AS 1210 Supp1—1990
Australian Standard
Unfired pressure vessels —
Advanced design and
construction
(Supplement to AS 1210—1989)
This Australian Standard was prepared by Committee ME/1, Boilers and Unfired
Pressure Vessels. It was approved on behalf of the Council of Standards Australia on
20 October 1989 and published on 2 April 1990.
The following interests are represented on Committee ME/1:
Aluminium Development Council
Australian Compressed Air Institute
Australian Institute for Non-destructive Testing
Australian Institute of Energy
Australian Institute of Petroleum
Australian Liquefied Petroleum Gas Association
Australian Valve Manufacturers Association
Boiler and Pressure Vessel Manufacturers Association of Australia
Bureau of Steel Manufacturers of Australia
Confederation of Australian Industry
Department of Defence
Department of Industrial Affairs, Qld
Department of Labour, S.A.
Department of Labour, Vic.
Department of Labour and Industry, Tas.
Department of Occupational Health, Safety and Welfare, W.A.
Department of the Arts, Sport, the Environment, Tourism and Territories
Electricity Supply Association of Australia
Institute of Metals and Materials Australasia
Institution of Engineers Australia
Insurance Council of Australia
Metal Trades Industry Association of Australia
National Association of Testing Authorities Australia
Railways of Australia Committee
Society of Mechanical Engineers of Australasia
Sugar Research Institute
Welding Technology Institute of Australia
Work Health Authority, N.T.
Workcover, N.S.W.
Review of Australian Standards. To keep abreast of progress in industry, Australian Standards are subject
to periodic review and are kept up to date by the issue of amendments or new edit ions as necessary. It is
important therefore that Standards users ensure that they are in possession of the latest editi on, and any
amendments thereto.
Full detail s of all Australi an Standards and related publications will be found in the Standards Australi a
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Standard’, which subscribing members receive, and which gives details of new publi cati ons, new editi ons
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Suggesti ons for improvements to Australi an Standards, addressed to the head offi ce of Standards Australi a,
are welcomed. Noti fi cati on of any inaccuracy or ambiguity found in an Australian Standard should be made
without delay in order that the matter may be investigated and appropriate action taken.
This Standard was issued in draft form for comment as DR 88113.
AS 1210 Supp1—1990
Australian Standard
Unfired pressure vessels —
Advanced design and
construction
(Supplement to AS 1210—1989)
First publi shed as AS CB1 Int.6—1969.
Revised and redesignated AS 1210 Supplement 1—1979.
Second editi on 1984.
Thir d editi on 1990.
Incorporating:
Amdt 1—1995
Amdt 2—1997
PUBLISHED BY STANDARDS AUSTRALIA
(STANDARDS ASSOCIATION OF AUSTRALIA)
1 THE CRESCENT, HOMEBUSH, NSW 2140
ISBN 0 7262 6003 7
AS 1210 Supp1—1990
2
PREFACE
This edition of this Supplement was prepared by the Standards Australia Committee
on Boilers and Unfired Pressure Vessels to supersede Supplement No 1 (June 1984)
to AS 1210, SAA Unfired Pressure Vessel Code, Class 1H Pressure Vessels of
Advanced Design and Construction. It forms part of the SAA Boiler Code (AS 1200)
which is referred to in Statutory Regulations in Australia, and which covers
requirements for land installations of shell boilers, water-tube boilers, unfired pressure
vessels, pressure piping, welder certification, and related matters.
The Supplement provides for additional classes of vessels which require more precise
design procedures to ensure that the higher design stresses can be tolerated for the
particular design and that fatigue will be avoided.
Revisions and additions have been made throughout the Supplement.
A major revision in this edition is the introduction of a new classification of welded
vessel (Class 2H) which permits the use of the higher design strengths applicable to
Class 1H vessels with reduced levels of non-destructive examination but with the
restrictions on the range and the thickness of materials used and the fatigue criteria
under which the Class 2H vessels may be used. The introduction of requirements for
Class 2H vessels was delayed until a full review of the material requirements in
AS 1210, SAA Unfired Pressure Vessels Code, for low temperature service had been
carried out.
An alternative method for assessing the need for a detailed fatigue analysis of the
vessel and its components has been introduced.
Other revisions in this edition include a change of the membrane stress intensity limits
for the test condition, clarification of the design strengths to be used in the design of
flanges, changes in the requirements for clad plate and for low temperature service and
clarification of coverage of cast and forged vessels.
The Supplement deals only with stationary vessels for a specific service where
operation and maintenance control is fully exercised during the useful life of the vessel
by the users in accordance with specified operating requirements for the vessel.
This Supplement lists only those requirements which differ from or are additional to
those for Class 1 vessels in AS 1210. Together with AS 1210 it will directly satisfy
the needs of most vessels. For complicated vessels or for vessels that are subject to
unusual loads or fatigue, a comprehensive stress/load analysis is required.
This Supplement requires that all vessels be reviewed to ensure that unusual and
excessive loads and fatigue cycling are maintained within safe limits. It prescribes
detailed fatigue analysis where and when necessary. For vessels that are cleared from
such a detailed investigation, the same design formulas as given in AS 1210 are used,
except where otherwise specified.
Where fatigue, vessel configuration or loading is such that detailed stress analysis is
required, the degree of such analysis can be determined only by a competent designer.
The designer will need to refer to recognized engineering texts and techniques. Some
authoritative national standards such as ANSI/ASME BPV-VIII-2, Boiler and Pressure
Vessel Code: Section VIII — Rules for construction of pressure vessels: Division 2 —
Alternative rules, and BS 5500, Specification for unfired fusion welded pressure
vessels, provide tested shortcuts to many solutions encountered in advanced vessel
design. These may be used, where appropriate by the designer as substitutes for
fundamental stress analysis.
Acknowledgement is gratefully made to the American Society of Mechanical Engineers
for permission to reproduce certain extracts from the ASME Boiler and Pressure
Vessel Code. In addition, acknowledgement is made of the considerable assistance
provided by British and other national Standards.
The International Organization for Standardization (ISO) Technical Committee
ISO/TC 11 — Boilers and Pressure Vessels, has prepared a draft International
Standard, ISO/DIS 2694, ISO draft recommendation for pressure Vessels, with the
object of achieving agreement regarding uniformity of approach in national standards
covering this subject. At this time, significant differences between the various national
standards and ISO/DIS 2694 remain and these differences are still to be resolved.
With the changes introduced by Amendment No. 2, this 1990 edition of AS 1210
Supplement 1 is suitable for use with the 1997 edition of AS 1210, Pressure vessels.
3
AS 1210 Supp1—1990
CONTENTS
Page
5
FOREWORD
SECTION S1. SCOPE AND GENERAL REQUIREMENTS
S1.1
SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S1.3
APPLICATION OF SUPPLEMENT . . . . . . . . . . . . . . .
S1.6
CLASSES OF VESSEL CONSTRUCTION . . . . . . . . . .
S1.7
APPLICATION OF VESSEL CLASSES AND TYPES . .
S1.8
DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S1.12 DESIGNATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S1.13 REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . .
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SECTION S2. MATERIALS
S2.1
MATERIAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S2.3
ALTERNATIVE MATERIAL AND COMPONENT SPECIFICATIONS . .
S2.4
MATERIAL IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S2.6
MATERIAL REQUIREMENTS FOR LOW TEMPERATURE SERVICE .
S2.7
MATERIAL REQUIREMENTS FOR HIGH TEMPERATURE SERVICE
S2.8
NON-DESTRUCTIVE TESTING OF MATERIALS . . . . . . . . . . . . . . . .
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SECTION S3. DESIGN
S3.1
GENERAL DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.2
DESIGN CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.3
DESIGN STRENGTHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.5
WELDED, RIVETED AND BRAZED JOINTS . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.7
THIN-WALLED CYLINDRICAL AND SPHERICAL SHELLS SUBJECT TO
INTERNAL PRESSURE AND COMBINED LOADINGS . . . . . . . . . . . . . . . . . . .
S3.8
THICK-WALLED CYLINDRICAL AND SPHERICAL SHELLS SUBJECT TO
INTERNAL PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.9
CYLINDRICAL AND SPHERICAL SHELLS SUBJECT TO EXTERNAL
PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.10 CONICAL ENDS AND REDUCERS SUBJECT TO INTERNAL PRESSURE . . . .
S3.11 CONICAL ENDS AND REDUCERS SUBJECT TO EXTERNAL PRESSURE . . . .
S3.12 DISHED ENDS SUBJECT TO INTERNAL PRESSURE . . . . . . . . . . . . . . . . . . .
S3.13 DISHED ENDS SUBJECT TO EXTERNAL PRESSURE . . . . . . . . . . . . . . . . . . .
S3.14 DISHED ENDS — BOLTED SPHERICAL TYPE . . . . . . . . . . . . . . . . . . . . . . . .
S3.15 UNSTAYED FLAT ENDS AND COVERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.16 STAYED FLAT ENDS AND SURFACES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.17 FLAT TUBEPLATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.18 OPENINGS AND REINFORCEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.19 CONNECTIONS AND BRANCHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.21 BOLTED FLANGED CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.22 PIPES AND TUBES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.23 JACKETED CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.24 VESSEL SUPPORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S3.25 ATTACHED STRUCTURES AND EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . .
S3.26 TRANSPORTABLE VESSELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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SECTION S4. CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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AS 1210 Supp1—1990
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Page
SECTION S5. TESTING AND QUALIFICATIONS
S5.10 HYDROSTATIC TESTS . . . . . . . . . . . . . . . . . . . . . . .
S5.11 PNEUMATIC TESTS . . . . . . . . . . . . . . . . . . . . . . . . .
S5.12 EXPERIMENTAL STRESS ANALYSIS . . . . . . . . . . . .
S5.13 LEAK TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S5.19 NON-DESTRUCTIVE EXAMINATION OF FORGINGS
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SECTION S6. WINSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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SECTION S7. MARKING AND REPORTS
S7.1
MARKING REQUIRED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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SECTION S8. PROTECTIVE DEVICES AND OTHER FITTINGS . . . . . . . . . . . . . . . . . . .
24
SECTION S9. PROVISIONS FOR DESPATCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24
APPENDICES
SA BASIS OF DESIGN STRENGTH (f) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SB POROSITY CHARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SC PRACTICE TO AVOID FATIGUE CRACKING . . . . . . . . . . . . . . . . . . . .
SD RECOMMENDED CORROSION PREVENTION PRACTICE . . . . . . . . . .
SE INFORMATION TO BE SUPPLIED BY THE PURCHASER TO THE
MANUFACTURER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SF INFORMATION TO BE SUPPLIED BY THE MANUFACTURER . . . . . . .
SH DESIGN REQUIREMENTS FOR LOADINGS AND COMPONENTS NOT
COVERED BY SECTION 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SK LOW TEMPERATURE VESSELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SR LIST OF REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . .
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 Copyright STANDARDS AUSTRALIA
Users of Standards are reminded that copyright subsists in all Standards Australia publications and software. Except where the Copyright Act
allows and except where provided for below no publications or software produced by Standards Australia may be reproduced, stored in a
retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia. Permission may be
conditional on an appropriate royalty payment. Requests for permission and information on commercial software royalties should be directed
to the head office of Standards Australia.
Standards Australia will permit up to 10 percent of the technical content pages of a Standard to be copied for use exclusively inhouse by purchasers of the Standard without payment of a royalty or advice to Standards Australia.
Standards Australia will also permit the inclusion of its copyright material in computer software programs for no royalty payment
provided such programs are used exclusively in-house by the creators of the programs.
Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standard is
amended or revised. The number and date of the Standard should therefore be clearly identified.
The use of material in print form or in computer software programs to be used commercially, with or without payment, or in commercial
contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia at any time.
5
AS 1210 Supp1—1990
FOREWORD
The application of the several Standards that form the SAA Boiler Code may give rise
to a need for consideration of unusual and other designs which do not comply in all
respects with the requirements of the relevant Standard or which are not adequately
covered in any Standard.
Where it is desired to use materials or methods which do not comply with the
requirements of, or are not adequately covered by the relevant Standard, designs
incorporating such departures should be submitted to the relevant Inspecting Authority
for approval. Where necessary, Standards Australia Committee ME/1, Boilers and
Unfired Pressure Vessels, may be asked to serve in an advisory capacity in the
determination of the suitability of such designs. (See also Clause 1.4.)
It is emphasized that this activity of the committee is limited to technical aspects of
the Code and that the committee has no power or jurisdiction to adjudicate upon
contractual matters or regulatory matters or the duties of any persons concerned with
the subject of the submission.
It is further emphasized that the committee will undertake consideration of only those
matters which relate to interpretation of, or proposed changes to, the Standards for
which it is responsible. In particular it will not consider or make recommendations
indicating approval of proprietary equipment, materials, components, or methods.
A method developed by the committee for communicating its findings is the use of
Rulings. A Ruling is issued in reply to a specific enquiry from a specific organization
and applies only to the set of circumstances referenced in the Ruling. Rulings may be
used by the authorities as the basis for approval of the particular application or for
approval of similar submissions from other organizations. Current Rulings are available
under the reference AS 1200 Supplement 1.
Where the committee judges the subject to be suitable, a Ruling may be incorporated
in an amendment to the relevant Standard, whereupon the Ruling is withdrawn. If the
timing is appropriate, the finding of the committee may be issued directly as an
amendment.
NOTES:
1. In the past some Rulings have been designated ‘Commit tee Opinions’, but this term is no longer used.
2. In the past, the commit tee has also issued ‘I nterpretations’ which were considered to be equivalent to
an amendment. The practice has been disconti nued, and all Interpretations have now been withdrawn.
COPYRIGHT
AS 1210 Supp1—1990
6
STANDARDS AUSTRALIA
Australian Standard
Unfired pressure vessels — Advanced design and construction
(Supplement to AS 1210—1989)
SECTION S1. SCOPE AND GENERAL REQUIREMENTS
S1.1 SCOPE. Clause 1.1 applies with the following
additions:
Supplement 1 (hereafter referred to as ‘the Supplement’
or ‘this Supplement’) specifies requirements for two
additional classes of vessel identified as Class 1H and
Class 2H with the latter further subdivided into
classifications 2HA and 2HB, and for cast and forged
vessels, which —
(a) utilize advanced design and construction methods;
(b) generally permit design strengths higher than those
specified in AS 1210; and
(c) comply with the requirements specified in AS 1210
for cast, forged or Class 1 welded vessels as
appropriate, except as modified by this Supplement.
This Supplement does not apply to transportable vessels
nor does it apply to vessels of riveted or brazed
construction. Only those requirements which supplement
or differ from those specified in AS 1210 for cast,
forged or Class 1 welded construction are specified in
this Supplement.
S1.3 APPLICATION OF SUPPLEMENT. Clause 1.3
applies except that the first paragraph shall be replaced
by the following:
The requirements of this Supplement are specifically
intended for application to unfired pressure vessels
having —
(a) design pressures above the curves in Figures 1.3.1
and 1.3.2; and
(b) operating temperature limits of various materials
and components as stated in the appropriate Section
of this Supplement.
NOTE: The Supplement does not specify a limitation on pressures
and is not all-inclusive for all types of construction. For very high
pressures, some additions to or deviations from the requirements of
this Supplement, to the satisfaction of the Inspecting Authority and
purchaser, may be necessary.
S1.6 CLASSES OF VESSEL CONSTRUCTION.
Clause 1.6 applies with the following addition:
This Supplement specifies the requirements for two
additional classes of vessels, viz Class 1H and Class 2H,
and the latter is subdivided into classifications 2HA and
2HB.
