EN 13445-3:2002/A1:2007

SLOVENSKI STANDARD
01-februar-2009
1HRJUHYDQHWODþQHSRVRGHGHO.RQVWUXLUDQMH
Unfired pressure vessels - Part 3: Design
Unbefeuerte Druckbehälter - Teil 3: Konstruktion
Récipients sous pression non soumis a la flamme - Partie 3: Conception
Ta slovenski standard je istoveten z: EN 13445-3:2002/A1:2007
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 13445-3:2002/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2007
ICS 23.020.30
English Version
Unfired pressure vessels - Part 3: Design
Récipients sous pression non soumis à la flamme - Partie Unbefeuerte Druckbehälter - Teil 3: Konstruktion
3: Conception
This amendment A1 modifies the European Standard EN 13445-3:2002; it was approved by CEN on 22 March 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references concerning such
national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13445-3:2002/A1:2007: E
worldwide for CEN national Members.

Contents Page
Foreword .4
2 Normative references.5
3 Terms and definitions .5
5 Basic design criteria .5
5.1 General .5
5.3.3 Failure modes considered in this Part .5
5.4.3 Vessels of testing group 4.6
6 Maximum allowed values of the nominal design stress for pressure parts .6
19 Creep design.7
19.1 Purpose .7
19.2 Specific definitions.7
19.3 Specific symbols and abbreviations .7
19.4 Design in the creep range .8
19.5 Nominal Design stress in the creep range .9
19.5.1 Case where no lifetime monitoring is provided .9
19.5.1.1 General.9
19.5.2 Case where lifetime monitoring is provided.13
19.6 Weld joint factor in the creep range .13
19.7 Pressure loading of predominantly non-cyclic nature in the creep range.13
19.8 Design procedures for DBF.13
Annex B (normative) Design by Analysis – Direct Route.17
B.1.1 General .17
B.1.2 Purpose .17
B.1.3 Special requirements .17
B.1.4 Creep design.17
B.3 Specific symbols and abbreviations .18
B.5 Methodology .18
B.5.1 General, design checks .18
B.7 Design models .20
B.7.1 General .20
B.7.4 Constitutive laws.20
B.7.5 Material parameters.20
B.8 Non-creep design checks.21
B.8.1 General .21
B.8.5 Cyclic Fatigue failure (F).23
B.9 Creep design checks.23
B.9.1 General .23
B.9.2 Welded joints .23
B.9.3 Material creep strength parameters .24
B.9.4 Creep Rupture (CR).24
B.9.5 Excessive Creep Strain (ECS).26
Annex M (informative) In service monitoring of vessels operating in fatigue or creep .31
M.1 Purpose .31
M.2 Fatigue operation .31
M.5 Measures to be taken when the calculated allowable fatigue lifetime has been
reached.32
M.6 Operation in the creep range .32
M.7 Measures to be taken when the calculated allowable creep lifetime has been
reached.33
M.8 Bibliography.33
Annex R (informative) Coefficients for creep-rupture model equations for extrapolation of
creep-rupture strength.34
R.1 General .34
R.2 Bibliography.37
Annex S (informative) Extrapolation of the nominal design stress based on time-
independent behaviour in the creep range.38
S.1 General rule.38
S.2 Results for EN 10028 materials.39
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of the EU Directive 97/23/EC on Pressure Equipment.44

