SIST EN 13445-3:2014/A6:2019
(Amendment)Unfired pressure vessels - Part 3 : Design
Unfired pressure vessels - Part 3 : Design
Amendment to Annex J for Tubesheets
Unbefeuerte Druckbehälter - Teil 3: Konstruktion
Dieser Teil 3 der Europäischen Norm legt die Anforderungen an die Konstruktion von unbefeuerten Druckbehältern
nach EN 13445-1:2014 und hergestellt aus Stählen nach EN 13445-2:2014 fest.
EN 13445-5:2014 gibt im Anhang C Bedingungen für die Konstruktion von Zugangs- und Besichtigungsöffnungen,
von Verschlüssen und besonderen Verschlusselementen.
ANMERKUNG Dieser Teil gilt für Konstruktion und Berechnung von Behältern vor der Inbetriebnahme. Er kann auch, mit
entsprechenden Anpassungen, für Berechnungen oder analytische Nachweise im Betrieb verwendet werden.
Récipients sous pression non soumis à la flamme - Partie 3 : Conception
Neogrevane (nekurjene) tlačne posode - 3. del: Konstruiranje - Dopolnilo A6
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 13445-3:2014/A6:2019
01-maj-2019
1HRJUHYDQH QHNXUMHQH 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/A6:2019
ICS:
23.020.32 7ODþQHSRVRGH Pressure vessels
SIST EN 13445-3:2014/A6:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 13445-3:2014/A6:2019
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SIST EN 13445-3:2014/A6:2019
EN 13445-3:2014/A6
EUROPEAN STANDARD
NORME EUROPÉENNE
March 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 A6 modifies the European Standard EN 13445-3:2014; it was approved by CEN on 27 August 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/A6:2019 E
worldwide for CEN national Members.
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EN 13445-3:2014/A6:2019 (E)
Contents Page
European foreword . 3
1 Modification to Clause 2, Normative references . 4
2 Modification to G.1, Purpose . 4
3 Deletion of Annex GA (informative), Alternative design rules for flanges and gasketed
flange connections . 4
4 Modification to Annex J (normative), Alternative method for the design of heat
exchanger tubesheets . 4
2
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European foreword
This document (EN 13445-3:2014/A6:2019) 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 September 2019, and conflicting national standards
shall be withdrawn at the latest by September 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.
3
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1 Modification to Clause 2, Normative references
Add the following new reference at the appropriate place:
“EN 13555:2014, Flanges and their joints — Gasket parameters and test procedures relevant to the design
rules for gasketed circular flange connections”.
2 Modification to G.1, Purpose
Replace the content of this clause with the following text:
“This annex provides a calculation method for bolted, gasketed circular flange joints. It is applicable to
flanges and bolted domed ends, and is an alternative to the methods in Clauses 11 and 12. Its purpose is
to ensure structural integrity and leak tightness for an assembly comprising two flanges, bolts and a
gasket. Flange loadings are shown in Figure G.3-1. Different types of bolts and gaskets are shown in
Figures G.3-2 to G.3-3.
Use of this alternative method is particularly recommended in case a more accurate calculation is
imposed by one of the following circumstances:
a) need of assuring leak tightness in presence of dangerous fluids;
b) multiple design or testing conditions;
c) presence of additional external loads;
d) presence of temperature differences among the different components of the bolted joint;
e) need to avoid overstress of the bolts and/or the gasket.
Using this alternative calculation method a controlled bolting-up method (see Table G.8-2) is
recommended and should be documented by the Manufacturer in the User’s manual.
This annex is based on EN 1591-1:2001, Flanges and their joints — Design rules for gasketed circular
flange connections — Part 1: Calculation method. The new edition of this standard, EN 1591-1:2013,
provides a calculation of a bolted joint considering specified leak rates through the gasket: such
calculation is however only possible if the gasket manufacturer is able to supply sufficient gasket
parameters, or if such parameters are the result of specific testing, carried out in accordance with
EN 13555:2014. Therefore, when specified leak rates are a design requirement and when sufficient
gasket data are available, EN 1591-1:2013 shall be used as an alternative either to this Annex or to
Clauses 11 and 12. The use of EN 1591-1:2013 is not applicable in the case of a bolted joint between a
flange and the flanged extension of a heat exchanger tubesheet (see Figures J.12 and J.13) and in the
case where a tubesheet is clamped between two flanges (see Figure J.11).”.
3 Deletion of Annex GA (informative), Alternative design rules for flanges and
gasketed flange connections
Delete the whole informative Annex GA.
