EN 14025:2008

SLOVENSKI STANDARD
01-oktober-2008
1DGRPHãþD
SIST EN 14025:2004
SIST EN 14025:2004/AC:2005
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Tanks for the transport of dangerous goods - Metallic pressure tanks - Design and
Construction
Tanks für die Beförderung gefährlicher Güter - Drucktanks aus Metall - Auslegung und
Bau
Citernes destinées au transport de matières dangereuses - Citernes métalliques sous
pression - Conception et fabrication
Ta slovenski standard je istoveten z: EN 14025:2008
ICS:
13.300 Varstvo pred nevarnimi Protection against dangerous
izdelki goods
23.020.20 Posode in vsebniki, montirani Vessels and containers
na vozila mounted on vehicles
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14025
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2008
ICS 13.300; 23.020.20 Supersedes EN 14025:2003
English Version
Tanks for the transport of dangerous goods - Metallic pressure
tanks - Design and Construction
Citernes destinées au transport de matières dangereuses - Tanks für die Beförderung gefährlicher Güter - Drucktanks
Citernes métalliques sous pression - Conception et aus Metall - Auslegung und Bau
fabrication
This European Standard was approved by CEN on 7 April 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a 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 European Standard 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
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14025:2008: E
worldwide for CEN national Members.

Contents
page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms, definitions and symbols.5
3.1 Terms and definitions .5
3.2 Symbols .5
4 Materials .6
4.1 General.6
4.2 Compatibility .6
5 Design .7
5.1 General.7
5.2 Reduction of shell thickness .7
5.3 Protection of the shell .7
5.4 Protection of equipment .8
6 Calculation.8
6.1 General.8
6.2 Design criteria.10
6.3 Calculation for internal pressure .10
6.4 Calculation for external pressure.27
6.5 Tank to frame connection/interface.28
7 Construction and Manufacturing .28
7.1 General Requirements .28
7.2 Cutting .29
7.3 Forming.29
7.4 Welding .30
7.5 Manufacturing tolerances .32
8 Repairs.33
8.1 General.33
8.2 Repair of surface defects in the parent metal.33
8.3 Repair of weld defects.33
Annex A (informative) RID/ADR references (2009 edition).34
A.1 Introduction.34
A.2 Tank-vehicles (Extract from chapter 6.8 ADR), Tank-containers (Extract from chapter 6.8
RID/ADR) and Tank-wagons (Extract from chapter 6.8 RID) .34
A.3 Special requirements applicable to Class 2 (Extract from chapter 6.8.3 ADR/RID).45
A.4 Relationship of test pressure and calculation pressure (Extract of sub-section 6.8.2.4.1
ADR/RID).45
Annex B (informative) Sample calculation.46
B.1 Introduction.46
B.2 Dimensions, characteristics of materials, operating and testing conditions .46
B.3 Calculation according to branch A .47
B.4 Calculation according to branch B .47
B.5 Calculation according to branch C .48
B.6 Calculation according to branch D .50
B.7 Results .57
Bibliography .59

Foreword
This document (EN 14025:2008) has been prepared by Technical Committee CEN/TC 296 “Tanks for transport of
dangerous goods”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by November 2008, and conflicting national standards shall be withdrawn at the latest
by November 2008.
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.
This document supersedes EN 14025:2003.
This European Standard has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports the objectives of the framework Directives on Transport of
Dangerous goods.
This standard is submitted for reference into the RID and/or in the technical annexes of the ADR.
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 the United Kingdom.

