Overview of Pressure Vessel Design
Instructor’s Guide
1
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2
Overview of Pressure Vessel Design
By:
Vincent A. Carucci
Carmagen Engineering, Inc.
Copyright © 1999 by
All Rights Reserved
3
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 Form
Instructor’s Biography Form
4
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 a mong 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.
5
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 4hour (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.
2.
3.
Organizing Unit Responsibilities
Instructor Guidelines and Responsibilities
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.
6
7
8
9
10
Suggested Outline/Teaching Plan
Time,
min.
Major
Interval
10
Class Segment
Introduction
Sub-Segment
Interval
5
5
25
General
10
10
5
20
Materials of
Construction
15
5
10
Exercise
10
10
55
Break
Design
10
10
25
20
Sub-Segment
Introduction/Logistics
Outline Module
Module based primarily on the
ASME Code Section VIII, Division
1. Divisions 2 and 3 will be briefly
described
Main Pressure Vessel Components
Scope of ASME Code Section VIII
• Division 1
• Division 2
• Division 3
Structure of Section VIII, Division 1
Material Selection Factors
• Strength
• Corrosion Resistance
• Resistance to Hydrogen Attack
• Fracture Toughness
• Fabricability
Maximum Allowable Stress
Material Selection Based On Fracture
Toughness
Design Conditions and Loadings
• Pressure
• Temperature
• Other Loadings
Design for Internal Pressure
• Weld Joints
• Cylindrical Shells
• Heads
• Conical Sections
Sample Problem
Design for External Pressure and
Compressive Stresses
• Cylindrical Shells
• Other Components
• Sample Problem
Overheads/
Participant
Pages
OV – 1
Part. – 65
OV – 2
Part. – 65
OV – 3-9
Part. – 67
OV – 10-13
Part. – 75
OV – 14
Part. –78
OV – 15-31
Part. – 79
OV – 32-34
Part. – 87
OV – 35-38
Part. – 91
OV – 39-43
Part. – 92
OV – 44-55
Part. - 98
OV – 56-65
Part. – 109
11
Suggested Outline/Teaching Plan, continued
Time,
min.
Major
Interval
10 - 50
Class Segment
Sub-Segment
Interval
Major Break
Sub-Segment
Overheads/
Participant
Pages
Lunch or Major Break
15
Exercise
15
Required Thickness for Internal
Pressure
OV – 66-68
Part. - 118
50
Design
(Cont’d.)
20
Reinforcement of Openings (Include
Sample Problem)
Flange Rating (Including Sample
Problem)
Flange Design
OV – 69-84
Part. – 119
OV – 85-90
Part. – 127
OV – 91-97
Part. – 131
OV – 98
Part. – 138
10
15
10
20
20
15
10
Break
Other Design
Considerations
Fabrication
Inspection and
Testing
Closure
5
Maximum Allowable Working
Pressure (MAWP)
10
Local Loads
10
Vessel Internals
10
Acceptable Welding Details
10
Postweld Heat Treatment
(PWHT)Requirements
10
Inspection
5
Pressure Testing
10
Summary
Questionnaire (fill in and collect)
CEU Form (hand out – individual
responsibility to return)
OV – 99
Part. – 139
OV – 100-102
Part. – 141
OV – 103-106
Part. – 143
OV – 107
Part. – 146
OV – 108-113
Part. – 148
OV – 114-115
Part. – 152
OV – 116
Part. - 155
12
Overview of Pressure Vessel Design
Instructor’s Personal Notes
OVERVIEW OF
PRESSURE VESSEL DESIGN
By: Vincent A. Carucci
Carmagen Engineering, Inc .
1
Instructor’s Outline
1. Course discusses pressure vessel
design and is introductory in nature.
Major Learning Points
Course Introduction
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.
13
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Course Overview
• General
• Materials of Construction
• Design
• Other Design Considerations
• Fabrication
• Inspection and Testing
2
Instructor’s Outline
1. The objective: Provide a general
knowledge of design requirements
for pressure vessels.
Major Learning Points
•
Establish course objectives.
•
Outline course content, a road map.
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
14
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Pressure Vessels
• Containers for fluids under pressure
• Used in variety of industries
– Petroleum refining
– Chemical
– Power
– Pulp and paper
– Food
3
Instructor’s Outline
Major Learning Points
1. Describe what a pressure vessel is.
•
Define pressure vessels.
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.
•
Identify wide variety of industrial
applications.
15
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Horizontal Drum on
Saddle Supports
Nozzle
A
Shell
Head
Head
Saddle Support
(Sliding)
Saddle Support
(Fixed)
A
SectionA-A
Figure 2.1
4
Instructor’s Outline
Major Learning Points
1. Use this and following overheads to
describe main pressure vessel
components and shapes.
Main pressure vessel components and
configurations.
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.
16
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Vertical Drum
on Leg Supports
Head
Shell
Nozzle
Head
Support
Leg
5
Instructor’s Outline
1. Most heads are curved shape for
strength, thinness, economy.
Figure 2.2
Major Learning Points
Main pressure vessel components and
shapes.
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.
17
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Tall Vertical Tower
Nozzle
Head
Trays
Shell
Nozzle
Cone
Nozzle
Shell
Nozzle
6
Instructor’s Outline
1. Nozzles used for:
•
Piping systems
•
Instrument connections
•
Manways
•
Attaching other equipment
Head
Skirt
Support
Figure 2.3
Major Learning Points
Main pressure vessel components and
shapes.
2. Ends typically flanged, may be
welded.
3. Sometimes extend into vessel.
18
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Vertical Reactor
Inlet
Nozzle
Head
Upper
Catalyst
Bed
Shell
Catalyst Bed
Support Grid
Lower
Catalyst
Bed
Outlet
Collector
Head
Outlet
Nozzle
Support
Skirt
7
Figure 2.4
Instructor’s Outline
Major Learning Points
1. Skirt supports typically used for tall
vertical vessels:
Main pressure vessel components and
shapes.
•
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.
19
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Spherical Pressurized
Storage Vessel
Shell
Support
Leg
Cross
Bracing
Figure 2.5
8
Instructor’s Outline
1. Spherical storage vessels typically
supported on legs.
Major Learning Points
Main pressure vessel components and
shapes.
2. Cross-bracing typically used to
absorb wind and earthquake loads.
20
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Vertical Vessel on
Lug Supports
9
Instructor’s Outline
1. Vessel size limits for lug supports:
•
1 – 10 ft diameter
•
2:1 to 5:1 height/diameter ratio
Figure 2.6
Major Learning Points
Main pressure vessel components and
configurations.
2. Vessel located above grade.
3. Lugs bolted to horizontal structure.
21
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Scope of ASME Code
Section VIII
• Section VIII used worldwide
• Objective: Minimum requirements for safe
construction and operation
• Division 1, 2, and 3
10
Instructor’s Outline
1. Section VIII is most widely used
Code.
Major Learning Points
Define scope of ASME Code Section
VIII.
2. Assures safe design.
3. Three divisions have different
emphasis.
22
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
11
Instructor’s Outline
Major Learning Points
1. Review scope of Division 1.
•
Scope of Division 1
2. Division 1 not applicable below 15
psig.
•
Exclusions from scope
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.
23
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Section VIII, Division 2,
Alternative Rules
• Scope identical to Division 1 but
requirements differ
– Allowable stress
– Stress calculations
– Design
– Quality control
– Fabrication and inspection
• Choice between Divisions 1 and 2 based on
economics
12
Instructor’s Outline
1. Review differences between
Divisions 1 and 2.
