EN 13445-3:2009/A2:2013

SLOVENSKI STANDARD
SIST EN 13445-3:2009/oprA5:2012
01-maj-2012
1HRJUHYDQHWODþQHSRVRGHGHO.RQVWUXLUDQMH'RSROQLOR$
Unfired pressure vessels - Part 3: Design
Unbefeuerte Druckbehälter - Teil 3: Konstruktion
Récipients sous pression non soumis à la flamme - Partie 3: Conception
Ta slovenski standard je istoveten z: EN 13445-3:2009/prA5
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
SIST EN 13445-3:2009/oprA5:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN 13445-3:2009/oprA5:2012

SIST EN 13445-3:2009/oprA5:2012

EUROPEAN STANDARD
DRAFT
EN 13445-3:2009
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA5
March 2012
ICS
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 draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 54.

This draft amendment A5, if approved, will modify the European Standard EN 13445-3:2009. If this draft becomes an amendment, 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.

This draft amendment was established by CEN 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-CENELEC Management Centre has
the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Turkey and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13445-3:2009/prA5:2012: E
worldwide for CEN national Members.

SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Contents Page
Foreword . 3
1 Modification to 16.12 . 4

SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Foreword
This document (EN 13445-3:2009/prA5:2012) has been prepared by Technical Committee CEN/TC 54
“Unfired pressure vessels”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
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(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
1 Modification to 16.12
Delete the existing text of 16.12. and substitute the following:
16.12 Vertical vessels with skirts
16.12.1 Purpose
This clause gives rules for the design of support skirts for vertical vessels. It deals with the skirt itself and
local stresses in the region where skirt and pressure vessel join and with the design of the base ring.
16.12.2 Specific symbols and abbreviations (see Figure 16.12-1 to Figure 16.12-4)
The following symbols and abbreviation are in addition to those in clauses 4 and 16.3:²
a is the lever-arm due to offset of centre-line of shell wall;
e is the thickness of vessel wall;
B
e is the thickness of skirt;
Z
f is the allowable design stress of skirt;
Z
f is the allowable design stress of the ring (Shape A);
T
r is the inside knuckle radius of torispherical end;
R is the inside crown radius of torispherical end;
D is the mean shell diameter;
B
D is the mean skirt diameter;
Z
F is the equivalent force in the considered point (n = p or n = q) in the skirt;
Zn
F is the weight of vessel without content;
G
∆F is the vessel weight below section 2-2;
G
F is the weight of content;
F
M is the global bending moment, at the height under consideration;
∆ M is the moment increase due to change of centre of gravity in cut-out section;
P is the hydrostatic pressure;
H
W is the section modulus of ring according to Figure 16.12-1;
α is a stress intensification factor (see equations 16.12-33 to 16.12-36);
γ is the knuckle angle of a domed end (see Figure 16.12-2);
a
γ is part of the knuckle angle (see Figure 16.12-2);
σ is the stress;
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Subscripts:
a refers to the external shell surface, i.e. side facing away from central axis of shell;
b refers to bending (superscript);
m refers to membrane stress (superscript);
i refers to the inside shell surface;
o refers to the outside shell surface;
p is the point in the section under consideration where the global moment causes the greatest
tensile force in the skirt (e.g. side facing the wind = windward side);
q is the point in the section under consideration where the global moment causes the greatest
compressive force in the skirt (e.g. side facing away from the wind = leeward side);
1 is the section 1-1 (see Figures 16.12-1 to 16.12-4);
2 is the section 2-2;
3 is the section 3-3;
4 is the section 4-4.
5 is the section 5-5.
16.12.3 Connection skirt/shell
16.12.3.1 Conditions of applicability
a) The load on the skirt shall be determined according to generally accepted practice;
NOTE For tall vertical vessels the loads on the skirt shall be determined according to clause 22.
b) Attention shall be paid to the need to provide inspection openings.
16.12.3.2 Forms of construction
The forms of construction covered in this section are:
a) Structure shape A: skirt connection via support in cylinder area - Figure16.12-1;
o
Cylindrical or conical skirt with angle of inclination ≤ 7 to the axis;
b) Structure shape B: Frame connection in knuckle area - Figure 16.12-2;
°
Cylindrical or conical stand frame with angle of inclination ≤ 7 to the axis and
° ° ;
welded directly onto the domed end in the area 0 ≤ γ ≤ 20
Wall thickness ratio: 0,5 ≤ e /e ≤ 2,25;
B z
Torispherical end of Kloepper or Korbbogen type (as defined in 7.2) or
elliptical end having an aspect ratio K ≤ 2 (where K as defined in equation
(7.5-18)) and a thickness not less than that of a Korbbogen-type end of same
diameter;
c) Structure shape C: skirt slipped over vessel shell - Figure 16.12-3;
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Cylindrical skirt slipped over vessel shell and welded on directly
It is assumed that, on either side of the joining seam for a distance of 3 e ,
B
there is no disturbance due to openings, end connections, vessel
circumferential welds, etc.;
Note has to be taken of the risk of crevice corrosion.
F = ∆ F
G G
NOTE Outside the above limitations, subclauses 16.12.3.4.1 and 16.12.3.4.2 do not apply. Nevertheless,
subclause 16.12.3.4.3 may be used subject to calculate existing stresses by elastic shell theories.
φ D
B
Figure 16.12-1 ― Shape A: Skirt connection with supporting ring
(Membrane forces due to self weight and fluid weight)

SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Figure 16.12-2 ― Shape B: Skirt connection in knuckle area
(Membrane forces due to self weight and fluid weight)

SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Figure 16.12-3 ― Shape C: Skipped-over skirt area
(Membrane forces due to self weight and fluid weight)

SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
(a) = Section 1-1 to 5-5 (b) = Section 4-4

Figure 16.12-4 ― Schematic diagram of stand frame - sections
16.12.3.3 Forces and moments
The values F and M at the respective sections n=1 to n=4 are determined as a function of the
n n
combination of all the loads to be taken into consideration in this load case (see Figure 16.12-4). Further
checking may be necessary if the wall thickness in the skirt is stepped.
16.12.3.4 Checking at connection areas (sections 1-1, 2-2 and 3-3)
In the connection area, sections 1 to 3 defined in Figure 16.12-1 to 16.12-3 have to be checked. Checking
is required for the membrane and the total stresses, while only the respective longitudinal components
are being taken into account.
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
The section force F in the skirt in the region of the joint depends on the position (n), i.e. whether the
Z
moment strengthen (q) or weakens (p) the load component:
M
F =−F −F −F +4 (16.12-1)
Zp 1 G F
D
Z
M
F =−F −F −F −4 (16.12-2)
Zq 1 G F
D
Z
where
F is the global additional axial force in section 1-1;
M is the resulting moment due to external loads in section 1-1 above the joint; between the
pressure-loaded shell and skirt.
1.1.1.1.1 Membrane stresses
The checking procedure for membrane stresses is the same for structural shapes A, B and C. The
membrane stresses at point 1-1 are:
F +∆F + F
PD
Zp G F
m
B
σ = + (16.12-3)
1p
πD e 4e
B B B
F +∆F + F
PD
Zq G F
m
B
σ = + (16.12-4)
1q
πD e 4e
B B B
check that:
m
σ ≤f (16.12-5)
1p
m
σ ≤f (16.12-6)
1q
The minimum required wall thickness in section 1-1 are obtained from next equations:
 F +∆F + F 
PD
1 Zp G F
m B
 
e = +
1p
 
f πD 4
B
 
(16.12-7)
 F +∆F + F 
1 PD
Zq G F
m
B
 
e = +
1q
 
f πD 4
B
 
(16.12-8)
The calculation of this wall thickness is necessary for structural shape A.
m m
If σ or σ is a compressive stress, a stability check shall be carried out according to 16.14. This check
1p 1q
is not required if the longitudinal stress component is less than 1,6 times the value of the resulting
meridian membrane compressive stress for a vacuum or partial vacuum load case, provided the latter
was checked according to clause 8. This applies also to other sections in the cylindrical area of the shell.
Regardless of the check point, the membrane stress in section 2-2 is:
F +∆F PD
m m m
F G B
σ =σ =σ = + (16.12-9)
2 2q 2p
πD e 4e
B B B
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
Check that:
m
σ ≤f (16.12-10)
The mathematically necessary wall thickness in section 2-2 is obtained from next equation:
1 ∆F + F PD 
m G F B
e =  +  (16.12-11)
 
