = dtrF

A = (8.625 - 1.0 + 0.125) × 0.487 × 1 = 3.775 in.2

• Calculate available reinforcement area in vesselshell, A1, as larger of A11 or A12

A11 = (Elt - Ftr)d

A12 = 2 (Elt-Ftr)(t + tn)

89




Review the relevant parameters.



77


Where:E l = 1.0 when opening is in base plate away from welds,

or when opening passes through circumferential jointin shell (excluding head to shell joints).

E l = ASME Code joint efficiency when any part of openingpasses through any other welded joint.

F = 1 for all cases except integrally reinforced nozzlesinserted into a shell or cone at angle to vessellongitudinal axis. See Fig. UG-37 for this specialcase.

tn = Nominal thickness of nozzle in corroded condition, in.

90




Available shell reinforcement area is determined.



78


A11 = (Elt - Ftr)d = (0.5625 - 0.0625 - 0.487) × 7.75 = 0.1 in.2

A12 = 2 (Elt - Ftr) (t + t n)

= 2(0.5625-0.0625-0.487) × (0.5625-0.0625+0.5 -0.0625)

= 0.0243 in.2

Therefore,A1= 0.1 in.2 available reinforcement in shell

91




Available reinforcement area in the nozzle is determined by checking two equations.



79


• Calculate reinforcement area available in nozzle wall, A2,as smaller of A21 or A22.

A21 = (tn-trn) 5t

A22 = 2 (tn-trn) (2.5 tn + te)

92




Review the relevant parameters.



80


Where:

trn = Required thickness of nozzle wall, in.

r = Radius of nozzle, in.

te = 0 if no reinforcing pad.

te = Reinforcing pad thickness if one installed, in.

te = Defined in Figure UG-40 for self-reinforcednozzles, in.

93




Calculate required thickness using the equation for a cylinder.



81


• Calculate required nozzle thickness, trn (Figure 4.6)

P6.0SEPr

t1

rn −=

.in0784.03006.01000,15

)0625.08125.3(300trn =

×−×+

=

94




1. The available reinforcement in the nozzle is determined.

2. Note that in this case, the nozzle has much more excess metal available than the shell.



82


• Calculate A2.

A21 = (tn - trn)5t = (0.5 - 0.0625 - 0.0784) × 5 (0.5625 - 0.0625)

= 0.898 in.2

A22 = 2 (tn - t rn) (2.5 tn + te) = 2 (0.5 - 0.0625 - 0.0784) [2.5 × (0.5 - 0625) + 0]

= 0.786 in.2

Therefore,A2 = 0.786 in.2 available reinforcement in nozzle.

95




1. The nozzle is not adequately reinforced because it does not have enough reinforcement available.

2. The problem now proceeds to determine the required dimensions of a reinforcement pad. Note, however, that the additional reinforcement could also be added by using a thicker nozzle or by using a thicker shell section near the nozzle.



83


• Determine total available reinforcement area, AT;compare to required area.

AT = A1 + A2 = 0.1 + 0.786 = 0.886 in.2

AT < A, nozzle not adequately reinforced, reinforcementpad required.

• Determine reinforcement pad diameter, Dp.

A5 = A - AT

A5 = (3.775 - 0.886) = 2.889 in.2

96




1. The reinforcement pad thickness was assumed to be equal to the shell thickness. This is common practice.

2. A final check is made to ensure that the reinforcement pad is within the reinforcement zone.



84


• Calculate Dp

te = 0.5625 in. (reinforcement pad thickness)

A5 = [Dp - (d + 2 tn)] te

2.889 = [Dp - (7.75 + 2(0.5 - 0.0625)] 0.5625

Dp = 13.761 in.

• Confirm Dp within shell reinforcement zone, 2d

2d = 2 × 7.75 = 15.5 in.