4 Modification to Annex J (normative), Alternative method for the design of heat
exchanger tubesheets
Replace the whole annex with the following one:
“
4
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Annex J
(normative)
Alternative method for the design of heat exchanger tubesheets
J.1 Purpose
This annex specifies alternative rules to those in Clause 13 for the design of shell and tube heat
exchanger tubesheets. They apply to heat exchangers of the following types:
— U-tube type, see Figure J.1; also to exchangers with capped tubes and one tubesheet only and
exchangers with curved tubes and a number of separate tubesheets;
— immersed floating head; see Figures J.2 a) and J.2 b);
— externally sealed floating head; see Figure J.3;
— internally sealed floating head; see Figure J.4;
— fixed tubesheet with expansion bellows; see Figure J.5;
— fixed tubesheet without expansion bellows; see Figure J.6.
J.2 Specific definitions
The following terms and definitions are in addition to those in Clause 3.
J.2.1
outer tube limit
circle which encloses all the tubes
J.2.2
load ratio
calculated load or moment applied to a component divided by the allowable load or moment
J.3 Specific symbols and abbreviations
J.3.1 General
The following symbols and abbreviations are in addition to those in Clause 4.
Figures J.1 to J.6 illustrate the six main types of shell and tube heat exchanger. Figures J.7 to J.13 cover
specific details. All Figures illustrate general characteristics. They are not intended to cover all of the
possible combinations for which the method is valid.
In Figures J.1 to J.6 the outer part of the stationary tubesheet may be either bolted or welded to the
adjoining shell(s). The details of this outer tubesheet portion with the relevant flanges (if any) have
been sketched with a dark colour, since they are not needed for the determination of the main axial
forces (calculation parameter PR). For simplification all the ends have been shown as flat (although
they are generally dished).
Baffles and support plates have not been included in the figures.
Other types not shown in Figures J.1 to J.6 include:
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— Figure J.1: Capped straight tubes; general curved tubes with two or more tubesheets;
— Figure J.2: Floating head completely welded;
— Figure J.3: Other types of sealing (e.g. O-ring instead of packed gland);
— Figure J.4: Other types of sealing (e.g. packed gland);
— Figure J.5: Other types of expansion bellows;
— Figure J.6: Tubesheets which are very thin.
Figure J.1 ― U-tube exchanger
6
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a) Floating tubesheet exchanger with an immersed floating head (floating tubesheet clamped
between two flanges)
b) Floating tubesheet exchanger with an immersed floating head (floating tubesheet with
flanged extension)
Figure J.2 ― Floating tubesheet exchanger with an immersed floating head
Figure J.3 ― Floating tubesheet exchanger with an externally sealed floating head
7
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Figure J.4 ― Floating tubesheet exchanger with an internally sealed floating tubesheet
Figure J.5 ― Fixed tubesheet exchanger with an expansion bellows
Figure J.6 ― Fixed tubesheet exchanger without an expansion bellows
J.3.2 Subscripts
NOTE Large Latin letters refer to components or areas of components or describe values. Small Latin letters
specify properties, types of loadings or types of reactions.
A for Outer zone of the perforated tubesheet area {C: German: “Außenbereich”};
B for Bolts or Baffle;
C for Channel;
D for Difference between two values;
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E for Effective values;
F for Flange;
G for Gasket;
I for Inner zone of the perforated tubesheet area {C: German: “Innenbereich”};
J for Expansion bellows {C: Clause 13};
K for Compensation {C: German: “Kompensation”};
M for Moment related values;
P for Plate (tubesheet); or
Pressure related values;
Q for Load related values {C: Similar to “P” and “R”};
R for Resultant load; or
Tube bundle {C: German: “Rohrbündel”}, perforated tubesheet area ; or
any value between “Q” and “S”;
S for Shell;
T for Tubes or tube side (channel side);
U for Unperforated tubesheet area;
W for Weight; or
Weld;
X for Tube-to-tubesheet connection;
av for average value;
b for bending;
c for compressive (stress or force);
e for external (pressure); or
effective;
i for internal (pressure);
l for longitudinal;
min for minimum value;
max for maximum value;
opt for optimum value;
red for reduced value;
t for tensile (stress or force); or
total
J.3.3 Symbols
NOTE Units are given in square brackets; [1] indicates a “dimensionless” quantity.