Foreword
This document (EN 13445-3:2002/A1:2007 - has been prepared by Technical Committee CEN/TC 54
“Unfired pressure vessels”, the secretariat of which is held by BSI.
This Amendment to the European Standard EN 13445-3:2002 shall be given the status of a national
standard, either by publication of an identical text or by endorsement, at the latest by December 2007,
and conflicting national standards shall be withdrawn at the latest by December 2007.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EU Directive 97/23/EC.
For relationship with EU Directive 97/23/EC, see informative Annex ZA, which is an integral part of this
document.
This amendment is based on EN 13445-3 up to issue 26 (April 2007).
The document includes the text of the amendment itself. The corrected pages of EN 13445-3 will be
delivered as issue 27 of the standard.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
2 Normative references
Amend the third reference to read:
EN 764-1:2004, Pressure equipment – Part 1: Terminology – Pressure, temperature, volume,
nominal size.
_________________________________________________________________________________
3 Terms and definitions
Add a new definition 3.23:
3.23
creep range
temperature range in which material characteristics used in design are time dependent
Add a NOTE:
NOTE See also 5.1.
_________________________________________________________________________________________
5 Basic design criteria
5.1 General
Replace the existing text with:
Part 3 is applicable only when:
a) materials and welds are not subject to localized corrosion in the presence of products which the
vessel is to contain or which can be present in the vessel under reasonably foreseeable
conditions.
b) either all calculation temperatures are below the creep range or a calculation temperature is in
the creep range and time dependent material characteristics are available in the materials
standard.
NOTE See definition 3.23 of creep range.
For the purpose of design, the creep range is the temperature range in which time independent
material characteristics are no more governing in the determination of the nominal design stress.
The material strength characteristics used shall be related to the specified lifetimes in the various
creep load cases
_________________________________________________________________________________
5.3.3 Failure modes considered in this Part
Add:
f) creep rupture;
g) creep deformation;
h) creep fatigue.
_________________________________________________________________________________
5.4.2 Vessels of all testing groups, pressure loading of predominantly non-cyclic nature
Change the beginning of the first paragraph to:
The DBF requirements specified in Clauses 7 to 16, Annexes G and J and in Clause 19 (for testing
subgroups 1c and 3c only), and the DBA requirements of Annex B and Annex C provide satisfactory
_________________________________________________________________________________
5.4.3 Vessels of testing group 4
Change to:
Pressure vessels to testing group 4, as defined in EN 13445-5, are intended for predominantly non-
cyclic operation and calculation temperatures below the creep range. They are limited for operation
up to 500 full pressure cycles or equivalent full pressure cycles.
NOTE When the number of equivalent full pressure cycles has reached 500, a hydraulic test should be
performed and followed by a complete visual examination. If the test is successfully passed, then the operation
can be continued for a new 500 cycles period.
_________________________________________________________________________________
Change the heading 5.4.4 to:
5.4.4 Vessels of testing group 1, 2, and 3, working below the creep range, pressure loading
of predominantly cyclic nature
_________________________________________________________________________________
5.7.1 General requirements
Replace the last sentence with:
Specific requirements are included when Design by Analysis – Direct Route of Annex B is used for
vessels or vessel parts working in the creep range.
_________________________________________________________________________________
6 Maximum allowed values of the nominal design stress for pressure parts
In 6.1.1 add the following at the end of the first paragraph:
The values to be used within the creep range are given in Clause 19.
_________________________________________________________________________________
Add the following new clause:
19 Creep design
19.1 Purpose
