SIST EN 13445-3:2002/A4:2005

SLOVENSKI STANDARD
SIST EN 13445-3:2002/A4:2005
01-november-2005
1HRJUHYDQHWODþQHSRVRGH±GHO.RQVWUXLUDQMH
Unfired pressure vessels - Part 3: Design
Unbefeuerte Druckbehälter - Teil 3: Konstruction
Récipients sous pression non soumis a la flamme - Partie 3: Conception
Ta slovenski standard je istoveten z: EN 13445-3:2002/A4:2005
ICS:
23.020.30
SIST EN 13445-3:2002/A4:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN 13445-3:2002/A4
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2005
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: Konstruction
3: Conception
This amendment A4 modifies the European Standard EN 13445-3:2002; it was approved by CEN on 14 April 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13445-3:2002/A4:2005: E
worldwide for CEN national Members.

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EN 13445-3:2002/A4:2005 (E)
Foreword
This document (EN 13445-3:2002/A4:2005) 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 January 2006, and conflicting
national standards shall be withdrawn at the latest by January 2006.
This amendment, relative to Clause 14, is based on EN 13445-3:2002 up to Issue 11 (May 2004).
The document includes the text of the amendment itself. The corrected pages of EN 13445-3 will be delivered
as issue xx 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, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
2

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EN 13445-3:2002/A4:2005 (E)
14 Expansion bellows
14.1 Purpose
Add at the end of the first sentence (after c):
subject to internal or external pressure and cyclic displacement.
Delete Note 1.
Rename Note 2 as Note.
Add the following paragraph at the end of the subclause:
If erosion or vibration is considered to be a concern due to the velocity of the medium conveyed, the use of an
internal sleeve should be considered.
14.2.5 Squirm
Replace the complete subclause by the following:
14.2.5 Reinforcing and equalizing rings
Devices that are tightly fitted into the roots of the convolutions in order to reinforce the bellows against internal
pressure.
Reinforcing rings are fabricated from tubing or round bars. Equalizing rings are approximately "T" shaped in
cross section and their primary purpose is to limit the total equivalent axial displacement range.
Figure 14.1-1c)
Replace by the following:
1
q
2
e
c
D
m
L
w
e
D
i

Key
(1) convolution
(2) reinforcing collar
c) Toroidal bellows
Figure 14.1-1 — Three types of expansion bellows
3

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EN 13445-3:2002/A4:2005 (E)
14.3 Specific symbols and abbreviations
Replace the description of E by the following:
o
E is the modulus of elasticity of bellows material at room temperature;
o
Replace the description of K by the following:
b
K is the bellows axial rigidity, given by equations (14.5.7-1, 14.6.8-1 or 14.7.8-1);
b
Add the following symbols in alphabetical order:
s is the strain caused by deformation during manufacturing, see 14.5.2.2;
d
α is the in-plane instability stress interaction factor, given by equation (14.5.2-12);
δ is the in-plane stress instability stress ratio, given by equation (14.5.2-11);
Add in the list of main subscripts:
r for reinforced
14.4.1 Geometry
Add a new subclause 14.4.1.4:
14.4.1.4 The number of plies shall be such that:
n ≤ 5
p
14.4.4 Materials
Replace the text of the subclause by the following:
These rules apply to ferritic steel, austenitic steel and nickel-chromium-iron, nickel-iron-chromium alloys.
14.4.5 Manufacture
Delete the whole subclause.
14.4.6 Welding seams
Replace the whole subclause by the following:
14.4.5 Welding seams
Expansion bellows may include one or several longitudinal welds. U-shaped unreinforced bellows may also
have circumferential welds (see 14.5.9).
The circumferential attachment welds of single and multi-ply expansion bellows shall be designed according to
the sketches given in Table 14.4.5-1.
Table 14.4.6-1
Replace Table 14.4.6-1 by the following:
4

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EN 13445-3:2002/A4:2005 (E)
Table 14.4.5-1 — Typical bellows attachment welds




1) In the case of fillet welds, the weld thickness "a“ shall fulfil following equation:
ae≥ 0,7
s

where e is the nominal thickness of the connecting shell.
s
2) A reinforcing collar is advisable, if the cylindrical end tangent of bellows L exceeds:
t
Le≥ 0,5D
tsi

3) The reinforcing collar shall be fixed axially by welding or mechanical devices.
4) In the case of butt welds, special tools are necessary for welding of multi-ply bellows.

5) The diameter of the weld shall not exceed the mean diameter of bellows D by more than 20 % of
m
the convolution height w.