Therefore, Dp = 13.761 in. acceptable

97




1. ASME B16.5 provides standard flange dimensional details.

2. Flange strength is based on dimensions and material used.


The flange rating establishes acceptable temperature/pressure combinations and is based on ASME B16.5

85

Flange Rating• Based on ASME B16.5

• Identifies acceptable pressure/temperature combinations

• Seven classes(150, 300, 400, 600, 900, 1,500, 2,500)

• Flange strength increases with class number

• Material and design temperature combinations withoutpressure indicated not acceptable

98




1. Acceptable flange materials are grouped based on similarities in strength.

2. The Material Group is determined based on the specified material.


Flange Material Group Number is based on material specification and product form.

86

Material Specification List

Figure 4.17

Material Groups Product FormsMaterial

GroupNumber

NominalDesignation

SteelForgings Castings Plates

Spec. No. Grade Spec. No. Grade Spec. No. Grade

1.1 Carbon A105 -- A216 WCB A515 7 0A350 LF2 -- -- A516 7 0

C-Mn-Si -- -- -- -- A537 Cl.11.2 Carbon -- -- A216 WCC -- --

-- -- A352 LCC -- --2 ½ Ni -- -- A352 LC2 A203 B3 ½ Ni A350 LF3 A352 LC3 A203 E

ASME B16.5, Table 1a, Material Specification List (Excerpt)

99




1. This table combines information for three Material Groups for illustrative purposes.

2. Review the information in this table and how it is used to determine the appropriate flange rating.


Pressure/temperature rating is a function of Material Group and design temperature.

87

Pressure - Temperature RatingsMaterial

Group No. 1.1 1.2 1.3

Classes 150 300 400 150 300 400 150 300 400Temp., °F-20 to 100 285 740 990 290 750 1000 265 695 925

200 260 675 900 260 750 1000 250 655 875300 230 655 875 230 730 970 230 640 850400 200 635 845 200 705 940 200 620 825500 170 600 800 170 665 885 170 585 775600 140 550 730 140 605 805 140 534 710650 125 535 715 125 590 785 125 525 695700 110 535 710 110 570 755 110 520 690750 95 505 670 95 505 670 95 475 630800 80 410 550 80 410 550 80 390 520850 65 270 355 65 270 355 65 270 355900 50 170 230 50 170 230 50 170 230950 35 105 140 35 105 140 35 105 1401000 20 50 70 20 50 70 20 50 70

Figure 4.18

100




1. Sample Problem 4 illustrates how to determine flange rating.




Sample Problem to illustrate determining flange rating.

88

Sample Problem 4Determine Required Flange Rating

Pressure Vessel Data:

Shell and Heads: SA-516 Gr.70

Flanges: SA-105

Design Temperature: 700°F

Design Pressure: 275 psig

101




Review the problem solution.



89

Sample Problem 4 - Solution• Identify flange material specification

SA-105

• From Figure 4.17, determine Material Group No.

Group 1.1

• From Figure 4.18 with design temperature andMaterial Group No. determined in Step 3

– Intersection of design temperature with MaterialGroup No. is maximum allowable design pressure forthe flange Class

102




1. Use the lowest flange class that is suitable for the design conditions. Flange cost increases as the class increases.

2. A given flange class is good for a range of temperature/pressure combinations for a particular Material Group.



90


– Table 2 of ASME B16.5, design information for allflange Classes

– Select lowest Class whose maximum allowabledesign pressure ≥ required design pressure.

• At 700°F, Material Group 1.1: Lowest Class thatwill accommodate 275 psig is Class 300.

• At 700°F, Class 300 flange of Material Group1.1: Maximum design pressure = 535 psig.

103




1. Division 1 Appendix 2 procedure for custom-designed flanges.

2. Used if flange size not covered by ASME B16.5 or ASME B16.47.

3. Typical application is girth flange for shell-and-tube heat exchanger.


ASME procedure must be used for custom-designed flanges.

91

Flange Design

• Bolting requirements

– During normal operation (based on designconditions)

– During initial flange boltup (based on stressnecessary to seat gasket and form tight seal

SWAm =

104




1. Applied loads act at different flange locations.

2. Flange moments are calculated for the operating and gasket seating cases.


Various flange loads are applied on corresponding moment arms.