The range of materials permitted for Class 2H
construction (see Clause S2.1.1) is limited but the extent
of non-destructive examination may be reduced from that
required for Class 1H construction (see Clause S5.3.4.1)
provided that criteria for design against fatigue failure,
as appropriate for Class 2HA and Class 2HB
respectively, are fulfilled (see Clause S3.1.5.4).
S1.7 APPLICATION OF VESSEL CLASSES AND
TYPES. Clause 1.7 applies with the following
modification:
S1.7.2.4 Mixed classes of construction. Clause 1.7.2.4
does not apply to this Supplement and the following
shall be substituted:
See Clause S3.1.5.4 for the permissible mixing of
components of Class 1H, Class 2HA, and Class 2HB
construction.
S1.8 DEFINITIONS. Clause 1.8 applies, with the
following additions and modifications to particular
Clauses.
S1.8.10 Design strength. Clause 1.8.10 does not apply
to this Supplement and the following shall be substituted:
Design strength (f) — the maximum allowable stress
value for use in the equations for the calculation of
pressure parts, and the basis for determining stress
intensity limits (see Clause S3.3).
S1.8.24 Parties concerned. Clause 1.8.24 does not apply
to this Supplement and the following shall be substituted:
Parties concerned — the purchaser, the manufacturer,
Inspecting Authority, and the designer (see
Clause S3.1.2).
S1.12 DESIGNATION. Clause 1.12 does not apply to
this Supplement and the following shall be substituted:
S1.12 DESIGNATION. Unfired pressure vessels
constructed to this Supplement shall be designated by the
number of the Standard to which it is a supplement, i.e.
AS 1210, and the method or class of construction:
For Class 1H welded construction . . AS 1210 — 1H
For Class 2HA welded construction AS 1210 — 2HA
For Class 2HB welded construction AS 1210 — 2HB
For cast construction . . . . . . . . . . AS 1210 — CH
For forged construction . . . . . . . . . AS 1210 — FH
For mixed construction — an appropriate combination
of symbols, e.g. . . . . . . . . . . AS 1210 — 1H/2HA
S1.13 REFERENCED DOCUMENTS. Clause 1.13
applies and this Supplement makes reference to the
following documents:
AS
1065
Non-destructive testing — Ultrasonic testing
of carbon and low alloy steel forgings
1200
SAA Boiler Code
1200
Supplement 1 — Rulings to the SAA Boiler
Code
COPYRIGHT
7
1210
1391
1548
1710
ISO
R 783
SAA Unfired Pressure Vessels Code
Methods for tensile testing of metals
Steel plates for boilers and pressure vessels
Non-destructive testing of carbon and low
alloy steel plate — Test methods and quality
classification
Mechanical testing of steel at elevated
temperatures — Determination of lower yield
stress and proof stress and proving test
6892
Metallic materials — Tensile testing
DIS 2694 Draft recommendations for pressure vessels
AS 1210 Supp1—1990
ANSI/ASME
BPV/VIII-2
ASTM
A 578
BS
3688
5500
COPYRIGHT
Boiler and pressure vessel code:
Section VIII — Rules for construction
of pressure vessels: Division 2 —
Alternative rules
Specification for straight-beam ultrasonic
examination of plain and clad steel plates for
special applications
Methods for mechanical testing of metals at
elevated temperatures
Part 1: Tensile testing
Specification for unfired fusion welded
pressure vessels
AS 1210 Supp1—1990
8
SECTION S2. MATERIALS
Section 2 of AS 1210 shall apply, with the following
additions and modifications to particular Clauses.
S2.1 MATERIAL SPECIFICATIONS. Clause 2.1
applies, with the following additions and modifications
to particular Clauses:
S2.1.1 General. Clause 2.1.1 does not apply to this
Supplement and the following shall be substituted:
Any material used in the construction of Class 1H
vessels shall comply with the specification listed in
Tables 3.3.1(A), 3.3.1(B) and 3.3.1(D) to 3.3.1(H), and
shall have the design strengths allocated in Table S3.3.1
(i) or (ii).
Any material used in construction of Class 2H vessels
shall be a Group A or Group K steel (see Note)
complying with a specification listed in Table 3.3.1(A)
or Table 3.3.1(B), and shall have the design strength
allocated in Table S3.3.1(i) or (ii). For Class 2H vessels,
the nominal shell plate thickness shall not exceed
38 mm.
NOTE: For steel groups, see Appendix P or Tables 3.3.1(A) and
3.3.1(B).
S 2.3 AL T ERNAT IVE M ATE RIAL AND
COMPONENT SPECIFICATIONS.Clause 2.3applies
with the following modification:
S2.3.3 Use of structural or similar quality steels.
Clause 2.3.3 does not apply and the following shall be
substituted:
Structural and similar quality steels shall be used only
where requirements of Clause 2.3.4 are complied with.
S2.4 MATERIAL IDENTIFICATION. Clause 2.4
applies, with the following additions and modifications.
S2.4.1 Unidentified material. The use of unidentified
material is not permitted.
Not permitted.
S2.4.2 Material not fully identified. The use of material
not fully identified is not permitted.
S2.6 MATERIAL REQUIREMENT FOR LOW
TEMPERATURE SERVICE. Clause 2.6 applies with
the following additions:
S2.6.2.6 Class 2H vessels. For Class 2H vessels, the
required MDMT as determined from Table 2.6.3 shall be
not less than 10°C below the MOT for vessel or vessel
part.
S2.6.3.2(e) Modification for liquefied gas. For Class 2H
vessels which contain liquefied gas, the required MDMT
at full design strength shall be not more than 10°C
higher than the atmospheric boiling point of the contents.
S2.7 MATERIAL REQUIREMENTS FOR HIGH
TEMPERATURE SERVICE. Clause 2.7 applies, with
the following additions and modifications to particular
Clauses:
S2.7.5 Steels. Clause 2.7.5 applies except that the first
and second paragraphs shall be replaced by the
following:
Steels for use at temperatures of 100°C or above shall be
supplied with elevated temperature properties verified or
hot-tested, except as provided below:
(a) Steels for which elevated temperature properties are
specified in the relevant material specification but
which have not been hot-tested or verified may be
used. The design strength value shall be either as
permitted by Table S3.3.1 or as determined by the
factors in Table SA1.1 of Appendix SA.
(b) Steels for which elevated temperature properties are
not specified in the relevant material specification
may be used. (See Table S3.3.1(ii) for the design
strength for such steels listed in ANSI/ASME
BPV-VIII-2 or BS 5500.)
Where steel is to be used at a design temperature
different from the standard test temperature in the
particular material specification and is ordered hot-tested,
the test shall be carried out at the nearest higher standard
temperature given in the particular material specification.
The material shall comply with the requirements of the
material specification at the test temperature.
S2.8 NON-DEST RUCT IVE TEST ING OF
MATERIALS. Clause 2.8 applies with the following
addition:
All plates 100 mm and over in thickness shall be
ultrasonically examined in accordance with AS 1710 or
other approved method, and shall comply with the
requirements for Class 2E quality level of AS 1710.
For clad plate, where credit for the thickness of cladding
on plate is permitted (see also Clause 3.3.1.2(c)), the
bond between the cladding and the baseplate shall be
ultrasonically examined.
All forgings 100 mm and over in thickness shall be
ultrasonically examined in accordance with, and shall
comply with the requirements of Clause S5.19.
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AS 1210 Supp1—1990
SECTION S3. DESIGN
Section 3 of AS 1210 shall apply, with the following
additions and modifications to particular Clauses:
S3.1 GENERAL DESIGN. Clause 3.1 applies with the
following additions and modifications to particular
Clauses:
S3.1.2 Design responsibility. Clause 3.1.2 does not
apply to this Supplement and the following shall be
substituted:
The design shall be carried out by a designer suitably
qualified and experienced in the design of pressure
vessels, who shall be responsible for the design of the
vessel in accordance with this Section; and the design
conditions shall either be specified by the purchaser (see
Appendix SE) or be specified by the designer and
approved by the purchaser.
A high level of qualification and experience would
normally be required of a designer or design organization
capable of adequately discharging the full requirements
of this Supplement.
The designer may be associated with either the purchaser
or the manufacturer, but, if not so associated, the
designer shall be deemed to be one of the parties in the
matters that require agreement of the parties concerned.
S3.1.3 Alternative design methods. Clause 3.1.3 does
not apply to this Supplement and the following shall be
substituted:
Where an alternative design method is adopted, the
general principles, design limits, fabrication, testing, and
inspecting requirements of this Supplement shall be
complied with.
In lieu of the requirements contained in this Supplement
pertaining to the evaluation of design stress in a vessel
or vessel component, it may be permitted to use a
rigorous mathematical stress analysis, e.g. finite element
method, or experimental stress analysis to evaluate the
actual design stress. However, where complete
requirements for the design of a vessel or vessel region
are not provided in this Section (S3), a complete stress
analysis (see Clause S5.12) shall be performed. Stress
values obtained from such an analysis shall be used in
conjunction with this Supplement to determine the
minimum thickness of the vessel or vessel region.
Other design methods may be used (see Foreword)
except that the minimum thickness, where only the
pressure loading is being considered, shall be not less
than that required by Clauses S3.7 to S3.13.
S3.1.4 Design against failure. Clause 3.1.4 does not
apply to this Supplement and the following shall be
substituted:
The overall design of the vessel shall ensure against any
mode of failure. The requirements of this Section (S3)
are intended for use to determine the minimum thickness
and other dimensions which provide safety against the
risk of —
(a) gross plastic deformation;
(b) incremental collapse;
(c) collapse through buckling;
(d) fatigue cracking; and
(e) creep rupture.
The requirements assume that the material has adequate
ductility at the service temperature and at the design
stresses considered, particularly in the regions of stress
concentration.
Requirements to provide protection against brittle
fracture and the requirements to ensure safe performance
at low temperature are given in this Section (S3) and in
AS 1210 (see Clause 2.6 and Appendix K).
The requirements of this Section (S3) also provide
limited guidance on design against corrosion and apply
only if the materials and welds are not subjected to stress
corrosion in the presence of the product which the vessel
is to contain.
S3.1.5 Design criteria.
S3.1.5.1 General. The minimum thickness of vessel parts
subject only to fluid pressure shall be calculated from the
equations given in Clauses S3.7 to S3.13. Where parts of
the vessel are subject to loads in addition to that of fluid
pressure, an equivalent stress intensity based on the
maximum shear stress theory shall be calculated. For
loads giving rise to primary membrane stresses, the
equivalent stress intensity shall not exceed the design
strength at the design temperature (see Clause S3.3)
except as allowed for in Table S3.1.5. Where in addition
to the primary membrane stress there are other stresses
present, the equivalent stress intensity at any location
shall not exceed the stress intensity limits given in
Appendix SH (see Figure SH1). Clauses S3.7 and S3.13
may not ensure against fatigue failure. Thus reference
shall be made to Clauses S3.1.5.4 to S3.1.5.7 to
determine when the above Clauses are applicable or
when recourse to further fatigue or other analysis is
required.
Irrespective of whether credit is taken or is not taken for
cladding in the computations for the dimensions of
components for integrally clad vessels designed for
operation at other than ambient temperature, calculation
of the primary membrane stresses in both the base
material and the cladding shall be performed and shall
take into account any differential coefficients of
expansion. The calculated stresses shall not exceed the
relevant design strengths given in Table S3.3.1.
S3.1.5.2 Maximum shear stress theory. The maximum
shear stress at a point is defined as one-half of the
algebraic difference between the largest and the smallest
of the three principal stresses. Thus if the principal
stresses are σ 1, σ2, and σ3 and if σ1 > σ2 > σ 3
(algebraically) the maximum shear stress is 0.5(σ 1 - σ3 ).
The maximum shear stress theory of failure states that
yielding in a component occurs when the maximum
shear stress reaches a value equal to the maximum shear
stress at the yield stress in a tensile test. In such a tensile
test —
σ1 =
fy; σ2 = 0; and σ3 = 0
where
fy
=
yield stress
and therefore the maximum shear stress is 0.5f y, and
yielding occurs when —
0.5(σ1 - σ3) = 0.5f y
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AS 1210 Supp1—1990
10
By analogy this equation can be written as —
(σ1 – σ3) = f ′
and the right-hand side is then called the equivalent
intensity of combined stress or simply ‘stress intensity’.
Thus the ‘stress intensity’ is defined as twice the
maximum shear stress and is equal to the largest
algebraic difference between any two of the three
principal stresses and is directly comparable to yield
stress values found from tensile tests.
S3.1.5.3 Application of maximum shear stress theory.
Considering a thin cylindrical shell subject only to
internal pressure loading, the following membrane
stresses apply:
σ1 = hoop stress
=
σ2 = axial stress
=
σ3 = radial stress
= -P at inner
surface
= 0 at outer surface
where
An element of a thin
D = inside diameter
of cylinder
cylindrical shell
P = internal pressure
f = design strength
t = wall thickness of cylinder
The mean radial stress for thin shells can therefore be
taken as —
(σrad) mean = σmean =
= -0.5P
From the above equations it then follows that the stress
intensity is governed only by σ1 and σ3 and becomes —
f ′ = σ1 – σ3
=
– (−0.5P)
=
+ 0.5P which must not exceed the
design strength f
Thus t =
which is Equation 3.7.3(1) with
joint efficiency equal to 1.
If in addition to internal pressure the vessel part is
subject to other loads, the absolute and the relative
values of σ1 , σ2, and σ3 will vary and could lead to a
wall thickness larger than that given by, say,
Equation 3.7.3(1). Thus, if a slender cylinder is subject
to bending, σ2 could become larger than σ1 and the
calculated stress intensity would become equal to
σ2 – σ3.
S3.1.5.4 Designing against fatigue failure — General.
During the operation of pressure vessels, important parts
may be subjected to cyclic or repeated stresses. Such
stresses may be caused by —
(a) applications or fluctuations of pressure;
(b) periodic temperature transients;
(c) restrictions of expansion or contraction during
normal temperature variations;
(d) forced vibrations; or
(e) variations in external loads.
Fatigue cracking will occur during the operational life if
the fatigue strength of the material used in any part of
the pressure vessel is exceeded for the particular number
of repeated stress cycles. To prevent fatigue cracking, the
level of cyclic stress or the expected number of cycles or
both shall be reduced accordingly.
TABLE S3.1.5
MEMBRANE STRESS INTENSITY LIMITS FOR VARIOUS LOAD COMBINATIONS
Condition
Design
Membrane stress
intensity limit (kf)
Load combination
Calculated stress limit basis
A The design pressure, the dead load of the
vessel, the contents of the vessel, the
imposed load of any mechanical equipment,
and external attachment loads
1.0f (see Note 1)
Based on the corroded thickness at design
metal temperature
B Condition A above plus wind forces
1.2f
Based on the corroded thickness at design
metal temperature
C Condition A above plus earthquake forces
NOTE: The condition of structural
instability or buckling must be considered
1.2f
Based on the corroded thickness at design
metal temperature
Operation
A The actual operating loading conditions.
This is the basis of fatigue life evaluation
See Clauses S3.1.5.4 to
S3.1.5.7
Based on corroded thickness at operating
pressure and operating metal temperature
Test
A The required test pressure, the dead load of
the vessel, the contents of the vessel, the
imposed load of any mechanical equipment,
and external attachment loads
See Clause S5.10.2.1 for
hydrostatic test, and
Clause S5.11.4 for
pneumatic test
Based on actual design values at test
temperature
NOTES:
1. f is the design strength at the design temperature as determined by Clause S3.3.1.
