SIST EN 13445-3:2014/A8:2019

SLOVENSKI STANDARD
01-maj-2019
1HRJUHYDQHQHNXUMHQHWODþQHSRVRGHGHO.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 13445-3:2014/A8:2019
ICS:
23.020.32 7ODþQHSRVRGH Pressure vessels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 13445-3:2014/A8
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2019
EUROPÄISCHE NORM
ICS 23.020.30
English Version
Unfired pressure vessels - Part 3: Design
Récipients sous pression non soumis à la flamme - Unbefeuerte Druckbehälter - Teil 3: Konstruktion
Partie 3 : Conception
This amendment A8 modifies the European Standard EN 13445-3:2014; it was approved by CEN on 19 November 2018.

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-CENELEC 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-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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13445-3:2014/A8:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Modifications to Clause 2, Normative references . 4
2 Modification to 5.3.1, Actions . 4
3 Addition of a new Subclause 5.3.2.4, Load combinations . 4
4 Addition of a new Subclause 6.7, Nominal design stress of anchor bolting . 8
5 Modifications to 8.4, General . 8
6 Modification to Subclause 16.4, Local loads on nozzles in spherical shells . 8
7 Modification to 16.5, Local loads on nozzles in cylindrical shells . 18
8 Modification to 16.6.6, Bending Limit Stress . 27
9 Modification to 16.7.2, Specific symbols and abbreviations . 28
10 Modification to 16.7.4, Applied force . 29
11 Modification to 16.7.5, Load limits for shell . 29
12 Modification to 16.8.6.2, Vessel under external pressure . 29
13 Modification to 16.8.7, Load limit at the saddle (without a reinforcing plate) . 29
14 Modification to 16.12.4.1, Specific symbols and abbreviations . 29
15 Modification to 16.12.4.3, Check of the skirt in regions with openings . 29
16 Modification to 16.12.5.1, Specific symbols and abbreviations . 30
17 Modifications to 16.12.5.2, Anchor bolt and concrete forces . 30
18 Modification to 16.14, Global loads . 30
19 Modification to 16.14.2, Specific symbols and abbreviations . 30
20 Modification to 16.14.8, Compressive stress limits . 32
21 Modification to 16.14.8.1, Calculation . 32
22 Modification to 16.14.8.2, Tolerances . 34
23 Modifications to 16.14.9, Wind and earthquake loads . 38
24 Modification to Clause 22, Static analysis of tall vertical vessels on skirts . 39
25 Modification to O.4.1, General. 49
26 Modification to O.4.2, Polynomial coefficients . 49
27 Modification to O.4.3, Figures for physical properties of steels . 50
28 Addition of a new Annex V (informative), Consider a buffer for unknown nozzle
loads — Opening design for unknown nozzle loads . 50