1 Scope
This European Standard specifies the minimum requirements for the design and construction of metallic pressure
tanks having a maximum working pressure exceeding 50 kPa (0,5 bar), for the transport of dangerous goods by road
and rail. This standard includes requirements for openings, closures and structural equipment; it does not cover
requirements of service equipment. For road tankers for the transport of LPG see EN 12493. For tanks for the
transport of cryogenic liquids see EN 13530-1 and EN 13530-2.
NOTE Design and construction of pressure tanks according to the scope of this standard are primarily subject to the
requirements of RID/ADR, 6.8.2.1, 6.8.3.1 and 6.8.5, as relevant. In addition, the relevant requirements of RID/ADR, columns 12
and 13 of Table A to chapter 3.2, 4.3 and 6.8.2.4 shall be met. For the structural equipment subsections 6.8.2.2 and 6.8.3.2
apply, as relevant. The definitions of RID/ADR 1.2.1 are referred to.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
EN 287–1, Qualification test of welders - Fusion welding - Part 1: Steels
EN 473, Non destructive testing — Qualification and certification of NDT personnel — General principles
EN 970, Non-destructive examination of fusion welds — Visual examination
EN 1435, Non-destructive examination of welds — Radiographic examination of welded joints
EN 1591-1, Flanges and their joints — Design rules for gasketed circular flange connections — Part 1: Calculation
method
EN 1708–1, Welding — Basic weld joint details in steel — Part 1: Pressurized components
EN 1714, Non-destructive examination of welds — Ultrasonic examination of welded joints
EN 12285-1:2003, Workshop fabricated steel tanks - Part 1: Horizontal cylindrical single skin and double skin tanks
for the underground storage of flammable and non-flammable water polluting liquids
EN 12561–6, Railway applications – Tank wagons – Part 6: Manholes
EN 13094:2008, Tanks for the transport of dangerous goods — Metallic tanks with a working pressure not
exceeding 0,5 bar — Design and construction
EN 13445-2, Unfired pressure vessels — Part 2: Materials
EN 13445-3:2002, Unfired pressure vessels — Part 3: Design
EN 13445-4, Unfired pressure vessels — Part 4: Fabrication
EN ISO 3834-1, Quality requirements for fusion welding of metallic materials — Part 1: Criteria for the selection of
the appropriate level of quality requirements (ISO 3834-1:2005)
EN ISO 3834-2, Quality requirements for fusion welding of metallic materials — Part 2: Comprehensive quality
requirements (ISO 3834-2:2005)
EN ISO 5817, Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) -
Quality levels for imperfections (ISO 5817:2003, corrected version:2005, including Technical Corrigendum 1:2006)
EN ISO 9606-2, Qualification test of welders - Fusion welding Part 2:— Aluminium and aluminium alloys (ISO
9606-2:2004)
EN ISO 10042, Welding — Arc-welded joints in aluminium and its alloys — Quality levels for imperfections
(ISO 10042:2005)
EN ISO 15607, Specification and qualification of welding procedures for metallic materials — General rules
(ISO 15607:2003)
EN ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 1: Arc welding (ISO 15609-1:2004)
EN ISO 15609-3, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 3: Electron beam welding (ISO 15609- 3:2004 )
EN ISO 15609-4, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 4: Laser beam welding (ISO 15609-4:2004)
EN ISO 15610, Specification and qualification of welding procedures for metallic materials — Qualification based
on tested welding consumables (ISO 15610:2003)
EN ISO 15611, Specification and qualification of welding procedures for metallic materials — Qualification based
on previous welding experience (ISO 15611:2003)
EN ISO 15612, Specification and qualification of welding procedures for metallic materials — Qualification by
adoption of a standard welding procedure (ISO 15612:2004)
EN ISO 15613, Specification and qualification of welding procedures for metallic materials — Qualification based
on pre-production welding test (ISO 15613:2004)
EN ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys (ISO 15614-1:2004)
EN ISO 15614-2, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 2: Arc welding of aluminium and its alloys (ISO 15614-2:2005)
ISO 1496–3, Series 1 freight containers — Specification and testing — Part 3: Tank containers for liquids, gases
and pressurized dry bulk
ISO 7005–1, Metallic flanges — Part 1: Steel flanges
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this standard, the following term and definition applies.
3.1.1
pressure-tank
tank as defined in the international regulations for the transport of dangerous goods by road or rail having a
maximum working pressure or a test pressure exceeding 50 kPa (0,5 bar)
3.2 Symbols
The following general symbols are used throughout the text. They are listed in alphabetical order and special symbols
are explained with the relevant formulae. Additional symbols used in the text are explained in Annex A.
A, A
p ; fm ; fb ; fp cross sectional areas reached for the calculation of nozzles reinforcement