2. k is a load factor.
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The alternative but technically equivalent methods for
determining the need for a detailed fatigue analysis of
Class 1H, Class 2HA, and Class 2HB vessels are given
in Clauses S3.1.5.5 to S3.1.5.7 inclusive. In the first
method, Clauses S3.1.5.5 and S3.1.5.6 specify
requirements for integral parts of vessels and non-integral
parts of vessels respectively, while the second method
given in Clause S3.1.5.7 covers both integral and
non-integral parts of the vessel.
In designing against fatigue, the designer shall pay
particular attention to the possibledeleterious effects of the
design features listed below. Unless their fatigue behaviour
is satisfactorily assessed, their use shall be avoided. Design
features to be assessed or avoided include —
(i) non-integral constructions, such as the use of pad
type reinforcements or of fillet welded attachments,
as opposed to integral construction;
(ii) pipe threaded connections, particularly for pipe
outside diameters in excess of 65 mm;
(iii) stud bolted attachments;
(iv) partial penetration welds; and
(v) major thickness changes between adjacent members.
Where corrosion is likely to be present in the area of
fatigue, consideration should be given to the use of lower
stress levels and to the extrapolation of the fatigue curves
beyond 106 cycles if necessary.
Procedures for determining compliance with the fatigue
requirements of this Supplement for Class 1H, Class 2HA
and Class 2HB vessels and vessel components shall be as
specified in (A), (B) and (C) respectively of this
Clause (S3.1.5.4).
(A) For Class 1H vessels or vessel components —
provided that the requirements of Clauses S3.1.5.5
and S3.1.5.6, or of Clause S3.1.5.7 are fulfilled, it
may be assumed that the requirements of this
Supplement are complied with. If those requirements
are not complied with by any component, peak
stresses occurring in that component shall be
calculated and a fatigue analysis of that component
shall be carried out.
The method of fatigue analysis shall be in accordance
with Appendix SC or other approved methods. In
particular cases, other methods of analysis may be
equally applicable, and the use of such methods
together with safety factors equivalent to those used
in Appendix SC shall be deemed to comply with the
requirements of this Supplement.
AS 1210 Supp1—1990
NOTE: For Class 2HA vessels, it is permissible to upgrade a
component or components to Class 1H requirements to satisfy
local fatigue requirements.
(C) For Class 2HB vessels and vessel components — all
components both integral and non-integral shall
comply with the requirements specified in
Clause S3.1.5.6, or as specified for non-integral parts
in Clause S3.1.5.7, for parts that do not require a
detailed fatigue analysis.
NOTE: For Class 2HB vessels, it is not permissible to upgrade a
componentor componentsto Class 2HA or Class 1H requirements
to satisfy local fatigue requirements.
3.1.5.5 Rules to determine need for a detailed fatigue
analysis of integral parts of Class 1H vessels. A detailed
fatigue analysis need not be made, provided that all of
Condition A below or all of Condition B below is satisfied;
a detailed fatigue analysis shall be made for those parts
which do not satisfy the conditions. The following
requirements are applicable to all integral parts of the
vessels, including integrally reinforced type nozzles. For
vessels having pad type nozzles or non-integral
attachments, the requirements of Clause S3.1.5.6 apply.
(a) Condition A. Condition A is applicable to both
ferrous and non-ferrous materials.
For Condition A, a detailed fatigue analysis is not
mandatory where the material has a specified
minimum tensile strength not exceeding 560 MPa for
parts other than bolts (see Paragraph SC3 of
Appendix SC for bolts), and where the total of the
expected number of cycles of types (i) plus (ii) plus
(iii) plus (iv), defined below, does not exceed 1000:
(i) The expected (design) number of full-range
pressure cycles including start-up and
shutdown.
(ii) The expected number of operating pressure
cycles in which the range of pressure variation
exceeds 20 percent of the design pressure.
The number of cycles in which the pressure variation
does not exceed 20 percent of the design pressure
shall be limited as follows except in unusual
configurations with high stress concentration factors:
(A) Ferrous materials — no limit.
(B) Non-ferrous materials — 106 cycles.
NOTE: Apart from nickel-copper alloy, Appendix SC is not
directly applicable to non-ferrous metals and alloys. For such
materials a fundamental approach may be used (see Foreword).
(B) For Class 2HA vessels and vessel components —
provided that the requirements for Class 1H vessels
on the need for a detailed fatigue analysis, i.e.
Clauses S3.1.5.5 and S3.1.5.6 or Clause S3.1.5.7, are
fulfilled, the requirements of this Supplement are
complied with for Class 2HA vessels. If the above
requirements are not complied with by any
component of the Class 2HA vessel, that component
may be upgraded to comply in full with requirements
for Class 1H vessel components, including the
requirements for non-destructive examination, and a
detailed fatigue analysis, in accordance with the
requirements in (A) for Class 1H vessel components,
shall be carried out.
*
†
NOTE: Pressure cycles caused by fluctuations in atmospheric
conditions need to be considered.
(iii) The effective number of changes in metal
temperature* between any two adjacent
points† in the pressure vessel, including
nozzles. The effective number of such changes
is determined by multiplying the number of
changes in metal temperature of a certain
magnitude by the factor given below, and by
adding the resulting numbers. The factors are as
follows:
Metal temperature differential °C
Factor
≤25 . . . . . . . . . . . . . . . . . . . . 0
>25 ≤55 . . . . . . . . . . . . . . . . . . . . 1
>55 ≤85 . . . . . . . . . . . . . . . . . . . . 2
>85 ≤140 . . . . . . . . . . . . . . . . . . . . 4
>140 ≤195 . . . . . . . . . . . . . . . . . . . . 8
>195 ≤250 . . . . . . . . . . . . . . . . . . . . 12
>250
. . . . . . . . . . . . . . . . . . . . 20
Thermal protecti on devices, such as thermal sleeves in nozzles, may be used to reduce temperature dif ferences or thermal shock.
Adjacent points are defi ned as points which are spaced less than the distance 2 (Rt) fr om each other, where R and t are the mean radius
and thickness, respecti vely, of the vessel, nozzle, flange, or other component in which the points are located. (Expression 2 (Rt) does
not apply to flat plates.)
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AS 1210 Supp1—1990
12
at the two points, and E is the modulus of elasticity
at the mean value of the temperatures at the two
points.
(iv) The range of temperature difference between
any two adjacent points* of the vessel does
not change during normal operation† by more
than the quantity Sa/(2Eα), where Sa is the
value obtained from the applicable design
fatigue curve for the total specified number of
significant temperature difference fluctuations.
A temperature difference fluctuation shall be
considered to be significant if its total algebraic
range exceeds the quantity S/(2Eα), where S is
the value of Sa obtained from the applicable
design curve for 106 cycles.
(v) For components fabricated from materials of
differing moduli of elasticity or coefficient of
thermal expansion or both, the total algebraic
rangeof temperature fluctuation experienced by
the vessel during normal operation does not
exceed the magnitude —
Sa/[2(E1α1 - E2α2)]
where Sa is the value obtained from the
applicable design fatigue curve for the total
specified number of significant temperature
fluctuations, E1 and E2 are the moduli of
elasticity, and α1 and α 2 are the values of the
instantaneous coefficients of thermal expansion
at the mean temperature value involved for the
two materials of construction. A temperature
fluctuation shall be considered to be significant
if its total excursion exceeds the quantity —
S/[2(E1α1 - E2α2)]
where S is the value of Sa obtained from the
applicable design fatigue curve for 106 cycles.
If the two materials used have different
applicable design fatigue curves, the lower
value of Sa shall be used in applying the rules
of this paragraph.
Example: Consider a design subject to the
following metal temperature differentials and
number of cycles:
∆t,°C
Cycles
25 . . . . . . . . . . . . . . . . . . . . . . . 1000
50 . . . . . . . . . . . . . . . . . . . . . . . . 250
220 . . . . . . . . . . . . . . . . . . . . . . . .
5
The effective number of changes in metal
temperature is —
1000(0) + 250(1) + 5(12) = 310
The number used as (iii) in performing the
comparison with 1000 is then 310. Temperature
cycles caused by fluctuations in atmospheric
conditions need not be considered.
(iv) The number of temperature cycleswhichcauses
the value of (α 1 - α2)∆T to exceed 0.000 34 for
components involving welds between materials
having different coefficients of expansionwhere
α1 and α 2 are the mean coefficients of thermal
expansion and ∆T is the operating temperature
range.
NOTE: This does not apply to cladding
(see Clause 3.3.1.2). Cladding should be the subject of a
detailed analysis of thermal stresses.
(b) Condition B. Condition B is applicable only to those
materials which are referred to in Appendix SC, i.e.
apart from nickel-copper alloy, it is not applicable to
non-ferrous materials.
For Condition B, detailed fatigue analysis is not
mandatory where all the following conditions are
satisfied:
(i) The expected (design) number of full-range
pressure cycles, including start-up and
shutdown, does not exceed the number of
cycles in the applicable fatigue curve of
Appendix SC corresponding to an Sa value of 3
times the f value found in Table S3.3.1 for the
material at the operating temperature.
(ii) The expected (design) range of pressure cycles
during normal operation* does not exceed 33
percent of the design pressure multiplied by
Sa/f, where Sa is the value obtained from the
applicable fatigue curve of Appendix SC for
the specified number of significant pressure
fluctuations and f is the design strength for the
operating temperature. If the specified number
of significant pressure fluctuations exceeds 10 6,
the Sa value at N = 106 may be used.
NOTE: Significant pressure fluctuations are those for
which the range exceeds the quantity of 33 percent of the
design pressure multiplied by S/f, where S = the value of
S a for 106 cycles.
(iii) The temperature difference between any two
adjacent points† of the vessel during normal
operation* and during start-up and shutdown
operation does not exceed S a/(2Eα), where Sa is
the value obtained from the applicable design
fatigue curve for the specified number of
start-up and shutdown cycles, α is the value of
the instantaneous coefficient of thermal
expansion at the mean value of the temperature
*
†
NOTE: This Clause does not apply to cladding (see
Clause 3.3.1.2). Cladding should be the subject of a
detailed analysis of thermal stresses.
(vi) The specified full range of mechanical loads,
excluding pressure but including piping
reactions, does not result in load stress
intensities whose range exceeds the S a value
obtained from the applicable design fatigue
curve for the total specified number of
significant load fluctuations. If the total
specifiednumberof significantload fluctuations
exceeds 106, the Sa value at N = 106 may be
used. A load fluctuation shall be considered to
be significant if the total excursion of load
stress intensity exceeds the value of Sa obtained
from the applicable design fatigue curve for 106
cycles.
S3.1.5.6 Rules to determine need for fatigue analysis of
nozzles with separate reinforcement and of non-integral
attachments of Class 1H vessels. A fatigue analysis of pad
type nozzles and non-integral attachments need not be
made provided that all of Condition AP below or all of
Condition BP below is satisfied.
Normal operati on is defined as any set of operating conditi ons other than start -up and shutdown, which are specifi ed for the vessel to
perf orm it s intended function.
Adjacent points are defi ned as points which are spaced less than the distance 2 (Rt) fr om each other, where R and t are the mean radius
and thickness, respecti vely, of the vessel, nozzle, fl ange, or other component in which the points are located. (Expression 2 (Rt) does
not apply to flat plates.)
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AS 1210 Supp1—1990
number of changes is determined by
multiplying the number of changes in metal
temperature of a certain magnitude by the
factor given below, and by adding the
resulting numbers. The factors are as follows:
In the application of Condition AP or Condition BP, all
fillet welds and partial penetration welds are non-integral
attachments except for the following:
(i) Welds connecting non-pressure parts not
subject to significant cyclic loads or
temperature variations and not closer to a
gross structural discontinuity than —
Metal temperature differential,
°C
≤25
..........
>25
≤55
..........
>55
≤85
..........
>85
≤140 . . . . . . . . . .
>140
≤195 . . . . . . . . . .
>195
≤250 . . . . . . . . . .
where
D =
i nt erna l di am et er at t he
discontinuity of the shell where the
attachment is welded. If a large
nozzle is considered to be a
discontinuity, the diameter of the
nozzle is used if the attachment is
welded to the nozzle wall, or the
diameter of the vessel if the
attachment is welded to the vessel.
If a knuckle in a dished end is
considered to be a discontinuity, the
diameter of the dish at the knuckle,
which will usually be the same as
the vessel diameter, is used.
ts = thickness of the shell where the
attachment is welded on
(ii) Welds for attachment of support skirts or
other supports involving similar attachment
orientation, where the effective throat
dimension of the attachment weld is not less
than the thickness of the attachment.
(a) Condition AP. Condition AP is applicable to both
ferrous and non-ferrous materials.
For Condition AP, detailed fatigue analysis of pad
type nozzles and non-integral attachments is not
mandatory where the material has a specified
minimum tensile strength not exceeding 560 MPa
for parts other than bolts (see Paragraph SC3 of
Appendix SC for bolts), and where the total of the
expected number of cycles of types (i) plus (ii) plus
(iii) plus (iv), defined below, does not exceed 400.
(i) The expected (design) number of full-range
pressure cycles including start-up and
shutdown.
(ii) The expected number of operating pressure
cycles in which the range of pressure variation
exceeds 15 percent of the design pressure. The
number of cycles in which the pressure
variation does not exceed 15 percent of the
design pressure shall be limited as follows
except in unusual configurations with very
high stress concentration factors:
(1) Ferrous materials — no limit.
(2) Non-ferrous materials — 106 cycles.
NOTE: Pressure cycles caused by fluctuations in
atmospheric conditions need not be considered.
(iii) The effective number of changes in metal
temperature between any two adjacent points
in the pressure vessel, including nozzles. In
the calculation of the temperature difference
between adjacent points, conductive heat
transfer shall be considered only through
welded or integral cross-sections with no
allowance for conductive heat transfer across
unwelded contact surfaces. The effective
Factor
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. 0
. 1
. 2
. 4
. 8
. 12
NOTES:
1. If metal temperature differential exceeds 250°C,
detailed analysis is required.
2. Temperature cycles caused by fluctuations in
atmospheric conditions need not be considered.
Example: Consider a design subject to metal temperature
differentials for the following number of times:
∆t,°C
Cycles
25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000
50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
220 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
The effective number of changes in metal temperature
is —
1000(0) + 250(1) + 5(12) = 310
The number used as (C) in performing the comparison
with 400 is then 310.
(iv) The number of temperature cycles which
causes the value of (α 1 - α 2)∆T to exceed
0.000 34 for components involving welds
between materials having different coefficients
of expansion, where α 1 and α 2 are the mean
coefficients of thermal expansion and ∆T is
the operating temperature range.
NOTE: This does not apply to cladding (see
Clause 3.3.1.2). Cladding should be the subject of a
detailed analysis of thermal stresses.
(b) Condition BP. Condition BP is applicable only to
those materials which are referred to in
Appendix SC, i.e. apart from nickel-copper alloy, it
is not applicable to non-ferrous materials.
For Condition BP, detailed fatigue analysis of pad
type nozzles and non-integral attachments is not
required where all the requirements of
Clause S3.1.5.5(b) are satisfied by the following
adjusted values:
(i) Use a value of 4 instead of 3 in
Condition B(i).
(ii) Use a value of 25 percent instead of
33 percent in Condition B(ii).
(iii) Use a value of 2.7 instead of 2 in the
denominator of Condition B(iii), (iv), and (v).
S3.1.5.7 Alternative method for the determination of need
for fatigue analysis of parts of vessel. This
Clause (S3.1.5.7) provides an alternative to the method
in Clauses S3.1.5.5 and S3.1.5.6 for determining the
need for a detailed fatigue analysis of parts of a vessel.
