CEN/TR 13445-102:2015

Unfired pressure vessels - Part 102: Example of application of vertical vessel with bracket supports

This Technical Report details the design, manufacturing, inspection and testing of a steel vessel submitted to pressure cycles, using the EN 13445 series for "Unfired pressure vessels", to guide the user of these standards in sequential decision making, together with some alternative choices.

Unbefeuerte Druckbehälter - Beispiel 2: Stehende Behälter mit Tragpratzen

Récipients sous pression non soumis à la flamme - Partie 102: Exemple d'application d'un récipient vertical avec supports de berceaux

Le présent Rapport technique du CEN détaille la conception, la fabrication, l’inspection et les essais d'un récipient en acier soumis à des cycles de pression, en utilisant la série EN 13445 pour les « Récipients sous pression non soumis à la flamme » afin de guider l’utilisateur de ces normes dans le processus décisionnel séquentiel, ainsi que certains choix alternatifs.

Neogrevane (nekurjene) tlačne posode - 102. del: Primer uporabe pokončne posode s konzolnimi podporami

General Information

• Status: Published
• Publication Date: 12-May-2015
• ICS: 23.020.30 - Pressure vessels, gas cylinders
• Technical Committee: CEN/TC 54 - Unfired pressure vessels
• Drafting Committee: CEN/TC 54 - Unfired pressure vessels
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 13-May-2015
• Due Date: 07-May-2016
• Completion Date: 13-May-2015
• Ref Project: SIST-TP CEN/TR 13445-102:2015 - Unfired pressure vessels - Part 102: Example of application of vertical vessel with bracket supports

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CEN/TR 13445-102:2015
01-julij-2015
1HRJUHYDQHQHNXUMHQHWODþQHSRVRGHGHO3ULPHUXSRUDEHSRNRQþQH
SRVRGHVNRQ]ROQLPLSRGSRUDPL

Unfired pressure vessels - Part 102: Example of application of vertical vessel with

bracket supports

Unbefeuerte Druckbehälter - Teil 102: Beispiel 2: Stehende Behälter mit Tragpratzen

Récipients sous pression non soumis à la flamme - Partie 102: Exemple d'application

d'un récipient vertical avec supports de berceaux
Ta slovenski standard je istoveten z: CEN/TR 13445-102:2015
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
SIST-TP CEN/TR 13445-102:2015 en,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 13445-102:2015
TECHNICAL REPORT
CEN/TR 13445-102
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2015
ICS 23.020.30
English Version
Unfired pressure vessels - Part 102: Example of application of
vertical vessel with bracket supports
Unbefeuerte Druckbehälter - Beispiel 2: Stehende Behälter
mit Tragpratzen

This Technical Report was approved by CEN on 10 February 2015. It has been drawn up by the Technical Committee CEN/TC 54.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 13445-102:2015 E

worldwide for CEN national Members.
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Contents Page

Foreword ..............................................................................................................................................................3

Introduction .........................................................................................................................................................4

3.1 Drawing of the vessel ............................................................................................................................5

3.2 Calculation model ..................................................................................................................................6

3.3 Operating conditions .............................................................................................................................7

3.4 Comments on the operating conditions provided by the User .........................................................7

4.1 General ....................................................................................................................................................8

4.2 Is EN13445 applicable to the vessel? ..................................................................................................8

4.3 Warning of Annex A of reference [1] ...................................................................................................8

4.4 Prerequisites of Annex A of reference [1] ...........................................................................................8

5.1 Permitted materials............................................................................................................................. 10

5.2 Requirements given in 4.2 of reference [2] ...................................................................................... 11

5.3 Requirements given in 4.3 of reference [2] ...................................................................................... 11

5.4 Requirements given in 4.4 of reference [2] ...................................................................................... 11

5.5 Materials selected for the vessel example 2 .................................................................................... 12

6.1 General ................................................................................................................................................. 15

6.2 Basic design ........................................................................................................................................ 15

6.3 Fatigue calculations ........................................................................................................................... 15

6.4 Determination of test pressures of the vessel in Annex C ............................................................. 17