(see 6.3.5.2 and Figure 7)
d inside diameter of an opening
i
D mean diameter of the cylindrical part of the tank at the junction of a cone
C
D outside diameter of the cylindrical part of the tank or the straight flange of the dished end
e
D inside diameter of the cylindrical part of the tank or the straight flange of dished end
i
e minimum required wall thickness (in mm) of the tank
e wall thickness of a conical part of a tank
k
e wall thickness of a hemispherical end
R
E Young's modulus
f nominal design stress (allowable stress)
d
h inside height of an ellipsoidal dished end
K shape factor of ellipsoidal ends
MWP maximum working pressure, in MPa

p design pressure, in MPa
p
dyn equivalent dynamic pressure
p test pressure, in MPa
test
p  vapour pressure at 50 °C or at the design temperature, whichever is the higher; to be taken as the
vap
numerical value of the absolute pressure
r inner knuckle radius, in mm
R inside spherical radius of the central part of a torispherical end
R guaranteed (upper) minimum yield strength or guaranteed minimum 0,2 % proof strength, in N/mm² (for
e
austenitic steel the 1 % proof strength may be chosen)
R guaranteed (upper) minimum yield strength or guaranteed minimum 0,2 % proof strength, at the relevant
e,t
design temperature, in N/mm² (for austenitic steel the 1 % proof strength at the relevant design temperature
may be chosen)
R guaranteed minimum tensile strength, in N/mm²
m
R guaranteed minimum tensile strength at the relevant design temperature, in N/mm²
m,t
λ welding coefficient
S
4 Materials
4.1 General
The tank shell shall be fabricated from metallic materials which shall be resistant to brittle fracture and of adequate
impact strength within the design temperature range. The material shall be suitable for shaping.
EN 13445-2 applies, but see also A.2 and A.3. For aluminium and aluminium alloys see also EN 14286.
Welded shells shall be fabricated from a material which has been shown to have acceptable welding characteristics.
4.2 Compatibility
Shells, fittings, and pipework shall be constructed from materials which are:
a) Substantially immune to attack by the substance(s) intended to be transported; or
b) Properly passivated or neutralised by chemical reaction; or
c) Lined with corrosion-resistant material directly bonded to the shell or attached by equivalent means;
(see also A.2).
Gaskets shall be made of materials not subject to attack by the substances intended to be transported. The
materials of the tank, including any devices, gaskets, linings and accessories, shall not adversely affect the
substances intended to be transported in the tank.
Guidelines on material specifications in relation to the substances to be transported may be taken from Annex B of
EN 12285-1:2003.
5 Design
5.1 General
Tanks shall be designed to withstand without loss of contents the:
1) operating conditions including static and dynamic forces in normal conditions of carriage;
2) test conditions;
3) explosion pressure proof conditions (if required);
under consideration of Clause 6.
NOTE The requirements coming from the relevant international regulations are given in Annex A for information.
5.2 Reduction of shell thickness
The minimum wall thickness of shells (see A.2) are allowed to be reduced by a maximum of 2 mm in the case of mild
steel or of an equivalent thickness of another metal, if protection of the shell against damage through lateral impact or
overturning is provided (see 5.3 and A.2).
For shells of rail tank wagons no reduction of the minimum wall thickness due to protection is allowed.
5.3 Protection of the shell
Shells of tank containers are protected against damage if one of the following measures is provided:
 structure, in which the shell is supported by a complete skeleton including longitudinal and transverse structural
members. This structure shall conform to the requirements of ISO 1496-3;
 double wall construction, where the aggregate thickness of the outer metal wall and the shell wall itself is not less
than the minimum wall thickness prescribed in A.2 for reduced wall thickness;
 "sandwich" construction, which means shells made with double walls having an intermediate layer of rigid solid
materials (e.g. foam, at least 50 mm thick), where the outer wall has a thickness of at least 0,5 mm of steel,
0,8 mm of aluminium or 2 mm of a plastics material reinforced with glass fibre. For other layer materials (e.g.
mineral wool, at least 100 mm thick), the outer wall has a thickness of at least 0,8 mm of austenitic steel. Other
combinations of materials used to provide protection against damage shall be shown to have equivalent strength
to the minimum thickness required in accordance with A.2. One method of comparing the strength of sheets of
materials is given in Annex B of EN 13094:2008.
For shells of road tank vehicles see also 6.8.2 of EN 13094:2008.
5.4 Protection of equipment
Items of equipment shall be protected against the risk of being wrenched off or damaged during transport or
handling.
Equipment shall be protected by strengthening rings, protective canopies or transverse or longitudinal members.
The protection of equipment shall comply with 6.14 of EN 13094:2008.
Items of equipment of tank containers are protected if placed within the contours of a skeleton structure (frame).
Equipment used on tanks for the transport of substances to which the special provision TE 19 of ADR (see
subsection 6.8.4 ADR) is allocated need additional protection.
NOTE For vacuum-operated waste tanks RID/ADR 6.10.3.1 applies.
6 Calculation
6.1 General
The calculation scheme given in Figure 1 shows how to determine the wall thickness of a shell to meet the
requirements of this standard and the relevant international regulations (i.e. RID and ADR).
Metallic pressure tanks
Design Data
RID/ ADR EN 14025
Cylindrical wall, ends and   All tank parts
covers
A B C D
Minimum wall Equivalent wall Test conditions Operating conditions
thickness thickness
formula(e) formula(e)
Determining  Determining Determining factors: Determining factors:
factors: factors:
P /D /σ /λ p / D /f /λ
T i i d s
e / R / A
P / D / σ / λ
T o m1 1
P / D /σ
C
With/ without
additional
protection
Largest value
e or e *) Largest value wall thickness
*) But see also absolute minimum values for the wall thickness
given in RID/ ADR depending on the diameter and the material
chosen respectively for tank vehicles on the volume of the tank.