European foreword
This document (EN 13445-3:2014/A8:2019) has been prepared by Technical Committee CEN/TC 54
“Unfired pressure vessels”, the secretariat of which is held by BSI.
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 October 2019, and conflicting national standards shall
be withdrawn at the latest by October 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
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
EN 13445-3:2014.
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, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
the United Kingdom.
1 Modifications to Clause 2, Normative references
Add a footnote number “ ” after the reference “EN 1991-1-4:2005” and the corresponding footnote at the
bottom of the page:
“ EN 1991-1-4:2005 is impacted by the stand-alone amendment EN 1991-1-4:2005/A1:2010 and the
corrigendum EN 1991-1-4:2005/AC:2010.”.
In the reference to EN 1991-1-6, replace "EN 1991-1-6" with “EN 1991-1-6:2005”.
Add the following new reference at the appropriate place:
“EN 12195-1:2010, Load restraining on road vehicles — Safety — Part 1: Calculation of securing forces”.
2 Modification to 5.3.1, Actions
Add the following note at the end of the subclause:
“
NOTE The combination of actions is given in 5.3.2.4.”.
3 Addition of a new Subclause 5.3.2.4, Load combinations
Insert the following new subclause:
“
5.3.2.4 Load combinations
5.3.2.4.1 General
Load combinations of non-pressure loads in Table 5.3.2.4-1 are used in connection with calculations
according to Clause 16 and Annex C (linear elastic behaviour). The basic calculation of pressure envelope
by design pressures and temperatures shall be made before Clause 16 (or Annex C) calculations. The load
combinations in Table 5.3.2.4-1 are minimum to be taken into account, if they are relevant. There may
also be other loads.
5.3.2.4.2 Specific definitions
5.3.2.4.2.1 Dead loads
Maximum dead load (G ) is the weight of the whole un-corroded vessel with all internals (trays,
max
packing, etc.), attachments, insulation, fire protection, piping, platforms and ladders.
Corroded dead load (G ) is defined as G but with the weight of the corroded vessel.
corr max
Minimum dead load (G ) is the weight of the un-corroded vessel during the installation phase, excluding
min
the weight of items not already mounted on the vessel before erection (e.g. removable internals,
platforms, ladders, attached piping, insulation and fire protection).
NOTE A scaffold is normally self-supported. In this case, the weight of the scaffold is not included in the vessel
weight.
Transport dead load (G ) is the case, when vessel has the removable internals and insulation already
trans
mounted on the vessel in the workshop.
5.3.2.4.2.2 Live loads
Live loads (L) used in this clause are weight loads of the contents (fluids or solids in the bottom of the
vessel, on trays and in packing) and traffic loads on platforms and ladders by personnel and machinery.
5.3.2.4.2.3 Wind loads
Wind loads (W) are horizontal global pressure loads caused by wind and acting on the projected area of
the vessel and its attachments, as influenced by the force coefficients (see 22.4.4).
5.3.2.4.2.4 Earthquake loads
Earthquake loads (E) are quasi-static horizontal forces on the vessel sections caused by seismic
accelerations at the base of vessel calculated by the “lateral force method of analysis” (see 22.4.5).
5.3.2.4.2.5 Forces from attached external piping
Reaction forces from attached external piping are forces resulting from weight (G), wind (W), earthquake
(E) and other additional forces (F) as far as they influence the global equilibrium of the vessel (see 22.4.6
for columns).
NOTE Forces and moments on nozzles and supports on the vessel caused by attached external piping can act as
internal and/or external loads. Internal loads are those that cause local loads only and have no influence on the
global equilibrium because they are self-compensating. Furthermore, attached pipes can either load the vessel or
restrain it depending on their layout. Consideration of these aspects is given in the recommendations in 22.4.6.
5.3.2.4.3 Specific symbols and abbreviations
The following specific symbols and abbreviations are used in Table 5.3.2.4-1 in addition to those in
Clause 4:
E earthquake load (see 5.3.2.4.2.4)
F additional loads from piping (thermal expansion loads) (see 5.3.2.4.2.5)
f nominal design stress for operation conditions for anchor bolts, see Formula (6.7–1)
B,op
G minimum dead loads (see 5.3.2.4.2.1)
min
G maximum dead loads (see 5.3.2.4.2.1)
max
G corroded dead loads (see 5.3.2.4.2.1)
corr
G transport dead loads (see 5.3.2.4.2.1)
trans
L live loads of each loading case (contents, etc.) (see 5.3.2.4.2.2)
P internal calculation pressure as defined in 5.3.10 for P > 0 (including hydrostatic pressure)
i
P external calculation pressure as defined in 5.3.10 for P < 0 (e.g. vacuum)
e
W wind load (Clause 22 and EN 1991-1-4)
σ maximum allowable compressive stress for operation conditions in accordance with 16.14.8,
c,all
with σ as defined in 8.4 and with a safety factor of 1,5 in Formula (16.14–29)
e
σc,all,test maximum allowable compressive stress for test conditions in accordance with 16.14.8, with σe
as defined in 8.4 and with safety factor 1,05 in Formula (16.14–29)
& operator which means: superposition of the different load types for the axial and lateral forces,
the bending moments and the resulting shear and longitudinal stresses using the beam theory
for non-pressure loads and the membrane theory for pressure loads
Table 5.3.2.4–1 — Load combinations
Load Types of load Load combination Allowable tensile Allowable compressive Allowable tensile Explanations
Case included including weighting stress for shells stress for shells stress for anchor
factors bolts
Operation with internal
LC0 P , G P and G f σ f
i max i max d c,all B,op
pressure
0,9·P and G and L and F Operation with internal
i max
LC1 P , G , L, F, W f σ f
i max d c,all B,op
b
and 1,1·W pressure and wind
P and G and L and F and Operation with external
e max
LC2 Pe, Gmax, L, F, W fd σc,all fB,op
1,1·W pressure and wind
Operation without pressure
LC3 G , L, F, W G and L and F and 1,1·W f σ f
max max d c,all B,op
but with wind
Shut down (no pressure,
LC4 G , W G and 1,1·W f σ l f contents and thermal
corr corr d c,al B,op
reactions)
LC5 G , W G and 0,7·W f σ f Installation
min min d c,all B,op
Operation with internal
c
LC6 P , G , L, E 0,9·P and G and L and E f σ 1,2· f
i max i max exp c,all,test B,op
pressure and earthquake
Operation with external
c
LC7 P , G , L, E P and G and L and E f σ 1,2· f
e max e max exp c,all,test B,op
pressure and earthquake
Operation without pressure
c
LC8 G , L, E G and L and E f σ 1,2· f
max max exp c,all,test B,op
but with earthquake
P , G , L , P and G and L and Test with test pressure, test
test max test test max test
LC9 f σ f
test c,all,test B,op
W 0,6·W filling and wind
LC10 G ≥ 1,5*G f σ N/A Lifting (Crane)
max max test c,all,test
a
LC11 G f σ N/A Transport
trans test c,all,test
a
Transport load case shall be taken into account on basis of manufacturer’s risk analysis for the vessel, if it proves to be critical for the vessel depending on the transport way
(road, ship or train). If no special regulations are specified the following transport loads shall be considered: downwards: 1,4 Gtrans, sidewards and upwards: 0,5*Gtrans driving
direction: 0,8*G . The transport loads shall be agreed with transport company so that the transport will not damage the vessel (see EN 12195-1).
trans
b
Real operating pressure may be used instead of 0,9*P , if it is limited either naturally (e.g. steam temperature) or by safety related control and instrumentation system.
i
c
After exceptional load case the vessel shall have re-inspection.
Remarks
For LC1 and LC2: If more than one combination of coincident design pressure and design temperature exists then all combinations shall be investigated.
Alternatively a single combination of the maximum pressure and maximum temperature of all the cases may be used. It is not certain that the governing condition of
coincident pressure and temperature is also governing for the load combinations.
For LC1 and LC6: The factor 0,9 is applied to the internal calculation pressure P because the internal operating pressure is normally 10 % below PS due to the
i
pressure limiting device.
For LC3 and LC8: These load cases are not required when both loading cases LC1 and LC2, or LC6 and LC7 are applicable, i.e. internal and external pressure are
applied.
For LC5: The wind load in this case depends on configuration at this time (with or without scaffold, platforms, insulation). The reduced factor for the wind load is in
accordance with EN 1991-1-6:2005 for duration times < 12 months.
For LC9: The reduced factor for the wind load is in accordance with EN 1991-1-6:2005 for duration times < 3 d.
In calculation of allowable bending stress σ for transport and lifting cases according to 16.6.6, the nominal design stress f can be used instead of f and K shall be
b,all test 2
set equal 1,05.
The global effect of additional piping loads on shell stresses or anchoring shall be taken into account by designer, if considered relevant.”.
4 Addition of a new Subclause 6.7, Nominal design stress of anchor bolting
Insert the following new subclause:
“
6.7 Nominal design stress of anchor bolting
The nominal design stress for the anchor bolts for the operation condition shall be calculated as follows:


RR
p0,2/TB m/20
f = min ; (6.7-1)

B,op
1,,65 2 062 5



where
TB is design temperature for anchor bolts
NOTE In most cases the design temperature TB of the anchor bolts will be 20 °C and will generally be much
lower than the design temperature of the vessel.”.
5 Modifications to 8.4, General
Replace the first sentence of 8.4.2 with the following one:
“
8.4.2 For shells made in non-austenitic steels, excluding ferritic, martensitic and precipitation
hardened stainless steels in material group 7 and austenitic ferritic stainless steels in material group 10,
the nominal elastic limit shall be given by:”.
Replace the first sentence of 8.4.3 with the following one:
“
8.4.3 For shells made in austenitic steels, ferritic, martensitic and precipitation hardened stainless
steels and austenitic ferritic stainless steels, the nominal elastic limit shall be given by:”.
6 Modification to Subclause 16.4, Local loads on nozzles in spherical shells
Replace Subclause 16.4 with the following one:
“
16.4 Local loads on nozzles in spherical shells
16.4.1 Purpose
This clause provides a method for the design of a spherical shell with a nozzle subjected to local loads
and internal pressure.
In cases where the loads are unknown see Annex V.
16.4.2 Additional specific symbols and abbreviations
The following symbols and abbreviations are in addition to those in Clause 4 and 16.3:
d is mean nozzle diameter;
d is inside nozzle diameter;
i
d is outside nozzle diameter;
e
d is outside diameter of a reinforcing plate;
e is analysis thickness of the combined shell and reinforcing plate;
c
e is equivalent shell thickness;
eq
e is nozzle thickness;
b
f is allowable design stress of nozzle material;
b
F is nozzle shear force;
S
F is axial nozzle force (positive when force is tensile or radially outwards);
Z
F is maximum allowable axial force on the nozzle;
Z,max
L is width of the reinforcing plate;
M is bending moment in the nozzle at the junction with the shell;
B
M is maximum allowable bending moment in the nozzle at the shell junction;
B,max
M is torsional nozzle moment
Z
R is mean shell radius at the nozzle;
scf , scf and scf are stress factors due to pressure, nozzle axial load and moment respectively;
P Z M
Δσ is stress range due to pressure;
P
Δσ is stress range due to axial nozzle load range;
FZ
Δσ is stress range due to moment range;
MB
κ is reinforcement rate factor;
λ is a geometric parameter applicable to nozzles in spheres;
S
τ is the shear stress in shell;
τ is the shear stress in shell caused by shear force;
F
τ is the shear stress caused by torsional moment;
Z
Φ is load ratio.
16.4.3 Conditions of applicability
The following conditions apply:
/ R ≤ 0,1 ;
a) 0,001 ≤ ea
NOTE Values of e / R < 0,001 are acceptable provided that the shell wall deflection does not exceed half the
a
wall thickness.
b) distances to any other local load in any direction shall be not less than ;
R⋅ e
c
.
c) nozzle thickness shall be maintained over a distance of l≥⋅de
b
16.4.4 Summary of design procedure
The design procedure is as follows:
a) calculate the basic dimensions e and L from the following:
c
1) at the nozzle outside diameter, when a reinforcing plate is fitted:
 