2
A is the cross-sectional area of the perforated tubesheet area, [mm ];
R
2
A is the minimum area of the perforated tubesheet area, [mm ], see J.5.1.1.3.2;
R(min)
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A is the cross-sectional area of the connection between tube and tubesheet,
X
2
[mm ];
a is the effective throat thickness of the tube end weld [mm], specified as
T
follows:
a at the plate (tubesheet); a at the tube; a between plate and tube;
T,P T,T T,R
B is the resulting factor for the tube bundle, shell and channel [1];
0
B , B , B are factors for the tube bundle [1];
R1 R2 R3
B , B , B are factors for shell and channel [1];
S1 S2 S3
b is the actual width of the tubesheet flanged extension [mm], see Figures J.10
F
to J.13;
b is the average width of the untubed rim subject to pressure on both sides
R
[mm], see J.5.1;
b is the actual width of the untubed rim [mm] subject to pressure on one side
S
only, may be positive or negative; see J.5.1;
b is the maximum width of the untubed rim [mm], obtained from the tubesheet
U
layout;
see Figures J.7, and J.9.3;
C , C , C , C , C , C are coefficients [1] to determine the buckling length, see J.7.1.3;
0 A C AA AC CC
C , C are factors used in the fatigue analysis [1], see Figure J.15;
1 2
D is the inside diameter of the expansion bellows [mm]; see 13.5;
J
d , d are the inside diameters of the channel cylinder (C), of the shell cylinder (S),
C S
[mm];
d , d is the tubehole diameter [mm], d is the actual value, d is the effective value;
0 0,e 0 0,e
d is the diameter where the tubesheet thickness changes from e to e ;
F P F
d is the diameter of the perforated tubesheet area to be used in the calculation
1
[mm], see J.5.1;
d
1(av)
is the average of d and d , [mm], see J.5.1.1.4;
1 min 1 max
( ) ( )
d
1(max) is the maximum value of d , [mm], see J.5.1.1.2;
1
d
1(min) is the minimum value of d , [mm], see J.5.1.1.3;
1
d is the actual diameter [mm] over which P and P act;
2 S T
d , d is the bolt pitch circle diameter [mm]; d for the actual value, d for the
3 3,e 3 3,e
effective value;
d , d are the effective gasket diameters [mm] for channel side (C), shell side (S);
GC GS
d is the diameter over which the axial forces act [mm]; for floating heads this is
K
the diameter of the sliding face at a packed gland or an O-ring seal; for
expansion bellows this is the mean inside diameter of the bellows: d = D + h ;
K J J
d is the tube outside diameter [mm];
T
E , E are the elastic moduli of the tubesheet (P = plate), of the tubes (T), [MPa];
P T
E , E are the elastic moduli of the channel (C), of the shell (S), [MPa];
C S
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E* is the effective elastic modulus of the tubesheet [MPa], see Figures 13.7.8–1
and/or 13.7.8–2;
e is the analysis thickness of the channel cylinder adjacent to the tubesheet
C
[mm];
e is the average thickness of the tubesheet flanged extension [mm],
F
see Figures J.10 to J.13;
e is the analysis thickness of the tubesheet (plate) [mm] in the perforated
P
tubesheet area and the untubed rim;
e is a possibly reduced thickness of the tubesheet (plate) at its outer periphery
P,red
[mm]; e ≤ e ;
P,red P
e is the analysis thickness of the shell cylinder adjacent to the tubesheet [mm];
S
e is the average thickness of the shell cylinder, taken over the overall length L
S,av T
[mm];
e is the tube thickness [mm];
T
e is the analysis thickness of the tubesheet in the unperforated tubesheet area
U
[mm]; normally e = e ;
U P
F is the total force applied by the bolts (total force for one flange connection)
B
[N], see Annex G;
Pending the elaboration of a specific method to calculate the bolt load in the
connection between a flange and a tubesheet bolted to it (see Figures J.12 and
J.13), the value of FB may be calculated considering the tubesheet as a flat
closure with the same thickness. For tubesheets clamped between two flanges
(see Figure J.11) the flange calculation may be done with a modified effective
gasket taking into account the tubesheet. See J.4.3.1 for further details;
F , F are the total gasket reaction forces [N], channel side (C), shell side (S);
G,C G,S
[F ], [F ] are the allowable total axial forces in the shell [N], [F ] for tension, [F ] for
t c t c
compression, see J.7.5;
F is the total axial force acting on tube bundle and shell [N], see J.7.5;
R