6.5 Determination of the deformation according to EN 13445-4 reference [4], Clause 9 in

Annex C ............................................................................................................................................... 19

6.6 Data used in example 2 ...................................................................................................................... 19

6.7 Conditions of applicability of calculations ...................................................................................... 20

7.1 General ................................................................................................................................................. 20

7.2 Material traceability ............................................................................................................................ 20

7.3 Manufacturing tolerances .................................................................................................................. 20

7.5 Welding, as in 8 of reference [4] ........................................................................................................ 26

7.6 Manufacture and testing of welds – Production test, as in 8 of reference [4] .............................. 26

7.7 Forming of pressure parts, as in 9 of reference [4] ......................................................................... 27

7.8 Post weld heat treatment (PWHT), as in 10 of reference [4] ........................................................... 27

8.1 Generality ............................................................................................................................................ 27

8.2 Non destructive testing, as in 4.3 of reference [5] .......................................................................... 27

8.3 Determination of extent of non-destructive testing, as in 6.6.2 of reference [5] .......................... 28

Annex A (informative) Drawing of example 2 .............................................................................................. 29

Annex B (informative) Nameplate of example 2 .......................................................................................... 30

Annex C (informative) Design calculation of example 2............................................................................. 31

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Foreword

This document (CEN/TR 13445-102:2015) has been prepared by Technical Committee CEN/TC 54 “Unfired

pressure vessels”, the secretariat of which is held by BSI.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

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Introduction

Harmonized standards under Pressure Equipment Directive (97/23/EC) have been adopted over the past few

years on the basis of mandate M 071. These standards give appropriate solutions for designing and building

safe pressure equipment complying with the pressure equipment directives.

Although the main standards for the major product groups are now available, further action is needed to

ensure a take-up by industry of these standards.

A recent public consultation on the use of EN Standards in the field of pressure equipment has shown that

better knowledge of content and better usability are the more substantial aspects to encourage the use of the

harmonized European standards (document CEN/PE/AN N 220).

The Pressure equipment Migration Help Desk, EN 13445/MHD, was created in August 2002 to give to the

standard users a central point where raising questions and obtaining authorized answers. From the questions

it received, the help desk has identified the publication of examples of application as a key issue and has

developed rules of procedure for their publication as CEN deliverables (document CEN/PE/AN N 128).

Examples of application is an efficient way to help the standard user to correctly understand and apply the

requirements of the standard and to be aware of the permissible deviations, possible alternatives, use of

normative reference documents, etc. It can also assist training organization and software developers.

The project, in its efforts to broaden the application of the European Standards harmonized for PED, will

support the actions of the European Commission in the field of safety of pressure equipment.

It will also promote the use of these European Standards on the global market.
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1 Scope

This Technical Report details the design, manufacturing, inspection and testing of a steel vessel submitted to

pressure cycles, using the EN 13445 series for "Unfired pressure vessels", to guide the user of these

standards in sequential decision making, together with some alternative choices.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated references,

the latest edition of the referenced document (including any amendments) applies.

EN 13445-1:2009_Issue 5, Unfired pressure vessels – Part 1: General [1]
EN 13445-2:2009_Issue 5, Unfired pressure vessels – Part 2: Materials [2]
EN 13445-3:2009_Issue 5, Unfired pressure vessels – Part 3: Design [3]
EN 13445-4:2009_Issue 5, Unfired pressure vessels – Part 4: Fabrication [4]

EN 13445-5:2009_Issue 5, Unfired pressure vessels – Part 5: Inspection and testing [5]

EN 10028-2:2003, Flat products made of steels for pressure purposes – Part 2: Non-alloy and alloy steels with

specified elevated temperature properties [6]
3 The vessel and its operating conditions
3.1 Drawing of the vessel

The technical drawing of the vessel and vessel details is represented in Annex A:

A note in the introduction of EN 13445-1, clearly says that "In EN 13445 the term pressure vessel includes the

welded attachments up to and including the nozzle flanges, screwed or welded connections".