other parts
cylindrical
wall, ends
Largest value and covers
Required minimum  Required
thickness dimensions
The wall thickness chosen, shall not be less than the maximum value resulting from the wall thickness determined
according to the relevant international regulations (i.e. RID/ADR, branches A and B in Figure 1 and A.2) on the one
hand and according to the following equations relevant to the test and service conditions (branches C and D in
Figure 1) on the other.
Figure 1 — Calculation scheme for the wall thickness of metallic pressure tanks for the transport of
dangerous goods
6.2 Design criteria
Design criteria (loads, allowable stresses, design temperature etc.) to be applied shall be taken from Table 1.
Table 1 — design criteria
Operating conditions Test conditions

MWP
p b
p
test
but not less than
a
(p − 1 bar) + p if applicable
vap dyn
f for ferritic steels and
d
min { R / 1,5; R / 2,4}
e,t m
aluminium alloys
f for austenitic steels
d
R / 1,5 min { 0,75 R ; 0,5 R }
e,t e m
with 30 % ≤ A ≤ 35 %
f for austenitic steels
d
c
max { R / 1,5; min (R / 1,2 ; R / 3)}
e,t e,t m,t
with A > 35 %
20 °C provided that the operating
temperature of the tank is within the range
Temperature at the pressure test
– 20 °C to + 50 °C. When the operating
Design temperature
(normally + 20 °C).
temperature is outside this range then the
design temperature shall be taken as the
extreme value of the operating temperature.
a
The dynamic forces shall be taken into account. This may be done by introducing an equivalent pressure p determined on the basis of
dyn
the forces specified in the relevant international regulations (see Annex A) but not less than 35 kPa ( 0,35 bar) and add it to the vapour gauge
pressure
(p – 1 bar). The largest compartment needs to be taken into account.
vap
b
To be taken from the relevant international regulation, (see also A.4).
c
It needs to be noted that the guaranteed minimum mechanical values differ with the temperature, and have to be chosen accordingly. If

no standard values are available, applicable values have to be determined otherwise.