f
(16.4-1)
e= ee+⋅min ;1
c a2
 
f
 
2) at the outside edge (d = d ) of a reinforcing plate, or when no reinforcing plate is fitted:
e = e (16.4-2)
c a
Width L of the reinforcing pad given by:
L 0,5 dd− (16.4-3)
( )
2 e
b) calculate the maximum allowable individual loads (see 16.4.5);
c) check the load ratios and the interaction of the loads (see 16.4.6);
d) if no reinforcing plate or a reinforcing plate with L≥ Re()+ e is fitted, go to step 6;
a2
e) calculate the maximum allowable individual loads at the edge of the reinforcing plate (d = d
and e = e ), and check the load ratios and the interaction of the loads using 16.4.5 and 16.4.6;
c a
f) calculate the equivalent shell thickness e (see 16.4.7.2) and check the combined stress range (see
eq
16.4.7) in cases only where one of the ranges for pressure ∆P, force ∆F or moment ∆M (calculated
Z B
according to Formulae (16.4-16) to (16.4-18) in 16.4.7.1) is larger than the extreme absolute values
of the pressure P, the force F or the moment M ;
Z B
alternatively the combined stress range (see 16.4.7) may be applied when the external loads
contain portions from thermal expansions of attached piping; in this case the checks of 16.4.5 and
16.4.6 may be applied for the pressure and the mechanical portions of the external loads only but
the check of 16.4.7 shall be done for the ranges of the pressure and the combined mechanical and
thermal loads;
g) check the nozzle longitudinal stresses (see 16.4.8);
h) if stresses or load ratios are excessive, increase the shell or nozzle thickness, or reduce the loads,
and return to step 1.
Step f) shall be made only at the nozzle edge.
16.4.5 Maximum allowable individual loads
16.4.5.1 To determine the maximum allowable values of pressure, axial load and bending moment,
which may be independently applied to a nozzle the following procedure shall be applied.
16.4.5.2 Determine the reinforcement rate factor:
=
 
2 fe.
e
bb
b
 
κ = min ; 10, (16.4-4)
 
fe. d
c
 
For the calculation of the allowable loads at the edge of the reinforcing plate or for a nozzle on a shell
without an opening, the reinforcement factor κ is equal to 1.
NOTE A shell without opening is used for trunnion loading.
16.4.5.3 Determine λ :
S
d
(16.4-5)
λ =
S
R⋅e
c
16.4.5.4 Calculate permissible pressure P from the general formula for reinforcement of isolated
max
openings in Clause 9. It is reproduced here from 9.5.2 for convenience and the notation is in 9.3.
(Af + Af ). f + Af ⋅ f + Af ⋅ f
s w s b ob p op
P = (16.4-6)
max
Ap + Ap + 0,5 Ap + 0,(5 Af + Af + Af + Af )
( )
s b φ s w bP
NOTE For application of this formula to different load cases, see 3.16, NOTE 1.
16.4.5.5 Determine the allowable axial nozzle load FZ,max either from Figure 16.4-1 or by calculation:
F = f⋅e 18, 2+ 24,. 1+⋅κ λ + 09, 1⋅κ .λ (16.4-7)
)
Z,max c ( S S
Non-dimensional upper and lower bounds are given in Figure 16.4-1.
16.4.5.6 Either read the allowable bending moment M from Figure 16.4-2 or calculate it using:
B,max
d
2 2
M = f⋅ e⋅ 4, 9+ 2,.0 1+⋅κ λ + 0, 91.κλ. (16.4-8)
( )
B,max c S S
Non-dimensional upper and lower bounds are given in Figure 16.4-2.
16.4.5.7 Shear stresses
2F
S
τ = (16.4-8a)
F
π⋅⋅de
c
2M
Z
τ = (16.4-8b)
Z
π⋅⋅de
c
ττ+τ (16.4-8c)
F Z
16.4.6 Combination of external loads and internal pressure
16.4.6.1 To determine the effects of the combination of pressure, axial load and bending moment
acting simultaneously, the following procedure shall be applied.
=
If the axial force and the bending moment include portions from the thermal expansions of attached
piping, the applied loads need not include the thermal expansion effects. In this case the stress ranges
check Subclause 16.4.7 shall be applied taking into account the total loads including the thermal
portions (see 16.4.4 step f), second paragraph).
16.4.6.2 Calculate the individual load ratios as follows:
P
(16.4-9)
Φ =
P
P
max
F
Z
Φ = (16.4-10)
Z
F
Z,max
M
B
Φ = (16.4-11)
B
M
B,max
2τ
Φ = (16.4-11a)
T
f
16.4.6.3 Check that each individual load ratio is limited as follows:
Φ ≤ 10, (16.4-12)
P
Φ ≤ 10, (16.4-13)
Z
Φ ≤ 10, (16.4-14)
B
Φ ≤1,0 (16.4-14a)
T
16.4.6.4 Check that the interaction of all the loads meets the following:
 