A detailed fatigue analysis of vessels or vessel
components need not be made, provided that each part of
the vessel complies with a relevant path in
Figure S3.1.5.7.
NOTE: This method is technically equivalent to the method given
in Clauses S3.1.5.5 and S3.1.5.6 but reference should also be made
to these Clauses for additional information.
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AS 1210 Supp1—1990
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FIGUR E S3.1.5.7 FLOW CH AR T FOR NEE D FOR DETAILED FATIGUE AN ALYS IS
TAB LE S3.1.5.7
POINT
1
2
3
4
5
6
VA LUES OF Sa/ N FOR PLOTTING IN DES IGN FATIGUE CUR VE S IN APP EN DIX SC
Sa
ef
ef∆ P/P
eE α∆T/1.5
eE α∆T/1.5
e ∆ T(E 1α1 − E2α2)/1.5
∆ S (mechanical other than above)
N = number of cycles
Full range pressure cycles including start up and shutdown
Pressure cycles duri ng normal operations whose range > S 6 P/ef
Start up and shutdown cycles
Temperature diff erence vari ation ∆ T whose range > 1.5S 6/ eEα
Temperature cycle whose range > 1.5 S 6 / e ( E 1α1 − E 2α2)
Mechanical stresses (other than above) whoses stress intensity range < S 5
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The notation and calculation parameters used in this
Clause are as follows:
E
= modulus of elasticity at mean temperature of
a part, in megapascals
E1, E2 = modulus of elasticity of two different
materials welded together, in megapascals
e
= factor from Figure S3.1.5.7
Fi
= temperature factors as follows
Metal temperature
Factor (F i)
differential (∆Ti)
≤25
............. 0
>25 ≤55
............. 1
>55 ≤85
............. 2
>85 ≤140 . . . . . . . . . . . . . 4
>140 ≤195 . . . . . . . . . . . . . 8
>195 ≤250 . . . . . . . . . . . . . 12
>250
. . . . . . . . . . . . . 20
f
= material design strength, in megapascals
N
= number of cycles
N(—) = number of cycles for a given condition
= expected (design) number of full range
ND
pressure cycles including start-up and
shutdown
NF
= ΣN iFi
Ni
= number of changes in metal temperature
difference between two points no more than
2 (Rt) apart for integral parts of vessels
OR
= number of changes in metal temperature
difference between any two adjacent points in
the pressure vessel, including nozzles for
non-integral parts
NT
= number of temperature cycles which causes
(α 1 - α2 )∆T to exceed 0.000 34 for parts of
dissimilar metals welded together
P
= design pressure, in megapascals
∆P
= pressure variation amplitude, in megapascals
R
= mean radius of the vessel, nozzle, flange or
other component in which the points are
located, in millimetres
= specified minimum tensile strength of material
Rm
at room temperature, in megapascals
S6
= Sa for 10 6 cycles, in megapascals
Sa
= stress amplitude from fatigue curve, in
megapascals
∆S
= stress amplitude from causes other than
thermal stress and pressure, in megapascals
T1 ,T2 = temperature of parts of adjacent dissimilar
metals welded together, in degrees Celsius
∆T
= temperature difference between two points no
more than 2 (Rt) apart for integral parts of
vessels, in degrees Celsius
OR
= temperature difference between any two
adjacent points in the pressure vessel,
including nozzles for non-integral parts (see
Note), in degrees Celsius
t
= thickness of the vessel, nozzle, flange or other
component in which the points are located, in
millimetres
AS 1210 Supp1—1990
α
α1 , α2
= instantaneous coefficient of thermal expansion
at the mean temperature of two points less
than 2 (Rt) apart, in reciprocal kelvins
= coefficient of thermal expansion of two
different materials welded together, in
reciprocal kelvins
NOTE: Conductive heat transfer is considered only through welded
or integral cross-sections with no allowance for conductive heat
transfer across unwelded contact surfaces.
S3.2 DESIGN CONDITIONS. Clause 3.2 applies, with
the following additions and modifications to particular
Clauses:
S3.2.2.3 Temperature fluctuations from normal
conditions. Clause 3.2.2.3 does not apply to this
Supplement and the following shall be substituted:
Where temperature fluctuations from normal conditions
occur, the vessel shall be designed in accordance with
Clause S3.1.5.4.
S3.2.3 Loadings. Clause 3.2.3 applies except that the last
paragraph shall be deleted and the following substituted:
(n) Forces due to fluctuating pressure or temperature.
Formal analysis of the effect of loading (h) to (n) is
required only where it is not possible to demonstrate the
adequacy of the design, e.g. by comparison with the
behaviour of comparable vessels.
The conditions under which a fatigue analysis that takes
into account loadings (h) to (n) is not required are set out
in Clauses S3.1.5.4 to S3.1.5.7.
S3.3 DESIGN STRENGTHS. Clause 3.3 applies with
the following additions and modifications to particular
Clauses:
NOTE: Within Clause 3.3 and where appropriate, substitute ‘design
strength (f)’ for ‘design tensile strength’, and ‘Table S3.3.1’ for
‘Table 3.3.1’.
S3.3.1 Design strength (f). Clause 3.3.1 applies, except
for the revised heading and with the following additions
and modifications to particular Clauses:
S3.3.1.1 General. Clause 3.3.1.1 does not apply to this
Supplement and the following shall be substituted:
The design strength (f) values for materials other than
bolting material, used in the construction of vessels to
the requirements of this Supplement are given in
Table S3.3.1. These values are based on the material
properties (see Appendix SA) and —
(a) are the maximum values to be used in the equations
presented by this Section for determining the
minimum thickness (or other dimensions) of vessel
parts; and
(b) form the basis for the various stress intensity limits
which are specified in Table S3.1.5 and
Appendix SH for loadings or components not
covered by Section 3.
NOTE: Some design strength values listed in Table S3.3.1 may
depart from values obtained by direct application of Appendix SA.
To these values a ligament efficiency (see Clause 3.6)
and casting quality factor shall be applied where
appropriate. The casting quality factor shall be 0.70
except that a higher factor of 0.90 may be used where
this factor is justified by the additional testing required
by Clause 5.9.
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AS 1210 Supp1—1990
16
For some vessels operating under special conditions and
as required by the design, it may be desirable to adopt a
reduced design strength to —
(a) limit deflection in close-fitting assemblies;
(b) allow for corrosion fatigue or stress corrosion
conditions;
(c) allow for an exceptionally long life; or
(d) provide for other design conditions not intended to
be covered by the stress criteria (see Clause S3.1.5).
TABLE S3.3.1 DESIGN STRENGTH (f) VALUES.
Table 3.3.1 shall apply except as specified in (a), (b),
and (c) below or as noted otherwise in this Supplement.
(a) AS 1548 carbon-manganese steel plate — design
strength values shall be as listed in Table S3.3.1(i).
(b) Other materials to Standards Australia
specifications — for other steels and non-ferrous
materials to Standards Australia specifications,
design strength values are under consideration, but
the design strength may be determined on the basis
of Appendix SA or may be taken equal to the
values of Table 3.3.1.
(c) Materials to BSI and ASTM specifications — design
strength values shall be as specified in
Table S3.3.1(ii).
S3.3.1.3 Bolting. Where bolt tensioning procedures are
established and detailed stress analysis of the bolted joint
is made, the alternative higher stress values as given in
ANSI/ASME BPV-VIII-2 may be used. In the absence
of the above procedure and analysis, bolt strengths as
listed in Table 3.21.5 shall be used.
TABLE S3.3.1(i)
DESIGN STRENGTH CARBON-MANGANESE STEEL PLATE TO AS 1548
Material
type
C-Mn
Standard
No
AS 1548
Grade
(see Note)
5-490N,T
Thickness
Group
No
A2
>16
>40
>80
7-430R, N, T
A1
>16
>40
>80
7-460R, N, T
A1
>16
>40
>80
7-490R, N, T
A2
>16
>40
>80
5-490NH, TH
A2
>16
>40
>80
7-430RH, NH, TH
A1
>16
>40
>80
7-460RH, NH, TH
A1
>16
>40
>80
7-490RH, NH, TH
A2
>16
>40
>80
mm
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
≤ 16
≤ 40
≤ 80
≤ 150
50
209
209
209
209
183
183
180
167
196
196
183
177
209
207
200
187
209
209
209
209
183
183
180
167
196
196
183
177
209
207
200
187
100
194
194
194
194
169
167
165
151
175
173
166
156
187
184
180
172
200
200
200
200
174
172
168
156
180
178
170
160
192
190
186
177
150
179
179
179
179
154
151
148
135
154
151
148
135
165
162
160
156
191
191
191
191
164
161
157
144
164
161
157
144
176
173
171
167
Design strength (f), MPa
Temperature, °C
200 250 300 325 350
168 150 138 134 130
168 150 138 134 130
168 150 138 134 130
168 150 138 134 130
139 124 110 108 105
138 124 110 108 105
135 124 110 108 105
130 124 110 108 105
139 124 110 108 105
138 124 110 108 105
135 124 110 108 105
130 124 110 108 105
150 132 120 117 114
148 132 120 117 114
146 132 120 117 114
142 132 120 117 114
179 160 147 143 139
179 160 147 143 139
179 160 147 143 139
179 160 147 143 139
148 132 117 114 112
147 132 117 114 112
144 132 117 114 112
139 132 117 114 112
148 132 117 114 112
147 132 117 114 112
144 132 117 114 112
139 132 117 114 112
160 141 128 125 121
157 141 128 125 121
156 141 128 125 121
152 141 128 125 121
375
126
126
126
126
102
102
102
102
102
102
102
102
111
111
111
111
133
133
133
133
108
108
108
108
108
108
108
108
118
118
118
118
400
122
122
122
122
99
99
99
99
99
99
99
99
108
108
108
108
127
127
127
127
105
105
105
105
105
105
105
105
115
115
115
115
NOTE: For a designation AS 1548 steel plate, the following criteria are to apply:
(a) A designation Type 5 plate shall not be used where the plate is to be in the non-normalized condition in the completed vessel.
(b) For A designation Type 7 plate which is to be in the non-normalized condition in the completed vessel, the design tensile strength values listed
for the otherwise equivalent R designation Type 7 plate may be used, provided that the test certificate for each plate is endorsed by the plate
manufacturer to show that the plate complies with both A and R designation requirements.
(c) For A designation plate which is to be in the normalized conditions in the completed vessel, the design tensile strength values listed for the
otherwise equivalent N designation plate may be used.
TABLE S3.3.1(ii)
DESIGN STRENGTH — MATERIALS TO BS AND ASTM SPECIFICATIONS
Material specification
BS specifications —
Material types and grades permitted in BS 5500
for Category 1 vessels
ASTM specifications —
Material types and grades specified in
ANSI/ASME BPV-VIII-2
Design strength (f)
Values equal to the ‘Design Strength Values’
specified in BS 5500
Values equal to the ‘Design Stress Intensity
Values’ specified in ANSI/ASME BPV-VIII-2
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17
S3.5 WELDED, RIVETED AND BRAZED JOINTS.
Clause 3.5 applies, with the following additions and
modifications.
S3.5.1 Welded joints. Clause 3.5.1 applies with the
following additions and modifications to particular
Clauses:
S3.5.1.7 Welded joint efficiency. Clause 3.5.1.7 applies
except that for welded main longitudinal and
circumferential joints of Class 2HA and Class 2HB
vessels complying with the requirements of this
Supplement, a joint efficiency of 1.0 may be used.
Only joints having an efficiency of 1.0 shall be used for
welded main joints.
S3.5.1.8 Butt-welding between plates of unequal
thickness. Clause 3.5.1.8 does not apply to this
Supplement and the following shall be substituted:
If two plates are to be welded by a butt joint and differ
in thickness by more than 25 percent of the thinner plate,
or by more than 3 mm, the thicker plate shall be reduced
as shown in Figure 3.5.1.8. In all such cases, the edge of
the thicker plate shall be trimmed to a smooth taper
extending for a distance of at least four times the offset
between the abutting surfaces so that the adjoining edges
will be approximately the same thickness. The length of
the required taper may include the width of the weld.
The maximum thickness through the weld shall be as
given in Table 3.1 of AS 4037—1992.
For attachment of ends to shells of differing thickness,
see Clause 3.12.6.
S3.5.2 Riveted joints. Not permitted.
S3.5.3 Brazed joins. Not permitted.
S3.7 THIN-WALLED CYLINDRICAL AND
SPHERICAL SHELLS SUBJECT TO INTERNAL
PRESSU RE AND COMBINED LOADINGS.
Clause 3.7 applies, with the following addition:
For components of simple vessels not subject to
additional external or internal loads and for which
detailed fatigue analysis is not required by
Clauses S3.1.5.4 to S3.1.5.7, the minimum thickness of
cylindrical and spherical shells shall be calculated from
the following equations:
For cylindrical shells —
t =
. . . . . . . . . . . . . . . . . . S3.7(1)
For spherical shells —
t =
. . . . . . . . . . . . . . . . . . S3.7(2)
Vessels or vessel components designed to resist
additional loads or requiring detailed fatigue analysis
shall be the subject of a detailed stress investigation.
S3.8 THICK-WALLED CYLINDRICAL AND
SPHERICAL SHELLS SUBJECT TO INTERNAL
PRESSURE. Clause 3.8 applies, with the following
additions:
For components of simple vessels not subject to
additional external or internal loads and for which
detailed fatigue analysis is not required by
Clauses S3.1.5.4 to S3.1.5.7, the minimum thickness
shall be calculated from equations given in Clause S3.7,
except that where P > 0.4f the following equations may
be used:
AS 1210 Supp1—1990
For cylindrical shells —
P = f loge
. . . . . . . . . . . . . S3.8(1)
For spherical shells —
. . . . . . . . . . . . S3.8(2)
P = 2f loge
loge is the natural logarithm, i.e. to the base e.
Vessels or vessel components designed to resist
additional loads or requiring detailed fatigue analysis
shall be the subject of a detailed stress investigation.
S3.9 CYLINDRICAL AND SPHERICAL SHELLS
SUBJECT TO EXTERNAL PRESSURE. Clause 3.9
applies in its entirety, including design strengths.
S3.10 CONICAL ENDS AND REDUCERS SUBJECT
TO INTERNAL PRESSURE. Clause 3.10 applies, with
the following additions:
For simple vessels not subject to additional external or
internal loads and for which detailed fatigue analysis is
not required by Clauses S3.1.5.4 to S3.1.5.7, the
minimum thickness of conical ends and reducers subject
to internal pressure shall be determined in accordance
with Clause 3.10, but with values for design strength
from Table S3.3.1.
Vessels or vessel components designed to resist
additional loads or requiring detailed fatigue analysis
shall be the subject of a detailed stress investigation.
S3.11 CONICAL ENDS AND REDUCERS SUBJECT
TO EXTERNAL PRESSURE. Clause 3.11 applies in
its entirety, including design strengths.
S3.12 DISHED ENDS SUBJECT TO INTERNAL
PRESSURE. Clause 3.12 applies with the following
addition and modifications:
For simple vessels or vessel components not subject to
loads additional to the loads due to internal pressure, not
requiring detailed fatigue analysis by Clauses S3.1.5.4 to
S3.1.5.7 and of shapes covered in Clause S3.12.5, the
minimum calculated thickness of dished ends shall be
determined from Clause S3.12.5 in lieu of the
requirements in Clause 3.12.5.
For other vessels or vessel components, dished ends shall
be the subject of a detailed stress analysis.