F is the total weight acting as a force on a tubesheet [N], see J.9.4;
W
f is the nominal design stress for the channel cylinder adjacent to the tubesheet
C
[MPa];
f is the nominal design stress for the tubesheet (plate) flanged extension [MPa];
F
normally f = f ;
F P
f is the nominal design stress for the tubesheet (plate) [MPa];
P
f is the nominal design stress for the shell cylinder adjacent to the tubesheet
S
[MPa];
f is the nominal design stress for the tubes [MPa];
T
f is the allowable longitudinal stress for the tubes in tension [MPa]; see J.7.3;
T,t
f is the allowable longitudinal stress for tubes in compression [MPa]; see J.7.3;
T,c
f is the calculated design stress for the tube-to-tubesheet connection [MPa];
X
see J.7.3;
f and f are special values of f ;
X,E X,W X
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H , H , H are factors used in the fatigue analysis [1], see Figure J.15;
1 2 3
h is the inside height of the expansion bellows [mm]; see 13.5;
J
j is an integer to identify any trapezoidal area (tubed or untubed);
k is an integer to identify an untubed (pass partition) zone;
K , K , K are effective stress-strain concentration factors [1] used in the fatigue
e1 e2 e3
analysis, see J.10;
L , L , L are loading parameters [1], used in the calculation of a load ratio, see J.9.1;
1 2 3
L is the actual total length of the tubes [mm]; in Figure J.9 shown between outer
T
faces of tubesheets;
l is the unsupported length of the tubes [mm] between the first tubesheet and
A
the first supporting baffle, see Figure J.9;
l is the maximum value of the unsupported lengths of tubes [mm] between two
B
adjacent supporting baffles, see Figure J.9.
l is the unsupported length of tubes [mm] between the last supporting baffle
C
and the second tubesheet, see Figure J.9;
l is a characteristic length of the tube bundle [mm], used for the fatigue
R
analysis, see J.10.3;
l is the buckling length of tubes [mm], see J.7.1;
T,K
l is the contact length between tube and tubesheet [mm], see J.5.2.1;
X
M is the resultant bending moment [Nmm/mm] at the diameter d ;
1 1
M is the resultant bending moment [Nmm/mm] at the diameter d ;
2 2
M is the active bolt load bending moment [Nmm/mm] at the diameter d ,
A 2
see J.8.2;
M is the active fluid pressure bending moment [Nmm/mm] at the diameter d ,
B 2
see J.8.3;
M is the reactive bending moment [Nmm/mm] from connected components,
C
see J.8.4;
M is the reactive bending moment [Nmm/mm] limitation at the diameter d ,
D 2
see J 8.5;
N is the number of baffles [1]; N is the actual number, N is the effective
B B,t B,e
number;
N is the number of load cycles [1];
C
N is the number of possible tubes, [1]; see J.5.1;
I
N is the total minimum number of potential extra tubes for the whole perforated
I(min)
tubesheet area, [1], see J.5.1.1.3.2;
NI(k) is the number of potential extra tubes in a given untubed trapezoidal area, [1],
see J.5.1.1.3.2;
N is the number of potential extra tubes in a given row, [1], see J.5.1.1.3.2;
I(r)
N is the number of tubeholes [1];
T
n is the number of bolts [1] in a flanged connection;
B
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P , P are the resultants of active and reactive axial forces per unit area in the tube
A I
2
bundle in the perforated tubesheet area [N/mm = MPa]; P in the outer zone,
A
P in the inner zone; see J.7.6;
I
P is the direct difference between tube side and shell side fluid pressure [MPa],
D
see J.6.2, J.7.2;
P is the effective differential pressure in the perforated tubesheet area [MPa],
E
see J.7.2;
P is an equivalent pressure [MPa], representing the resultant bending moment
M
M (resultant of active and reactive moments, may be zero) at the diameter of
1
the perforated tubesheet area, see J.8.6;
P is an equivalent pressure [MPa], representing the resultant effective axial
Q
force (resultant of active and reactive forces, may be zero) at the diameter of
the perforated tubesheet area [MPa], see J.6.3, J.7.6;
P is an equivalent pressure [MPa], representing the resultant active axial shear
R
force at the diameter of the perforated tubesheet area [MPa], see J.6.2, J.7.5;
p is the tube pitch in the perforated tubesheet area [mm], see Figure J.7;
p is the tube pitch in relation to the height of the trapezoidal area, [mm];
b
p is the tube pitch in relation to the width of the trapezoidal area, [mm];
c
Q , Q are reactive axial forces per unit area of the tube bundle in the perforated