6.3 Calculation for internal pressure
6.3.1 General
The thickness of the cylindrical section of the shell shall be determined in accordance with 6.3.2. The thickness of the
ends (including partitions) of the shell shall be determined in accordance with 6.3.3; for partitions and surge plates see
also A.2. The thickness of a conical section and the reinforcement of the cone to cylinder junction shall be determined
in accordance with 6.3.4. For flanges, joints and their bolts see 6.3.6.
Openings in the shell shall be designed in accordance with 6.3.5.
The calculation for construction types not given hereafter shall be in accordance with to EN 13445-3.
6.3.2 Wall thickness of the cylindrical section
The wall thickness shall not be less than the value given by Equation (1).
p × D
i
e = (1)
2 f ×λ − p
d S
6.3.3 Wall thickness of ends
6.3.3.1 General
The thickness of the ends, subject to the limitations in 6.3.3.2, shall not be less than that given by 6.3.3.3 and 6.3.3.4,
6.3.3.5 or 6.3.3.6 as applicable.
6.3.3.2 Design limitations
The following design limitations shall apply to the tank ends (compare Figure 2):
(a) Hemispherical ends 0,001 D ≤ e ≤ 0,16 D
e e
(b) Torispherical ends  0,001 D ≤ e ≤ 0,08 D
e e
0,06 D ≤ r ≤ 0,2 D
i i
r ≥ 2 e
R ≤ D
e
(c) Ellipsoidal ends 0,001D ≤ e ≤ 0,08 D
i i
3,4 ≤ D /h ≤ 4,4
i
The four relationships in (b) and the two relationships in (c) shall be simultaneously fulfilled.
NOTE Kloepper and Korbbogen-type ends are particular cases of torispherical ends:
kloepper type
torispherical end for which R/D = 1,0 and r/D = 0,1
e e
korbbogen type
torispherical end for which R/D = 0,8 and r/D = 0,154
e e
Figure 2 — Geometry of ends
6.3.3.3 Thickness of the flange of the end
The wall thickness of the cylindrical or straight flange of the end shall not be less than the thickness as determined in
accordance with 6.3.2 for a cylindrical section having the same inside diameter D .
i
6.3.3.4 Thickness of hemispherical ends
The thickness of a hemispherical end shall be not less than that determined by Equation (2).
p × D
i
e = (2)
R
4 f × λ − p
d S
6.3.3.5 Thickness of torispherical ends
6.3.3.5.1 General
The minimum thickness of torispherical ends shall be the greatest of the values of e e or e as determined by
y, s b
Equations (3) to (5).
p (0,75× R + 0,2× D )
i
e = β (3)
y e
f
d
where β is calculated from Equations (6) to (14).
e
p × R
e = (4)
s
2 f × λ − 0,5× p
d S
( )
0,825 3
 
p  D 
 i 
e = (0,75 × R + 0,2 × D )   (5)
b i
 
 
111 f r
 
d
 
If ends are manufactured from several elements then the welding coefficient λ may be taken equal to 1,0 (for
S
thickness calculations only) if the weld crosses the crown area 0,6 D (see Figure 3).
e
λ = 0,8 resp. 1,0   λ = 1,0    λ = 1,0 λ = 0,8 resp.1,0
S S S S
according to 7.4.3        according to 7.4.3
a) weld outside 0,6 D  b) weld inside 0,6 D   c) composed ends

e e
Figure 3 — Position of welds in ends
6.3.3.5.2 Formulae for calculation of ββββ
e
Y = min (e / R ; 0,04) (6)
Z = log (1/ Y ) (7)
X = r / D (8)
i
N = 1,006 − (9)
6,2 + (90 Y )
For X = 0,06:
3 2
β = N (−0,3635 Z + 2,2124 Z − 3,2937 Z +1,8873) (10)
e 0,06
For 0,06 < X < 0,1:
β = 25 [(0,1− X )β + (X − 0,06)β ] (11)
e e 0,06 e 0,1
For X = 0,1:
3 2
β = N (−0,1833 Z +1,0383 Z −1,2943 Z + 0,837) (12)
e 0,1
For 0,1 < X < 0,2:
β = 10 [(0,2 − X )β + (X − 0,1)β ] (13)
e e 0,1 e 0,2
For X = 0,2:
β = max { 0,95 (0,56 −1,94 Y − 82,5 Y ) ; 0,5 } (14)
e 0,2
6.3.3.5.3 Openings within the knuckle area of Kloepper- and Korbbogen-type ends
6.3.3.5.3.1 In this clause rules are given for increasing the thickness of a dished end to compensate for
branches within the knuckle area.
The rules are limited in application to Kloepper- and Korbbogen-type ends for which:
a) 6d / D ≤ 0,           (15)
i e
d
i
b) ≤ 6,7          (16)
e × D
e
The increased thickness required by this clause applies to the whole knuckle area. Welded-on compensation is not
permitted.
6.3.3.5.3.2 Determine β from the procedure in Table 2
k
Replace p by (β p) in Equation (3) to arrive at the required thickness. Equations (4) and (5) continue and apply
k
without modification.
Table 2 — Procedure for calculation of weakening factor ββββ for openings in the knuckle region (design)
k
Step Kloepper type end Korbbogen type end
1    
p p
V = log 1000  V = log 1000 
10 10
   
f f
 d   d 
2 2 3 3
A = max {0,5; 0,264 + 0,938 V − 0,592 V + 0,14 V } A = 0,54 + 0,41V − 0,044V
3 2 2
B = min {4,2 ; 4,91− 2,165 V + 0,151V } B = 7,77 − 4,53 V + 0,7441V
4    
d d d d
i i i i
  β = max  A + B ; 1+ 0,5 B 
β = max A + B ; 1+ 0,3 B
k k
   