92

Flange Loads and Moment Arms

t h

W

C

A

G BHD

HT

hT

hG

HG

hD

g0

g1

Gasket

FlangeRing

Flange Hub

Figure 4.19

105




1. Various stresses are calculated for each case and must be kept within allowable limits.

2. Flange dimensions are adjusted as needed to meet allowable stresses (e.g., increase thickness, change hub dimensions, etc.).

3. Equipment suppliers use computer programs to “optimize” flange design to be least weight (i.e., lowest cost).


• Flange stresses are calculated and compared to allowable values.

• Both operating and gasket seating cases must be checked.

93

Stresses in Flange Ringand Hub

• Calculated using:

– Stress factors (from ASME code)

– Applied moments

– Flange geometry

• Calculated for:

– Operating case

– Gasket seating case

106




1. Flange is designed for specific gasket type, dimensions, and facing details. Changing any of these after flange is fabricated (e.g., gasket type) can adversely affect in-service performance.

2. TEMA specifies minimum gasket width and bolt spacing criteria.


Various parameters affect flange design and performance.

94

Flange Design andIn-Service Performance

Factors affecting design and performance

• ASME Code m and y parameters.

• Specified gasket widths.

• Flange facing and nubbin width, w

• Bolt size, number, spacing

107




1. This is an excerpt from Table 2-5.1.

2. Review the variation in m and y with gasket type.


• Gasket m and y factors are based on gasket type.

• Gasket type also affects gasket width used in calculations.

95

ASME Code m and y Factors

Gasket Type and MaterialGasketFactor,

m

Min.Design

SeatingStress y,

psi

Facing Sketchand Column in

ASME Table 2-5.2(Figure 4.21)

Flat metal, jacketed asbestos filled:Soft aluminumSoft copper or brassIron or soft steelMonel4-6% chromeStainless steels and nickel-base alloys

3.253.503.753.503.753.75

5,5006,5007,6008,0009,0009,000

(1a), (1b), (1c),(1d); (2);Column II

Solid flat metal:Soft aluminumSoft copper or brassIron or soft steelMonel or 4-6% chromeStainless steels and nickel-base alloys

4.004.755.506.006.50

8,80013,00018,00021,80026,000

(1a), (1b), (1c),(1d); (2), (3), (4),(5); Column I

Figure 4.20

108




1. This is an excerpt from Table 2-5.2.

2. Review the flange facings shown.


The gasket width used in the calculations depends on the type of flange facing.

96

ASME Code Gasket Widths

Figure 4.21

Basic Gasket Seating Width boFacing Sketch(Exaggerated)

Column I Column II

(1a) N N

(1b)N

N 2N

2N

(1c) N

wT

w ≤ N

(1d)N

wT

w ≤ N

++ max

4Nw;

2Tw

++

max4

Nw;

2

Tw

HG

G hG

bO.D. Contact Face

For b o > ¼ in. For b o < ¼ in.

HG

G hG

GasketFace

CL

ASME Code Gasket Widths (Table 2-5.2 excerpt)

109




Review the additional gasket information shown.


Information on additional gasket types.

97

Gasket Materialsand Contact Facings

Figure 4.22

Gasket Materials and Contact Facings

Gasket Factors m for Operating Conditions and Minimum Design Seating Stress y

Gasket Material GasketFactor

m

Min.DesignSeating

Stress y,psi

Sketches FacingSketch andColumn inTable 2-5.2

Flat metal, jacketed asbestos filled:Soft aluminumSoft copper or brassIron or soft steelMonel4% - 6% chromeStainless steels and nickel-base alloys

3.253.503.753.503.753.75

550065007600800090009000

(1a), (1b),(1c),2, (1d) 2,

(2)2,Column II

110




1. Emphasize that MAWP is based on the as-supplied component thicknesses.

2. Thicknesses used exclude corrosion allowance and thickness added to absorb other loads.

3. MAWP is useful to know for potential future rerate.


MAWP is defined.

