1 Overview of Pressure Vessel Design Instructor’s Guide
1
Overview of Pressure Vessel Design
Instructor’s Guide
2
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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
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Overview of Pressure Vessel Design
By:
Vincent A. CarucciCarmagen Engineering, Inc.
Copyright © 1999 by
All Rights Reserved
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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.
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8
9
10
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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Overview of Pressure Vessel Design
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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
Major Learning Points
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
• 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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Main pressure vessel components and shapes.
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Vertical Drum on Leg Supports
Figure 2.2
Head
Shell Nozzle
Head
SupportLeg
18
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Nozzles used for:
• Piping systems
• Instrument connections
• Manways
• Attaching other equipment
2. Ends typically flanged, may be welded.
3. Sometimes extend into vessel.
Major Learning Points
Main pressure vessel components and shapes.
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Tall Vertical Tower
Figure 2.3
Trays
NozzleHead
Shell
Nozzle
Cone
Shell
Nozzle
NozzleSkirtSupport
Head
19
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Main pressure vessel components and shapes.
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Vertical Reactor
Figure 2.4
InletNozzle
Head
Shell
UpperCatalyst
Bed
Catalyst BedSupport Grid
LowerCatalyst
BedOutletCollector
Head
SupportSkirt
OutletNozzle
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Spherical storage vessels typically supported on legs.
2. Cross-bracing typically used to absorb wind and earthquake loads.
Major Learning Points
Main pressure vessel components and shapes.
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Spherical Pressurized Storage Vessel
Figure 2.5
CrossBracing
SupportLeg
Shell
21
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Main pressure vessel components and configurations.
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Vertical Vessel on Lug Supports
Figure 2.6
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Section VIII is most widely used Code.
2. Assures safe design.
3. Three divisions have different emphasis.
Major Learning Points
Define scope of ASME Code Section VIII.
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Scope of ASME CodeSection VIII
• Section VIII used worldwide• Objective: Minimum requirements for safe
construction and operation• Division 1, 2, and 3
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
• Scope of Division 1
• Exclusions from scope
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Differences between Division 1 and 2.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Scope of Division 3
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• 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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Basic organizational structure of Division 1.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Primary factors that influence pressure vessel material selection.
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Material Selection Factors
• Strength• Corrosion Resistance• Resistance to Hydrogen Attack• Fracture Toughness• Fabricability
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Strength: Material’s ability to withstand imposed loading.
2. Higher strength material → thinner component.
3. Describe properties that are used to define strength.
Major Learning Points
Material strength and pressure vessel design.
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Strength
• Determines required component thickness• Overall strength determined by:
– Yield Strength– Ultimate Tensile Strength– Creep Strength– Rupture Strength
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Importance of corrosion resistance in materials selection.
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Corrosion Resistance
• Deterioration of metal by chemical action• Most important factor to consider
• Corrosion allowance supplies additionalthickness
• Alloying elements provide additionalresistance to corrosion
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.”
Major Learning Points
Hydrogen attack can damage carbon and low-alloy steel.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Describe brittle fracture as equivalent to dropping a piece of glass.
2. Material selection must ensure that brittle fracture will not occur.
Major Learning Points
Brittle fracture and its consequences.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. A brittle fracture will occur the first time the appropriate conditions occur.
2. Brittle fracture occurs without warning and is catastrophic.
Major Learning Points
Three conditions that are required for a brittle fracture to occur.
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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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Describe influence of material and temperature factors on fracture toughness.
2. Other factors increase brittle fracture risk.
Major Learning Points
Primary factors that influence material fracture toughness.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Charpy V-Notch test is most widely used measure of material fracture toughness.
2. Describe test set-up.
Major Learning Points
Charpy V-Notch testing.
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Charpy V-Notch Test Setup
Starting PositionHammer
Scale
Pointer
End of swing
Anvil
Specimen
h'
h'
35
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Components to consider is ASME Code brittle fracture evaluation.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Describe the distinction between MDMT and CET.
• MDMT is a materialproperty.
• CET is an environmental factor.
2. Important to understand this distinction.
Major Learning Points
Two temperatures to be considered in brittle fracture evaluation.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Outline ASME procedure.
2. Details described in following overheads.
Major Learning Points
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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Material group classifications for brittle fracture evaluations.
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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
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Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Material group classifications for brittle fracture evaluations.
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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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review additional requirements.
2. Note that most flanges will not require impact testing.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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).
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Describe fabricability.
Major Learning Points
Definition of fabricability.