D D D D
 e e   e e 
6.3.3.6 Thickness of ellipsoidal ends
An ellipsoidal end is an end that is made on a former that has a true ellipsoidal shape. Ellipsoidal ends shall have a
shape factor K with a value between 1,7 and 2,2.
D
i
K = (17)
2 h
Ellipsoidal ends shall be designed as torispherical ends in accordance with 6.3.3.5 with values of r and R as given
by the following:
 0,5 
r = − 0,08 D (18)
 
i
K
 
R = (0,44 K + 0,02) D (19)
i
6.3.4 Wall thickness of conical sections
6.3.4.1 General
The conical section of the tank shell shall conform to the design limitations in 6.3.4.2. The wall thickness shall be
determined in accordance with 6.3.4.3. For more information compare also EN 13445-3.
6.3.4.2 Design limitations of the conical section
This clause gives rules for right circular cones and cone/cylinder intersections where the cone and the cylinder are
of the same axis of rotation. It applies only to cones with an apex angle not greater than 120 ° and cones for which
e × cosα / D > 0,001 (20)
c
For the angle α see Figure 4.
For offset cones between two cylinders the cylinders shall have parallel centrelines offset from each other by a
distance not greater than the difference of the radii. A required thickness shall be calculated in accordance with
6.3.4.3.3 for the junction at the large end and in accordance with 6.3.4.3.4 for the junction at the small end. Since
the thickness calculated above is the minimum allowable at that point along the case, it is permissible to build a
cone from plates of different thickness provided that at every point the minimum is achieved.
Figure 4 — Junction between cylinder and cone; angle αααα
6.3.4.3 Determination of the wall thickness of the conical section
6.3.4.3.1 The minimum thickness of the wall of the conical section e of the shell shall be not less than the
k
lowest value given by Equation (21), unless otherwise required by the subclauses of 6.3.4.3.
 
p × D  1 
i
 
e =   (21)
k
 
2 f × λ − p cosα
 
d S
 
6.3.4.3.2 Wall thickness at the junction of cylindrical and conical sections of the shell.
The conditions and design calculations for the large end of the cone are given in 6.3.4.3.3 and for the small end of
the cone in 6.3.4.3.4.
6.3.4.3.3 Large end of the cone without a knuckle at the joint
The joint shall be made with a butt weld and there shall be a smooth transition across the joint from cylindrical
section to the conical section.
The joint shall be subjected to 100 % radiographic or ultrasonic inspection, unless the actual thickness is 40 %
greater than the minimum thickness determined in accordance with this subclause.
The minimum thickness of the wall of the shell at the junction of the conical and cylindrical sections shall be
determined from the following two equations by iteration.
p × D × β
c c
e = (22)
2 f
d
 
 
1 D tanα
c
 
 
β = − 0,15 (23)
c
 
 
3 e
1+1/ cosα
1  
 
This thickness shall be maintained for a distance of at least 1,4 l , from the junction along the cylinder. The
required thickness e of the cone adjacent to the junction is the greater of e and e . This thickness shall be
2 k
maintained for a distance of at least 1,4 l from the junction along the cone, see Figure 4. The distance l and
2 1
l are determined as follows:
l = D × e (24)
1 c 1
D × e
c 2
l = (25)
cosα
6.3.4.3.4 Minimum thickness at the small end of the cone
This clause applies provided that:
a) junction is more than 2 l along the cylinder and 2 l along the cone from any other junction or major
1 1
discontinuity, such as another cone/cylinder junction or flange,
b) minimum thickness of the cylinder e is maintained for a distance l and that of the cone e is maintained for a
1 1 2
distance l from the junction; l and l are calculated according to Equations (24) and (25) using Figure 5
2 1 2
and
c) thickness meets the requirements of 6.3.2 and 6.3.4.3.1.