max Φ +ΦΦΦ;; −⋅0,2Φ +Φ +Φ ≤1,0 (16.4-15)
( )
PZ Z P Z B T
 
 
The above formula is based on a linear interaction of pressure and axial load with the bending moment
and yields a conservative result. In specific cases design by analysis, as given in Clause 5, may show that
a circular interaction is less conservative.
16.4.7 Stress ranges and their combination
16.4.7.1 From the minimum and maximum values of the pressure and local loads, determine the
following load ranges:
ΔP = max (P ; 0) – min (P ; 0) (16.4-16)
ΔF = max (F ; 0) – min (F ; 0) (16.4-17)
Z Z Z
ΔM = max (M ; 0) – min (M ; 0) (16.4-18)
B B B
ΔF = max (F ; 0) – min (F ; 0) (16.6-18a)
S S S
ΔM = max (M ; 0) – min (M ; 0) (16.4-18b)
Z Z Z
16.4.7.2 At the nozzle edge only, calculate the equivalent shell thickness e . This is equal to e unless
eq c
a reinforcing plate of width L< Re()+ e is used, in which case eeq is given by:
a2


e ⋅ L f

 (16.4-19)
e=e+⋅min ;e min ;1

eq a 2

f

Re + e 
( )
a 2

16.4.7.3 Determine the following stresses:
Due to the pressure range:
 
∆PR⋅
 
∆σ = scf (16.4-20)
PP
 
2e
 
eq
 
Due to the range of the axial load:

∆F
R
Z

∆σ = scf (16.4-21)
FZ Z

π⋅⋅de e
eq eq

Due to the moment range:

4∆M
R
B
∆σ = scf (16.4-22)
MB M

e

π⋅⋅de
eq
eq

where
scf , scf and scf are taken from Figures 16.4–3 to 16.4–8.
P Z M
NOTE The scf factors in Figures 16.4–3 to 16.4–8 are from BS 5500:1997, G2.5 (see L.2 - ref [6]).
Range of shear stresses
2∆F
S
∆τ = (16.4-22a)
F
π⋅⋅de
c
2∆M
Z
∆τ = (16.4-22b)
Z
π⋅⋅de
c
∆∆ττ+∆τ (16.4-22c)
FZ
16.4.7.4 The equivalent stress range shall be restricted as follows:
∆∆σσ+ +∆σ +⋅43∆τ ≤ f (16.4-23)
( )
P FZ MB
=
16.4.8 Nozzle longitudinal stresses
This subclause may be ignored for a nozzle intended to be attached to a piping of the same resistance
(thickness multiplied by allowable stress).
16.4.8.1 Maximum longitudinal tensile stress in the nozzle shall be limited as follows:
Pd 4 M
F
B
Z
+ +≤ f (16.4-24)
b
4 e π de
π d e
bb
b
F shall be set to zero when resulting in an axial compressive stress.
Z
16.4.8.2 The longitudinal stability of the nozzle shall be checked (with P = 0) as follows:
||F
M
Z
B
+≤ 10, (16.4-25)
MF
max max
F shall be set to zero when resulting in axial tensile stress. M and F are respectively the allowable
Z max max
global moment and force in the nozzle. They are calculated in 16.14.

Figure 16.4-1 — Non-dimensional graphical form of F
Z,max
(upper curve = maximum reinforced, lower curve = unreinforced)
Figure 16.4-2 ― Non-dimensional graphical form of M
B,max
(upper curve = maximum reinforced, lower curve = unreinforced)

Figure 16.4-3 ― Stress factor in sphere for internal pressure (flush nozzle)
Figure 16.4-4 — Stress factor in sphere for internal pressure (protruding nozzle)

Figure 16.4-5 — Stress factor in sphere for moment loading (flush nozzle)
Figure 16.4-6 — Stress factor in sphere for moment loading (protruding nozzle)