NOTE: The design method given in Clause S3.12.5 and the methods
for the design of ends in other relevant Standards which form part
of the SAA Boiler Code are currently under review with the
objective of having a consistent basis for the design of ends. In the
meantime, designers should be aware that there are differences
between these Standards.
S3.12.5 Thickness of ends.
(a) Torispherical ends. The minimum calculated
thickness of torispherical ends shall be determined
by Equation S3.12.5(1) or Equation S3.12.5(2) as
follows:
COPYRIGHT
(i)
For
≥ 0.002 and
≤ 0.08 —
t = R × 10G . . . . . . . . . . . . . . S3.12.5(1)
(ii)
For
t=
> 0.08 —
[e(P/f) - 1]
. . . . . . . . S3.12.5(2)
AS 1210 Supp1—1990
18
where
G
=
A + B log 10(P/f) + C[log10(P/f)]
A
=
−0.5480 − 1.9771(r/D) +
12.5655( r/D) 2
B
=
0.6630 − 2.2471(r/D) +
15.6830( r/D) 2
2
S3.15 UNSTAYED FLAT ENDS AND COVERS.
Clause 3.15 applies, with the following addition:
−5
C
=
6.1891 × 10 − 0.9731(r/D) +
4.3469(r/D) 2
f
=
design strength at the design
temperature (see Table S3.3.1),
in megapascals
e
=
base of natural log
≈
2.7183
The inside crown radius shall be not greater than
the outside diameter (D o ) of the end.
The inside knuckle radius shall be not less than
6 percent of the outside diameter (D o) or 3 times
the end thickness.
ends.
The minimum
thickness of 2:1 ellipsoidal (
calculated
= 4) ends shall
be determined as follows:
(i)
For 0.002 ≤
t
= D × 10
≤ 0.08 —
H
. . . . . . . . . . S3.12.5(3)
(ii) For
= −0.35237 + 0.90748 log10
Ends designed to resist additional loads or requiring
detailed fatigue analysis shall be the subject of a
detailed stress investigation.
S3.16 STAYED FLAT ENDS AND SURFACES.
Clause 3.16 applies, with the following addition:
Stayed flat ends are frequently subject to internal
force and deflection and therefore require a detailed
analysis for assessment of the working stresses. For
proven simple vessels that are not subject to large
temperature differentials, stayed ends may be
designed in accordance with Clause 3.16 with values
for design strength from Table S3.3.1.
S3.17 FLAT TUBEPLATES. Clause 3.17 applies,
with the following exceptions:
The design of flat tubeplates shall be in accordance
with Clause 3.17, except that the design strength from
Table S3.3.1 may be used in conjunction with
AS 3857. When adopting the TEMA method, the
design strength from Table 3.3.1 shall be used.
Where
H
The thickness of unstayed flat ends shall be
determined in accordance with Clause 3.15, but with
values for design strength from Table S3.3.1. Where
the ends are attached by welding, the welds shall be
of the full penetration type.
S3.15.5 Internally fitted doors. Clause 3.15.5 applies,
except that design strength from Table S3.3.1 may be
used.
For other notation, see Clause 3.12.1.
(b) Ellipsoidal
Vessels or vessel components designed to resist
additional loads or requiring detailed fatigue analysis
shall be the subject of a detailed stress investigation.
−
S3.18 OPENINGS AND REINFORCEMENT.
Clause 3.18 excluding Clause 3.18.6 applies with the
following addition and modification.
> 0.08 —
Design strengths from Table S3.3.1 may be used.
by Equation S3.12.5(2)
(c) Hemispherical ends. The minimum calculated
thickness for hemispherical ends shall comply
with Clause S3.7 or S3.8 as appropriate.
Departures from the above ‘reinforcement’
requirements are permitted if supported by theoretical
or experimental investigation or where sufficient
practical experience has demonstrated the adequacy
of an alternative design.
S3.13 DISHED ENDS SUBJECT TO EXTERNAL
PRESSURE. Clause 3.13 applies in its entirety,
including design strengths.
S3.18.6 Unreinforced openings. Clause 3.18.6 does
not apply and the following shall be substituted:
S3.14 DISHED ENDS — BOLTED SPHERICAL
TYPE. Clause 3.14 applies, with the following
addition:
For simple vessels not subject to additional external
or internal loads and for which detailed fatigue
analysis is not required by Clauses S3.1.5.4 to
S3.1.5.7, the minimum thickness of dished ends of
the bolted spherical type shall be determined in
accordance with Clause 3.4, but with values for
design strength from Table S3.3.1.
Circular openings are not required to have
reinforcement other than that inherent in the
construction where all of the following conditions
apply as applicable:
(a) A single opening shall have a diameter d
(see Clause 3.18.2) not exceeding 0.2 (Rm T1), or
if there are two or more openings within any
circle of diameter 2.5 (R mT1 ) then the sum of the
diameters of such unreinforced openings shall
not exceed 0.25 (R mT1 ), where R m is the mean
radius of the shell or end at the location of the
openings.
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19
(b) No two unreinforced openings shall have their
centres closer to each other, measured on the inside
of the vessel wall, than 1.5 times the sum of their
diameters.
(c) No unreinforced opening shall have its centre closer
than 2.5 (RmT1) to the edge of a locally stressed
area in the shell or end; locally stressed area means
any area in the shell or end where the primary local
membrane stress exceeds 1.1f, but excluding those
areas where such primary local membrane stress is
due to an unreinforced opening.
S3.19 CONNECTIONS AND BRANCHES.
Clause 3.19 applies with the following addition:
Design strengths from Table S3.3.1 may be used.
Welded branches shall be attached by full penetration
welds unless it can be shown by theory, experiment or
records of past experience, that alternative types of
connections are satisfactory.
S3.21 BOLTED FLANGED CONNECTIONS.
Clause 3.21 applies with the following addition:
Design strengths for flange bolting shall comply with
Clause S3.3.1.3.
For components of bolted flanged connections other than
bolting and gaskets, design strengths as listed in
Table 3.3.1 shall be used unless a detailed stress analysis
of the bolted joint is made and this analysis verifies the
acceptability of higher design strengths.
S3.22 PIPES AND TUBES. Clause 3.22 applies, with
the following addition:
Where appropriate to the type of vessel covered by this
Supplement, Clause 3.22 applies. Where minimum
AS 1210 Supp1—1990
thicknesses are determined by calculation, design
strengths from Table S3.3.1 may be used.
S3.23 JACKETED CONSTRUCTION. Clause 3.23
applies, with the following addition:
NOTE: Jacketed vessels can give rise to high local stresses due to
restrained movements of various vessel components, i.e. at jacket
closures.
In areas of high local stress concentration a detailed
stress analysis shall be required except that in simple
cases and where the temperature differential is low or
where there is good evidence of satisfactory past
experience, Clause 3.23 and design strengths given in
Table S3.3.1 may be used.
S3.24 VESSEL SUPPORTS. Clause 3.24 applies, with
the following additions and modifications:
Design strengths from Table S3.3.1 may be used.
NOTE: Clause 3.24 should adequately cover support design for most
vessels; however, in exceptional cases, e.g. very large, heavy vessels,
or operations with large temperature differentials, the designer may
be required to carry out a detailed stress analysis.
S 3.25 AT TACHE D S T RUCTURE S AND
EQUIPMENT. Clause 3.25 applies, with the following
addition:
The designer shall assess the severity of any loads
imposed by an attachment. If such loads are significant,
a detailed stress analysis shall be carried out to calculate
actual stresses.
S3.26 TRANSPORTABLE VESSELS. Clause 3.26
does not apply to this Supplement and the following
shall be substituted:
Not permitted.
SECTION S4. CONSTRUCTION
Section 4 of AS 1210 shall apply.
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AS 1210 Supp1—1990
20
SECTION S5. TESTING AND QUALIFICATIONS
Section 5 of AS 1210 shall apply, with the following
additions and modifications to particular Clauses:
S5.10 HYDROSTATIC TESTS. Clause 5.10 applies,
with the following additions and modifications to
particular Clauses:
S5.10.2.1 Single-wall vessels designed for internal
pressure. Clause 5.10.2.1 does not apply to this
Supplement and the following shall be substituted:
For single-wall vessels designed for internal pressure, the
hydrostatic test pressure Ph shall be at least that
determined by the following equation:
Ph
=
1.25
where
Ph
P
fh
=
=
=
hydrostatic test pressure, in megapascals
design pressure of vessel, in megapascals
design strength at test temperature (from
Table S3.3.1), in megapascals
=
design strength at design temperature
(from Table S3.3.1), in megapascals
f
. . . . . . . . . . . S5.10.2
The expression with the brackets of Equation S5.10.2
shall be termed the ‘equivalent design pressure’, i.e. the
design pressure of the weakest part of the vessel in the
‘new and cold’ condition. Where necessary, the
‘equivalent design pressure’ shall take into account
differences in design conditions which may be specified
for different sections of the compartment of the vessel
under test.
This test pressure shall include any static head acting
during the test on the part under consideration. All
loadings including static head which may exist during the
test and which differ from those specified for the design
conditions shall be given special consideration.
The test pressure should be as close as practicable to the
pressure determi ned i n accordance wi th
Equation S5.10.2. If higher pressures are used, either
intentionally or accidentally, the vessel may become
visibly and permanently distorted beyond the dimensional
limits specified in this Supplement, it may leak at
mechanical joints, or cracking may occur. In such cases,
the vessel is liable to rejection by the Inspector.
The test pressure shall be such that the general
membrane stress in any part of the vessel during test will
not exceed 90 percent of the specified minimum yield or
proof stress of the material at the test temperature.
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21
S5.11 PNEUMATIC TESTS. Clause 5.11 applies, with
the following additions and modifications to particular
Clauses:
S5.11.3 Test pressure. Clause 5.11.4 does not apply to
this Supplement and the following shall be substituted:
Unless otherwise approved, the test pressure shall be
1.15 times the equivalent design pressure or pressure
differential, as required by Clause S5.10.2.1,
Clause 5.10.2.2, or Clause 5.10.2.3.
S5.11.4 Application of pressure. AS 4037 applies
except where modified by the following:
The pressure shall be gradually increased to not more
than 50 percent of the required test pressure. Thereafter,
the test pressure shall be increased slowly and steadily,
pausing at increments of approximately 10 percent or
less of the final test pressure until the required test
pressure is reached. The pressure shall then be reduced
to a value equal to the equivalent design pressure and
held at this pressure for sufficient time to permit visual
inspection of the vessel.
S 5.11.5 Comb in ed h yd rostati c/ p neu mati c
test AS 4037 applies except where modified by the
following:
The liquid level is set so that the maximum stress
including the stress produced by the pneumatic pressure
at any point in the vessel (usually near the bottom or at
the support attachments) does not exceed 90 percent of
the specified minimum yield or proof stress of the
material at the test temperature.
S5.12 EXPERIMENTAL STRESS ANALYSIS.
Clause 5.12 does not apply to this Supplement and the
following shall be substituted:
S5.12.1 Application. The critical stresses in parts for
which theoretical stress analysis is inadequate or for
which design rules are not available shall be
substantiated by experimental stress analysis.
The extent of experimental stress analysis performed
shall be sufficient to determine the critical stresses for
which design values are not available. Where possible,
combined analytical and experimental methods shall be
used to distinguish between primary, secondary and local
stresses.
Where experimental stress analysis is used, the general
principles, design rules, construction, testing and
inspection requirements of this Supplement shall be
complied with.
S5.12.2 Types of test. Permissible types of test for the
determination of critical stresses are strain measurement
test and photoelastic tests. Fatigue tests may be used to
evaluate the adequacy of a part for cyclic loading.
(See Paragraph SC4, Appendix SC.)
S5.12.3 General requirements.
S5.12.3.1 Hydrostatic testing. The general requirements
for hydrostatic tests in Clause S5.10, which are relevant
shall apply.
S5.12.3.2 Prior pressure. The vessel or vessel part for
which the design or calculation pressure is to be
established shall not have been previously subjected to a
pressure greater than the equivalent design pressure. (See
Clause S5.10.2.1.)
AS 1210 Supp1—1990
S5.12.3.3 Safety. Serious consideration shall be given to
the safety of all personnel prior to the conducting of any
tests. Particular attention should be paid to the
elimination of any air pocket in the vessel.
S5.12.3.4 Witnessing of tests. Testing shall be witnessed
by an Inspector approved by the Inspecting Authority.
Test results shall be recorded.
S5.12.3.5 Duplicate vessels or vessel parts. Where the
critical stresses of a vessel or vessel part have been
substantiated by experimental stress analysis, duplicate
parts of the same materials, design and construction need
not be re-tested under Clause S5.12 but shall be given a
hydrostatic test in accordance with Clause S5.10 or a
pneumatic test in accordance with Clause S5.11. The
dimensions, including minimum thickness, of the vessel
or vessel part tested shall not vary significantly from
those actually used.
S5.12.3.6 Retests. A retest shall be allowed on a
duplicate vessel or vessel part if errors or irregularities
are obvious in the test results.
S5.12.4 Strain gauge tests.
S5.12.4.1 Strain gauges. Principal strains shall be
measured by means of a device (or combination of
devices) having an accuracy of ±7 percent and a
sensitivity of better than 5 percent. The range of the
device should be approximately three times the yield
strain of the material under test.
S5.12.4.2 Mounting of strain gauges. Strain gauges shall
be mounted on the unpressurized vessel before the test,
and after any pressure cycling.
The strain gauges shall be attached in a manner which
will assure accurate measurement of strain.
The positioning of strain gauges shall enable strains to be
measured in the direction of the maximum stress in the
most highly stressed areas. This may require the use of
a number of strain gauges which should be located on
both the inside and outside surfaces. Application of a
brittle coating may be required, by the Inspecting
Authority, to verify that the strain gauges are located in
the high stress areas.
The vessel may be cycled several times to 50 percent of
the equivalent design pressure in order to relieve initial
residual stresses.
S5.12.4.3 Application of pressure. The hydrostatic
pressure in the vessel or vessel part shall be steadily
increased until approximately 50 percent of the
equivalent design pressure is reached. Thereafter, the test
pressure shall be steadily increased, pausing at
increments of approximately 10 percent or less of the
equivalent design pressure, until the pressure required by
the test procedure is reached.
Any observations or measurement shall be made while
the pressure is maintained at a constant value.
S5.12.4.4 Strain and pressure readings. After each
increment of pressure has been applied, readings of strain
and pressure shall be taken and recorded. After any
pressure increment where there is an indication of an
increase of strain proportionately greater than the
previous increments, the pressure shall be released to
zero to permit determination of any permanent strain.
Whenever the pressure is released, any permanent strain
at each gauge shall be determined. After such readings
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AS 1210 Supp1—1990
22
have been taken, the pressure shall be reapplied as often
as necessary, as specified in Clause S5.12.4.3.
S5.12.4.5 Plotting of strain. Two curves of strain vs test
pressure shall be plotted for each gauge as the test
progresses, one showing total strain under pressure, and
the other showing total strain as the pressure is removed.
S5.12.4.6 Maximum test pressure. The test may be
discontinued when either —
(a) the test pressure reaches the value which will justify
the desired design (or calculation) pressure; or
(b) the measured strain becomes equivalent to 1.25
times the expected permissible design strain in the
vessel component under investigation (the
permissible design strain is deduced from the
appropriate stress category permitted in the vessel
component under investigation).
S5.12.4.7 Determination of actual yield (or proof) stress.
The value reported for the yield or proof stress shall be
the arithmetic mean of four separate tests carried out on
four separate test specimens cut from the vessel
following the completion of the pressure test.