Figure 5 — Geometry of cone/cylinder intersection; small end
Minimum thickness e and e shall be chosen so that:
1 2
p × D × β
c H
e = (26)
2 f × λ
d S
where
Dc tanα
β = 0,4 × + 0,5 (27)
H
e τ
S 1+ S
τ = S × + if S < 1 (28)
cosα 2
1+ S
τ = 1+ × S if S ≥ 1 (29)
2 cosα
e
S = (30)
e
NOTE The above requirements do not provide values for e and e separately. They may have to be adjusted relative to
1 2
each other to suit the needs of the design.
6.3.5 Openings and reinforcements
6.3.5.1 Openings in the shell
6.3.5.1.1 General
Openings in the shell shall be either circular or elliptical. The size of the openings shall be not greater than that
given in 6.3.5.1.2. The distance between the openings shall not be less than that given in 6.3.5.1.3.
The ration of major to minor axis of elliptical openings shall not exceed 2:1. The axis of elliptical openings in the
shell along the line of the shell shall be taken as the diameter of the opening for design purposes.
For elongated openings its larger length shall be taken as the diameter.
The ratio of the wall thickness of the branch to the wall thickness of the main body shall comply with the limits of
Figure 6.
Figure 6 — Wall thickness ratio for branches
6.3.5.1.2 Size of openings in the shell
The size of the openings shall be not greater than the following:
d
i
≤ 1 (31)
D
i
in the cylindrical sections;
d
i
≤ 0,6 (32)
D
i
in the dished ends.
6.3.5.1.3 The distance between openings
The distance between openings when measured from the outside of the branch or the reinforcement, as applicable,
shall be no less than 2 l ,
m
where l = (2 r + e )× e (33)
m im m m
D
i
where for shells r = (34)
im
for torispherical ends r = R (35)
im
0,22 D
 
i
for elliptical ends r = D × + 0,02 (36)
 
im i
h
 
where
e is the analysis thickness of the shell (end) maintained within the length l ;
m
m
l is the length of the shell considered as effective compensation, measured along the material centreline
m
from the edge of the opening without a branch or outside of the branch (or pad).
For distances less than 2 l the remaining cross-section between openings shall be checked to ensure that it is
m
adequate to sustain the load acting on it (see also Equation (37)).
6.3.5.2 Nozzle reinforcement
6.3.5.2.1 The design method specified below only applies to cylindrical shells, and dished ends having circular or
elliptical openings, where the assumptions and conditions specified in 6.3.5.1 are satisfied.
6.3.5.2.2 Shells with openings shall be reinforced where necessary. The reinforcement of the main body can be
obtained by:
a) set-in or set-on pads,
b) set-in or set-on branches or
c) combinations thereof.
6.3.5.2.3 The reinforcement area of the main body with openings cannot be calculated directly but shall be
assumed in the first instance. This assumption may be verified by means of the following method. The applied
method is based on basic pressure thicknesses derived from equations in 6.3.2 for cylindrical shells and from
equations in 6.3.3 for dished ends and leads to relationships between a pressure loaded area A and a stress
p
loaded cross sectional area which is the sum of A , A and A (see Figure 7). The calculation may need to be
fm fp fb
repeated using a corrected assumption of the reinforcement area.
6.3.5.2.4 Where necessary, sufficient reinforcement shall be provided in all planes through the axis of the opening
branch.
6.3.5.2.5 In the case of elliptical openings the ratio between the major and the minor axis shall not exceed 2. For
elliptical openings in cylindrical shells the opening axis parallel to the longitudinal axis of the cylinder shall be taken as
the diameter for design purposes. For elliptical openings in dished ends the major axis shall be so taken.
6.3.5.2.6 Set-in or set-on fillet welded branches shall only be considered in the calculation if the ratio of the
diameter is d /D ≤ 1/3 and the ratio of the wall thickness e /e is less than 0,7. Each fillet weld shall have a throat
i e b m
thickness not less than 0,7 times the thinner wall thickness.