Major Learning Points
Differences between Division 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.
24
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Division 3, Alternative Rules
High Pressure Vessels
• Applications over 10,000 psi
• Pressure from external source, process
reaction, application of heat, combination
of these
• Does not establish maximum pressure
limits of Division 1 or 2 or minimum limits
for Division 3.
13
Instructor’s Outline
1. Review application of Division 3.
Major Learning Points
Scope 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.
25
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
14
Instructor’s Outline
1. Review Division 1 organization
2. Fabrication methods:
•
Welded
•
Forged
•
Brazed
Major Learning Points
Basic organizational structure of
Division 1.
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.
26
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Material Selection Factors
•
•
•
•
•
Strength
Corrosion Resistance
Resistance to Hydrogen Attack
Fracture Toughness
Fabricability
15
Instructor’s Outline
1. ASME Code does not specify
particular materials to use in each
application. Owner must do this.
Major Learning Points
Primary factors that influence pressure
vessel material selection.
2. ASME Code specifies permitted
materials and the requirements that
these must meet.
27
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Strength
• Determines required component thickness
• Overall strength determined by:
– Yield Strength
– Ultimate Tensile Strength
– Creep Strength
– Rupture Strength
16
Instructor’s Outline
1. Strength: Material’s ability to
withstand imposed loading.
Major Learning Points
Material strength and pressure vessel
design.
2. Higher strength material → thinner
component.
3. Describe properties that are used to
define strength.
28
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Corrosion Resistance
• Deterioration of metal by chemical action
• Most important factor to consider
• Corrosion allowance supplies additional
thickness
• Alloying elements provide additional
resistance to corrosion
17
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.
Major Learning Points
Importance of corrosion resistance in
materials selection.
3. Alloy materials are used in services
where corrosion allowance would be
unreasonably high if carbon steel
were used.
29
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Resistance to
Hydrogen Attack
• At 300 - 400°F, monatomic hydrogen
forms molecular hydrogen in voids
• Pressure buildup can cause steel to crack
• Above 600°F, hydrogen attack causes
irreparable damage through component
thickness
18
Instructor’s Outline
1. Low-temperature H 2 attack can
cause cracking.
Major Learning Points
Hydrogen attack can damage carbon
and low-alloy steel.
2. Higher temperature H 2 attack causes
through-thickness strength loss and
is irreversible.
3. H2 attack is a function of H 2 partial
pressure and design temperature.
•
Increased alloy content (i.e., Cr)
increases H 2 attack resistance.
•
Reference API-941 for “Nelson
Curves.”
30
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Brittle Fracture
and Fracture Toughness
• Fracture toughness: Ability of material to
withstand conditions that could cause
brittle fracture
• Brittle fracture
– Typically at “low” temperature
– Can occur below design pressure
– No yielding before complete failure
19
Instructor’s Outline
1. Describe brittle fracture as
equivalent to dropping a piece of
glass.
Major Learning Points
Brittle fracture and its consequences.
2. Material selection must ensure that
brittle fracture will not occur.
31
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Brittle Fracture and
Fracture 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
20
Instructor’s Outline
1. A brittle fracture will occur the first
time the appropriate conditions
occur.
Major Learning Points
Three conditions that are required for a
brittle fracture to occur.
2. Brittle fracture occurs without
warning and is catastrophic.
32
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Factors That Influence
Fracture Toughness
• Fracture toughness varies with:
- Temperature
- Type and chemistry of steel
- Manufacturing and fabrication processes
• Other factors that influence fracture
toughness:
21
Instructor’s Outline
1. Describe influence of material and
temperature factors on fracture
toughness.
- Arc strikes, especially if over repaired area
- Stress raisers or scratches in cold formed thick
plate
Major Learning Points
Primary factors that influence material
fracture toughness.
2. Other factors increase brittle fracture
risk.
33
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Charpy V-Notch Test Setup
Scale
Starting Position
Hammer
Pointer
h'
End of swing
Specimen
h'
Anvil
22
Instructor’s Outline
1. Charpy V-Notch test is most widely
used measure of material fracture
toughness.
Major Learning Points
Charpy V-Notch testing.
2. Describe test set-up.
34
Overview of Pressure Vessel Design
Instructor’s Personal Notes
ASME Code and
Brittle Fracture Evaluation
• Components to consider
– Shells
– Manways
– Heads
– Reinforcing pads
– Backing strips
that remain in
place
– Nozzles
– Tubesheets
– Flanges
– Flat cover plates
– Attachments essential
to structural integrity
that are welded to
pressure parts
23
Instructor’s Outline
Major Learning Points
1. ASME Code contains brittle fracture
evaluation procedure.
Components to consider is ASME Code
brittle fracture evaluation.
2. Review components to be included only items that relate to structural
integrity of pressure-containing
shell.
35
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
24
Instructor’s Outline
1. Describe the distinction between
MDMT and CET.
•
MDMT is a material property.
•
CET is an environmental factor.
Major Learning Points
Two temperatures to be considered in
brittle fracture evaluation.
2. Important to understand this
distinction.
36
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Simplified ASME
Evaluation Approach
• Material specifications classified into
Material 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 and
thickness not exempt, then must impact test
at CET
25
Instructor’s Outline
1. Outline ASME procedure.
2. Details described in following
overheads.
Major Learning Points
Simplified ASME brittle fracture
evaluation procedure.
37
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Material Groups
MATERIAL
GROUP
Curve A
APPLICABLE MATERIALS
• All carbon and low alloy steel plates, structural shapes, and bars not
listed in Curves B, C & D
• SA-216 Gr. WCB & WCC, SA-217 Gr. WC6, if normalized and tempered
or water-quenched and tempered
Curve B
• SA-216 Gr. WCA, if normalized and tempered or water-quenched and
tempered
• SA-216 Gr. WCB & WCC for maximum thickness of 2 in., if produced
to fine grain practice and water-quenched and tempered
• SA-285 Gr. A & B
•
•
•
•
SA-414 Gr. A
SA-515 Gr. 60
SA-516 Gr. 65 & 70, if not normalized
Except for cast steels, all materials of Curve A if produced to fine
grain practice and normalized which are not included in Curves C & D
• All pipe, fittings, forging, and tubing which are not included in Curves
C & D
Table 3.1 (Excerpt)
26
Instructor’s Outline
1. Materials are grouped based on
common fracture toughness
properties.
Major Learning Points
Material group classifications for brittle
fracture evaluations.
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.
38
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Material Groups, cont’d
MATERIAL
GROUP
Curve C
Curve D
Bolting
and Nuts
APPLICABLE MATERIALS
•
•
SA-182 Gr. 21 & 22, if normalized and tempered
SA-302 Gr. C & D
•
SA-336 Gr. F21 & F22, if normalized and tempered
•
SA-387 Gr. 21 & 22, if normalized and tempered
•
•
SA-516 Gr. 55 & 60, if not normalized
SA-533 Gr. B & C
•
SA-662 Gr. A
•
All material of Curve B if produced to fine grain practice and
normalized which are not included in Curve D
•
SA-203
•
SA-537 Cl. 1, 2 & 3
•
SA-508 Cl. 1
•
SA-612, if normalized
•
SA-516, if normalized
•
SA-662, if normalized
•
SA-524 Cl. 1 & 2
•
SA-738 Gr. A
•
See Figure UCS-66 of the ASME Code Section VIII, Div. 1, for impact
test exemption temperatures for specified material specifications
Table 3.1 (Excerpt)
27
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.