6) Fittings and reinforcing collars opposite to the pressure bearing side of the bellows shall have a radius
or a bevel at the edge in contact with the bellows and tangent.

NOTE These sketches are not exhaustive. Other configurations can be used, provided they lead to
an equivalent level of safety.
5

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EN 13445-3:2002/A4:2005 (E)
14.4.7 Installation
Renumber as 14.4.6.
14.5.1.1 Scope
Replace the first sentence by the following:
This subclause applies to two types of unreinforced bellows having nominally U-shaped convolutions:
Add the following sentence before Figure 14.5.1-1:
Each convolution consists of a sidewall and two tori of nearly the same radius (at the crest and root of the
convolution), in the neutral position, so that the convolution profile presents a smooth geometrical shape as
shown in Figure 14.5.1-1.
14.5.1.2 Conditions of applicability
Replace the text of the subclause by the following:
The following conditions of applicability apply in addition to those listed in 14.4.
a) A variation of 10 % between the crest convolution radius r and the root convolution radius r is
ic ir
permitted (see Figure 14.5.1 -2 for definitions of r and r ).
ic ir
b) The torus radius shall be such that:
r ≥ 3 e ,
i p
where
r + r
ic ir
r = .
i
2
c) The off-set angle of the sidewalls, α, in the neutral position shall be such that:
−15 ≤ α ≤ +15 degrees (see Figure 14.5.1-2).
D
i
d) The convolution height shall be such that: w ≤ .
3
14.5.2 Determination of intermediate quantities
Transfer the whole of the text of 14.5.2 into a new subclause, 14.5.2.1 General. Add an introductory sentence
to 14.5.2.1, as follows.
14.5.2.1 General
The following formulae are used in the determination of the intermediate factors.
….

Add the following equations to 14.5.2.1, after equation 14.5.2-10.
6

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EN 13445-3:2002/A4:2005 (E)
σ
m,b
δ = (14.5.2-11)
3σ
θ,I
224
αδ=+1 2 + 1−24δ +δ (14.5.2-12)
()
Add the following new subclause 14.5.2.2.
14.5.2.2 Determination of strain caused by deformation
The maximum true strain caused by deformation for bellows is given by:
22
s=+1,04ss (14.5.2-13)
d θ b
The circumferential true strain caused by deformation s depends on the forming process. For the common
c
forming processes the following formulas shall be used:
 for hydraulic or similar processes where the forming is performed 100 % to the outside of the initial
cylinder:
w
s=+ln 1 2 (14.5.2-14)
θ
D
i
 for roll forming processes with 50 % forming to the inside and 50 % to the outside of the initial cylinder:

w
s=+ln 1 (14.5.2-15)
θ 
D
i
 for half-convolutions manufactured from ring plates by roller bending or other methods, where the
maximum strain occurs at the inner crest:
π

−+1 2re
()
 ip

2

s =− ln1− (14.5.2-16)
θ
De+

ip


The bending component of the true strain caused by deformation s is independent of the forming process and
b
given by:
 e 
p
s = ln1+ (14.5.2-17)
 
b
2r +e
 
i p
 

14.5.3.3 Bellows convolutions
Replace the 2 last lines of list item d) by:
where
7

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EN 13445-3:2002/A4:2005 (E)
 K = 3,0 for as-formed bellows (with cold work) (14.5.3-8)
f
 K = 1,5 for annealed bellows (without cold work) (14.5.3-9)
f

14.5.4 Squirm due to internal pressure
Replace the whole subclause by the following
14.5.4 Instability due to internal pressure
14.5.4.1 Column instability
The allowable internal design pressure to avoid column instability, P , is given by:
s,c
πK
b
P = 0,34 (14.5.4-1)
s,c
Nq
The internal pressure P shall not exceed P :
s,c
P ≤ P
s,c
14.5.4.2 In-plane instability
The allowable internal design pressure to avoid in-plane instability, P , is given by:
s,i
∗
AR
e
P=−(2π ) (14.5.4-2)
s,i
Dq α
m
* is the effective proof stress at design temperature of bellows material in the as-formed or annealed
where R
e
condition.
In absence of values for R * in material standards, the following values shall be used for austenitic steel:
e
*
a) for as-formed bellows (with cold work) (14.5.4-3)
RK = R
edp1,0/t
*
b) RR =0,75    for annealed bellows (without cold work) (14.5.4-4)
ep1,0/t
where
R is the yield stress at 1 % at design temperature, as defined in clause 4;
p1,0/t
K is the bellows cold-work factor, given by:
d
1+ 5×s if s ≤ 0.2