A = A + A
A = A + A
p ps pb
p ps pb
r  d 
D  d 
im e
i e
A = l + 
A = l + 
ps m
ps m  
 
2 2
2 2
 
 
d
d
i
i
A =()e + e
A =()l + e
pb pa m
pb b m
A = e ×l
A = e ×()l + e
fm m m
fm m m b
A = e ×l
A = e ×l
fp p p
fb b b
a) d)
A = A + A
A = A + A
p ps pb
p ps pb
D d
r d  
 
i i
im e
A = l + 
A = l + 
ps  m 
ps m
 
2 2
2 2
 
 
d
d
i
i
A =()e + e
A =()l + e
pb m p
pb b m
A = e ×l
A = e ×l
fm m m
fm m m
A = e ×l
A =()l + e + l ×e
fp p p
fb b m bi b
b) e)
A = A + A
p ps pb
A = A + A
p ps pb
r d
 
im e
A = l + 
D  d 
i e ps m
 
A = l +  2 2
ps m  
 
2 2
 
d
i
A =()l + e
d
i pb b m
()
A = e + e 2
pb pa m
A = e ×l
fm m m
A = e ×l
fm m m
A = e ×()l + e + l
fb b b m bi
A = e ×l
fp p p
A = e × l
fp p p
c) f)
Figure 7 — Shells with isolated openings; examples for reinforcement
a), c) and e) calculation scheme for cylindrical shells; b), d) and f) calculation scheme for spherical shells
6.3.5.2.7 All openings shall satisfy the following general relationship:
p × [A + 0,5 (A + A + A )] ≤ (f × A + f × A + f × A ) (37)
p fm fb fp d fm d,b fb d,p fp
where
p is the design pressure;
A is the pressure loads area as shown Figure 7, calculated using internal dimensions;
p
A is the cross sectional area of branch within the compensation limits;
fb
A is the cross sectional area of the shell within the compensation limits;
fm
A is the cross sectional area of the pad within the compensation limits;
fp
f is the lower of the nominal design stress of the branch and f ;
d,b d
f is the lower of the nominal design stress of the pad and f .
d,p d
NOTE Simplified formulae for calculation of Afm, Afp and Afb for various geometries are given below the diagrams in
Figure 7. These formulae are considered to give acceptable results within the accuracy of the method. However, the designer
can choose to calculate more precise values, based on the true geometry, if he so wishes.
6.3.5.2.8 Only set-in or set-on welded pads in accordance with Figure 7 shall be used.
The width of the padsl considered as contributing to the reinforcement shall not exceedl :
p m
l ≤l (38)
p m
The value of the thickness of the pad e used in the determination of A shall not exceed twice the value of the wall
p fp
thickness of the shell (minus tolerance and wastage) e :
m
e ≤ 2 e (39)
p m
6.3.5.2.9 The wall thickness of branches (nozzles) shall, if necessary, be in excess of the thickness calculated
to withstand internal pressure for a length l measured from the exterior surface of the shell:
b
l = (d + e )× e (40)
b e a,b a,b
where
d outside diameter of branch
e
e analysis thickness of the branch maintained within the length l .

a,b b
6.3.5.2.10 Areas A , A , A , shall be determined in accordance with Figure 7 where the lengths contributing to
fm fp
p
the reinforcement shall be not more thanl for the shell, and l for the branch.
m b
The maximum value to be used in the calculation of the part extending inside, if any, in the case of set-through
branches (see Figure 7) shall be:
l = 0,5l (41)
bi b
6.3.5.3 Manhole and Inspection Openings
6.3.5.3.1 General
The shell or each of its compartments shall be fitted with a means of access to allow inspection of the interior. The
means of access shall be
 manhole or
 for tanks or compartments of tanks with a capacity less than 3 000 l, an inspection opening with a diameter of
not more than 300 mm.
When designing manhole openings, due regard shall be taken of the need to allow access with full rescue facilities
including self contained breathing apparatus.
Manholes shall be large enough to permit the entry and the rescue of persons. Inspection openings shall be so small
that persons cannot enter, however, they shall be large enough to permit adequate inspection.
The minimum dimensions of manhole and inspection openings in lined shells shall be maintained after the lining is
applied.
The spacing between adjacent manholes or inspection openings shall be not less than that described in 6.3.5.1.3.
6.3.5.3.2 Reinforcement of Manhole and Inspection Openings
A shell containing a manhole or inspection opening shall have adequate reinforcement (compensation) in the area
adjacent to the manhole or inspection opening. Reinforcement shall be in accordance with 6.3.5.2 and may be
obtained by
 increasing the wall thickness of the shell,
 use of a reinforcement plate,
 use of a circumferential reinforcement ring,
 increasing the wall thickness of the neck ring or
 combination of the above measures.
Figure 7 also shows exampl
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