Major Learning Points
Material group classifications for brittle
fracture evaluations.
2. Highlight points.
•
Lower strength grades of same
specification have better
fracture toughness.
•
Normalization improves fracture
toughness.
39
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Impact Test Exemption Curves
for Carbon and Low-Alloy Steel
140
120
Minimum Design Metal Temperature, F
100
B
A
80
60
C
40
D
20
0
-20
-40
-55
-60
Impact testing required
-80
0.394
1
2
3
4
5
Nominal Thickness, in.
(Limited to 4 in. for Welded Construction)
Figure 3.1
28
Instructor’s Outline
1. Describe relationship between
Material Group, component
thickness, and MDMT.
Major Learning Points
Impact test exemption curves.
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.
40
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Additional ASME Code Impact
Test 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 unless
specifically exempt
29
Instructor’s Outline
1. Review additional requirements.
Major Learning Points
Additional impact test requirements.
2. Note that most flanges will not
require impact testing.
41
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Additional ASME Code
Impact 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 steel
and not required by code
• MDMT reduction if calculated stress <
allowable stress
30
Instructor’s Outline
1. Review additional requirements.
Major Learning Points
Additional impact test 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).
42
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Fabricability
• Ease of construction
• Any required special fabrication practices
• Material must be weldable
31
Instructor’s Outline
Describe fabricability.
Major Learning Points
Definition of fabricability.
43
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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 for
permitted material specifications
32
Instructor’s Outline
1. Discuss the use of allowable stress
in determining vessel component
design.
Major Learning Points
•
Description of allowable stress.
•
ASME Code allowable stress tables
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.
44
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Maximum Allowable
Stress, cont’d
ALLOWABLE STRESS IN TENSION FOR CARBON AND
LOW-ALLOY STEEL
Nominal
P-No.
Group No. Min. Yield Min. Tensile
Composition
(ksi)
(ksi)
Carbon Steel Plates and Sheets
SA-515
55
C-Si
1
1
30
55
60
C-Si
1
1
32
60
65
C-Si
1
1
35
65
70
C-Si
1
2
38
70
Spec No.
SA-516
Grade
55
60
65
70
C-Si
C-Mn-Si
C-Mn-Si
C-Mn-Si
Plate - Low Alloy Steels
SA-387
2 Cl.1
1/2Cr-1/2Mo
2 Cl.2
1/2Cr-1/2Mo
12 Cl.1
1Cr-1/2Mo
12 Cl.2
1Cr-1/2Mo
11 Cl.1 1 1/4Cr-1/2Mo-Si
11 Cl.2 1 1/4Cr-1/2Mo-Si
22 Cl.1
2 1/4Cr-1Mo
22 Cl.2
2 1/4Cr-1Mo
1
1
1
1
1
1
1
2
30
32
35
38
55
60
65
70
3
3
4
4
4
4
5
5
1
2
1
1
1
1
1
1
33
45
33
40
35
45
30
45
55
70
55
65
60
75
60
75
ASME Maximum Allowable Stress (Table 1A Excerpt)
Figure 3.2
33
Instructor’s Outline
1. Describe information contained in
first section of table.
Major Learning Points
ASME Code allowable stress tables.
2. Information is grouped by material
chemistry and material form.
45
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Maximum Allowable
Stress, cont’d
ALLOWABLE STRESS IN TENSION FOR CARBON AND LOW ALLOY STEEL
Max Allowable Stress, ksi (Multiply by 1,000 to Obtain psi)
for Metal Temperature, °F, Not Exceeding
650
700
750
800
13.8
15.0
16.3
17.5
13.3
14.4
15.5
16.6
12.1
13.0
13.9
14.8
10.2
10.8
11.4
12.0
8.4
8.7
9.0
9.3
6.5
6.5
6.5
6.5
4.5
4.5
4.5
4.5
2.5
2.5
2.5
2.5
Spec
No.
1050 1100
1150
1200
Carbon Steel Plates and Sheets
----SA-515
----SA-515
----SA-515
----SA-515
13.8
15.0
16.3
17.5
13.3
14.4
15.5
16.6
12.1
13.0
13.9
14.8
10.2
10.8
11.4
12.0
8.4
8.7
9.0
9.3
6.5
6.5
6.5
6.5
4.5
4.5
4.5
4.5
2.5
2.5
2.5
2.5
-----
13.8
17.5
13.8
16.3
15.0
18.8
15.0
17.7
13.8
17.5
13.8
16.3
15.0
18.8
15.0
17.2
13.8
17.5
13.8
16.3
15.0
18.8
15.0
17.2
13.8
17.5
13.8
16.3
15.0
18.8
15.0
16.9
13.8
17.5
13.4
15.8
14.6
18.3
14.4
16.4
13.3
16.9
12.9
15.2
13.7
13.7
13.6
15.8
9.2
9.2
11.3
11.3
9.3
9.3
10.8
11.4
5.9
5.9
7.2
7.2
6.3
6.3
8.0
7.8
Plate-Low Alloy Steels (Cont'd)
----SA-387
----SA-387
4.5
2.8
1.8
1.1
SA-387
4.5
2.8
1.8
1.1
SA-387
4.2
2.8
1.9
1.2
SA-387
4.2
2.8
1.9
1.2
SA-387
5.7
3.8
2.4
1.4
SA-387
5.1
3.2
2.0
1.2
SA-387
850
900
950
1000
-----
-----
-----
SA-516
SA-516
SA-516
SA-516
ASME Maximum Allowable Stress (Excerpt), cont'd
Figure 3.2, cont'd
34
Instructor’s Outline
1. Review allowable stress vs. design
temperature.
Major Learning Points
ASME Code allowable stress tables.
2. Most ferritic materials have a
constant allowable stress at
temperatures through 650°F.
46
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Material Selection Based
on 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?
35
Instructor’s Outline
Major Learning Points
1. This independent Exercise gives the
Participants practice in material
selection based on fracture
toughness.
Participant Exercise 1 covering 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.
47
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
36
Instructor’s Outline
1. Review difference between
normalized and non-normalized
material with respect to fracture
toughness.
Major Learning Points
Solution to Participant Exercise.
2. Review MDMT determination in each
case.
3. Note difference between MDMT and
CET in each case.
48
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Exercise 1 - Solution, cont’d
• One approach to correct: Impact test 1 in. plate
at -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
37
Instructor’s Outline
1. Review possible solutions for the
1 in. plate.
Major Learning Points
Solution to Participant Exercise.
49
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Exercise 1 - Solution, cont’d
• Choice of option based on cost, material
availability, whether likely that 1 in. thick nonnormalized plate would pass impact testing
38
Instructor’s Outline
1. Review rationale for which option to
select.
Major Learning Points
Solution to Participant Exercise 1.
50
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Design Conditions
and Loadings
• Determine vessel mechanical design
• Design pressure and temperature, other
loadings
• Possibly multiple operating scenarios to
consider
• Consider startup, normal operation,
anticipated deviations, shutdown
39
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.
51
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Design Pressure
PT = Design Pressure at
Top of Vessel
γ = Weight Density of
Liquid in Vessel
H = Height
of Liquid
PBH = Design Pressure of
Bottom Head
Figure 4.1
40
Instructor’s Outline
1. May have internal of external
pressure, or both at different times.
Major Learning Points
Design pressure as a mechanical
design condition.
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.