This clause is for the design of vessels or vessel parts if the calculation temperature is in the creep
range. It may be applied for pressure and mechanical loading.
NOTE 1 A definition of the creep range is given in 3.8. See also 5.1b.
NOTE 2 A pre-supposition of the requirements in this clause is usage of sufficiently creep ductile materials. In
that regard, the steels and steel castings listed in Table A.2-1 of EN 13445-2:2002 for which, for the relevant
temperature range, creep strengths are given in the referred to material standards, are considered to be
sufficiently creep ductile.
19.2 Specific definitions
period
duration of a load case with constant loading and constant temperature inside the creep range.
NOTE All individual intervals of time with identical creep conditions (same temperature and same applied
loading) occurring separately during the vessel life should be grouped to form a unique period.
single creep load case
case where only one period occurs in the whole lifetime of the vessel.
multiple creep load case
case where more than one period occur in the whole lifetime of the vessel.
lifetime monitoring
requirements for control and examination as stated in the operating instructions with the minimum
requirement for continuous recording of pressure and temperature and retention of records.
NOTE See Annex M for guidance.
19.3 Specific symbols and abbreviations
n   is the total number of periods of f ,T .
i
Fi
SF  is the safety factor for mean creep rupture strength (see 19.5.1 and 19.5.2)
c
R is the mean 1% creep strain limit at calculation temperature T and lifetime t
p1,0/T / t
R  is the mean creep rupture strength at calculation temperature T and lifetime t
m/T / t
NOTE The creep rupture strengths given in harmonised material standards are always mean values.
T  is the calculation temperature in °C
t  is the specified lifetime in hours (h) of the pressure vessel (see 19.4)
t  is the duration (h) of the i-th period, during which the fictitious design stress f acts
i Fi
at the calculation temperature T .
i
t is the allowable time (h) to damage (caused by creep rupture or creep strain) for the
D,f ,T
Fi i
material at fictitious design stress f and temperature T , taken from the creep design curve or
i
Fi
formula (19-11) respectively.
t is the allowable time (h) to reach the 1% creep strain limit for the material at fictitious
P,f ,T
Fi i
design stress f and temperature T calculated according to formula (19-20).
i
Fi
t is the allowable time (h) to creep rupture for the material at fictitious design stress f
Fi
R,f ,T
Fi i
and temperature T calculated according to formula (19-12) or (19-17) respectively.
i
f  is the fictitious design stress for creep design of the i-th period, as defined in 19.8.2.
Fi
f  is the nominal design stress based solely on time independent behaviour, as defined in
nc
19.5.1
z  is the weld creep strength reduction factor, as defined in 19.6.
c
19.4 Design in the creep range
This sub-clause applies for the design by formula in Clauses 7, 9, 10, 11, 12, 15 and 16 with the
exception of bolts according to Clause 11 and 12 and the exception of compressive stresses in 16.14.
For Clauses 8, 13, 14, 16.14 and Annexes G and J the design in the creep range is only applicable as
far as the modulus of elasticity is known in the creep range. In this case in Clause 8 the minimum yield
R
p1,0 /T / t
strength R has to be replaced by .
p0,2/T
1,3
 When the vessel has to be designed for a single creep load case only: the design procedure
described in 19.8.1 shall be used. This procedure is based on use of the nominal design stress
defined in 19.5. For determination of that nominal design stress, the lifetime t = 100.000 h shall
be used if no lifetime t is specified.
 When the vessel has to be designed for multiple creep load cases: the design procedure based
on cumulative damage described in 19.8.2 shall be used. Alternatively, a simplified and
conservative design may also be made, using the procedure described in 19.8.1, replacing the
various applied creep load cases by a unique one whose temperature shall be the highest among
all individual creep load cases and whose duration shall be the total of that of all individual creep
load cases.
In both procedures, the weld joint factor shall be modified by the weld creep strength reduction factor
according to 19.6.
19.5 Nominal Design stress in the creep range
19.5.1 Case where no lifetime monitoring is provided
19.5.1.1 General
R
 