The briefed lay-out is given as in Figure 1.
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Figure 1 — Briefed lay-out
3.2 Calculation model
The calculation model is presented in 3D in Figure 2.
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Figure 2 — Calculation model
3.3 Operating conditions
The general characteristics given by the user are reproduced below:
a) content: gas group 1, density of 0,48;
b) internal pressure: 18 bar / 0,5 bar;
c) temperature: 20 °C/260 °C;
d) number of expected full pressure cycles: 1200.
3.4 Comments on the operating conditions provided by the User

The gas group 1 is a dangerous fluid according to Council Directive 67/548/EEC of 27 June 1967 on the

approximation of the laws, regulations and administrative provisions relating to the classification, packaging

and labelling of dangerous substances.
See also:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31967L0548:en:NOT
and further information on

https://osha.europa.eu/nl/legislation/directives/exposure-to-chemical-agents-and-chemical-safety/osh-related-

aspects/58

In the contract 1 200 pressure cycles from 18 bar (1,8 MPa) to 0,5 bar (0,05 MPa) are expected. A design

pressure of 1,8 MPa will not be used to avoid a short duration pressure surge at each cycle (See Pressure

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Equipment Directive, Annex I, clause 2.11.2 Pressure limiting devices). Therefore the safety valve will be set

at 2 MPa (pressure higher than 1,8 MPa + 10 %) and the design pressure of 2 MPa will be used in design

calculations for static loadings.
4 Application of EN 13445-1 [1]
4.1 General

This part contains general information on the scope of the standard as well as terms, definitions, quantities,

symbols and units which are applied throughout the standard.

Before designing and manufacturing the vessel according to the standard, the manufacturer shall verify the

applicability of the standard EN 13445 and perform a number of prerequisites.
4.2 Is EN13445 applicable to the vessel?

The answer is yes, since the vessel does not belong to the vessels mentioned in Clause 1 of reference [1]

which are:
 Vessels of riveted construction;

 Vessels of lamellar cast iron or any material not included in part 2, 6 or 8 of the standard;

 Multilayered, autofrettaged or pre-stressed vessels.
4.3 Warning of Annex A of reference [1]

The standard EN 13445 is harmonized under the Pressure Equipment Directive (97/23/EC). This means that if

the vessel meets the requirements of this standard, it can be presumed to conform to those essential safety

requirements which are listed in the Annexes ZA of each individual part.

In this connection, it should be understood that the standard is indivisible. The design and manufacturing of

the vessel requires application of all relevant parts of the standard, in this case of Part 1 General [1], Part 2

Materials [2], Part 3 Design [3], Part 4 Fabrication [4] and Part 5 Inspection and testing [5], since the vessel is

a steel vessel.
Part 7 and Part 9 are not mandatory parts in this sense.
4.4 Prerequisites of Annex A of reference [1]
4.4.1 Operating conditions

Operating conditions provided by the User will be used in the design calculations, but a design pressure of

2 MPa will be used in calculations for static loadings, as it is mentioned in 4.3.

4.4.2 Actions to be considered according to the list in 5.3.1 of EN 13445-3 reference [3]

a) internal pressure;
b) maximum static head of contained fluid;
c) weight of the vessel;
d) maximum weight of contents under operating conditions;
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e) weight of water under hydraulic pressure test conditions;
f) wind, snow, and ice loading (not present);
g) earthquake loading (negligible);

h) other loads supported by or reacting on the vessel, including loads during transport and installation

(negligible);

i) stresses caused by supporting lugs, ring, girders, saddles, internal structures or connecting piping or

intentional offsets of median lines on adjacent components. (Only stresses caused by bracket supports

will be considered);

j) shock loads caused by water hammer or surging of the vessel contents (not present);

k) bending moments caused by eccentricity of the centre of the working pressure relative to the neutral axis

of the vessel (not present);

l) stresses caused by temperature differences including transient conditions and by differences in

coefficients of thermal expansion (Not requested by the User);

m) stresses caused by fluctuations of pressure, temperature and external loads (Stresses caused by

fluctuations of pressure and temperature will be considered);
n) stresses caused by the decomposition of unstable fluids (not present).
4.4.3 Classification of load cases
4.4.3.1 Normal load cases

Normal load cases are those acting on the pressure vessel during normal operation, including start-up and

shutdown. They result of combination of actions mentioned in 5.3.2.
4.4.3.2 Exceptional load cases

Exceptional load cases are those corresponding to events of very low probability requiring the safe shutdown

and inspection of the vessel or plant. No such exceptional load case is expected.