52
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Temperature Zones
in Tall Vessels
Section 4
(T-Z)
Section 3
(T-Y)
Section 2
(T-X)
Section 1
(T) F
Support Skirt
Grade
Figure 4.2
41
Instructor’s Outline
1. Margin required between operating
temperature and design temperature.
Major Learning Points
Design temperature as a mechanical
design condition.
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.
53
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Additional Loadings
• Weight of vessel and normal contents
under operating or test conditions
• Superimposed static reactions from weight
of attached items (e.g., motors, machinery,
other vessels, piping, linings, insulation)
• Loads at attached internal components or
vessel supports
• Wind, snow, seismic reactions
42
Instructor’s Outline
1. Highlight other loads that must be
considered in the mechanical
design.
Major Learning Points
Loadings other than pressure and
temperature must also be considered.
2. These other loads may govern the
mechanical design in local areas.
54
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Additional Loadings, cont’d
• Cyclic and dynamic reactions caused by
pressure or thermal variations, equipment
mounted on vessel, and mechanical loadings
• Test pressure combined with hydrostatic
weight
• Impact reactions (e.g., from fluid shock)
• Temperature gradients within vessel
component and differential thermal
expansion between vessel components
43
Instructor’s Outline
1. Review these additional other loads.
Major Learning Points
Additional other loadings to consider.
55
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Weld Joint Categories
C
C
C
A
A
A D
B
D
B
A
C
B
C
D
A
D
B
B
D
A
C
Figure 4.3
44
Instructor’s Outline
1. Review the ASME Code Weld Joint
Categories.
Major Learning Points
ASME Code defines welded joints by
category.
2. Only specific weld types may be
used in each category.
56
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Weld Types
Buttjointsasattainedbydouble-weldingorbyother
means which will obtain the same quality of deposited
weld metal on the inside and outside weld surface.
1
Backing strip, if used, shall be removed after
completionofweld.
Single-welded butt joint with backing strip which
remainsinplaceafterwelding.
2
For circumferential
joint only
3
Single-welded butt joint without backing strip.
4
Double-fullfilletlapjoint.
5
Single-full fillet lap joint with plug welds.
6
Single-full fillet lap joint without plug welds.
Figure 4.4
45
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.
57
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Weld Joint Efficiencies
Joint
Type
Acceptable Joint Categories
Degree of
Radiographic 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
46
Instructor’s Outline
1. Weld joint efficiency, E, is a measure
of weld quality and accounts for
stress concentrations.
Major Learning Points
Weld joint efficiency vs. Joint Type,
Category, Radiographic Examination.
2. E is needed in component thickness
calculations.
3. Review information in table.
4. Note that corrosion allowance was
previously discussed.
58
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Summary Of ASME
Code Equations
Part
Thickness,
tp , in.
Cylindrical shell
Pr
SE1 − 0.6P
SE 1t
r + 0.6t
P(r + 0.6t)
tE1
Spherical shell
Pr
2SE1 − 0.2P
2SEt
r + 0.2t
P(r + 0.2t )
2tE
PD
2SE − 0.2P
2SEt
D + 0.2t
P(D + 0.2t )
2tE
0.885PL
SE − 0.1P
SEt
0.885L + 0.1t
P (0.885L + 0.1t )
tE
PD
2 cos α (SE − 0.6P)
2SEt cos α
D + 1.2t cos α
P(D + 1.2t cos α)
2tE cos α
2:1
Semi - Elliptical
head
Torispherical head
with 6% knuckle
Conical Section
( α = 30°)
Pressure,
P, psi
Stress,
S, psi
Figure 4.6
47
Instructor’s Outline
1. Circumferential stress governs
minimum required component
thickness in most cases.
Major Learning Points
ASME Code equations for various
components under internal pressure.
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.
59
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Typical Formed Closure Heads
t
t
R
sf
sf
ID
ID
Flanged
Hemispherical
t
t
h
sf
h
Elliptical
α
sf
Flanged and Dished
(torispherical)
α
t
t
sf
r
ID
Toriconical
ID
Conical
48
Instructor’s Outline
1. Review the different head types.
2. The 2:l semi-elliptical head is the
most common.
Figure 4.7
Major Learning Points
Different types of closure heads may be
used.
60
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Hemispherical
Head to Shell Transition
th
l ≥ 3y
Thinner Part
Thinner Part
th
l ≥ 3y
Tangent Line
y
Length of required taper, l,
may include the width
of the weld
ts
y
ts
Figure 4.8
49
Instructor’s Outline
Major Learning Points
1. Required thickness of a
hemispherical head is about half that
of the connected cylindrical shell.
Thickness transition at a hemispherical
head.
2. Must have a tapered thickness
transition in the head to end up
matching the shell thickness.
61
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1
Hemispherical
4' - 0"
60' - 0"
DESIGN INFORMATION
Design Pressure = 250 psig
Design Temperature = 700° F
Shell and Head Material is SA-515
Gr. 60
Corrosion Allowance = 0.125"
Both Heads are Seamless
Shell and Cone Welds are Double
Welded and will be Spot
Radiographed
The Vessel is in All Vapor Service
Cylinder Dimensions Shown are
Inside Diameters
10' - 0"
6' - 0"
30' - 0"
2:1 Semi-Elliptical
Figure 4.9
50
Instructor’s Outline
1. Sample Problem 1 illustrates
calculation of required shell and
head thicknesses for internal
pressure.
Major Learning Points
Sample Problem to illustrate calculation
of required thickness for internal
pressure.
2. Review the given information.
3. Review the problem solution with
the Participants.
62
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1 - Solution
• Required thickness for internal pressure of cylindrical
shell (Figure 4.6):
tp =
Pr
SE1 − 0. 6P
• 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
51
Instructor’s Outline
1. Review the relevant equation for a
cylindrical shell.
Major Learning Points
Sample Problem 1 solution.
2. Note the sources used for the
various parameters.
63
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1
Solution, cont’d
• For 6 ft. - 0 in. shell
r = 0.5D + C = 0.5 × 72 + 0.125 = 36.125 in.
Pr
250 × 36.125
tp =
=
S E1 − 0.6P 14,400 × 0.85 − 0.6 × 250 = 0.747 in.
t = tp + c = 0.747 + 0.125
t = 0.872 in., including corrosion allowance
52
Instructor’s Outline
1. The corrosion allowance must be
added to obtain the inside radius.
Major Learning Points
Sample Problem 1 solution.
2. The corrosion allowance must be
added to the calculated thickness.
64
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1
Solution, cont’d
• For 4 ft. - 0 in. shell
r = 0.5 × 48 + 0.125 = 24.125 in.
tp =
250 × 24.125
14,400 × 0. 85 − 0. 6 × 250
= 0.499 in.
t = 0.499 + 0.125
t = 0.624 in., including corrosion allowance
53
Instructor’s Outline
1. The calculation is repeated for the
other cylindrical shell section.
Major Learning Points
Sample Problem 1 solution.
65
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1
Solution, cont’d
Both heads are seamless, E = 1.0.
Top Head - Hemispherical (Figure 4.6)
r = 24 + 0.125 = 24.125 in.
tp =
Pr
250 × 24.125
= 0.21 in.
=
2SE1 − 0.2P 2 × 14,400 × 1 − 0.2 × 250
t = tp + c = 0.21 + 0.125
t = 0.335 in., including corrosion allowance
54
Instructor’s Outline
1. Review the relevant equation for a
hemispherical head.
Major Learning Points
Sample Problem 1 solution.
2. Note the sources for the relevant
parameters and how corrosion
allowance is accounted for.