m /T/ t
 
f = min f ; ;R (19-1)
 
nc p1,0 /T/ t
SF
 
c
 
where:
SF = 1,5
c
Determination of f shall be made in accordance with Clause 6, with the following provisions:
nc
 For calculation temperatures T not exceeding by more than 200 °C the highest temperature T
H
f
at which material characteristics are available in the material standard, extrapolated values of
nc
can be taken as given in Annex S.
 For calculation temperatures T >T + 200 °C the nominal design stress f shall be ignored in
H nc
formula (19-1) and the further terms in this formula shall be determined for a lifetime not shorter
than the lowest lifetime for which material creep characteristics are available in the material
standard.
NOTE The extrapolated values given in Annex S for T > T + 200°C are useful only for determination of
H
the hydrotest pressure (See 10.5.3.3 in EN 13445-5:2002)
19.5.1.2 Case where material creep characteristics are available for the specified lifetime but
not for the calculation temperature
19.5.1.2.1 General
In the case where for the calculation temperature T no mean creep rupture strength or no mean 1%
creep strain limit is available in the harmonised materials standard, the interpolation formulae (19-3),
(19-4) or (19-5), (19-6) respectively may be used (or the value in the harmonised material standard for
the higher temperature may be used as a conservative value) to determine the appropriate creep
characteristics.
If the calculation temperature is higher than the highest temperature for which a mean creep rupture
strength or a mean 1 % creep strain limit is available, application of Clause 19 is not permitted.
19.5.1.2.2 Mean creep rupture strength
R ⋅ (T −T )+ R ⋅ (T −T )
m/T / t 2 m/T / t 1
1 2
R = for T -T ≤ 20 °C (19-2)
2 1
m /T/ t
(T −T )
2 1
Z
R
 R 
m/T / t
 
= ⋅ for T -T > 20 °C (19-3)
R R
2 1
 
m /T/ t m/T / t
R
 
m/T / t
 1 
where:
lgT − lgT
Z = with: lg= log (19-4)
R
lgT − lgT
2 1
T is the nearest temperature below T for which a mean creep rupture strength is available in the
harmonised material standard
T is the nearest temperature above T for which a mean creep rupture strength is available in the
harmonised material standard
19.5.1.2.3 Mean 1% creep strain limit
R ⋅(T −T )+ R ⋅(T −T )
p1,0/T / t 2 p1,0/T / t 1
1 2
R = for T -T ≤ 20 °C (19-5)
2 1
p1,0/T/t
(T −T )
2 1
Z
P
 
R
p1,0/T /t
 
R = R ⋅ for T -T > 20 °C (19-6)
2 1
 
p1,0/T/t p1,0/T /t
1 R
 
p1,0/T /t
 1 
where:
lgT − lgT
Z = with: lg= log
P
lgT − lgT
2 1
T is the nearest temperature below T for which a mean 1 % creep strain limit is available in the
harmonised material standard
T is the nearest temperature above T for which a mean 1 % creep strain limit is available in the
harmonised material standard.
19.5.1.3 Case where material creep characteristics are available for the calculation
temperature (including cases where these values are calculated by 19.5.1.2) but not for the
specified lifetime t
19.5.1.3.1 General
In the case where for the specified lifetime t no mean creep rupture strength value or no mean 1 %
creep strain limit is available in the harmonised material standard the interpolation formula (19-7) or
(19-9) respectively may be used (or the value in the harmonised material standard for a lifetime longer
than the specified lifetime can be used as a conservative value) to determine the appropriate creep
characteristics.
In the case where the specified lifetime t is longer than the highest lifetime for which a mean creep
rupture strength is available in the harmonised materials standard, the extrapolation method given in
the informative Annex R may be applied.
In the case where the specified lifetime t is longer than the highest lifetime for which a mean 1 %
creep strain limit is available in the harmonised material standard, the value for the highest lifetime
for which a mean 1% creep strain limit is available shall be used in formula (19-1).
NOTE In the case of the last paragraph, the accumulated creep strain may exceed the 1% limit before the
end of the lifetime.
19.5.1.3.2 Mean creep rupture strength
X
R
 R 
m/T/ t
 
B
R = R ⋅ (19-7)
m/T/ t m/T/ t  
A R
 
m/T/ t
A
 
where:
lgt − lgt
A
X = with: lg= log (19-8)
R
lgt − lgt
B A
R is the mean creep rupture strength for the nearest lifetime t below t for which a mean
m/T /t A
A
creep rupture strength is available
R is the mean creep rupture strength for the nearest lifetime t above t for which a mean
m/T /t B
B
creep rupture strength is available
In the case where the specified lifetime t is shorter than the lowest lifetime for which a mean creep
rupture strength is available in the material standard, then the following terms may be used in
formulae (19-7) and (19-8) respectively:
R and R are the mean creep rupture strengths for the two shortest lifetimes t and
m/T /t m/T /t A
A B
t for which a mean creep rupture strength is available
B
An alternative method for extrapolation to shorter time is given in Annex R.
19.5.1.3.3 Mean 1 % creep strain limit
X
P
 