4.4.3.3 Testing load cases

Testing load cases include testing load cases for final assessment and testing load cases in service. Only the

hydraulic test for final assessment will be considered.

4.4.4 The Category of the vessel as defined in the Pressure Equipment Directive (PED)

Taking into consideration:
 The maximum allowable pressure PS: 20 bar
 The fluid group: 1
 The volume of the vessel: 2.656 L
 The potential energy content product PS.V = 53.120 bar.L
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The vessel category is IV (See Figure 3, Excerpt from Table 1 of Annex II of the PED where the case is

represented by a red dark dot or see Figure A-1 of CR 13445-7).
Figure 3 — Vessel category
4.4.5 The Conformity Assessment Module to be used

Applicable modules of Category IV are B+D, B+F, G, H1. Module G is used throughout this example (this is

according to the drawing Example 2).
5 Application of EN 13445-2 [2]
5.1 Permitted materials
5.1.1 General
Clause A.4 Materials of reference [1] recalls the principles.

Specific requirements apply to materials for pressure-bearing parts. They are given in 4.1, 4.2, 4.3 and 4.4 of

reference [2].
5.1.2 Requirements given in 4.1 of reference [2]

 Materials shall be selected to be compatible with anticipated fabrication steps and to be suitable for

internal fluid and external environment

 Materials shall be accompanied by inspection documents in accordance with EN 10204:2004

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NOTE 1 This is not properly speaking a design requirement, but a means to inspect material properties.

 Materials shall be free from surface and internal defects which can impair their intended usability

 Steels shall have a specified minimum elongation after fracture: 14 %

 Steels shall have a specified minimum impact energy measured on a Charpy V-notch impact test

specimen greater or equal to 27 J for ferritic steels, etc.

 The chemical composition of ferritic steels intended for welding and forming shall not exceed 0,25 % C,

0,035 % P, 0,025 % S.

Only materials which are qualified for pressure equipment may be used. Qualification of materials can be

made in three different ways:

 Materials from European harmonized Standards, see 4.3.1 of reference [2]. Certain materials supplied in

accordance with European material Standards are accepted as qualified for use in pressure-bearing parts.

These materials are enumerated in Table E.2-1 of reference [2].

 Materials with a European Approval for materials (EAM), see 4.3.2 of reference [2]. Materials with an

EAM, which states that they can be used for products under the PED, are qualified for use in relevant

products according to this standard. EAMs are published in the Official Journal, and the European

Commission maintains a list of EAMs on their web site.
NOTE 2 This web site is presently accessible under the address

http://ec.europa.eu/enterprise/pressure_equipment/ped/materials/published_en.html.

 Materials with a Particular Material Appraisal (PMA), see 4.3.3 of reference [2]. Materials, which have

been subject to a PMA are qualified. This appraisal is carried out by the manufacturer (and in certain

cases checked by a Notified Body).

NOTE 3 The European Commission and Member States have in November 2006 agreed on "Guiding Principles for the

contents of Particular Materials Appraisals". The document is published on:
http://ec.europa.eu/enterprise/pressure_equipment/ped/materials/index_en.html.
5.2 Requirements given in 4.2 of reference [2]

Materials for example 2 are high temperatures steels for which the requirements of 4.2.2 Design temperature

above 20 °C apply.

In 4.2.5 specific requirements are given for steels for fasteners (bolts, nuts, etc.).

5.3 Requirements given in 4.3 of reference [2]

4.3 addresses Technical delivery conditions for steels and welding consumables. For example 2, the

European standards for plates, tubes, and forgings will be used. European standards will also be used for

welding consumables.

Table E.2-1 of reference [2] provides an overview on materials for pressure purposes. This Table will be

used for example 2.
5.4 Requirements given in 4.4 of reference [2]

4.4 addresses Marking. This marking ensures traceability between the product and the inspection documents.