66
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 1
Solution, cont’d
• Bottom Head - 2:1 Semi-Elliptical (Figure 4.6)
D = 72 + 2 × 0.125 = 72.25 in.
tp =
PD
250 × 72 .25
=
= 0.628 in.
2SE − 0.2P 2 × 14,400 × 1 − 0.2 × 250
t = 0.628 + 0.125
t = 0.753 in., including corrosion allowance
55
Instructor’s Outline
1. Review the relevant equation for a
semi-elliptical head.
Major Learning Points
Sample Problem 1 solution.
2. Note the sources for the relevant
parameters and how corrosion
allowance is accounted for.
67
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Design For External
Pressure 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
56
Instructor’s Outline
Major Learning Points
1. Buckling of a shell under external
pressure or compressive forces is
analogous to column buckling under
a compressive force.
Different procedures are used to design
for external pressure or compressive
loads.
2. Addition of stiffener rings reduces
effective buckling length.
68
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Design For
External Pressure and
Compressive Stresses, cont’d
• ASME procedures for cylindrical shells,
heads, conical sections. Function of:
– Material
– Diameter
– Unstiffened length
– Temperature
– Thickness
57
Instructor’s Outline
1. Highlight the main parameters that
affect buckling strength.
Major Learning Points
Parameters that affect compressive
strength.
2. ASME Code has design procedure
for each type of shell or head.
69
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Stiffener Rings
Moment Axis of Ring
h/3
L
L
L
L
L
L
L
L
L
L
h/3
h = Depth of Head
Figure 4.10
58
Instructor’s Outline
1. Stiffener rings reduce the buckling
length of a shell and may be either
inside or outside.
Major Learning Points
Use and location of stiffener rings.
2. Stiffener rings are not used for
heads.
70
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
DESIGN INFORMATION
Design Pressure = Full Vacuum
Design Temperature = 500° F
Shell and Head Material is
SA-285 Gr. B, Yield Stress = 27 ksi
Corrosion Allowance = 0.0625"
Cylinder Dimension Shown
is Inside Diameter
4' - 0"
150' - 0"
2:1 Semi-Elliptical
(Typical)
Figure 4.11
59
Instructor’s Outline
Major Learning Points
1. Sample Problem 2 illustrates
procedure for calculation of required
cylindrical shell thickness for
external pressure.
Sample Problem to illustrate 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.
71
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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/t
Account for corrosion allowance:
t = 7/16 – 1/16 = 6/16 = 0.375 in.
Do/t = 48.875 / 0.375 = 130
L/Do = 1808 / 48.875 = 37
60
Instructor’s Outline
1. Corroded shell diameter and
thickness are used in the
calculations.
Major Learning Points
Sample Problem 2 solution.
2. The unstiffened length of the shell
must include part of the head depth.
72
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
Solution, 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, use
L/Do = 0.05
61
Instructor’s Outline
1. Factor A is determined based only
on geometry.
Major Learning Points
Sample Problem 2 solution.
2. Note the source of Factor A.
73
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
Solution, cont’d
4 5 6 789
Do/t = 100
D o/t = 125
D o/t = 150
D /t = 200
2
1.6
1.4
2.0
1.8
2.5
3.5
3.0
6.0
4.0
7.0
5.0
8.0
10.0
9.0
14.0
20.0
18.0
16.0
25.0
30.0
35.0
40.0
50.0
12.0
0
00
,00
00
00
800
= 4 t=5 t = 6
=1
/t
/
/
/t =
/t
Do
Do
Do
Do
Do
D o/t = 300
.00001
3
o
D o/t = 250
1.2
Do /t = 130
.0001
A = 0.000065
Length + Outside Diameter = L/Do
L/Do = 37
Factor A
Figure 4.12
62
Instructor’s Outline
1. Note how Factor A is determined
from these curves.
Major Learning Points
Sample Problem 2 solution.
2. After determine Factor A, go to
applicable material chart.
74
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
Solution, cont’d
up to 300°F
500°F
14,000
700°F
12,000
800°F
10,000
900°F
9,000
8,000
7,000
E=29.0 x 106
6,000
E=27.0 x 106
5,000
E=24.5 x 106
E=22.8 x 106
4,000
E=20.8 x 106
3,500
3,000
2,500
2,000
2
.00001
3 4 5 6 789
.0001
A=0.000065
63
Instructor’s Outline
1. Different material charts are used for
different material types. This is
chart used for most carbon and lowalloy steels.
2
3
4 5 6 789
2
3 4 5 6789
.001
2
3
4 5 6 789
.01
.1
FACTOR A
Factor B
Figure 4.13
Major Learning Points
Sample Problem 2 solution.
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.
75
FACTOR B
20,000
18,000
16,000
GENERAL NOTE: See Table CS-1 for tabular values
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
Solution, cont’d
• Calculate maximum allowable external pressure
Pa =
2AE
3(Do / t )
Where:
E = Young's modulus of elasticity
E = 27 × 106 psi (Figure 4.13) at T = 500°F
P a = 9 psi
64
Instructor’s Outline
1. Pa is calculated using indicated
equation because A is not under
curves.
Major Learning Points
Sample Problem 2 solution.
2. Must use E from curves at design
temperature.
76
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 2
Solution, cont’d
Since Pa < 15 psi, 7/16 in. thickness not sufficient
• Assume new thickness = 9/16 in.,
corroded thickness L = 1/2 in.
Do 48. 875
=
= 97.75
t
0. 5
A = 0.000114
Pa =
L
= 3 7 (as before)
Do
2 × 0.000114 × 27 × 10 6
= 15. 7 psi
3 × 130. 33
65
Instructor’s Outline
1. Since P a < 15 psi, must either
increase shell thickness or add
stiffeners to decrease L.
Major Learning Points
Sample Problem 2 solution.
2. Problem illustrates results if
increase thickness.
3. Choice of whether to increase
thickness or add stiffeners depends
on cost.
77
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Exercise 2 - Required
Thickness for Internal Pressure
•
•
•
•
•
•
•
•
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
66
Instructor’s Outline
Major Learning Points
1. This independent Exercise gives the
Participants practice in determining
required vessel thicknesses for
internal pressure.
Participant Exercise 2 covering required
thickness 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.
78
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Exercise 2 - Solution
• For shell
tp =
Pr
SE 1 − 0 .6P
P = 650 psig
r = 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
tp =
650 × 63. 125
= 2. 53 in.
(16,600 ×1 .0 ) − (0 .6 × 650)
67
Instructor’s Outline
1. Note the relevant equation for the
cylindrical shell and the appropriate
parameters.
Major Learning Points
Exercise 2 solution.
2. Note how corrosion allowance is
accounted for.
79
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Exercise 2 - Solution, cont’d
Add corrosion allowance
tp = 2.53 + 0.125 = 2.655 in.
• For the heads
tp =
PD
2 SE − 0. 2P
tp =
650 (126 × 0 . 9) + 0 . 250
= 2 . 23 in.
(2 × 16, 600) − (0 . 2 × 650 )
Add corrosion allowance
68
Instructor’s Outline
1. Note the relevant equation for the
heads and the appropriate
parameters.
tp = 2.23 + 0.125 = 2.355 in.
Major Learning Points
Exercise 2 solution.
2. Note how corrosion allowance is
accounted for.
80
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
69
Instructor’s Outline
1. Simplified ASME rules do not require
stress calculations. Use “area
replacement” approach.
Major Learning Points
Openings must be reinforced to
account for metal removed.
2. Metal removed must be replaced by
equivalent metal.