Figure 16.4-7 — Stress factor in sphere for thrust loading (flush nozzle)
Figure 16.4-8 ― Stress factor in sphere for thrust loading (protruding nozzle)
”.
7 Modification to 16.5, Local loads on nozzles in cylindrical shells
Replace Subclause 16.5 with the following one:
“
16.5 Local loads on nozzles in cylindrical shells
16.5.1 Purpose
This clause provides a method for the design of a cylindrical shell with a nozzle subjected to local loads
and under internal pressure.
In cases where the loads are unknown see Annex V.
16.5.2 Additional specific symbols and abbreviations
The following symbols and abbreviation are in addition to those in Clause 4 and 16.3:
a to a are the coefficients of the polynomials;
0 4
C to C are factors;
1 4
D is the mean shell diameter at the opening;
d is the inside nozzle diameter;
i
d is the outside nozzle diameter;
e
d is the mean nozzle diameter;
d is the external diameter of a reinforcing plate;
ec is the combined analysis thickness of the shell and reinforcing plate;
e is the equivalent shell thickness;
eq
e is the nozzle analysis thickness;
b
f is allowable design stress of nozzle material;
b
F is the shear nozzle force in longitudinal direction of the shell (Figure 16.5–1);
X
F is the shear nozzle force in circumferential direction of the shell (Figure 16.5–1);
Y
F is the axial nozzle force (Figure 16.5–1);
Z
F is the maximum allowable axial nozzle force;
Z,max
L is the width of the reinforcing plate;
M is the circumferential moment applied to the nozzle (Figure 16.5–1);
X
MY is the longitudinal moment applied to the nozzle (Figure 16.5–1);
M is the maximum allowable circumferential moment applied to the nozzle;
X,max
M is the maximum allowable longitudinal moment applied to the nozzle;
Y,max
M is the torsional nozzle moment;
Z
R is mean shell radius at the nozzle;
Δσ is the stress range due to pressure;
P
Δσ is the stress range due to axial nozzle load;
FZ
Δσ is the stress range due to circumferential moment;
Mx
Δσ is the stress range due to longitudinal moment;
My
λ is a parameter applicable to nozzles in cylinders;
C
τ is maximum total shear stress in shell at nozzle outside diameter ;
τ is the maximum shear stress in shell at nozzle outside diameter due to shear force F
X X
(Figure 16.5–1);
τ is the maximum shear stress in shell at nozzle outside diameter due to shear force F
Y Y
(Figure 16.5–1);
τ is the shear stress in shell at nozzle outside diameter due to torsional moment M
Z Z
(Figure 16.5–1);
Φ is a load ratio.
16.5.3 Conditions of applicability
The following conditions apply:
a) 0,001 ≤ e / D ≤ 0,1;
a
d
b) ;
λ ≤ 10
C
De
c
c) distances to any other local load in any direction shall be not less than D⋅ e ;
c
d) nozzle thickness shall be maintained over a distance of: l≥⋅de .
b
=
16.5.4 Summary of design procedure
The design procedure is as follows:
a) calculate the basic dimensions e and L from the following:
c
1) at the nozzle outside diameter, when a reinforcing plate is fitted:
 
f
e= ee+⋅min ;1
c a2
 
f
 
2) at the outside edge (d = d ) of a reinforcing plate, or when no reinforcing plate is fitted:
e = e
c a
The width L of the reinforcing pad is given by:
L = 0,5 (d2 – de)
b) calculate the maximum allowable individual loads (see 16.5.5);
c) check the load ratios and the interaction of the loads (see 16.5.6);
d) if no reinforcing plate or if a reinforcing plate is applied with L≥ D ()e + e go to step f);
a2
e) calculate the maximum allowable individual loads at the edge of the reinforcing plate (d = d ; e = e
2 c a
and e / e ≥ 0,5) and check the load ratios and the interaction of the loads using 16.5.5 and 16.5.6;
b c
f) calculate the equivalent shell thickness e (see 16.5.7.2) and check the combined stress range
eq
(see 16.5.7) in cases only where one of the ranges for pressure ΔP, force ΔF or moments ΔM and
Z X
ΔM (calculated according to Formulae (16.5-16) to (16.5-19) in 16.5.7.1) is larger than the extreme
Y
absolute values of the pressure P, the force F or the moments M and M ;
Z X Y
alternatively the combined stress range (see 16.5.7) may be applied when the external loads
contain portions from thermal expansions of attached piping; in this case the checks of 16.5.5 and
16.5.6 may be applied for the pressure and the mechanical portions of the external loads only but
the check of 16.5.7 shall be done for the ranges of the pressure and the combined mechanical and
thermal loads;
g) check the nozzle strength (see 16.5.8);
h) if stresses or load ratios are excessive, increase the shell or nozzle thickness, or reduce the loads
and return to step 1.
Step f) shall be made only at the nozzle edge.
16.5.5 Maximum allowable individual loads
16.5.5.1 To determine the maximum allowable values of pressure, axial load and bending moment,
which may be independently applied to a nozzle the following procedure shall be applied.
16.5.5.2 Determine λ thus:
C
d
λ = (16.5-1)
C
De
c
16.5.5.3 Calculate permissible pressure P from the general formula for reinforcement of isolated
max
openings given in Clause 9. It is reproduced from 9.5.2 for convenience and the notation is in 9.3.
(Af + Af ). f + Af ⋅ f + Af ⋅ f
s w s b ob p op
P = (16.5-2)
max
Ap + Ap + 0,5 Ap + 0,(5 Af + Af + Af + Af )
( )
s b φ s w bP
NOTE For application of this formula to different load cases, see 3.16, NOTE 1.
16.5.5.4 Determine the allowable axial nozzle load F from the following:
Z,max
(16.5-3)
F = f⋅⋅e C
Z,max c 1
in which C is either read from Figure 16.5-2 or calculated from:
 23 4 
C max⋅ aa+ ⋅λ+ a⋅λλ+ a⋅ + a⋅λ ; 1, 81 (16.5-4)
( )
1 0 1 C 2 C 3 C 4 C
 
 
and coefficients a to a are given in Table 16.5-1.
0 4
16.5.5.5 Determine the allowable circumferential moment M from:
X,max
d
M = f⋅e⋅⋅ C (16.5-5)
X,max c 2
in which C is either read from Figure 16.5-3 or calculated from:
23 4
C max aa+⋅λ+ a⋅λλ+ a⋅+ a⋅λ ;4, 90 (16.5-6)
( )
2 0 1 C 2 C 3 C 4 C