The specimens shall be cut from a location where the
stress during the test has not exceeded the yield stress,
and shall be representative of the material where
maximum stress occurs.
Where excess stock from the same piece of wrought
material is available and has been given the same heat
treatment as the pressure part, the test specimens may be
cut from this excess stock.
Specimens shall not be removed by thermal-cutting or
any other method involving sufficient heat to affect the
properties of the specimen.
S5.12.4.8 Interpretation of results. In the evaluation of
stresses from strain gauge data, the calculations shall be
performed under the assumption that the material is
elastic. The elastic constants used in the evaluation of
experimental data shall be those applicable to the
material at the test temperature.
S5.12.4.9 Use of models for strain measurement. Strain
gauge data may be obtained from the actual vessel or
from a vessel model. The material of the model need not
be the same as the material of the vessel, but the
material of the model shall have an elastic modulus
which is either known or has been measured at the test
conditions. The requirements of dimensional similitude
shall be met as closely as possible.
S5.12.5 Photoelastic tests. Either two-dimensional or
three-dimensional techniques may be used provided that
the model represents the structural effects of the loading.
S5.13 LEAK TEST. Clause 5.13 applies, with the
following modifications:
S5.13.4 Preliminary leak test. Clause S5.13.4 applies
except where modified by the following:
A preliminary leak test may be applied to any vessel
without observing the requirements applying to high
pressure pneumatic testing (see Clause S5.11), provided
that the test pressure does not exceed 10 percent of the
design pressure or 35 kPa, whichever is the lesser.
S5.19 NON-DESTRUCTIVE EXAMINATION OF
FORGINGS.
S5.19.1 Type and extent. All forgings, as required by
Clause S2.8, shall be subject to ultrasonic examination
in accordance with this Clause (5.19).
S5.19.2 Ultrasonic examination procedure. The
procedure for ultrasonic examination shall be as follows:
(a) The preparation of forgings and the method and
procedure for ultrasonic examination shall comply
with AS 1065.1, or other approved Standards as
appropriate.
(b) The level of sensitivity used shall be such that the
examination is capable of detecting the artificial
defects in a reference block or specimen of a type
suitable for the particular application. The reference
specimen shall have the same nominal thickness,
composition, and steel grouping as the forging to be
examined in order to have substantially the same
structure.
(c) All conditions such as surface finish, ultrasonic
frequency, instrument settings, type of transducer,
and couplant used during calibration shall be
duplicated during the actual examination.
(d) In so far as practicable, all forgings shall be
examined by the normal beam method from two
directions approximately at right angles. Rings,
flanges, and other straight hollow forgings shall be
examined by the angle beam method from one
circumferential surface and from one face or surface
normal to the axis. Disc forgings shall be examined
from one flat side and from the circumferential
surface. Forgings requiring angle beam examination
shall be examined in the circumferential direction,
unless wall thickness or geometric configuration of
the forgings make angle beam examination
impracticable.
The entire volume of material shall be examined
ultrasonically at some stage of manufacture,
preferably after final heat treatment. If contours of
the forging preclude complete ultrasonic
examination after final heat treatment, the maximum
permissible volume shall be examined prior to final
heat treatment.
S5.19.3 Ultrasonic acceptance standards. Forgings for
use as critical vessel components, e.g. ends, shall not
have any of the following discontinuities:
(a) For normal beam method.
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(i)
One or more discontinuities which produce
indications accompanied by a complete loss of
back reflection not associated with or
attributable to the geometric configuration.
(ii)
One or more indications with amplitudes
exceeding adjacent back reflections.
23
(iii) One or more discontinuities which produce
travelling indications accompanied by reduced
back reflections. (A travelling indication is
defined as an indication which displays sweep
movement of the oscilloscope screen at
relatively constant amplitude as the transducer
is moved.)
(b) For angle beam method.
(i) One or more discontinuities which produce
indications exceeding in amplitude the
indication from the calibration notch.
(ii) Indications having an amplitude exceeding 50
percent of the calibration notch amplitude.
(iii) Clusters of indications located in a small area
of the forging with amplitude less than
50 percent of the calibration notch amplitude.
AS 1210 Supp1—1990
(A cluster of indications is defined as three or more
indications exceeding 10 percent of the standard
calibration notch amplitude and located in any volume
approximating a 50-millimetre or smaller cube.)
Forgings for use as non-critical vessel components, e.g.
baffles, supports, should comply with the requirements of
this Clause.
NOTE: Where a discontinuity is at the limiting conditions specified
in Clause S5.19.3, acceptance of that forging is subject to agreement
between the parties concerned.
S5.19.4 Interpretation of ultrasonic indication.
Additional non-destructive examination procedures or
trepanning may be employed to resolve questions of
interpretation of ultrasonic indications.
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SECTION S6. INSPECTION
Section 6 of AS 1210 shall apply.
SECTION S7. MARKING AND REPORTS
Section 7 of AS 1210 shall apply with the following modification:
S7.1 MARKING REQUIRED. Clause 7.1 shall apply with the exception that item (g) shall
be replaced by the following:
(g) The designation number (see Clause S1.12).
SECTION S8. PROTECTIVE DEVICES AND OTHER FITTINGS
Section 8 of AS 1210 shall apply.
SECTION S9. PROVISIONS FOR DESPATCH
Section 9 of AS 1210 shall apply.
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AS 1210 Supp1—1990
APPENDIX A
BASIS OF DESIGN STRENGTH (f)
(This Appendix forms an integral part of this Supplement.)
Appendix A of AS 1210 does not apply to this Supplement and the following shall be
substituted:
SA1 MATERIALS TO SAA SPECIFICATIONS.
SA1.1 Introduction. The design strengths given in Table S3.3.1 (for other than bolting) are
based on criteria given in Table SA1.1 using mechanical properties of the material as
indicated. These values do not include any allowance for casting quality factor or other
factors applicable as this is provided in the appropriate Clauses of this Supplement.
In some instances the design strength values listed in Table S3.3.1 vary from the values
derived from the above criteria. This occurs where satisfactory evidence of safe use of the
higher values has been established.
SA1.2 Materials. The basis given herein is limited to materials having adequate qualities
for plastic deformation at stress concentration points in connection with the service
temperature and the design strengths considered. This requirement should be met by all the
steels listed in Table S3.3.1.
SA2 MATERIALS TO BRITISH SPECIFICATIONS. The basis for the ‘design strength
values’ listed in BS 5500 is given in Appendix K of that Standard.
SA3 MATERIALS TO AMERICAN SPECIFICATIONS. The basis for the ‘design stress
intensity values’ listed in ANSI/ASME BPV-VIII-2 is given in Appendix 1 of that Standard.
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TABLE SA1.1
FACTORS USED FOR DETERMINING DESIGN STRENGTH VALUES
FOR MATERIALS TO SAA SPECIFICATIONS EXCLUDING BOLTING MATERIAL
(Design strength is obtained by dividing specified value by the given factor)
Material type and design
temperature
Material
verification
Specified minimum
tensile strength at room
temperature
(see Note 1)
Specified minimum yield
(or proof) stress at room
temperature
(see Notes 1 and 2)
Specified minimum yied
(or proof) stress at design
temperature
(see Notes 2 and 3)
Verified or hot tested
2.35
1.5
—
Not verified nor
hot tested
2.35
1.5
—
CARBON, CARBONMANGANESE AND LOW
ALLOY STEELS
(a)
Design temperature
≤50°C
(b)
Design temperature
>50°C and <150°C
See Note 4
—
—
—
(c)
Design temperature
≥150°C
Verified or
hot tested
2.35
—
1.5
Not verified nor
hot tested
2.35
—
1.6
Verified or
hot tested
2.5
1.5
—
Not verified nor
hot tested
2.5
1.5
—
HIGH ALLOY STEELS
(a)
Design temperature
≤50°C
(b)
Design temperature
>50°C and <150°C
See Note 4
—
—
—
(c)
Design temperature
≥150°C
Verified or
hot tested
2.5
—
1.35
Not verified
nor hot tested
2.5
—
1.45
Verified or
hot tested
3
1.5
—
Not verified
nor hot tested
3
1.5
—
NON-FERROUS METALS
AND ALLOYS
(a)
Design temperature
≤50°C
(b)
Design temperature
>50°C and <100°C
See Note 4
—
—
—
(c)
Design temperature
≥100°C
Verified or
hot tested
3
1.5
1.5
Not verified
nor hot tested
3
—
1.7
NOTES:
1.
Tested in accordance with AS 1391 or ISO 6892.
2.
Proof stress determined at—
0.2 percent offset value for ferritic steels.
1 percent offset value for austenitic steels.
3.
Tested in accordance with BS 3688:Part 1 or ISO/R 783.
4.
Strength values are based on linear interpolation between values obtained from (a) and (c).
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AS 1210 Supp1—1990
APPENDIX SB
Appendix B of AS 1210 shall apply.
APPENDIX SC
PRACTICE TO AVOID FATIGUE CRACKING
(This Appendix forms an integral part of this Supplement.)
Appendix C of AS 1210 does not apply to this Supplement and the following shall be
substituted:
SC1 ANALYSIS FOR CYCLIC OPERATION.
SC1.1 General. Unless the specified operation of the vessel meets all of the conditions of
Clauses S3.1.5.4 to S3.1.5.7, a detailed analysis for cyclic operation is required.
This Appendix gives rules for determining the suitability of a vessel or vessel component
for specified operating conditions involving cyclic application of loads or thermal conditions.
SC1.2 Allowable amplitude of alternating stresses. The conditions and procedures of
Clauses S3.1.5.4 to S3.1.5.7 and Paragraph SC2 are based on a comparison of peak stresses
with strain-cycling fatigue data. The strain-cycling fatigue data are represented by the design
fatigue strength curves of Figures SC1.2.1 and SC1.2.2. These curves show the allowable
amplitude (Sa) of the following stress component (50 percent of the alternating stress range)
plotted against the number of cycles. This stress amplitude is calculated on the assumption
of elastic behaviour, and hence, has the dimensions of stress but it does not represent a real
stress when the elastic range is exceeded. The fatigue curves are obtained from uniaxial
strain strain-cycling data in which the imposed strains have been multiplied by the elastic
modulus and a design margin has been provided, so as to make the calculated stress
intensity and amplitude and the allowable stress amplitude directly comparable. The curves
have been adjusted where necessary to include the maximum effects of mean stress, which
is the condition where the stress fluctuates about a mean value other than zero. As a
consequence of this procedure, it is essential that the requirements of this Supplement be
complied with at all times, with transient stresses included, and that the calculated value of
the alternating stress intensity be proportional to the actual strain amplitude. To evaluate the
effect of alternating stresses at varying amplitudes, a linear damage relation is assumed in
Paragraph SC2.2.5.
SC1.3 Loadings to be considered. The loadings to be considered shall include those loads
that are due to testing of the vessel where such testing is in addition to that required by this
Supplement.
SC2 DESIGN FOR CYCLIC LOADINGS.
SC2.1 Adequacy of design for cyclic loading. The ability of the vessel to withstand the
specified cyclic operation without fatigue failure shall be determined in accordance with this
Paragraph (SC2). The determination shall be made on the basis of the stresses at a point of
the vessel and the allowable stress cycles shall be adequate for the specified operation at
every point. Only the stresses due to the specified cycle of operation need be considered;
stresses produced by any load or thermal condition which does not vary during the cycle
need not be considered, since they are mean stresses and the maximum possible effect of
mean stress is included in the fatigue design curves.
SC2.2 Design procedure.
SC2.2.1 Where principal stress direction does not change. For any case in which the
directions of the principal stresses at the point being considered do not change during the
cycle, the alternating stress intensity shall be determined by the following steps:
(a) Principle stresses. Consider the values of the three principal stresses at the point versus
time for the complete stress cycle, taking into account both the gross and local
structural discontinuities and the thermal effects which vary during the cycle. These are
designated as σ1 , σ2 and σ3 for later identification.
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NOTES:
1. Rm = specified minimum tensile strength at room temperature.
2. Interpolate for Rm for 550 MPa to 790 MPa.
FIGURE SC1.2.1 DESIGN FATIGUE CURVES FOR CARBON, LOW ALLOY,
SERIES 4XX HIGH ALLOY STEELS AND HIGH TENSILE STEELS FOR
TEMPERATURES ≤375°C
FIGURE SC1.2.2 DESIGN FATIGUE CURVE FOR SERIES 3XX HIGH
ALLOY STEELS, NICKEL-CHROMIUM IRON ALLOY, NICKEL-IRON-CHROMIUM
ALLOY, AND NICKEL-COPPER ALLOY FOR TEMPERATURES ≤425°C
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AS 1210 Supp1—1990
(b) Stress differences. Determine the stress differences
S12 = σ 1 - σ2 , S23 = σ2 - σ3, S31 = σ3 - σ1
versus time for the complete cycle. In what follows, the symbol S ij is used to represent
any one of these three stress differences.
(c) Alternating stress intensity. Determine the extremes of the range through which each
stress difference, Sij fluctuates and find the absolute magnitude of this range for each
Sij. Call this magnitude Srij and let Saltij = 0.5Srij. The alternating stress intensity Salt is
the largest of the values of Saltij.
SC2.2.2 Where principal stress direction changes. For any case in which the directions of
the principal stresses at the point being considered changes during the stress cycle, it is
necessary to use the following more general procedure:
(a) Consider the values of the six stress components σ t, σl, σr, τlt, τ lr, τ rt, versus time for
the complete stress cycle, taking into account both the gross and local structural
discontinuities and the thermal effects which vary during the cycle.
(b) Choose a point in time when the conditions are one of the extremes for the cycle
(either maximum or minimum, algebraically) and identify the stress components at this
time by the subscript i. In most cases it will be possible to choose at least one time
during the cycle when the conditions are known to be extreme. In some cases it may
be necessary to try different points in time to find the one which results in the largest
value of alternating stress intensity.
(c) Subtract each of the six stress components σ ti, σli, etc from the corresponding stress
components σt, σl, etc at each point in time during the cycle and call the resulting
components σ t’, σl’, etc.
(d) At each point in time during the cycle, calculate the principal stresses σ 1’, σ2’, σ3 ’
derived from the six stress components, σt’, σl’, etc. Note that the directions of the
principal stresses may change during the cycle but each principal stress retains its
identity as it rotates.
(e) Determine the stress differences
S12′ = σ1′ – σ2′, S23′ = σ2′ – σ3 ′, S31′ = σ3 ′ – σ1′
versus time for the complete cycle and find the largest absolute magnitude of any stress
difference at any time. The alternating stress intensity S alt is 50 percent of this
magnitude.
SC2.2.3 Design fatigue curves. The applicable fatigue design curves for some of the
materials permitted by this Supplement are contained in Figures SC1.2.1 and SC1.2.2.
SC2.2.4 Use of design fatigue curves. The alternating stress intensity S alt as determined by
Paragraph SC2.2.1 and Paragraph SC2.2.2 shall be multiplied by the ratio of the modulus
of elasticity given on the design fatigue curve to the value used in the analysis. The
applicable design stress shall be entered at this value on the ordinate axis and the
corresponding number of cycles found on the axis of abscissa. If the operational cycle being
considered is the only one which produces significant fluctuating stresses, this is the
allowable number of cycles. When there are two or more types of stress cycle which
produce significant stresses, their cumulative effect shall be evaluated in accordance with
Paragraph SC2.2.5.