f πD 4
 B 
The calculation of this wall thickness is necessary for structural shape A.
In section 3-3 of the skirt, the membrane stresses are equal to:
F
Zp
m
(16.12-12)
σ =
3p
πD e
Z Z
F
Zq
m
(16.12-13)
σ =
3q
πD e
Z Z
Check that:
m
σ ≤f (16.12-14)
3p Z
m
σ ≤f (16.12-15)
3q Z
The mathematically necessary wall thicknesses in section 3-3 are obtained from next equations:
 F 
m Zp
e =   (16.12-16)
3p
 
f πD
Z Z
 F 
m Zq
 
e = (16.12-17)
3q
 
f πD
Z Z
The calculation of this wall thickness is necessary for structural shape A.
m m
If σ or σ is a compressive stress, the stability check may also be carried out according to 16.14.
3p 3q
16.12.3.4.2 Bending stresses
a) Structural shape A - Figure 16.12-1
The local bending moment at points p and q is:
M =0,5()D −D F (16.12-18)
p Z B Zp
M =0,5()D −D F (16.12-19)
q Z B Zq
The total section modulus of the support ring at the point n is calculated as follows:
2 2 2
π
 2 2 m m 2 m 
   
W =()D +e −D −e h + 2e −e −e D +0,5 e −e D (16.12-20)
   
p Z Z B B B 1p 2 B Z 3p Z
 
   
4 
SIST EN 13445-3:2009/oprA5:2012
EN 13445-3:2009/prA5:2012 (E)
2 2 2
π
 2 2 m m 2 m 
   
W =()D +e −D −e h +2e −e −e D +0,5e −e D (16.12-21)
q Z Z B B B 1q 2 B Z 3q Z
 
   
4 
The factor 0,5 in the third summand allows for the type of transition from the skirt to the connecting ring as
shown in Figure 16.12-1. If the allowable stresses f of the vessel and/or fZ of the skirt are less then that of
the support ring fT, the 2nd and/or the 3rd summand in equations (16.12-20) and (16.12-21) have to be
reduced with the respective ratio f / fT and/or fZ / fT
b) Structural shape B - Figure 16.12-2
The eccentricity a of the shell wall centreline causes a bending moment at point n:
M =a.F (16.12-22)
p Zp
M =a.F (16.12-23)
q Zq
with
2 2
a=0,5 e +e +2e e cos()γ (16.12-24)
B Z B Z
D +e −D +e
B B Z Z
cos()γ =1− (16.12-25)
2()r+e
B
The corresponding bending stresses in sections 1-1 to 3-3 at the outer surface (a):
6M
p
b b
σ ()a =σ ()a =C (16.12-26)
1p 2p
πD e
B B
6M
q
b b
σ ()a =σ ()a = C
1q 2q
πD e
B B
(16.12-27)
6M
p
b
σ ()a =C
3p
πD e
Z Z
(16.12-28)
6M
q
b
σ ()a =C
3q
πD e
Z Z
(16.12-29)
Within the range 0,5 ≤ e /e ≤ 2,25, the correction factor C can be taken approximately equal to:
B z
2 (16.12-30)
C = 0,63 - 0,057 (e /e )
B z
This relationship was determined from numerical calculations using the finite element method. Because of
the large number of parameters, a simplification is made which, under certain circumstances, can lead to
significant over-dimensioning, e.g. in the case of “Korbbogen” ends.
In the region of sections 1-1 to 2-2 the above bending stress components are superimposed by the
bending effect caused by the internal pressure in the knuckle.
()P+P D  γ 
b b H B
 
σ ()p =σ ()p = α−1 (16.12-31)
1 2
 
4e γ
B  a 
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