81
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Cross Sectional View of
Nozzle Opening
Dp
tn
te
2.5t or 2.5t n + te
Use smaller value
t
2.5t or 2.5t n
Use smaller value
Rn
t rn
tr
c
h
d
d or R n + tn + t
d or R n + tn + t
Use larger value
Use larger value
For nozzle wall inserted
through the vessel wall
For nozzle wall abutting
the vessel wall
Figure 4.14
70
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.
82
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
71
Instructor’s Outline
1. Note the different nozzle design
details that may be used.
Figure 4.15
Major Learning Points
Typical nozzle configurations.
2. The actual detail used in each case
depends on the design conditions
and the needed reinforcement.
83
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
72
Instructor’s Outline
1. The method used to provide
additional reinforcement depends on
the particular situation.
Major Learning Points
Requirements for additional
reinforcement.
2. The ASME Code specifies
circumstances where nozzle
reinforcement evaluation is not
needed. The opening is considered
to be “inherently” reinforced in
these cases.
84
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3
DESIGN INFORMATION
Design Pressure = 300 psig
Design Temperature = 200° F
Shell Material is SA-516 Gr. 60
Nozzle Material is SA-53 Gr. B, Seamless
Corrosion Allowance = 0.0625"
Vessel is 100% Radiographed
Nozzle does not pass through Vessel Weld Seam
NPS 8 Nozzle
(8.625" OD)
0.5" Thick
0.5625" Thick Shell, 48" Inside Diameter
Figure 4.16
73
Instructor’s Outline
1. Sample Problem 3 illustrates
evaluation of an opening for
adequate reinforcement.
Major Learning Points
Sample Problem to illustrate evaluation
of nozzle reinforcement.
2. Review the given information.
3. Review the problem solution with
the Participants.
85
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 - Solution
• Calculate required reinforcement area, A
A = dtrF
Where:
d = Finished diameter of circular opening, or
finished dimension of nonradial opening in
plane under consideration, in.
tr = Minimum required thickness of shell using
E = 1.0, in.
F = Correction factor, normally 1.0
74
Instructor’s Outline
1. Required replacement area is based
on the cross-sectional area removed.
Major Learning Points
Sample Problem 3 solution.
2. Calculated using the required shell
thickness, not the actual.
86
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
75
Instructor’s Outline
1. Corrosion allowance is accounted
for.
Major Learning Points
Sample Problem 3 solution.
2. tr is calculated using the appropriate
shell equation.
87
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
• Calculate A
A = dtr F
A = (8.625 - 1.0 + 0.125) × 0.487 × 1
= 3.775 in.2
• Calculate available reinforcement area in vessel
shell, A 1, as larger of A 11 or A1 2
A1 1 = (E lt - Ftr)d
76
Instructor’s Outline
1. Required area is calculated using
the previously calculated
parameters.
A1 2 = 2 (Elt-Ftr)(t + tn)
Major Learning Points
Sample Problem 3 solution.
2. Two equations must be checked to
determine the reinforcement area
available in the shell.
88
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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 joint
in shell (excluding head to shell joints).
E l = ASME Code joint efficiency when any part of opening
passes through any other welded joint.
F = 1 for all cases except integrally reinforced nozzles
inserted into a shell or cone at angle to vessel
longitudinal axis. See Fig. UG-37 for this special
case.
tn = Nominal thickness of nozzle in corroded condition, in.
77
Instructor’s Outline
Review the relevant parameters.
Major Learning Points
Sample Problem 3 solution.
89
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
A 11 = (Elt - Ftr)d = (0.5625 - 0.0625 - 0.487) × 7.75 = 0.1 in.2
A 12 = 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
78
Instructor’s Outline
Available shell reinforcement area is
determined.
Major Learning Points
Sample Problem 3 solution.
90
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
• Calculate reinforcement area available in nozzle wall, A2,
as smaller of A21 or A22.
A21 = (tn-tr n) 5t
A22 = 2 (t n-tr n) (2.5 tn + t e)
79
Instructor’s Outline
Available reinforcement area in the
nozzle is determined by checking two
equations.
Major Learning Points
Sample Problem 3 solution.
91
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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-reinforced
nozzles, in.
80
Instructor’s Outline
Review the relevant parameters.
Major Learning Points
Sample Problem 3 solution.
92
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
• Calculate required nozzle thickness, trn (Figure 4.6)
t rn =
t rn =
Pr
SE1 − 0. 6P
300 (3. 8125 + 0. 0625)
= 0. 0784 in.
15,000 × 1 − 0. 6 × 300
81
Instructor’s Outline
Calculate required thickness using the
equation for a cylinder.
Major Learning Points
Sample Problem 3 solution.
93
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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.
82
Instructor’s Outline
1. The available reinforcement in the
nozzle is determined.
Major Learning Points
Sample Problem 3 solution.
2. Note that in this case, the nozzle has
much more excess metal available
than the shell.
94
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
• Determine total available reinforcement area, A T;
compare to required area.
AT = A1 + A2 = 0.1 + 0.786 = 0.886 in.2
AT < A, nozzle not adequately reinforced, reinforcement
pad required.
• Determine reinforcement pad diameter, Dp.
A5 = A - AT
A5 = (3.775 - 0.886) = 2.889 in.2
83
Instructor’s Outline
1. The nozzle is not adequately
reinforced because it does not have
enough reinforcement available.
Major Learning Points
Sample Problem 3 solution.
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.
95
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 3 Solution, cont’d
• Calculate Dp
te = 0.5625 in. (reinforcement pad thickness)
A 5 = [Dp - (d + 2 t n)] 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.
84
Instructor’s Outline
1. The reinforcement pad thickness
was assumed to be equal to the shell
thickness. This is common practice.
Therefore, Dp = 13.761 in. acceptable
Major Learning Points
Sample Problem 3 solution.
2. A final check is made to ensure that
the reinforcement pad is within the
reinforcement zone.
96
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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 without
pressure indicated not acceptable
85
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
97
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Material Specification List
Material Groups
Material
Group
Number
Nominal
Designation
Steel
1.1
Carbon
1.2
C-Mn-Si
Carbon
2 ½ Ni
3 ½ Ni
Product Forms
Forgings
Castings
Plates
Spec. No.
Grade
Spec. No.
Grade
Spec. No.
Grade
A105
A350
----A350
-LF2
----LF3
A216
--A216
A352
A352
A352
WCB
--WCC
LCC
LC2
LC3
A515
A516
A537
--A203
A203
70
70
Cl.1
--B
E
ASME B16.5, Table 1a, Material Specification List (Excerpt)
Figure 4.17
86
Instructor’s Outline
1. Acceptable flange materials are
grouped based on similarities in
strength.
Major Learning Points
Flange Material Group Number is based
on material specification and product
form.
2. The Material Group is determined
based on the specified material.
98
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Pressure - Temperature Ratings
Material
Group No.
Classes
Temp., °F
-20 to 100
200
300
400
500
600
650
700
750
800
850
900
950
1000
1.1
1.2
1.3
150
300
400
150
300
400
150
300
400
285
260
230
200
170
140
125
110
95
80
65
50
35
20
740
675
655
635
600
550
535
535
505
410
270
170
105
50
990
900
875
845
800
730
715
710
670
550
355
230
140
70
290
260
230
200
170
140
125
110
95
80
65
50
35
20
750
750
730
705
665
605
590
570
505
410
270
170
105
50
1000
1000
970
940
885
805
785
755
670
550
355
230
140
70
265
250
230
200
170
140
125
110
95
80
65
50
35
20
695
655
640
620
585
534
525
520
475
390
270
170
105
50
925
875
850
825
775
710
695
690
630
520
355
230
140
70
Figure 4.18
87
Instructor’s Outline
1. This table combines information for
three Material Groups for illustrative
purposes.