SC2.2.5 Cumulative damage. Cumulative damage shall be evaluated in accordance with the
following:
(a) Designate the specified number of times each type of stress cycle of types, 1, 2, 3, etc,
will be repeated during the life of the vessel as n1 , n2, n3, etc, respectively. In the
determination of n 1, n2, n3, etc, consideration shall be given to the superposition of
cycles of various origins which produce a total stress-difference range greater than the
stress-difference ranges of the individual cycles.
(b) For each type of stress cycle, determine the alternating stress intensity S alt in
accordance with the procedures of Paragraph SC2.2.1 or Paragraph SC2.2.2. Define
these quantities S alt1, Salt2, Salt3, etc.
(c) For each value, Salt1, Salt2, Salt3, etc, use the applicable design fatigue curve to determine
the maximum of repetitions N 1, N2, N3, etc, respectively which would be allowable if
this type of cycle were the only one acting.
(d) For each type of stress cycle, calculate the usage factors, U 1, U2 , U3, etc from —
U1 =
, U2 =
, etc.
(e) Calculate the cumulate usage factor U, from U = U 1 + U 2 + U 3 + .. etc.
(f) The cumulative usage factor U shall not exceed 1.0.
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SC2.2.6 Local structural discontinuities. The effects of local structural discontinuities shall
be evaluated by the use of theoretical stress concentration factors for all conditions, except
that experimentally determined fatigue strength reduction factors may be used when
determined in accordance with Paragraph SC5.
SC2.2.7 Fillet welds. Fillet welds shall not be used in vessels for joints of categories A, B,
C, and D (see Figure 3.5.1.1) except as permitted for joints of category C for slip-on flanges
and for joints of category D as permitted in Clause S3.19. Fillet welds may be used for
attachments to pressure vessels using one-half of the stress limit given in Paragraph SH2.4.3
(a) to (d), Appendix SH for primary and secondary stresses.
Evaluation for cyclic loading shall be made in accordance with Appendix SC using a fatigue
strength reduction factor of 4 and shall include consideration of temperature differences
between the vessel and the attachment and expansion or contraction of the vessel caused by
internal or external pressure.
SC3 FATIGUE ANALYSIS OF BOLTS.
SC3.1 Need for fatigue analysis. Unless the vessel on which they are installed satisfies all
the conditions of Paragraph SC1.2 and thus requires no fatigue analysis, the suitability of
bolts for cyclic operation shall be determined in accordance with this Paragraph (SC3).
SC3.2 Methods of fatigue analysis. Bolts made of materials which have specified minimum
tensile strengths of less than 686 MPa shall be evaluated for cyclic operation in accordance
with Paragraph SC2 using the applicable design fatigue curves of Figure SC1.2.1 or
Figure SC1.2.2 and an appropriate stress concentration factor.
High strength alloy steel bolts and studs may be evaluated for cyclic operation in accordance
with Paragraph SC2 using the design fatigue curve of Figure SC3.2 provided that the
following requirements are complied with:
(a) The material is within the following limits:
Chromium
0.8 percent to 1.15 percent
Nickel
1.65 percent to 2.00 percent
Molybdenum
0.20 percent to 0.65 percent
Specified yield strength
539 MPa to 981 MPa
Specified tensile strength
686 MPa to 1128 MPa
FIGURE SC3.2 DESIGN FATIGUE CURVES FOR HIGH STRENGTH STEEL
BOLTING FOR TEMPERATURES ≤375°C
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AS 1210 Supp1—1990
(b) The maximum value of the service stress at the periphery of the bolt cross-section
(resulting from direct tension plus bending and neglecting stress concentrations) shall
not exceed 2.7f if the higher of the two fatigue design curves shown in Figure SC3.2
is used or shall not exceed 3f if the lower of the two curves is used. In both cases the
actual direct tension stress (averaged across the bolt cross-section) produced by the
combination of preload, pressure, and differential thermal expansion, but neglecting
stress concentrations, shall not exceed 2f.
(c) Threads shall be of ‘V’ type, having a minimum thread root radius not less than
0.075 mm.
(d) Fillet radii at the end of the shank shall be such that the ratio of fillet radius to shank
diameter is not less than 0.060.
Unless it can be shown by analysis or test that a lower value is appropriate, the fatigue
strength reduction factor used in the fatigue evaluation of threaded members shall be not
less than 4.0.
S3.3 Cumulative damage. The bolts shall be acceptable for the specified cyclic application
of loads and thermal stresses provided that the cumulative usage factor U as determined in
accordance with Paragraph SC2.2.5 does not exceed 1.0.
SC4 FATIGUE TEST FOR CYCLIC OPERATION.
SC4.1 Basic assumption. The general procedure in fatigue evaluation is based on the use
of strain controlled fatigue data. The resulting fatigue design curve is a composite curve. In
the low cycle range the stress amplitude is primarily a function of the true fracture strain
multiplied by the elastic modulus. In the high cycle range the stress amplitude is, as a matter
of convenience, made equal to the endurance limit.
This method should result in families of curves rather than the curves in Figures SC1.2.1
and SC1.2.2 which are based on a large number of tests carried out on steels having diverse
material properties. However, owing to the very wide scatter of test points it was found that
only a lower limit curve could be justified.
The method, therefore, discriminates against a number of steels, particularly against those
in the high strength range. To permit a better evaluation of the fatigue strength of such
materials, or where it is desired to use higher peak stresses than can be justified by the
methods of the previous rules, the adequacy of a part to withstand cyclic loading may be
demonstrated by means of a fatigue test. However, the fatigue test shall not be used as
justification for exceeding the allowable values of primary or primary-plus-secondary
stresses.
SC4.2 Testing of component. The test component or that portion to be tested shall be
constructed of material having the same composition as the vessel component and shall be
subjected to the same mechanical working and heat treatment so as to produce mechanical
properties equivalent to those of the material in the prototype component. Geometrical
similarity must be maintained, at least in those portions whose ability to withstand cyclic
loading is being investigated and in those adjacent areas which affect the stresses in the
portion under test.
The test component or portion thereof shall withstand the number of cycles as specified
below without failure. Failure is defined herein as a propagation of a crack through the
entire thickness, such as would produce a measurable leak in a pressure-retaining member.
The minimum number of cycles (hereinafter referred to as ‘test cycles’) which the
component must withstand, and the magnitude of the loading (hereinafter referred to as ‘the
test loading’) to be applied to the component during the test, shall be determined by
multiplying the design service cycles by a specified factor K n′, and the design service loads
by Ks′. Values of these factors shall be determined from a composite fatigue curve
constructed in accordance with Paragraph SC4.3.
SC4.3 Construction of test fatigue curve. The fatigue test curve is drawn from the
applicable original fatigue curve. It is less conservative than the original curve in order to
compensate for the higher allowable stresses.
(a) Construct the test fatigue curve by multiplying the values of S a of the original curve
by the factor K s and draw a new fatigue curve Sas through these points, as shown in
Figure SC4.3. Next, construct a second fatigue curve by multiplying the values of N
in the original curve by Kn and draw a second fatigue curve San through these points,
as shown in Figure SC4.3. The test fatigue curve S a′ is constructed using the higher
segments of S as and San, as shown in Figure SC4.3. (See Paragraph SC4.3 (c) for
notation.)
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(b) Assume the service condition for the prototype vessel to be S a and N, defined by point
A on the original curve. Project point A vertically and horizontally to points D and C
on the test curves Sa′. The segment of Sa′ between the two points C and D embraces
all allowable combinations of K s′ and Kn′. The values for a point B determines the
following corresponding values of K s′ and Kn′:
Ks ′ =
Kn′ =
Test loading Pt = K s′ × design service loading
Test cycles N n = K n′ × design service cycles
The designer therefore has available a choice of test cycling conditions ranging from —
Point D,
where Ks′ = ordinate A; Kn′ = 1, signifying a maximum increase of load amplitude
and no change in number of cycles,
to —
Point C,
where Ks′
= 1; Kn′ = abscissa D/abscissa A, signifying an increase of number of
cycles and no change of load amplitude, when compared with the
fatigue design requirements of the prototype vessel.
(c) The values of K s and K n are the multiples of factors which account for the effects of
size, surface finish, cyclic rate, temperature, and the number of replicate tests
performed. They shall be determined as follows:
Ksl × K sf × K ss but shall never be allowed to be less than 1.25
Ks =
K
=
Ks4.3 but shall never be allowed to be less than 2.6
Ksl
=
factor for the effect of size on fatigue life = 1.5 – 0.5 (LM/LP), where
LM/LP is the ratio of linear model size to prototype size
FIGURE SC4.3 CONSTRUCTION OF TEST FATIGUE CURVE
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Ksf
=
Kss
=
=
AS 1210 Supp1—1990
factor for the effect of surface finish = 1.75 - 0.175 (SFM/SFP)
where (SFM/SFP) is the ratio of the model surface finish to the prototype
surface finish expressed in arithmetic average
factor for the statistical variation in test results
1.220 - 0.44 × number of replicate tests
No value of Ksl, K sf or Kss less than 1.0 may be used in the calculation of K s.
(d) Additional K-factors can be found in technical literature, covering other conditions. The
designer will also be faced with conditions for which data are not available, in which
case the K-factors must be developed from tests in accordance with Paragraph SC5.
SC5 DETERMINATION OF FATIGUE STRENGTH REDUCTION FACTORS. The
following criteria are applicable in the determination of fatigue strength reduction factors:
(a) A reduction in fatigue strength of a component may be due to the presence of a notch,
a ‘notch’ for the purpose of this Supplement being an actual notch or an abrupt change
in cross-section, or a transition section of differing curvatures, or attachments for
supports, or penetrations into shells, e.g. drill holes and welded nozzles with varying
diameters and corner radii.
(b) The fatigue strength reduction factor shall be determined by tests on ‘notched’ and
‘unnotched’ specimens and calculated as the ratio of the ‘unnotched’ stress to the
‘notched’ stress for failure or other equivalent methods.
(c) The test part shall be fabricated from the same material and shall be subjected to the
same heat treatment as the component.
(d) The stress level in the specimen shall not exceed the limit given in
Paragraph SH2.4.3(d), Appendix SH, and shall be such that failure does not occur in
less than 1000 cycles.
(e) The configuration, surface finish, and stress state of the specimen shall closely simulate
those expected in the components. In particular, the stress gradient shall not be more
abrupt than expected in the component.
(f) The cyclic rate shall be such that appreciable heating of the specimen does not occur,
nor shall it exceed 100 Hz.
SC6 CYCLIC THERMAL STRESSES. The following requirements are applicable to
cyclic thermal stress conditions:
(a) Pressure vessels which operate at elevated or subzero temperature should be heated or
cooled slowly, and should be efficiently lagged to minimize temperature gradients in
the shells. Rapid changes of shell temperature should be avoided during service.
(b) The vessels should be able to expand and contract without undue restraint.
(c) Provided that the conditions in (a) and (b) above and those of Paragraph SC3 are
observed, estimates of thermal stresses due to temperature changes need not be
specially considered.
(d) The use of pad-type reinforcement or partial penetration joints is not suitable for cases
where there are significant temperature gradients, especially where these are of a
fluctuating nature.
SC7 FORCED VIBRATIONS. Pulsations of pressure, wind-excited vibrations or vibrations
transmitted from plant, e.g. rotating or reciprocating machinery, may cause vibrations of
piping or local resonance of the shell of a pressure vessel. In most cases these cannot be
anticipated at the design stage. It is therefore advisable to make an examination of plant
following initial start-up. If such vibration occurs and is considered to be excessive, the
source of the vibration should be isolated, by stiffening, additional support or damping
which should be introduced at a location local to the vibration.
SC8 CORROSION FATIGUE. Corrosion conditions are detrimental to the endurance of
carbon steels, carbon-manganese steels, and ferritic alloy steels. Fatigue cracks may occur
under such conditions at low levels of fluctuation of applied stress. Since the tensile strength
of a steel has little or no effect upon the fatigue strength under corrosive conditions, the use
of high strength steels in severe corrosion fatigue service will offer no advantage unless the
surface is effectively protected from the corrosive medium. Where corrosion fatigue is
expected, it is desirable to minimize the range of cyclic stresses and carry out inspection at
sufficiently frequent intervals to establish the pattern of behaviour.
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APPENDIX SD
RECOMMENDED CORROSION PREVENTION PRACTICE
Appendix D of AS 1210 applies.
APPENDIX SE
INFORMATION TO BE SUPPLIED BY THE PURCHASER
TO THE MANUFACTURER
Appendix E of AS 1210 applies, with the following addition:
It is the purchaser’s responsibility to specify or cause to be specified (see Clause S3.1.2) the
following:
(a) Information in sufficient detail that the need for a fatigue analysis can be determined
and that any required analysis can be carried out.
(b) Whether or not a corrosion (and erosion) allowance is required, and if so the amount.
(c) Whether or not the vessel will contain lethal material (see Clause 1.7.1).
APPENDIX SF
INFORMATION TO BE SUPPLIED BY THE MANUFACTURER
Appendix F of AS 1210 applies.
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AS 1210 Supp1—1990
APPENDIX SH
DESIGN REQUIREMENTS FOR LOADINGS AND COMPONENTS
NOT COVERED BY SECTION 3
(This Appendix forms an integral part of this Supplement.)
Appendix H of AS 1210 does not apply to this Supplement and the following shall be
substituted:
SH1 GENERAL. This Appendix specifies design criteria for stress systems resulting from
the application of loads or the use of components of types not covered explicitly by
Section S3.
The intention is to ensure that the design basis for these components and loadings shall be
consistent with that underlying the specific requirements given in Section S3.
Formal analysis in accordance with this Appendix is required only in the case of significant
additional loadings, or for components significantly different from those dealt with in
Section S3. Relevant experience of similar designs may be considered in deciding whether
an analysis is required.
SH2 NON-CREEP CONDITIONS.
SH2.1 Design criteria. For design temperatures at which the nominal design strength is
governed by one of the two short-term mechanical properties R e(T) and R m, the following
design criteria shall be applied:
(a) Gross plastic deformation. There should be the same theoretical margin against gross
plastic deformation for all design details as that provided against gross plastic
deformation in major membrane areas. For this purpose, the required margin against
gross plastic deformation may be assumed to be R e(T)/f for materials covered in
Table S3.3.1. For other materials the value of the nearest equivalent material in
Table S3.3.1 should be assumed.
(b) Incremental collapse. The stress systems imposed shall shakedown to elastic action
within the first few operating cycles. The operating loads to be considered include
pressure and simultaneous loadings of types listed in Clause S3.2.3 including thermal
stresses.
(c) Buckling. For components or loadings associated with substantial compressive stresses,
buckling shall not occur under a combined load less than twice the design combined
load, at design temperature*. The design is to include pressure and simultaneous
loadings of types given in Clause S3.2.3.
The design shall also take into consideration all permissible fabrication imperfections.
(d) Fatigue. The need, or otherwise, for a fatigue analysis shall be determined in
accordance with Clauses S3.1.5.4 to S3.1.5.7.
SH2.2 Design acceptability. The results of experimental or theoretical investigations shall
be employed to demonstrate the conformity of a design with the criteria of Paragraph SH2.1.
Local stresses in the vicinity of attachments, supports, etc, may be deemed acceptable if
they comply with the requirements of Paragraph SH2.3.
In the establishing of compliance with Paragraph SH2.1(a), investigations should take
account of plastic behaviour. If the theory of plastic limit analysis is employed, the limit
load may be taken as the load that produces gross plastic deformation, although this may
be a conservative estimate. Where it is impracticable to perform a plastic analysis, an elastic
analysis may be employed as detailed in Paragraph SH3.4; alternatively, strain
measurements may be made on the actual vessel during pressure and load tests.