31
Fabricability
• Ease of construction• Any required special fabrication practices• Material must be weldable
44
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Describe information contained in first section of table.
2. Information is grouped by material chemistry and material form.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review allowable stress vs. design temperature.
2. Most ferritic materials have a constant allowable stress at temperatures through 650°F.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review possible solutions for the 1 in. plate.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review rationale for which option to select.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review conditions to be considered.
2. Worst case operating scenario determines mechanical design.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Highlight other loads that must be considered in the mechanical design.
2. These other loads may govern the mechanical design in local areas.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review these additional other loads.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review the ASME Code Weld Joint Categories.
2. Only specific weld types may be used in each category.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review the different weld types.
2. Limited applications for Types 3 through 6.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review the different head types.
2. The 2:l semi-elliptical head is the most common.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review the relevant equation for a cylindrical shell.
2. Note the sources used for the various parameters.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. The corrosion allowance must be added to obtain the inside radius.
2. The corrosion allowance must be added to the calculated thickness.
Major Learning Points
Sample Problem 1 solution.
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. The calculation is repeated for the other cylindrical shell section.
Major Learning Points
Sample Problem 1 solution.
53
Sample Problem 1Solution, cont’d
• For 4 ft. - 0 in. shell
r = 0.5 × 48 + 0.125 = 24.125 in.
= 0.499 in.
t = 0.499 + 0.125
t = 0.624 in., including corrosion allowance
2506.085.0400,14125.24250
tp ×−××
=
66
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review the relevant equation for a hemispherical head.
2. Note the sources for the relevant parameters and how corrosion allowance is accounted for.
Major Learning Points
Sample Problem 1 solution.
54
Sample Problem 1Solution, cont’d
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
t = 0.335 in., including corrosion allowance
2502.01400,142125.24250
P2.0SE2Pr
t1
p ×−×××
=−
=
67
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 1 solution.
55
Sample Problem 1Solution, cont’d
• Bottom Head - 2:1 Semi-Elliptical (Figure 4.6)
D = 72 + 2 × 0.125 = 72.25 in.
t = 0.628 + 0.125
t = 0.753 in., including corrosion allowance
in. 0.628 2502.01400,142
25.72250P2.0SE2
PDtp =
×−×××
=−
=
68
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Highlight the main parameters that affect buckling strength.
2. ASME Code has design procedure for each type of shell or head.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
3. Review the given information.
4. Review the problem solution with the participants.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 2 solution.
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Factor A is determined based only on geometry.
2. Note the source of Factor A.
Major Learning Points
Sample Problem 2 solution.
61
Sample Problem 2Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Note how Factor A is determined from these curves.
2. After determine Factor A, go to applicable material chart.
Major Learning Points
Sample Problem 2 solution.
62
Sample Problem 2Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 2 solution.
63
Sample Problem 2Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Pa is calculated using indicated equation because A is not under curves.
2. Must use E from curves at design temperature.
Major Learning Points
Sample Problem 2 solution.
64
Sample Problem 2Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 2 solution.
65
Sample Problem 2Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Note the relevant equation for the cylindrical shell and the appropriate parameters.
2. Note how corrosion allowance is accounted for.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Note the relevant equation for the heads and the appropriate parameters.
2. Note how corrosion allowance is accounted for.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Simplified ASME rules do not require stress calculations. Use “area replacement” approach.
2. Metal removed must be replaced by equivalent metal.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Sample Problem 3 illustrates evaluation of an opening for adequate reinforcement.
2. Review the given information.
3. Review the problem solution with the Participants.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Required replacement area is based on the cross-sectional area removed.
2. Calculated using the required shell thickness, not the actual.
Major Learning Points
Sample Problem 3 solution.
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Corrosion allowance is accounted for.
2. tr is calculated using the appropriate shell equation.
Major Learning Points
Sample Problem 3 solution.
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 3 solution.
76
Sample Problem 3 -Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review the relevant parameters.
Major Learning Points
Sample Problem 3 solution.
77
Sample Problem 3 -Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Available shell reinforcement area is determined.
Major Learning Points
Sample Problem 3 solution.
78
Sample Problem 3 -Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Available reinforcement area in the nozzle is determined by checking two equations.
Major Learning Points
Sample Problem 3 solution.
79
Sample Problem 3 -Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review the relevant parameters.
Major Learning Points
Sample Problem 3 solution.
80
Sample Problem 3 -Solution, cont’d
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Calculate required thickness using the equation for a cylinder.
Major Learning Points
Sample Problem 3 solution.