NOTE Marking has no incidence on design calculations.
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5.5 Materials selected for the vessel example 2

Characteristics of the steels, fasteners and gaskets selected for the vessel are given in Table 1 and

reproduced in Annex C to this report.

P355 GH of the European harmonized standard EN 10028-2 [6] was selected for the shell (upper, lower),

dished end and cone elements of the vessel (also support brackets). This steel was preferred to P295GH to

have a smaller weight ( approximately 15 % or 120 kg for all plate made materials) with a slightly higher price

(approximate price difference in Western Europe is 100 € per metric ton).

P280 GH of the European harmonized standard EN 10222-2 was selected for the main flange upper and

lower side.
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Table 1 — Materials and main material characteristics in example 2

Vessel part Material Material EN 13445-2 Dimensions Material Main material characteristics

designation reference (mm) group to
Tensile Min yield Min elong Min impact Min impact
CR ISO
(see also
min/max MPa A5 at energy KV, energy KV,
Annex C) 15608
MPa room J at J at +20 °C
temp - 20 °C

Cylindrical Ferritic steel EN 10028-2 See Table e < 16 mm 1.2 510-650 355 20 27 40

shell upper,
plate for high P355 GH E.2-1 of
en = 12 for
lower temperature (1.0473) EN 13445-2
lower part,
service
en = 10 for
upper part

Conical shell Ferritic steel EN 10028-2 See Table e < 16 mm 1.2 510-650 355 20 27 40

plate for high P355 GH E.2-1 of
e = 12
temperature (1.0473) EN 13445-2
service

Dished end Ferritic steel EN 10028-2 See Table e < 16 mm 1.2 510-650 355 20 27 40

plate for high P355 GH E.2-1 of
e = 14
temperature (1.0473) EN 13445-2
service

Main flange Forging EN 10222-2 See Table 50,00 < t < 160 1.2 490-610 280-305 22 27

upper and
P280 GH E.2-1 of mm
lower side (1.0426) EN 13445-2
e = 95 for
lower part,
e = 103 for
upper part

Bolts(fastene 25CrMo4(+Q EN 10269 See Table Number=68 — 800-950 Upper 0,2%600 15 27-32

rs) main T) (dia.< 100 mm) E.2-1 of M22x2,5
flange: EN 13445-2
M22x2,5 a)
Gasket Spirally Gasket —
wound parameters
mineral filled m=3, y=69
stainless MPa
steel -Monel
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Table 1 — Materials and main material characteristics in example 2 (continued)

Vessel Material Material EN 13445-2 Dimensions Material Main material characteristics

part group designation reference (mm) group to
(see also CR ISO
Annex C) 15608
Tensile Min Min elong Min impact Min impact
min/max yield A5 at room energy KV, J at energy KV, J at
MPa MPa temp. -20°C +20°C
Nozzle N3 Standard EN 10216-2 See Table Deb=219,10 1.1 410-570 265 23 28 —
(DN200) XS P265GH E.2-1 of eb=12,70
(1.0425) EN 13445-2
Nozzle N4 Standard EN 10216-2 See Table Deb=168.3 1.1 410-570 265 23 28 —
DN150
XS (1.0425) E.2-1 of eb=10,97
EN 13445-2
LWN PN25 EN 10222-2 See Table 25 bar rating 1.2 460-580 280 21 27
Flange at
P280GH E.2-1 of 235/102,3
N1/N2 (DN (1.0477) EN 13445-2
eb=19,85
100)
Standard PN25 EN 10222-2 See Table 25 bar rating 1.2 460-580 280 21 27
flange P280GH E.2-1 of 235/102,3
pos. at N3 (1.0477) EN 13445-2 eb = 19,85
(DN 200)
Standard PN25 EN 10222-2 See Table 25 bar rating 1.2 460-580 280 21 27
flange P280GH E.2-1 of 235/102,3
pos. at N4 (1.0477) EN 13445-2 eb = 28
(DN 150)
Brackets Ferritic T < 16 mm 1.2 510-650 355 20 27 40
EN 10028 -2 See Table
and steel
P355 GH E.2-1 of
web
reinforce plate for
1.0477 EN 13445-2
en=15,base
ment high
(1.0473)
plate en=20
plates tempe-
reinforcing
rature
plate
service
en=10
a) not applicable
b) at 100 °C
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6 Application of EN 13445-3 [3]
6.1 General

General definitions and general requirements are in Clauses 1 to 6 of reference [3]. Design requirements for

the various components are contained in the relevant clauses of reference [3]. Specific design requirements

for the simplified fatigue analysis are contained in Clause 17.