Major Learning Points
Pressure/temperature rating is a
function of Material Group and design
temperature.
2. Review the information in this table
and how it is used to determine the
appropriate flange rating.
99
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 4
Determine Required Flange Rating
Pressure Vessel Data:
Shell and Heads:
SA-516 Gr.70
Flanges:
SA-105
Design Temperature: 700°F
Design Pressure:
275 psig
88
Instructor’s Outline
1. Sample Problem 4 illustrates how to
determine flange rating.
Major Learning Points
Sample Problem to illustrate
determining flange rating.
2. Review the given information.
3. Review the problem solution with
the Participants.
100
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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 and
Material Group No. determined in Step 3
– Intersection of design temperature with Material
Group No. is maximum allowable design pressure for
the flange Class
89
Instructor’s Outline
Review the problem solution.
Major Learning Points
Sample Problem 4 solution.
101
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Sample Problem 4 Solution, cont’d
– Table 2 of ASME B16.5, design information for all
flange Classes
– Select lowest Class whose maximum allowable
design pressure ≥ required design pressure.
• At 700°F, Material Group 1.1: Lowest Class that
will accommodate 275 psig is Class 300.
• At 700°F, Class 300 flange of Material Group
1.1: Maximum design pressure = 535 psig.
90
Instructor’s Outline
1. Use the lowest flange class that is
suitable for the design conditions.
Flange cost increases as the class
increases.
Major Learning Points
Sample Problem 4 solution.
2. A given flange class is good for a
range of temperature/pressure
combinations for a particular
Material Group.
102
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Flange Design
• Bolting requirements
– During normal operation (based on design
conditions)
– During initial flange boltup (based on stress
necessary to seat gasket and form tight seal
Am =
W
S
91
Instructor’s Outline
1. Division 1 Appendix 2 procedure for
custom-designed flanges.
Major Learning Points
ASME procedure must be used 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.
103
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Flange Loads and
Moment Arms
Flange
Ring
Gasket
h
t
A
hG
W
hT
hD
C
g1
HT
G
HG
HD
B
g0
Flange Hub
Figure 4.19
92
Instructor’s Outline
1. Applied loads act at different flange
locations.
Major Learning Points
Various flange loads are applied on
corresponding moment arms.
2. Flange moments are calculated for
the operating and gasket seating
cases.
104
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Stresses in Flange Ring
and Hub
• Calculated using:
– Stress factors (from ASME code)
– Applied moments
– Flange geometry
• Calculated for:
– Operating case
– Gasket seating case
93
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.).
Major Learning Points
•
Flange stresses are calculated and
compared to allowable values.
•
Both operating and gasket seating
cases must be checked.
3. Equipment suppliers use computer
programs to “optimize” flange
design to be least weight (i.e., lowest
cost).
105
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Flange Design and
In-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
94
Instructor’s Outline
Major Learning Points
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.
Various parameters affect flange design
and performance.
2. TEMA specifies minimum gasket
width and bolt spacing criteria.
106
Overview of Pressure Vessel Design
Instructor’s Personal Notes
ASME Code m and y Factors
Gasket
Factor,
m
Min.
Design
Seating
Stress y,
psi
Flat metal, jacketed asbestos filled:
Soft aluminum
Soft copper or brass
Iron or soft steel
Monel
4-6% chrome
Stainless steels and nickel-base alloys
3.25
3.50
3.75
3.50
3.75
3.75
5,500
6,500
7,600
8,000
9,000
9,000
(1a), (1b), (1c),
(1d); (2);
Column II
Solid flat metal:
Soft aluminum
Soft copper or brass
Iron or soft steel
Monel or 4-6% chrome
Stainless steels and nickel-base alloys
4.00
4.75
5.50
6.00
6.50
8,800
13,000
18,000
21,800
26,000
(1a), (1b), (1c),
(1d); (2), (3), (4),
(5); Column I
Gasket Type and Material
Facing Sketch
and Column in
ASME Table 2-5.2
(Figure 4.21)
Figure 4.20
95
Instructor’s Outline
Major Learning Points
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.
107
Overview of Pressure Vessel Design
Instructor’s Personal Notes
ASME Code Gasket Widths
Basic Gasket Seating Width bo
Facing Sketch
(Exaggerated)
N
(1a)
Column I
Column II
N
2
N
2
N
N
N
(1b)
w
T
N
(1c)
w
(1d)
w ≤N
w + T ;  w + N max 


2
 4

T
N
w+ T  w+ N
;
max
2
 4

w ≤N
HG
HG
G
O.D. Contact Face
hG
b
G
hG
Gasket
C
L Face
For b o > ¼ in.
For b o< ¼in.
ASME Code Gasket Widths (Table 2-5.2 excerpt)
Figure 4.21
96
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.
108
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Gasket Materials
and Contact Facings
Gasket Materials and Contact Facings
Gasket Factors m for Operating Conditions and Minimum Design Seating Stress y
Gasket Material
Gasket
Factor
m
Min.
Design
Seating
Stress y,
psi
Flat metal, jacketed asbestos filled:
Soft aluminum
Soft copper or brass
Iron or soft steel
Monel
4% - 6% chrome
Stainless steels and nickel-base alloys
3.25
3.50
3.75
3.50
3.75
3.75
5500
6500
7600
8000
9000
9000
Sketches
Facing
Sketch and
Column in
Table 2-5.2
(1a), (1b),
(1c),2, (1d) 2,
(2)2,
Column II
Figure 4.22
97
Instructor’s Outline
Review the additional gasket
information shown.
Major Learning Points
Information on additional gasket types.
109
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Maximum Allowable
Working Pressure (MAWP)
Maximum permitted gauge pressure at top of
vessel in operating position for designated
temperature
• MAWP ≥ Design Pressure
• Designated Temperature = Design Temperature
• Vessel MAWP based on weakest component
98
Instructor’s Outline
1. Emphasize that MAWP is based on
the as-supplied component
thicknesses.
– Originally based on new thickness less corrosion
allowance
– Later based on actual thickness less future corrosion
allowance needed
Major Learning Points
MAWP is defined.
2. Thicknesses used exclude corrosion
allowance and thickness added to
absorb other loads.
3. MAWP is useful to know for potential
future rerate.
110
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Local Loads
• Piping system
• Platforms, internals, attached equipment
• Support attachment
99
Instructor’s Outline
1. Review the typical external loads
that may be applied.
Major Learning Points
Externally applied loads must also be
considered in vessel design.
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).
111
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
100
Instructor’s Outline
Major Learning Points
1. Different types of internals are used
to perform various process
functions.
Several types of vessel internals may be
installed.
2. Review list of internals.
3. ASME Code does not cover design
of internals. End-user, vessel
vendor, and/or contractor must
develop requirements.
112
Overview of Pressure Vessel Design
Instructor’s Personal Notes
ASME Code and
Vessel Internals
• Loads applied from internals on vessel to be
considered in design
• Welding to pressure parts must meet ASME
Code
101
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.
113
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Corrosion Allowance
For 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
102
Instructor’s Outline
1. Potential corrosion of internals
should not be ignored.
Major Learning Points
Corrosion allowance should be
considered in the design of internals.