d d
K = (14.5.4-5)

d
2,0 if s > 0,2
d


For non-austenitic steel: R * = R
e p 0,2/t
8

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EN 13445-3:2002/A4:2005 (E)
The internal pressure P shall not exceed P :
s,i
P ≤ P
s,i
14.5.6.3.1 General
Replace the second paragraph by:
The allowable number of cycles given by the following formulae includes a reasonable safety margin (factor 3
on cycles and 1,25 on stresses) and represents the maximum number of cycles for the operating condition
considered.
In the third paragraph, replace squirm by instability.
In the fourth paragraph, replace cycles of pressure or displacement by cycles of displacement.
Replace the fifth paragraph by:
Use of specific fatigue curves established by a manufacturer will be covered later and specific requirements to
be applied will be set-up in Annex K.3 (in course of consideration by CEN/TC 54/WG C).
14.5.6.3.2 Austenitic steels and other similar materials
Replace the text of the subclause by the following:
This following formula applies to as-formed bellows made of austenitic steel, nickel-chromium-iron and nickel-
iron-chromium alloys.
The allowable number of cycles is given by (see Figure 14.5.6-1):
E
0 2
 If σ ≥1080 N/mm :
eq
E
b
3,4


9283,3
N (14.5.6-4)
=
alw
E
0
σ − 372,3
eq

E
b
2
where σ is expressed in N/mm .
eq
E
0 2
 If σ <1080 N/mm :
eq
E
b
3,4


10259, 4
N = (14.5.6-5)
alw
E
0

σ − 297,9
eq

E
b
2
where σ is expressed in N/mm .
eq
9

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EN 13445-3:2002/A4:2005 (E)
E
0 2 6
 If σ ≤ 297,9 N/mm : N = 10 cycles shall be used.
eq alw
E
b
6
The curve and the equations are only valid for: 370 ≤ N ≤10
alw
Figure 14.5.6-1
Replace figure 14.5.6-1 by the following
10

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EN 13445-3:2002/A4:2005 (E)
10 000
Y
1 000
100
100 1 000 1 0000 1 00000 1 000 000
X

Key
X number of cycles N
2
Y σ in N/mm
eq
Figure 14.5.6-1 — Fatigue curve at room temperature (E =E ) for unreinforced as-formed bellows
b 0

11

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EN 13445-3:2002/A4:2005 (E)
Figure 14.5.6-2
Delete the figure.
Figure 14.5.8-2
In the figure title, replace Revolutions by Convolutions.
14.5.8.3 Fabrication
Delete the whole subclause and Table 14.5.8-1.
14.5.8.4 Inspection and testing
Delete the whole subclause.
14.6 U-shaped reinforced bellows
Replace the Note by the following:
14.6.1 Purpose
This subclause applies to bellows that have nominally U-shaped convolutions with rings to reinforce the
bellows against internal pressure.
Each convolution consists of a sidewall and two tori of the same radius (at the crest and root of the
convolution), in the neutral position, so that the convolution profile presents a smooth geometrical shape as
shown in Figure 14.6.1-1.
L
f
X - X
6
A
f
q X
5
1
X
4
3
2
W
e
c
L
t
L
t
A A A
r r r
e
D
i

Key
(1) convolution (3) reinforcing collar (5) equalizing ring
(2) end tangent (4) end equalizing ring (6) reinforcing rings
Figure 14.6.1-1 — U-shaped reinforced bellows
12

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EN 13445-3:2002/A4:2005 (E)
The following symbols apply in addition to those listed in clause 4 and 14.3.
A is the cross sectional metal area of one reinforcing fastener, see Figure 14.6.1-1;
f
A is the cross sectional metal area of one bellows reinforcing ring member, see Figure 14.6.1-1;
r
C is the convolution height factor for reinforced bellows, given by equation 14.6.3-11;
r
E is the modulus of elasticity of reinforcing fastener material at design temperature;
f
E is the modulus of elasticity of reinforcing ring member material at design temperature;
r
H is the resultant total internal pressure force acting on the bellows and reinforcement, given by
equation (14.6.3-12);
f is the allowable stress of reinforcing fastener material at design temperature;
f
f is the allowable stress of reinforcing ring member material at design temperature;
r
R is the ratio of the internal pressure force resisted by the bellows on the internal pressure force
resisted by the reinforcement, given by equation14.6.4-3.
14.6.2 Conditions of applicability
The following conditions of applicability apply in addition to those listed in 14.4.
a) A variation of 10 % between the crest convolution radius r and the root convolution radius r shall be
ic ir
permitted (see Figure 14.5.1-2 for definitions of r and r ).
ic ir
b) The torus radius shall be such that:
r ≥ 3 e
i p
r + r
ic ir
where r = .
i
2
c) The off-set angle of the sidewalls, α, in the neutral position shall be such that:
−15 ≤ α ≤ +15 degrees (see Figure 14.5.1-2).
D
i
d) The convolution height shall be such that: w ≤ .
3
14.6.3 Determination of intermediate quantities
The following formulae are used in the determination of the intermediate factors.
en= e (14.6.3-1)
pp
DD=+ 2 e+e (14.6.3-2)
ci c
DD=+w+e (14.6.3-3)
mi
13