98

Maximum AllowableWorking Pressure (MAWP)

Maximum permitted gauge pressure at top ofvessel in operating position for designatedtemperature

• MAWP ≥ Design Pressure• Designated Temperature = Design Temperature• Vessel MAWP based on weakest component

– Originally based on new thickness less corrosionallowance

– Later based on actual thickness less future corrosionallowance needed

111




1. Review the typical external loads that may be applied.

2. External loads cause local stresses that must be evaluated.

3. Other industry standards must be used to evaluate local stresses (e.g., WRC 107 and 297).


Externally applied loads must also be considered in vessel design.

99

Local Loads

• Piping system

• Platforms, internals, attached equipment

• Support attachment

112




1. Different types of internals are used to perform various process functions.

2. Review list of internals.

3. ASME Code does not cover design of internals. End-user, vessel vendor, and/or contractor must develop requirements.


Several types of vessel internals may be installed.

100

Types of Vessel Internals• Trays

• Inlet Distributor

• Anti-vortex baffle

• Catalyst bed grid and support beams

• Outlet collector

• Flow distribution grid

• Cyclone and plenum chamber system

113




Discuss ASME requirements for loads applied to vessel and welding to pressure parts.


ASME Code requires that internals be considered only to extent of their effect on pressure shell.

101

ASME Code andVessel Internals

• Loads applied from internals on vessel to beconsidered in design

• Welding to pressure parts must meet ASMECode

114




1. Potential corrosion of internals should not be ignored.

2. Corrosion allowance should be considered in a practical and cost-effective manner.


Corrosion allowance should be considered in the design of internals.

102

Corrosion AllowanceFor Vessel Internals

• Removable internals: CA = CA of shell

– Costs less

– Easily replaced

• Non-removable internals: CA = 2 (CA of shell)– Corrosion occurs on both sides

115




1. Review typical acceptable welding and fabrication details.

2. Details for openings were previously reviewed.

3. Highlight thickness taper.

4. Intermediate heads should retain fillet weld in refinery applications.


ASME Code specifies acceptable welding and fabrication details.

103

Head-to-Shell Transitions

FilletWeld

Butt Weld

Intermediate Head Attachment

th

y

l

ts

Thi

nner

par

t

TangentLine

th

y

l

ts

Thi

nner

par

t

th

y

l

ts

Thi

nner

par

t

TangentL ine

th

y

l

ts

Thi

nner

par

t

Figure 6.1

116




Review thickness taper requirements.


ASME Code fabrication details.

104

Typical Shell Transitions

l

l

y

CL

CL

CLIn all cases, l shall notbe less than 3y.

Figure 6.2

117




Thickness taper may be required in nozzle neck.



105

Nozzle NeckThickness Tapers

Figure 6.3

118




1. Vacuum stiffening ring attachment details.

2, ASME Code specifies weld spacing, size, and length.



106

Stiffener Rings

In-LineIntermittent Weld

StaggeredIntermittent Weld

Continuous Fillet Weld OnOne Side, Intermittent Weld

On Other Side

Figure 6.4

119




1. ASME Code specifies PWHT requirements only for relief of residual stresses.

2. Need for PWHT due to other reasons must be specified by end-user or contractor.

• Service considerations (e.g., wet H2S, caustic)

• Weld hardness reduction


ASME Code PWHT requirements.

107

Post Weld Heat Treatment

• Restores material properties• Relieves residual stresses• ASME Code PWHT requirements

– Minimum temperature and hold time– Adequate stress relief– Heatup and cooldown rates

120




Highlight main areas included in inspection.


ASME Code inspection requirements.

108

Inspection and TestingInspection includes examination of:

• Base material specification and quality

• Welds

• Dimensional requirements

• Equipment documentation

121




Review common types of weld defects.


Particular types of weld defects may occur.

109

Common Weld Defects

Undercut

Incomplete Penetration

Lack of Fusion

Between Weld Bead and Base Metal Between Adjacent Passes

Incomplete Filling at Root on One Side Only Incomplete Filling at Root

Internal Undercut

External Undercut

Figure 7.1

122




Review why weld defects can reduce vessel integrity.


Presence of unacceptable weld defects reduces vessel integrity.