R
p1,0/T/ t
 
B
R = R ⋅ (19-9)
 
p1,0 /T/ t p1,0/T/ t
A R
 
p1,0/T/ t
 A
where:
lgt − lgt
A
X = with: lg= log
P
lgt − lgt
B A
t
R is the mean 1 % creep strain limit for the nearest lifetime t below for which a
p1,0 / T / t A
A
mean 1 % creep strain limit is available
R is the mean 1 % creep strain limit for the nearest lifetime t above t for which a
B
p1,0 / T / t
B
mean 1 % creep strain limit is available
In case where the specified lifetime t is shorter than the lowest lifetime for which a mean 1 % creep
strain limit is available in the material standard then the third term (creep strain) within the minimum in
formula (19-1) does not apply.
NOTE In that case the accumulated creep strain may exceed the 1 % limit before the end of the lifetime.
19.5.1.4 Case where material creep characteristics are available neither for the calculation
temperature nor for the specified lifetime:
In the case where values for creep characteristics are not available in the material standard for both
the calculation temperature T and the specified lifetime t , the nominal design stress shall be
determined using 19.5.1.2 first and 19.5.1.3 afterwards.
A typical form for the creep design curve showing the nominal design stress f as a function of lifetime
t and calculation temperature T is shown in Figure 19.1.

Key:
1) maximum time t = 2⋅ t for which linear log-log extrapolation versus time is
R,T ,max B
i
allowed
2) longest time t for which time depending creep strength data are available in the materials
B
standard
a) curve of time dependent material characteristics
b) curve of short time (time independent) material characteristics
Figure 19.1 - Typical creep design curves for explanation of the method

19.5.2 Case where lifetime monitoring is provided
Nominal design stress in the creep range shall be calculated using formula (19-10):
 R 
 m/T/t
f = min f ; (19-10)
 
nc
SF
 
c
 
where:
SF = 1,25
c
NOTE See informative Annex M for monitoring.
19.6 Weld joint factor in the creep range
In the creep range, the value of the weld joint factor z to be used in the relevant design formulae shall
be that defined in Table 5.6-1 multiplied by the weld creep strength reduction factor z .
c
NOTE For vessels working in the creep range the testing sub-groups 1c and 3c only are allowed, see EN
13445-5:2002.
The values for the weld creep strength reduction factor shall be:
z = 1,0 determined by tests according to Annex C of EN 13445-2:2002 if the conditions for the
c
value 1 are fulfilled
z < 1,0 determined by tests according to Annex C of EN 13445-2:2002 if the conditions for the
c
value 1 are not fulfilled
z = 0,8 otherwise, except for specific cases where the literature or industrial feedback indicates
c
a lower value
19.7 Pressure loading of predominantly non-cyclic nature in the creep range
The requirement for pressure loading of non-cyclic nature given in 5.4.2 is considered to be met (i.e.
the number of full pressure cycles or equivalent full pressure cycles is less than 500) when the vessel
design fulfils all relevant formulae in clauses of Part 3 defined in 19.4, making use of the nominal
design stress determined as defined in 19.5.
NOTE In the present edition of the standard no rule concerning creep/fatigue interaction is given in this
clause. If this interaction is to be taken into account, the design methods of Annex B may be used.
19.8 Design procedures for DBF
19.8.1 When the vessel has to be designed for a single creep load case only, f shall be obtained
from 19.5 and the required component thickness shall be determined or checked according to the
clauses of this Part defined in 19.4.
19.8.2 When the vessel has to be designed for multiple creep load cases an assessment of the
cumulative creep damage resulting from all creep load cases occurring during the lifetime of the vessel
shall be made, according to the following procedure:
a) An analysis thickness e for the component shall be assumed.
a
NOTE 1 The assumed thickness e should at least be equal to the largest thickness found necessary
a
through the calculations made in application of 19.8.1 for the load cases of greatest significance. During
application of the given procedure this start value will be increased as far as necessary.
b) For each load case, e is inserted into the relevant DBF formulae (clauses of this Part defined in
a
19.4) and the equations solved for the fictitious design stress for creep design f which gives the
Fi
thickness e exactly. This fictitious stress f is the minimum value for the design stress f which fulfils
a Fi
all the design conditions of the relevant clause of this Part for the analysis thickness e and for the
a
load case i under consideration.
NOTE 2 This may require a trial and error calculation.
c) For each load case, the allowable time to damage, t shall be calculated according to the
D,f ,T
Fi i
following procedure:
1) If f > f then e shall be increased ( t = 0 )
Fi nc a D,f ,T
Fi i
2) If f ≤ f then:
Fi nc
 