In the establishing of compliance with Paragraph SH2.1(b), a shake-down analysis should
preferably be performed; alternatively, an elastic analysis may be employed as detailed in
Paragraph SH2.3.
SH2.3 Specific criteria for local stresses in vicinity of attachments, supports, etc.
Elastically calculated stresses due to local loads at attachments, supports, etc, may be
deemed acceptable provided that —
(a) they occur in areas at a distance not less than 2.5 (Rt) from shell discontinuities and
have a dimension in the circumferential direction not greater than one-third of the shell
circumference;
* Care is to be taken under test conditi ons to avoid buckling.
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(b) the direct stress intensity under relevant conditions of local loading does not exceed f
or 1.2f as permitted in Table S3.1.5; and
(c) the stress intensity due to the sum of direct and bending stresses does not exceed 2f.
For nozzles and openings such stresses may be deemed acceptable provided that —
(i) a nozzle or opening is not less than 2.5 (Rt) from other shell discontinuities;
(ii) the nozzle or opening is reinforced in accordance with Clause 3.19; and
(iii) the maximum surface stress calculated for the gross structural discontinuity does not
exceed 2.25f.
Where significant compressive stresses are present, the possibility of buckling should be
investigated and the design modified if necessary (see Paragraph SH2.1(c)).
In cases where external load is highly localized, an acceptable procedure should be to limit
the algebraic sum of all stresses acting at the point to 0.9 of the specified minimum yield
stress of the material.
Where only shear stress is present, it should not exceed 0.5f.
The maximum permissible bearing stresses should not exceed 1.5f.
SH2.4 Specific criteria for general application.
SH2.4.1 General. Paragraphs SH2.4.2 to SH2.4.5 provide the criteria for acceptability of
design on the basis of elastic stress analysis. The analysis should take account of gross
structural discontinuities, e.g. nozzles, changes in shell curvature, but not of local stress
concentrations due to changes in profile such as fillet welds.
The rules require the calculated stresses to be grouped in five stress categories (see
Paragraph SH2.4.3) and appropriate stress intensities f m, fL, fb, fg , and fp to be determined
from the principal stresses f 1, f2, and f3 in each category, in accordance with the maximum
shear theory of failure. Appropriate stress limits are given for the stress intensity so
calculated.
SH2.4.2 Terms relating to stress analysis. Terms used in this Appendix relating to stress
analysis are defined as follows:
(a) Stress intensity — twice the maximum shear stress. In other words, the stress intensity
is the difference between the algebraically largest principal stress and the algebraically
smallest principal stress at a given point. Tension stresses are considered positive and
compression stresses are considered negative.
(b) Gross structural discontinuity — a source of stress or strain intensification which
affects a relatively large portion of a vessel and which has a significant effect on the
overall stress or strain pattern or has a significant effect on the vessel as a whole.
Examples of gross structural discontinuities are head-to-shell and flange-to-shell
junctions, nozzles and junctions between shells of different diameters or thicknesses.
(c) Local structural discontinuity — source of stress or strain intensification which affects
a relatively small volume of material but which does not have a significant effect on
the overall stress or strain pattern or on the structure as a whole.
Examples of local structural discontinuities are small fillet radii, small attachments and
partial penetration welds.
(d) Normal stress — the component of stress normal to the plane of reference. (This is
also referred to as ‘direct stress’.)
Usually the distribution of normal stress is not uniform through the thickness of a part,
so this stress is considered to be made up in turn of two components, one of which is
uniformly distributed and equal to the average value of stress across the thickness of
the section under consideration and the other of which varies with the location across
the thickness.
(e) Shear stress — the components of stress tangent to the plane of reference.
(f) Membrane stress — the component of normal stress which is uniformly distributed and
equal to the average value of stress across the thickness of the section under
consideration.
(g) Primary stress — a stress produced by mechanical loadings only and which is so
distributed in the structure that no redistribution of load occurs as a result of yielding.
It is a normal stress or a shear stress developed by the imposed loading which is
necessary to satisfy the simple laws of equilibrium of external and internal forces and
moments. Primary stresses that considerably exceed the yield stress will result in
failure, or at least in gross distortion. A thermal stress is not classified as a primary
stress. Primary stress is divided into ‘general’ and ‘local’ categories. The local primary
stress is defined in (h) below.
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Examples of general primary stresses are —
(i) the stress in a circular, cylindrical or spherical shell due to internal pressure or
to distributed live loads; and
(ii) bending stress in the central portion of a flat head due to pressure.
(h) Local primary stress — cases arise in which a membrane stress produced by pressure
or other mechanical loading and associated with a primary or a discontinuity effect or
both, produces excessive distortion in the transfer of load to other portions of the
structure. Conservatism requires that such a stress be classified as a local primary
membrane stress even though it has some characteristics of a secondary stress. A
stressed region may be considered as local if the distance over which the stress
intensity exceeds 1.1f does not extend in the meridional direction more than 0.5 (Rt)
and if it is not closer in the meridional direction than 2.5 (Rt) to another region where
the limits of general primary membrane stress are exceeded. (R is the distance
measured along the perpendicular to the surface from the axis of revolution of the
vessel to the midsurface of the vessel; t is the wall thickness at the location where the
general primary membrane stress limit is exceeded.)
An example of a primary local stress is the membrane stress in a shell produced by
external load and moment at permanent support or at a nozzle connection.
(i) Secondary stress — a normal stress or a shear stress developed by the constraint of
adjacent parts or by self-constraint of a structure. The basic characteristic of a
secondary stress is that it is self-limiting. Local yielding and minor distortions can
satisfy the conditions which cause the stress to occur, and failure from one application
of the stress is not to be expected.
An example of secondary stress is bending stress at a gross structural discontinuity.
(j) Peak stress — the basic characteristic of a peak stress is that it does not cause any
noticeable distortion and is objectionable only as a possible source of a fatigue crack
or a brittle fracture. A stress which is not highly localized falls into this category if it
is of a type which cannot cause noticeable distortion.
Examples of peak stress are —
(i) the thermal stress in the austenitic steel cladding of a carbon steel vessel;
(ii) the surface stresses in the wall of a vessel or pipe produced by thermal shock;
and
(iii) the stress at a local structural discontinuity.
SH2.4.3 Stress categories and stress limits. A calculated stress depending upon the type of
loading or the distribution of such stress will fall within one of the five basic stress
categories defined below. For each category, a stress intensity value is derived for a specific
condition of design. This stress intensity, to satisfy the analysis, should fall within the limit
specified in each category. The limits are summarized in Figure SH2.4.3.
(a) General primary membrane stress category — the stresses falling within this category
are those defined as general primary stresses in Paragraph SH2.4.2(g) and are produced
by pressure and mechanical loads, but exclude all secondary and peak stresses. The
value of the membrane stress intensity is obtained by averaging these stresses across
the thickness of the section under consideration. The limiting value of this stress
intensity (f m) is kf, using values of k as permitted in Table S3.1.5.
(b) Local primary membrane stress category — the stresses falling within this category are
those defined in Paragraph SH2.4.2(h) and are produced by pressure and mechanical
loads, but exclude all thermal and peak stresses. The stress intensity (f L) is the average
value of these stresses across the thickness of the section under consideration and is
limited to 1.5kf.
(c) General or local primary membrane plus primary bending stress category — the
stresses falling within this category are those defined in Paragraph SH2.4.2(g), but the
stress intensity value [(f b), (fm + fb), or (fL + fb)] is the highest value of those stresses
acting across the section under consideration excluding secondary and peak stresses.
fb is the primary bending stress intensity, which means the component of primary stress
proportional to the distance from the centroid of the solid section. The stress intensity
[(fb), (fm + fb ), or (fL + f b)] is limited to 1.5kf.
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(d) Primary plus secondary stress category — the stresses falling within this category are
those defined in Paragraph SH2.4.2(g) plus those of Paragraph SH2.4.2(j) produced by
pressure, mechanical loads and general thermal effects. The effects of gross structural
discontinuities but not of local structural discontinuities (stress concentrations) should
be included. The stress intensity value [(f m + fb + f g) or (fL + fb + fg)] is the highest
value of these stresses acting across the section under consideration and is to be limited
to 3.0kf (see also Note 1 of Figure SH2.4.3).
(e) Peak stress category — the stresses falling within this category are a combination of
all primary, secondary and peak stresses produced by specified operating pressures and
mechanical loads and by general and local thermal effects, including the effects of
gross and local structural discontinuities. The stress intensity is the highest value of
these stresses acting at any point across the thickness of the section under
consideration. The allowable value of this stress intensity is dependent on the range of
the stress difference from which it is derived and on the number of times it is to be
applied. The stress intensity is to be compared with the allowable value obtained by
the methods of analysis for cyclic operation when fatigue analysis is required according
to Appendix SC.
Figure SH2.4.3 and Table SH2.4.3 have been included to guide the designer in
establishing stress categories for some typical cases and stress intensity limits for
combinations of stress categories. There will be instances when reference to definitions
of stresses will be necessary to classify a specific stress condition to a stress category.
Item (f) below explains the reason for separating them into two categories ‘general’ and
‘secondary’.
(f) Thermal stress — a self-balancing stress produced by a non-uniform distribution of
temperature or by differing thermal coefficients of expansion. Thermal stress is
developed in a solid body whenever a volume of material is prevented from assuming
the size and shape that it normally should under a change in temperature.
For the purpose of establishing allowable stresses, two types of thermal stress are
recognized, depending on the volume or area in which distortion takes place, as
follows:
(i) General thermal stress is associated with distortion of the structure in which it
occurs. If a stress of this type, neglecting stress concentrations, exceeds twice the
yield strength of the material, the elastic analysis may be invalid and successive
thermal cycles may produce incremental distortion. Therefore, this type is
classified as secondary stress in Table SH2.4.3 and Figure SH2.4.3.
Examples of general thermal stress are —
(A)
stress produced by an axial thermal gradient in a cylindrical shell; and
(B)
stress produced by the temperature difference between a nozzle and the
shell to which it is attached.
(ii) Local thermal stress which is associated with almost complete suppression of the
differential expansion and thus produces no significant distortion. Such stresses
shall be considered only from the fatigue standpoint and are therefore classified
as peak stresses in Table SH2.4.3 and Figure SH2.4.3.
Examples of local thermal stress are —
(A)
the stress in a small hot spot in a vessel wall;
(B)
stress from a radial temperature gradient in a cylindrical shell; and
(C)
the thermal stress in a cladding material which has a coefficient of
expansion different from that of the base metal.
SH2.4.4 Value of Poisson ratio. The value of Poisson ratio shall be determined as follows:
(a) In the evaluation of stresses for comparison with any stress limits other than those
allowable under fatigue conditions, stresses shall be calculated on an elastic basis using
the elastic value of Poisson ratio.
(b) In the evaluation of stresses for comparison with the allowable stress limits associated
with fatigue conditions, the elastic equations shall be used, except that the numerical
value substituted for Poisson ratio should be determined from the following equation:
ν = 0.5 - 0.2
≥ 0.3
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where
fy
= yield strength of the material at the mean value of the temperature of
the cycle
Sa
= value obtained from the applicable design fatigue curve (Appendix
SC, Figures SC1.2.1 and SC1.2.2) for the specific number of cycles
of the condition being considered
SH2.4.5 Triaxial stresses. The algebraic sum of the three principal stresses (σ 1 + σ2 + σ3 )
in any category shall not exceed 3.75f.
SH3 CREEP CONDITIONS. Comprehensive design criteria for components in the creep
range are not yet available. In the meantime, the requirements of Section 3 may be used.
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TABLE SH2.4.3
CLASSIFICATION OF STRESSES FOR SOME TYPICAL CASES
Vessel component
Cylindrical or spherical
shell
Any shell or end
Dished end or conical end
Flat end
Perforated end or shell
Nozzle
Location
Shell plate remote from
discontinuities
Origin of stress
Type of stress
Classification
Internal pressure
General membrane gradient
through plate thickness
fm
Axial thermal gradient
Membrane
Bending
fg
fg
Junction with head or
flange
Internal pressure
Membrane
Bending
fL
fg
Any section across entire
vessel
External load or moment,
or internal pressure
General membrane averaged
across full section. Stress
component perpendicular to
cross-section
fm
External load or moment
Bending across full section.
Stress component perpendicular
to cross-section
fm
Near nozzle or other
opening
External load or moment,
or internal pressure
Local membrane
Bending
Peak (fillet or corner)
fL
fg
fp
Any location
Temperature difference
between shell and head
Membrane
Bending
fg
fg
Crown
Internal pressure
Membrane
Bending
fm
fb
Knuckle or junction to shell
Internal pressure
Membrane
Bending
fL*
fg
Centre region
Internal pressure
Membrane
Bending
fm
fb
Junction to shell
Internal pressure
Membrane
Bending
fL
fg
Typical ligament in a
uniform pattern
Pressure
Membrane averaged through
cross-section
Bending (averaged through width
of ligament, but gradient through
plate)
Peak
fm
fb
fp
Isolated or typical ligament
Pressure
Membrane
Bending
Peak
fg
fp
fp
Cross-section perpendicular
to nozzle axis
Internal pressure or external
load or moment
General membrane (averaged
across full section). Stress
component perpendicular to
section
fm
External load or moment
Bending across nozzle section
fm
Internal pressure
General membrane
Local membrane
Bending
Peak
fm
fL
fg
fp
Differential expansion
Membrane
Bending
Peak
fg
fg
fp
Nozzle wall
Cladding
Any
Differential expansion
Membrane
Bending
fp
fp
Any
Any
Thermal gradient through
plate thickness
Bending
fp†
Any
Any
Stress concentration (notch
effect)
fp
* Consideration should also be given to the possibility of buckling and excessive deformation in vessels with large diameter/thickness ratio.
† Consider possibility of thermal stress ratchet.
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NOTES:
1.
This limitation applies to the range of stress intensity. Where the secondary stress is due to a temperature excursion at the point at which the
stresses are being analysed, the value of f is to be taken as the average of the f-values for the highest and the lowest temperature of the metal
during the transient. Where part or all of the secondary stress is due to mechanical load, the value of f is to be taken as the f-value for the
highest temperature of the metal during the transient.
2.
The stresses in category fg are those parts of the total stress which are produced by thermal gradients, structural discontinuities, etc, and do not
include primary stresses which may also exist at the same point. It should be noted however, that a detailed stress analysis frequently gives the
combination of primary and secondary stresses directly and, when appropriated, this calculated value represents the total of fm (or fL) + fb + fg
and not fg alone. Similarly, if the stress in category fp is produced by a stress concentration, the quantity p is the additional stress produced by
the notch, over and above nominal stress. For example, if a plate has a nominal stress intensity f1 and has a notch with a stress concentration
factor K, then fm = f1, fb = 0, fp = fm(K – 1) and the peak stress intensity equals fm + fm (K – 1) = Kfm.
3.
S a is obtained from the fatigue curves (Appendix SC, Figures SC1.2.1 and SC1.2.2). The allowable stress intensity for the dull range of
fluctuation is 2Sa .
4.
The symbols fm, fL, fb, fg and fp do not represent single quantities, but rather six quantities representing the six stress components, σt, σ l, σ r, τ t,
τ lr and τrt.
5.
The factor k is obtained from Table S3.1.5.
FIGURE SH2.4.3 STRESS CATEGORIES AND LIMITS OF STRESS INTENSITY
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APPENDIX SK
LOW TEMPERATURE VESSELS
Appendix K of AS 1210 applies.
APPENDIX SR
LIST OF REFERENCED DOCUMENTS
Appendix R of AS 1210 applies.
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