110

Weld DefectsPresence of defects:

• Reduces weld strength below that required• Reduces overall strength of fabrication• Increases risk of failure

123




1. Review NDE methods and types of defects detected.

2. Review advantages and limitations of each NDE method.


• Different NDE methods are best suited to detect particular defect types.

• Each NDE method has advantages and disadvantages.

111

Types of NDENDE TYPE DEFECTS

DETECTEDADVANTAGES LIMITATIONS

Radiographic Gas pockets, slaginclusions,incompletepenetration, cracks

Producespermanent record.Detects small flaws.Most effective forbutt-welded joints.

Expensive.Not practical forcomplex shapes.

Visual Porosity holes, slaginclusions, weldundercuts,overlapping

Helps pinpointareas for additionalNDE.

Can only detectwhat is clearlyvisible.

Liquid Penetrant Weld surface-typedefects: cracks,seams, porosity,folds, pits,inclusions,shrinkage

Used for ferrousand nonferrousmaterials. Simpleand less expensivethan RT, MT, or UT.

Can only detectsurfaceimperfections.

Magnetic Particle Cracks, porosity,lack of fusion

Flaws up to ¼ in.beneath surface canbe detected.

Cannot be used onnonferrousmaterials.

Ultrasonic Subsurface flaws:laminations, slaginclusions

Can be used forthick plates, welds,castings, forgings.May be used forwelds where RT notpractical.

Equipment must beconstantlycalibrated.

Figure 7.2

124




Review typical setup for RT inspection.


Typical RT setup.

112

Typical RT Setup

Test Specimen

Film

X-Ray

X-Ray Tube

Figure 7.3

125




Review how pulse echo UT system can detect defects.


Typical pulse echo UT system.

113

Pulse Echo UT System

Figure 7.4

A

Transducer

Cable

Flaw

Couplant

B

Test Specimen

Read Out

Base Line

Cathode Ray Tube (CRT)

CB

A

Input-OutputGenerator

C

126




1. Water is a safer test medium than air. Pneumatic testing should only be used on an exception basis.

2. “Ratio” is the lowest value of:


Pressure test is used as final demonstration of vessel integrity.

)etemperaturdesign(S)etemperaturtest(S

114

Pressure Testing• Typically use water as test medium• Demonstrates structural and mechanical

integrity after fabrication and inspection• Higher test pressure provides safety margin• PT = 1.5 P (Ratio)

127




Review additional pressure test design considerations.


Pressure test considerations.

115

Pressure Testing, cont’dHydrotest pressures must be calculated:• For shop test. Vessel in horizontal position.• For field test. Vessel in final position with

uncorroded component thicknesses.• For field test. Vessel in final position and with

corroded component thicknesses.• PT ≤ Flange test pressure• Stress ≤ 0.9 (MSYS)• Field test with wind

128




1. Highlight the subjects covered in the course.

2. Note that much more time is required for an in-depth discussion of pressure vessel design. This course provides a good starting point to proceed further for those who need to.

3. Provide the evaluation form for the class to complete. Collect these and return them to the sponsoring unit.

4. Distribute the CEU form to the participants and point out that they will have to mail it in themselves, with the required standard fee. All the information is on the form.


Summarize course.

116

Summary

– Materials– Fabrication– Testing

– Design– Inspection

• Overview of pressure vessel mechanical design• ASME Section VIII, Division 1• Covered

Appendix AReproducible Overheads

Appendix BCourse & Instructor Evaluation Form

131

ASME Career Development Series Course Evaluation

Course Title: ________________________________________________Location: ___________________________________________________Instructor: __________________________________________________Please assist us in the evaluation of this program. Answer the following questions by circling only one answer

unless otherwise stated. We will be using your feedback to plan future programs. Your assistance is most appreciated. Please return to instructor as requested.

A. Course EvaluationPlease record your overall reaction to the program by placing a circle around the appropriate number on the scale.

10 9 8 7 6 5 4 3 2 1 0Excellent Good Fair Poor

Please evaluate the course by circling E (excellent), G (good), F (fair), or P (poor) in the appropriate location.