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EN 13445-3:2002/A4:2005 (E)
D
*
i
(14.6.3-4)
ee=
pp
D
m
**
en= e (14.6.3-5)
pp


L
t


k = min  ; ()1,0 (14.6.3-6)

1,5 De
ip


*
A=+ ew2 (π−2)(2r+e) (14.6.3-7)
[ ]
i
2re+
i
C = (14.6.3-8)
1
w
2re+
i
C = (14.6.3-9)
2
*
1,1 De
mp
qr=+42e (14.6.3-10)
i
2
100

 (14.6.3-11)
C=−0,3
r
1,5
1048P + 320

2
where P is expressed in N/mm
HP= Dq (14.6.3-12)
m
AE
b
R = (14.6.3-13)
1
AE
rr
AELD
b fm
R=+ (14.6.3-14)
2
DAE AE
mff rr
14.6.4 Stresses due to internal pressure
14.6.4.1 End tangent
The circumferential membrane stress due to pressure:
2

()De+ LEk
1
it b
σ P =P (14.6.4-1)
()
θ,t
2 ++
e()D e LE eDLEk
it b cccc

shall comply with:
σ P ≤ f
()
θ,t

14

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EN 13445-3:2002/A4:2005 (E)
14.6.4.2 Collar
The circumferential membrane stress due to pressure:
2

DLEk
1
ct c
σ ()P = P (14.6.4-2)

θ,c
2 eD()++e LE eDLEk
itb cccc

shall comply with:
σ P ≤ f
()
θ,c c
14.6.4.3 Bellows convolutions
a) The circumferential membrane stress due to pressure:
HR

σ = (14.6.4-3)
θ 
2AR +1

shall comply with:σ ≤ f
θ
where
 for integral reinforcing ring members, given by equation 14.6.3-12;
R=R
1
 for reinforcing ring members joined by fasteners, given by equation 14.6.3-13.
R=R
2
NOTE In the case of reinforcing members that are made in sections, and joined by fasteners in tension, this equation
assumes that the structure used to retain the fastener does not bend in order to permit the reinforcing member to expand
diametrically. In addition, the end reinforcing members must be restrained against the longitudinal annular pressure load of
the bellows.
b) The meridional membrane stress due to pressure is given by:
wC− q
()
r
σ P = 0,85 P (14.6.4-4)
()
m,m
∗
2e
c) The meridional bending stress due to pressure is given by:
2

0,85 wC− q
r
(14.6.4.-5)
σ ()P = P

m,b
∗

22ne
pp

d) The meridional membrane and bending stresses shall comply with:
σσP+≤PKf (14.6.4.-6)
() ()
m,m m,b f
where
K =3,0 for as-formed bellows (with cold work);
f
K =1,5 for annealed bellows (without cold work).
f
15

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EN 13445-3:2002/A4:2005 (E)
14.6.4.4 Reinforcing ring member
The circumferential membrane stress due to pressure

H 1
'
σ P = (14.6.4-7)
()

θ,r
2AR +1
r1
shall comply with:
'
σ P ≤ f
()
θ,r r
NOTE In the case of equalizing rings, this equation provides only the simple membrane stress and does not include
the bending stress caused by the eccentric fastener location. Elastic analysis and/or actual tests can be used to determine
these stresses.
14.6.4.5 Reinforcing fastener
The membrane stress due to pressure:

H 1
''
σ P = (14.6.4-8)
()
θ,f 
2AR +1
f2
shall comply with:
"
σ ()P ≤ f
θ ,f f
14.6.5 Instability due to internal pressure
14.6.5.1 Column instability
The allowable internal design pressure to
...