and coefficients a to a are taken from Table 16.5-2.
0 4
16.5.5.6 Determine the allowable longitudinal moment M from
Y,max
d
(16.5-7)
M = f⋅ e⋅⋅ C
Y,max c 3
in which C is either read from Figure 16.5-4 or calculated from:
23 4
C max aa+⋅λ+ a⋅λλ+ a⋅+ a⋅λ ;4, 90 (16.5-8)
( )
3 0 1 C 2 C 3 C 4 C


and coefficients a to a are given in Table 16.5-3.
0 4
If the thickness ratio e /e is situated between 0,2 and 0,5, the factor C is obtained by linear
b c 3
interpolation (Figure 16.5-4).
NOTE The curves of Figures 16.5–2 to 16.5–4 are derived from WRCB No. 297 – see [5] in Annex L, while the
allowable loads are based on a maximum stress concentration factor of 2,25.
=
=
=
16.5.5.7 Shear stresses (directions, see Figure 16.5-1)
2F
X
τ = (16.5-8a)
X
π⋅⋅de
c
2F
Y
τ =
(16.5-8b)
Y
π⋅⋅de
c
2M
Z
τ = (16.5-8c)
Z
π⋅⋅de
c
Total shear stress in shell at nozzle
τ τ++τ τ (16.5-8d)
XY Z
16.5.6 Combination of external loads and internal pressure
16.5.6.1 To determine the effects of the combination of pressure, axial load and bending moments,
acting simultaneously the following procedure shall be applied:
If the axial force and the bending moment include portions from the thermal expansions of attached
piping, the applied loads need not include the thermal expansion effects. In this case the stress ranges
check 16.5.7 shall be applied taking into account the total loads including the thermal portions
(see 16.5.4 step f), second paragraph).
16.5.6.2 Calculate the individual load ratios as follows:
P
(16.5-9)
Φ =
P
P
max
F
Z
Φ = (16.5-10)
Z
F
Z,max
   
MM
XY
   
Φ + (16.5-11)
B
   
MM
X,max Y,max
   
2τ
Φ = (16.5-11a)
T
f
16.5.6.3 Check that each individual load ratio is limited as follows:
Φ ≤ 10, (16.5-12)
P
Φ ≤ 10, (16.5-13)
Z
Φ ≤1,0 (16.5-14)
B
=
=
Φ ≤1,0 (16.5-14a)
T
16.5.6.4 Check that the interaction of all the loads meets the following:


ΦΦ
PP 22


max +Φ ;;Φ −⋅0,2Φ +ΦΦ+ ≤1,0 (16.5-15)
Z Z Z BT

CC


Factor C shall equal 1,1 where nozzle connections are attached to a piping system designed with due
allowance for expansion, thrusts, etc. It shall equal 1,0 for ring reinforcements or rigid attachments. It
shall not exceed 1,10.
NOTE In Formula (16.5–15) a circular interaction with the bending moment load is accepted on the grounds
of a conservative estimate of the stress concentration factor in WRCB No. 297 (see ref [5] in Annex L).
16.5.7 Stress ranges and their combination
16.5.7.1 From the minimum and maximum values of the pressure and local loads in operating
conditions, determine the following load ranges:
ΔP = max (P ; 0) – min (P ; 0) (16.5-16)
ΔF = max (F ; 0) – min (F ; 0) (16.5-16a)
X X X
ΔF = max (F ; 0) – min (F ; 0) (16.5-16b)
Y Y Y
ΔF = max (F ; 0) – min (F ; 0) (16.5-17)
Z Z Z
ΔM = max (M ; 0) – min (M ; 0) (16.5-18)
X X X
ΔM = max (M ; 0) – min (M ; 0) (16.5-19)
Y Y Y
ΔM = max (M ; 0) – min (M ; 0) (16.5-19a)
Z Z Z
16.5.7.2 At the nozzle edge only, calculate the equivalent shell thickness e .This is equal to e unless
eq c
a reinforcing ring of width L< D ()e + e is used, in which case e is given by:
eq
a2

eL.  
f

ee+ min ;.e min ;1 (16.5-20)

eq a 2
 
f

D e + e  
( )
a2

16.5.7.3 Determine the following stresses:
Due to pressure range:
de⋅
d dD
b
2++2 1,25
 DD⋅ e De
∆PD⋅ eq eq

(16.5-21)
∆σ =
p

2e
e de⋅
eq
 b b
1+
e De⋅
eq eq
=
Due to the range of the axial load:
 
∆F
2,25
 Z
∆σ = (16.5-22)
FZ
 
C
 
e
eq
 
Due to the range of the circumferential moment:

4∆M
2,25
X
∆σ = (16.5-23)
MX

C

ed⋅
eq

Due to the range of the longitudinal moment:
 