1. Course content Relevance of Newmatches brochure course notes/ Applicability Knowledge Overall

description workbook to your job Gained Rating

1.1 E G F P 1.2 E G F P 1.3 E G F P 1.4 E G F P 1.5 E G F P

2. What do you think was the best feature of the course?

3. What changes, if any, would you make in the program content and/or format?

4. Can you share with us any comments about this program that we coul use as a quote on our course literature?

Optional Information:Name: _______________________________ Title: _______________________________Company: ____________________________ City, State: __________________________

132

B. Instructor’s EvaluationPlease evaluate the instructor(s) by circling E (excellent), G (good), F (fair), or P (poor) in the appropriate location

5. Effective Effectiveness Effective Openness to knowledge of of teaching use of Class Overallsubject matter method class time Participation Rating

1.1 E G F P 1.2 E G F P 1.3 E G F P 1.4 E G F P 1.5 E G F P

C. Facilities6. How would you rate the meeting site?

7. How would you rate the overnight accommodations (if applicable)?

8. In what other cities would you like to see this course held?

9. Additional Comments:

D. Future Courses and Educational Products (Video, Self Study, Software)10. What other courses would you like to see sponsored?

11. What educational products would you like to see sponsored by ASME and in what medium?

E. On-Site Company Training12. Would your organization be interested in holding this course or other ASME courses at your

facility? If so, please indicate the area of interest and the contact person. Thank you.

13. Course Name/Topic: _________________________________________________________

14. Contact Name: ________________________________ Phone No.: ___________________

133

Appendix C

Continuing Education Unit (CEU) Submittal Form

Course Improvement Form

134

ASME Career Development SeriesContinuing Education Unit (CEU) Request Form

Each 4-hour ASME Career Development Series Course earns 0.4 CEU’s

PLEASE PRINT ALL YOUR INFORMATION CLEARLYYOUR CERTIFICATE WILL BE PREPARED FROM THIS FORM

Title of Program: _____________________________________________________Date Held: __________________________________________________________Instructor: __________________________________________________________Location: ___________________________________________________________Number of CEU’s Earned: (0.4 per 4-hour module) ____________Last Name: __________________________________________First Name, Middle Initial: ______________________________Title/Position: ________________________________________Company: ___________________________________________Address: ____________________________________________City: _______________________ State: __ Zip: ____________Telephone: __________________ Fax: ____________________Email: _________________________

Please send this form, along with a check made out to ASME for the standard fee of $15.00 to:

ASME Continuing Education InstituteThree Park Avenue

New York, NY 10016-5990

Your Certificate will be prepared and sent to the address you indicated above.

135

ASME Career Development SeriesCourse Improvement Form

Important Note: Submission of this form is optional. However, we would like to solicit the comments of the Instructor so that we may continuing improve on the Career Development Series. Any instructors who would like to write a course should indicate so on this form and an authors package will be forwarded to you.

Thank you for helping us with the Career Development Series

Name: _________________________________________________________Address: _______________________________________________________City/State/Zip: __________________________________________________Telephone: ______________________________Fax: ____________________________________Email: __________________________________

Comments:

Please send this form to:ASME Continuing Education Institute

Three Park AvenueNew York, NY 10016-5990

136

ASME Career Development SeriesInstructor’s Biography Form

Important Note: Submission of this form is required every time a Career Development Series Course is taught. ASME cannot process attendees’ CEU requests without this form.

Attachments to this form must include:1. A biographical sketch of the instructor.2. Course evaluations filled out by the participants at the completion of the course.

Course: ____________________________________________________

Date Presented: ______________________________________________

Location: ___________________________________________________

Instructor: __________________________________________________

Number of participants: ________________________________________

Sponsoring Unit: _____________________________________________

137

Your Path to Lifelong Learning

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FOR MORE INFORMATION CALL 1-800-THE-ASME__________________________________________________________________________

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1-800-THE-ASME, or email [email protected] .

Send me information on the following:____ Short Courses ____ In-House Training ____ Self-Study Programs____ FE Exam Review ____ PE Exam Review (videotape) ____ PE Exam Review (Online)____ PE Exam Review (Online Live)

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