2. Corrosion allowance should be
considered in a practical and costeffective manner.
114
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Head-to-Shell Transitions
l
y
Thinner part
th
Thinner part
th
l
Tangent
Line
y
t
ts
th
Tangent
Line
t
y
Thinner part
l
Thinner part
y
s
th
l
t
s
s
Fillet
Weld
Butt Weld
Intermediate Head Attachment
Figure 6.1
103
Instructor’s Outline
1. Review typical acceptable welding
and fabrication details.
Major Learning Points
ASME Code specifies 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.
115
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Typical Shell Transitions
CL
In all cases, l shall not
be less than 3y.
CL
y
l
l
C
L
Figure 6.2
104
Instructor’s Outline
Review thickness taper requirements.
Major Learning Points
ASME Code fabrication details.
116
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Nozzle Neck
Thickness Tapers
Figure 6.3
105
Instructor’s Outline
Thickness taper may be required in
nozzle neck.
Major Learning Points
ASME Code fabrication details.
117
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Stiffener Rings
In-Line
Intermittent Weld
Staggered
Intermittent Weld
Continuous Fillet Weld On
One Side, Intermittent Weld
On Other Side
Figure 6.4
106
Instructor’s Outline
1. Vacuum stiffening ring attachment
details.
Major Learning Points
ASME Code fabrication details.
2, ASME Code specifies weld spacing,
size, and length.
118
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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
107
Instructor’s Outline
1. ASME Code specifies PWHT
requirements only for relief of
residual stresses.
Major Learning Points
ASME Code PWHT requirements.
2. Need for PWHT due to other reasons
must be specified by end-user or
contractor.
•
Service considerations (e.g.,
wet H 2S, caustic)
•
Weld hardness reduction
119
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Inspection and Testing
Inspection includes examination of:
• Base material specification and quality
• Welds
• Dimensional requirements
• Equipment documentation
108
Instructor’s Outline
Highlight main areas included in
inspection.
Major Learning Points
ASME Code inspection requirements.
120
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Common Weld Defects
Between Weld Bead and Base Metal
Between Adjacent Passes
Lack of Fusion
Incomplete Filling at Root on One Side Only
Incomplete Filling at Root
Incomplete Penetration
ExternalUndercut
Internal Undercut
Undercut
Figure 7.1
109
Instructor’s Outline
Review common types of weld defects.
Major Learning Points
Particular types of weld defects may
occur.
121
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Weld Defects
Presence of defects:
• Reduces weld strength below that required
• Reduces overall strength of fabrication
• Increases risk of failure
110
Instructor’s Outline
Review why weld defects can reduce
vessel integrity.
Major Learning Points
Presence of unacceptable weld defects
reduces vessel integrity.
122
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Types of NDE
NDE TYPE
Radiographic
Visual
Liquid Penetrant
Magnetic Particle
Ultrasonic
DEFECTS
DETECTED
Gas pockets, slag
inclusions,
incomplete
penetration, cracks
Porosity holes, slag
inclusions, weld
undercuts,
overlapping
Weld surface-type
defects: cracks,
seams, porosity,
folds, pits,
inclusions,
shrinkage
Cracks, porosity,
lack of fusion
Subsurface flaws:
laminations, slag
inclusions
ADVANTAGES
Produces
permanent record.
Detects small flaws.
Most effective for
butt-welded joints.
Helps pinpoint
areas for additional
NDE.
LIMITATIONS
Expensive.
Not practical for
complex shapes.
Can only detect
what is clearly
visible.
Used for ferrous
Can only detect
and nonferrous
surface
materials. Simple
imperfections.
and less expensive
than RT, MT, or UT.
Flaws up to ¼ in.
beneath surface can
be detected.
Can be used for
thick plates, welds,
castings, forgings.
May be used for
welds where RT not
practical.
Cannot be used on
nonferrous
materials.
Equipment must be
constantly
calibrated.
Figure 7.2
111
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.
123
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Typical RT Setup
X-Ray Tube
X-Ray
Film
Test Specimen
Figure 7.3
112
Instructor’s Outline
Review typical setup for RT inspection.
Major Learning Points
Typical RT setup.
124
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Pulse Echo UT System
Cathode Ray Tube (CRT)
A
C
Read Out
B
BaseLine
Input-Output
Generator
Cable
Transducer
A
Couplant
Test Specimen
B
C
Flaw
Figure 7.4
113
Instructor’s Outline
Review how pulse echo UT system can
detect defects.
Major Learning Points
Typical pulse echo UT system.
125
Overview of Pressure Vessel Design
Instructor’s Personal Notes
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)
114
Instructor’s Outline
1. Water is a safer test medium than
air. Pneumatic testing should only
be used on an exception basis.
Major Learning Points
Pressure test is used as final
demonstration of vessel integrity.
2. “Ratio” is the lowest value of:
S( test temperatur e)
S ( design temperatur e)
126
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Pressure Testing, cont’d
Hydrotest 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
115
Instructor’s Outline
Review additional pressure test design
considerations.
Major Learning Points
Pressure test considerations.
127
Overview of Pressure Vessel Design
Instructor’s Personal Notes
Summary
• Overview of pressure vessel mechanical design
• ASME Section VIII, Division 1
• Covered
– Materials
– Fabrication
– Testing
– Design
– Inspection
116
Instructor’s Outline
1. Highlight the subjects covered in the
course.
Major Learning Points
Summarize 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.
128
Appendix A
Reproducible Overheads
Appendix B
Course & Instructor Evaluation Form
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 Evaluation
Please record your overall reaction to the program by placing a circle around the appropriate
number on the scale.
10 9
Excellent
876
Good
Fair
543
Poor
210
Please evaluate the course by circling E (excellent), G (good), F (fair), or P (poor) in the appropriate location.
1.
Course content
Relevance of
New
matches brochure course notes/
Applicability
Knowledge Overall
description
workbook
to your job
Gained
1.1 E G F P
1.2 E G F P
1.3 E G F P
Rating
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: _______________________________
Company: ____________________________
Title: _______________________________
City, State: __________________________
131
B.
5.
Instructor’s Evaluation
Please evaluate the instructor(s) by circling E (excellent), G (good), F (fair), or P (poor) in the
appropriate location
Effective
knowledge of
subject matter
1.1 E G F P
Effectiveness
Effective
of teaching
use of
Class
method
class time
1.2 E G F P
1.3 E G F P
Openness to
Overall
Participation Rating
1.4 E G F P 1.5 E G F P
C.
6.
Facilities
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.
10.
Future Courses and Educational Products (Video, Self Study, Software)
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.
12.
On-Site Company Training
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.: ___________________
132
Appendix C
Continuing Education Unit
(CEU) Submittal Form
Course Improvement Form
133
ASME Career Development Series
Continuing Education Unit (CEU) Request Form
Each 4-hour ASME Career Development Series Course earns 0.4 CEU’s
PLEASE PRINT ALL YOUR INFORMATION CLEARLY
YOUR 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 Institute
Three Park Avenue
New York, NY 10016-5990
Your Certificate will be prepared and sent to the address you indicated above.
134
ASME Career Development Series
Course 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 Avenue
New York, NY 10016-5990
135
ASME Career Development Series
Instructor’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: _____________________________________________
136
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.
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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
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math, logic and theory. Videotape, Online, or Online Live Revie w available.
FOR MORE INFORMATION CALL 1-800-THE-ASME
__________________________________________________________________________
INFORMATION REQUEST FORM
Please 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 infocentral@asme.org.
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: ______________________________________________
137