t = min t ;t (19-11)
 
D,f ,T R,f ,T P,f ,T
Fi i  Fi i Fi i
3) Allowable time to creep rupture:
Y
R
 t 
B
 
t = t ⋅ (19-12)
R,f ,T A
 
t
Fi i
A
 
where:
lg(f )− lg(f )
Rt
Fi A
y = with: lg= log (19-13)
R lg(f )− lg(f )
Rt Rt
B A
with:
R
m/T / t
i A
f = (19-14)
Rt
SF
A
c
and:
R
m/T / t
i B
f = (19-15)
Rt
SF
B
c
f and f being the closest values to f with the corresponding lifetimes t and t , as defined
Rt Fi A B
Rt
B
A
in 19.5.1.3, which fulfil the condition:
f ≥ f ≥ f
(19-16)
Rt Fi Rt
A B
If f is smaller than the smallest available value f (this is the value at the longest lifetime for which
Fi Rt
B
mean creep rupture strength is available in the material standard) then the following formula shall be
used instead of formula (19-12):
 
t = min t ;t (19-17)
 
R,f ,T R,f ,T ,ex R,T ,max
Fi i  Fi i i 
where:
t is the allowable time (h) to damage (caused by creep rupture) for the material at fictitious
R,f ,T ,ex
Fi i
design stress f and temperature T which may be calculated according to the informative Annex R.
Fi i
t is the maximum time for which the extrapolation method used is valid (the informative
R,T ,max
i
Annex R may be used)
Alternatively the following formulae may be used:
t = 2⋅ t (19-18)
R,T ,max B
i
Y
R
 
t
B
 
t = t ⋅ (19-19)
R,f ,T ,ex A
 
t
Fi i
A
 
where:
t is the longest lifetime for which a mean creep rupture strength is available in the material
B
standard
t is the next lower lifetime which a mean creep rupture strength is available in the material
A
standard
Y as given in formulae (19-13) until (19-15) calculated for the here defined lifetimes t and t
R A B
NOTE 3 The extrapolation is not based on experimental verification. Possible changes in the long term creep
strength due to micro-structural changes are not considered.
NOTE 4 It is advisable to determine as far as possible the complete creep design curve versus lifetime for the
needed calculation temperatures (see Figure 19.1) for a better overview to find the relevant times t and t for
A B
which condition (19-16) or (19-24) respectively is fulfilled.
4) Allowable time to reach the 1 % creep strain limit.
This allowable time shall be calculated only if no monitoring is provided. If monitoring is provided
t shall be omitted in (19-11).
P,f ,T
Fi i
Y
P
 t 
B
 