4∆M
2,25
 Y
∆σ = (16.5-24)
MY
 
C
 
ed⋅
eq
 
Range of shear stresses
2∆F
X
∆τ = (16.5-24a)
X
π⋅⋅de
c
2∆F
Y
∆τ = (16.5-24b)
Y
π⋅⋅de
c
2∆M
Z
∆τ = (16.5-24c)
Z
π⋅⋅de
c
Total shear stress range at nozzle
∆τ ∆∆ττ+ +∆τ (16.5-24d)
XY Z
16.5.7.4 The equivalent stress range shall be restricted as follows:
22 2
∆σσ+∆ + ∆σ +∆σ +⋅43∆τ ≤ f (16.5-25)
( )
( )
P FZ MX MY
with value of f as defined in C.7.3.
16.5.8 Nozzle longitudinal stresses
This subclause may be ignored for a nozzle intended to be attached to a piping of the same resistance
(thickness multiplied by allowable stress).
16.5.8.1 Maximum longitudinal tensile stress in the nozzle shall be limited as follows:
4⋅ M + M
( )
XY
P F
d Z
+ +≤ f (16.5-26)
b
4e π de
π de
bb
b
F shall be set to zero when resulting in an axial compressive stress.
Z
=
16.5.8.2 The longitudinal stability of the nozzle shall be checked (with P = 0) as follows:
M + M
)
( XY ||F
Z
+≤ 10, (16.5-27)
MF
max max
F shall be set to zero when resulting in axial tensile stress. M and F are respectively the allowable
Z max max
global moment and force in the nozzle. They are calculated in 16.14.
Table 16.5–1 — Coefficients for C
e / e a a a a a
b c 0 1 2 3 4
All 0,600 721 81 0,951 962 57 0,005 195 788 1 −0,001 406 381 0
Table 16.5–2 — Coefficients for C
e / e a a a a a
b c 0 1 2 3 4
All 4,526 315 0,064 021 889 0,158 876 38 −0,021 419 298 0,001 035 040 7
Table 16.5–3 — Coefficients for C
e / e a a a a a
b c 0 1 2 3 4
≤ 0,2 4,851 751 1 0,025 101 2 0,742 862 4 - 0,015 315 3 0
≥ 0,5 4,858 863 9 2,187 088 7 1,456 705 3 - 0,331 643 0 0,025 385 0
Figure 16.5-1 — Moment and force vectors

Figure 16.5-2 — Graphical form of C
Figure 16.5-3 — Graphical form of C
Figure 16.5-4 — Graphical form of C
”.
8 Modification to 16.6.6, Bending Limit Stress
Replace the content of Subclause 16.6.6 with the following:
“The bending limit stress is obtained from Formula (16.6-6), which is a function of the membrane
stresses due to local loading and global loadings.
σ = K K f (16.6-6)
b,all 1 2
— for design conditions: K = 1,25;
— for test, transport and lifting conditions: K = 1,05 and f = f .
2 test
The value of K is a function of υ and υ and shall be obtained from Figure 16.6-1 or Formula (16.6-7):
1 1 2
1−υ
K = (16.6-7)
 
1 1
+υυ + +υυ +−1 υ υ
 
( )
1 2 1 2 2 1
3 3
 
with:
σ
m
(16.6-8)
υ =
Kf
where
υ and σ : see Formula (16.6–14) with the corresponding explanation for υ , or Formula (16.6–
1 m 2
18) respectively.
In this figure when υ < 0, the signs of υ and υ shall be changed simultaneously to determine K .
2 1 2 1
Figure 16.6-1 — Factor K
”.
9 Modification to 16.7.2, Specific symbols and abbreviations
Replace:
“W is the total vessel weight”
with:
“G is the total vessel weight”.
max
10 Modification to 16.7.4, Applied force
Replace the content of the subclause with the following one:
“The applied force F acting on the lifting lug shall be calculated. In case of a symmetric vessel with two
R
lifting lugs according to Figure 16.7-3(a):
1,5G
max
F = (16.7-1)
R
2cosβ
”.
11 Modification to 16.7.5, Load limits for shell
Replace Step 4) with the following one:
“
4) With the appropriate values of λ, υ and υ , calculate the bending limit stress from 16.6.6,
1 2
Formula (16.6-6);”.
12 Modification to 16.8.6.2, Vessel under external pressure
Replace the NOTE with the following one:
“
NOTE For determination of P and M for different load cases, see 3.16, NOTE 1, Table 5.3.2.4–1 and
max max
8.4.4.”.
13 Modification to 16.8.7, Load limit at the saddle (without a reinforcing plate)
After Formula (16.8-29), replace the NOTE with the following one:
“
NOTE For determination of Pmax and Mmax for different load cases, see 3.16, NOTE 1, Table 5.3.2.4–1 and
8.4.4.”.
14 Modification to 16.12.4.1, Specific symbols and abbreviations
Replace the existing explanation of variables for F and M with the following ones respectively:
c,max max
“
F maximum compressive force according to Formula (16.14–2)
c,max
with σ according to Formula (16.14–29) as defined in Table 5.3.2.4–1
c,all
M maximum bending moment according to Formula (16.14–3)
max
with σc,all according to Formula (16.14–29) as defined in Table
...