In this document, the principles of the calculations are presented. For details, it is recommended to examine

the calculation sheets obtained by software. Each calculation sheet follows step by step the paragraphs of the

relevant clause of reference [3].

The calculations sheets are gathered in pages 7 to 58 of Annex C to this report. Main results of the

calculations are in pages 1 to 6.
6.2 Basic design
6.2.1 Verification of thicknesses

The first step is the verification of the thicknesses of the various components or parts composing the pressure

vessel under the design loading:
P = 2 MPa
T = 260 °C

This is done successively for the cylindrical shells and their flanges, the ellipsoidal head and the attached

nozzles, the conical shell, the cylindrical shell, the nozzle N4 and the brackets.

6.2.2 Determination of the maximum permissible pressure Pmax

Then the maximum permissible pressure defined in 3.16 is calculated for each component or vessel part using

the formula given in the column entitled Maximum permissible pressure Pmax of Table 17-1 of reference [3].

For example, for cylindrical shells Pmax is given in Clause 7 of reference [3] by Formula (7.4.3).

As explained in 17.6.1, Pmax will be used in the fatigue calculations.
6.3 Fatigue calculations
6.3.1 General

Fatigue calculations of example 2 are performed using the formulae of Clause 17 of reference [3]. This is

done in six steps.
6.3.2 Determination of fatigue sensitive locations
These locations are:
 Welded zones
 Unwelded zones with stress concentration
For guidance, see Table 17-1 of reference [3].
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6.3.3 Determination of pseudo-elastic stress range ∆σ
∆σ shall be calculated from the pressure range ∆P as follows:
∆σ= .η . f (17.6-1)
P max
where

 Pmax is the maximum permissible pressure of the component or vessel part under consideration as

defined in Clause 4, except for dished ends where a specific definition of Pmax applies (see NOTE 2 of

Table 17-1)

 f is the nominal stress of the component or vessel part under consideration, at calculation temperature.

 The value of η is obtained from Table 17-1 for each weld detail. It is an upper bound of the following ratio:

maximum structural stress in detail under consideration under pressure P
max
nominal design stress at calculation pressure

Where ∆σ > 3 f , ∆σ shall be increased according to the rule given in 18.8 to account for elastic-plastic cyclic

conditions.
6.3.4 Stress factors η and associated maximum permissible pressures

Stress factors and associated permissible pressure are given in Table 17-1 for each component or vessel

part. Stress factors η depend on shape imperfections.
6.3.5 Fictitious stress range
6.3.5.1 General

The fictitious stress range is used for determination of the allowable number of cycles. It includes the

thickness and temperature corrections: C and C at a welded joint or vessel part and also the effective

e T

stress concentration factor K for notch effect at an unwelded part. These factors are defined in 17.6.2

6.3.5.2 At a welded joint
∆σ = ( ) (17.6-9)
C ⋅ C
e T
6.3.5.3 At a unwelded region
∆σ = ( )⋅ K (17.6.10)
C ⋅ C
e T
6.3.6 Determination of the allowable number of cycles
6.3.6.1 General

The allowable number of cycles is obtained by introducing ∆σ in the appropriate fatigue design curve

among the curves of Figure 17-4 Total fatigue damage index.
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6.3.6.2 Classification of welded joints

The welded joints shall be allocated to the classes given in Table 17-4 which are testing group dependent. For

example 2, only the column testing group 3 is to consider.
6.3.6.3 Unwelded regions
For unwelded regions, the class UW fatigue design curve in Figure 17-4 applies.
6.3.7 Fatigue results
All fatigue damage index computed in Annex C are accept
...