t = t ⋅ (19-20)
P,f ,T A
 
Fi i t
 A
where:
lg(f )− lg(f )
Fi Pt
A
y = with: lg= log (19-21)
P lg(f )− lg(f )
Pt Pt
B A
with:
f = R (19-22)
Pt p1,0/T /t
A i A
and:
f = R (19-23)
Pt p1,0/T / t
B i
B
f and f being the closest values to f with the corresponding lifetimes t and t , as
Pt Pt Fi A B
A B
defined in 19.5.1.3, which fulfils the condition:
f ≥ f ≥ f (19-24)
Pt Fi Pt
A B
If f is smaller than the smallest available value f (this is the value at the longest lifetime for
Fi Pt
B
t
which mean 1 % creep strain limit is available in the material standard) then may be omitted
P,f ,T
Fi i
in (19-11).
NOTE 5 If more than one material in the creep range is used in the part or component under consideration,
then a more general procedure should be used. The aim of this procedure is to search the allowable time to
damage t for which (using the different f values according to 19.5 for the different materials at
D,f ,T
Fi i
t = t ) all the design conditions and formulae are fulfilled for the analysis thickness e and for the load
D,f ,T a
Fi i
case i under consideration.
d) The accumulated creep damage resulting from all applied load cases shall be determined by the
following time-fraction rule:
n
t
i
∑ ≤ 1,0
(19-25)
t
i = 1 D,f ,T
Fi i
e) If condition (19-25) is not fulfilled the assumed thickness shall be increased and the procedure
shall be repeated starting from b).
If the quantity on the left hand side of condition (19-25) does not reach the value of 1,0 the assumed
thickness may be decreased and the procedure shall be repeated starting from b).