81
Sample Problem 3 -Solution, cont’d
• Calculate required nozzle thickness, trn (Figure 4.6)
P6.0SEPr
t1
rn −=
.in0784.03006.01000,15
)0625.08125.3(300trn =
×−×+
=
94
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 3 solution.
82
Sample Problem 3 -Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 3 solution.
83
Sample Problem 3 -Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 3 solution.
84
Sample Problem 3 -Solution, cont’d
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. ASME B16.5 provides standard flange dimensional details.
2. Flange strength is based on dimensions and material used.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Acceptable flange materials are grouped based on similarities in strength.
2. The Material Group is determined based on the specified material.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Sample Problem 4 illustrates how to determine flange rating.
2. Review the given information.
3. Review the problem solution with the Participants.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review the problem solution.
Major Learning Points
Sample Problem 4 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
Sample Problem 4 solution.
90
Sample Problem 4 -Solution, cont’d
– 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Applied loads act at different flange locations.
2. Flange moments are calculated for the operating and gasket seating cases.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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).
Major Learning Points
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. This is an excerpt from Table 2-5.1.
2. Review the variation in m and y with gasket type.
Major Learning Points
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. This is an excerpt from Table 2-5.2.
2. Review the flange facings shown.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review the additional gasket information shown.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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).
Major Learning Points
Externally applied loads must also be considered in vessel design.
99
Local Loads
• Piping system
• Platforms, internals, attached equipment
• Support attachment
112
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Discuss ASME requirements for loads applied to vessel and welding to pressure parts.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Potential corrosion of internals should not be ignored.
2. Corrosion allowance should be considered in a practical and cost-effective manner.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review thickness taper requirements.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Thickness taper may be required in nozzle neck.
Major Learning Points
ASME Code fabrication details.
105
Nozzle NeckThickness Tapers
Figure 6.3
118
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Vacuum stiffening ring attachment details.
2, ASME Code specifies weld spacing, size, and length.
Major Learning Points
ASME Code fabrication details.
106
Stiffener Rings
In-LineIntermittent Weld
StaggeredIntermittent Weld
Continuous Fillet Weld OnOne Side, Intermittent Weld
On Other Side
Figure 6.4
119
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Highlight main areas included in inspection.
Major Learning Points
ASME Code inspection requirements.
108
Inspection and TestingInspection includes examination of:
• Base material specification and quality
• Welds
• Dimensional requirements
• Equipment documentation
121
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review common types of weld defects.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review why weld defects can reduce vessel integrity.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
1. Review NDE methods and types of defects detected.
2. Review advantages and limitations of each NDE method.
Major Learning Points
• 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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review typical setup for RT inspection.
Major Learning Points
Typical RT setup.
112
Typical RT Setup
Test Specimen
Film
X-Ray
X-Ray Tube
Figure 7.3
125
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review how pulse echo UT system can detect defects.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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:
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
Review additional pressure test design considerations.
Major Learning Points
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
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Instructor’s Outline
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.
Major Learning Points
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.
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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
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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.: ___________________
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Appendix C
Continuing Education Unit (CEU) Submittal Form
Course Improvement Form
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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.
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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
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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: _____________________________________________
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Your Path to Lifelong Learning
ASME offers you exciting, rewarding ways to sharpen your technical skills, enhance personal development and prepare for advancement.
Short Courses – More than 200 short courses offered each you keep you up to speed in the technology fast lane—or, help you fill in any gaps in your technical background.
Customized Training at your organization’s site – Do you have ten or more people at your site who could benefit from an ASME course? Most of our courses can be offered in-house and tailored to your latest engineering project. Bring course to your company too.
Self-study materials meet the needs of individuals who demand substantive, practical information, yet require flexibility, quality and convenience. Return to each program again and again, as a refresher or as an invaluable addition to your reference library.
FE Exam Review– A panel of seasoned educators outline a wide range of required topics to provide a thorough review to help practicing engineers as well as engineering students prepare for this challenging examination. Videotape Review
PE Exam Review– A comprehensive review of all the major exam topics that demonstrates the necessary math, logic and theory. Videotape, Online, or Online Live Revie w available.
FOR MORE INFORMATION CALL 1-800-THE-ASME__________________________________________________________________________
INFORMATION REQUEST FORMPlease mail to ASME at 22 Law Drive, P. O. Box 2900, Fairfield, NJ 07007-2900, or fax to 973-882-1717, call
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)
Name: ______________________________________________Title: _______________________________________________Organization: _________________________________________Business Address: _____________________________________City: _________________ State: __ Zip Code: _____________Business Phone: _________________ Fax: ________________Email: ______________________________________________