Annex B
(normative)
Design by Analysis – Direct Route

Add new sub-clause B.1:
B.1 Introduction
B.1.1 General
This annex is currently limited to sufficiently ductile materials, like the whole standard, but it is, for
components operating in the creep range, also limited to sufficiently creep ductile materials.
NOTE The steels and steel castings listed in Table A.2-1 of EN 13445-2:2002 for which, for the relevant
temperature range, creep strengths are given in the referred to material standards, are considered to be
sufficiently creep ductile".
_________________________________________________________________________________
Replace the title of B.1 and change to new subclause B.1.2:
B.1.2 Purpose
_________________________________________________________________________________
Change last paragraph of B1.2 into a new sub-clause B.1.3
B.1.3 Special requirements
Due to the advanced methods applied, until sufficient in-house experience can be demonstrated, the
involvement of an independent body, appropriately qualified in the field of DBA, is required in the
assessment of the design (calculations) and the potential definition of particular NDT requirements.
_________________________________________________________________________________
Add a new paragraph B.1.4
B.1.4 Creep design
For components which, under reasonably foreseeable conditions, may operate in the creep range, the
lifetime of this creep load case (or the lifetimes for more than one of such load cases) shall be
specified (by the user or his representative). For each load case which includes operation in the creep
range, the specified time for operation in the creep range shall not be less than 10 000 h. If none is
specified, the manufacturer shall assume a reasonable time, but at least 100 000 h.
NOTE Whereas for structures with solely non-creep load cases the load cases can be specified quite
independently, the specification of load cases for structures with creep load cases requires careful consideration
of the total design life taking into consideration all reasonably foreseeable load cases. Alternative total design
lives may be used.
The (specified or assumed) design life shall be stated in the Technical Documentation.
If calculation temperatures are below the creep range (See 5.1) no creep design checks are required,
and B.5.1.3 and B.9 do not apply.
If the minimum of the two values:
a) the product of 1,2 and the creep rupture strength at calculation temperature and for the relevant
lifetime,
b) the product of 1,5 and the 1% creep strain strength at calculation temperature and for the relevant
lifetime
is larger than the 0,2% proof strength at calculation temperature, no creep design checks are required,
and B.5.1.3 and B.9 do not apply. If the minimum of the two values is not larger than the 0,2% proof
strength at calculation temperature, creep design checks are required, and B.5.1.3 and B.9 apply.
The designations creep rupture strength and 1 % creep strain strength refer to mean values, as
specified in the material standard, for which a scatter band of experimental results of ± 20 % is
assumed. For larger scatter bands 1,25 times the minimum band values shall be used instead of
mean values.
For interpolation and possible extrapolation of strength values, and for the determination of time to
creep rupture or 1 % creep strain, the procedures given in Clause 19 shall be used.
_________________________________________________________________________________
B.3 Specific symbols and abbreviations
Add at the end of the first sentence:
and in Clause 19 for creep operation.
In B.3.1 Subscripts, add:
all allowed
c creep
e related to elastic limit
u related to strain limiting
_________________________________________________________________________________
In B.5.1 add new text before the last two paragraphs
B.5 Methodology
B.5.1 General, design checks
B.5.1.1 General
To each relevant failure mode, relevant with regard to the scope of this standard, there corresponds a
single design check (DC). Each design check represents one or more failure modes.
The design checks shall be carried out for the following (classes of) load cases, where relevant
 normal operating load cases, where normal conditions apply
 special load cases, where conditions for testing, construction, erection or repair apply
 exceptional load cases, see 5.3.2
_________________________________________________________________________________
New B.5.1.2
B.5.1.2 Design checks for calculation temperatures below the creep range
The design checks to be considered are:
 Gross Plastic Deformation Design Check (GPD-DC), see B.8.2;
 Progressive Plastic Deformation Design Check (PD-DC), see B.8.3;
 Instability Design Check (I-DC) , see B.8.4;
 Fatigue Design Check (F-DC) , see B.8.5;
 Static Equilibrium Design Check (SE-DC), see B.8.6.
NOTE The design checks are named after the main failure mode they deal with. Some design checks may
not be relevant for a particular design. The list of design checks is not exhaustive. In some cases, it may be
necessary to investigate additional limit states. For example, with austenitic stainless steel, failure by GPD shall
be checked (as an ultimate limit state) but leakage may also need to be checked (as either an ultimate or a
serviceability limit state), see Table B.4-1.
_________________________________________________________________________________
New B.5.1.3
B.5.1.3 Design checks for calculation temperatures in the creep range
If creep design checks are required, see B.1.4, the design checks which shall be considered, in
addition to those listed in B.5.1.2, are:
 Creep Rupture Design Check (CR-DC), see B.9.4,
 Excessive Creep Strain Design Check (ECS-DC), see B.9.5,
 Creep Fatigue Interaction Design Check (CFI-DC), see B.9.6.
NOTE For some load cases creep rupture design checks may make corresponding gross plastic deformation
design checks superfluous.
_________________________________________________________________________________
In B.7.1 replace the fifth paragraph:
B.7 Design models
B.7.1 General
In case of structures and actions resulting in an unfavourable (weakening) effect, geometrically non-
linear effects shall be taken into account in design checks against gross plastic deformation, creep
rupture, creep excessive strain, and fatigue.
_________________________________________________________________________________
Replace paragraph B.7.4:
B.7.4 Constitutive laws
The constitutive law to be used in the model depends on the design check:
 in the gross plastic deformation design check, B.8.2, a linear-elastic ideal-plastic law with Tresca's
yield condition (maximum shear stress condition) and associated flow rule;
 in the progressive plastic deformation design check, B.8.3, in the creep rupture design check,
B.9.4, in the creep excessive strain design check, B.9.5, a linear-elastic ideal-plastic law with von
Mises' yield condition (maximum distortion energy condition) and associated flow rule;
 in the fatigue design check, B.8.5, a linear-elastic law;
 in the instability design check, B.8.4, either a linear-elastic or a linear-elastic ideal-plastic law,
depending on the approach.
In the GPD-DC von Mises' yield condition may also be used, but the design material strength
parameter (design yield strength) shall then be modified, see B.8.2.1.
In the F-DC, which shall be performed by usage of the requirements of Clause 18, continuing
plastification is accounted for by application of plasticity correction factors, see 18.8.
In the creep-fatigue interaction design check results of F-DC and ECS-DC are used.
_________________________________________________________________________________
Add a new title to B.7.5.1, a
...