A I
tubesheet area [MPa];
Q in the outer zone, Q in the inner zone; see J.7.4;
A I
[Q ], [Q ] are the allowable axial forces per unit area of the tube bundle in the
t c
perforated tubesheet area [MPa]; [Q] for tension, [Q] for compression;
t c
see J.7.3;
q is a factor for the tube support [1], see J.9.3;
r is an integer to identify a tube row;
r is the radius of the outermost tube hole centre [mm]; see Figure J.7 a) and last
o
paragraph in Subclause J.5.1.1.2 (also Figure 13.7.3–1);
T , T are temperature ranges [K] between maximum and minimum temperature for
S T
shell (S), tubes (T). For the purpose of determining these values, the ambient
temperature shall be assumed to be +20°C;
u, v, w are factors [1], used in J.7.6;
x , x are relative areas of the tubesheet [1] subject to P and P respectively;
S T S T
see J.7.1;
Y is a factor [1], used in J.7.1;
−1
αS, αT are the thermal expansion coefficients of the shell, of the tubes [K ];
β is a factor given by Formula (J.10.2–3);
γ is the rigidity factor for the untubed rim, see J.10.3;
R
Δd
(act)
is the difference between d and d , [mm];
1 max 1 min
( ) ( )
Δd
(all)
is the allowable difference between d and d , [mm];
1 max 1 min
( ) ( )
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ΔM , ΔM are ranges of bending moments in the tubesheet [Nmm/mm], used in a fatigue
1 2
analysis;
ΔP , ΔP , ΔP are ranges of pressures [MPa], used in a fatigue analysis, see J.10.2;
F S T
ΔS , ΔS are ranges of shear forces in the tubesheet [N/mm], used in a fatigue analysis,
1 2
see J.10.3;
Δσ , Δσ are ranges of calculated bending stresses in the tubesheet [MPa], used in a
b1 b2
fatigue analysis, see J.10.3;
Δσ is the range of calculated longitudinal stresses in the tubes [MPa], used in a
lT
fatigue analysis;
Δσ is the allowable stress range in the tubesheet (plate) [MPa], used in a fatigue
R
analysis;
δ is a factor for tube-to-tubesheet relative strength [1], see J.5.2;
X
ζ is the force distribution parameter [1] for supported tubesheets; this is the
relative radius of the boundary between the reactions Q and Q , see J.7.1.1
I A
and J.7.6.2;
η is the moment distribution parameter [1] for all tubesheets; this is the relative
radius of the boundary between the constant and variable tangential bending
moment in the tubesheet, see J.6.3, J.7.1.1 and J.7.6.3;
ϑ is the relative cross-sectional area of the tubes [1]; see J.7.1;
κ is the relative shear strength of the tubesheet [1], see J.5.2;
P
λ , λ are geometric parameters for tube buckling [1], see J.7.1;
A C
λ , λ are geometric parameters for untubed rims [1], see J.5.1;
R S
μ is the coefficient of friction [1] for expanded tube-to-tubesheet joints, see J.7.3;
X
μ* is the tubesheet ligament efficiency in bending (Clause 13); it is in this annex
replaced by φ ;
P
ν is the Poisson’s ratio for the unperforated tubesheet (plate) [1];
P
ν is the Poisson’s ratio for the shell cylinder [1];
S
ν is the Poisson’s ratio for the tubes [1];
T
ν* is the effective Poisson’s ratio for the perforated tubesheet [1], obtained from
13.7;
σ is an active general stress [MPa], to be specified by subscripts, see J.7.3, σ ;
T(P)
[σ] is an allowable general stress [MPa], to be specified by subscripts, see J.7.5;
σ is an average longitudinal stress in the tubes [MPa], divided by safety factor
T(P)
1,50, see J.7.3;
Φ , Φ , Φ , Φ and Φ are load ratios [1], see J.2.2 and J.9;
B S U W P,t
φP is the relative bending strength of the tubesheet [1], see J.5.2;
χ is a parameter for the unperforated tubesheet area at the boundary [1],
see J.9.3;
ψ is the stiffness parameter for the perforated tubesheet area [1], see J.10.3;
E
ω is the rigidity factor for the perforated tubesheet area [1], see J.10.3.
R
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SIST EN 13445-3:2014/A6:2019
EN 13445-3:2014/A6:2019 (E)
J.4 General
J.4.1 Scope
J.4.1.1 Geometry and materials
The method applies for tube bundles (and some connected components) under the following
conditions:
— The whole tube bundle (as the main component of a shell and tube heat exchanger) is
axisymmetric.
Permitted deviations from the axisymmetry are defined and limited below.
— Each tubesheet (also called “plate”, subscript P) has only one central tubed area (nearly circular).
Within the tubed area there are permitted small unperforated tubesheet areas, e.g. for pass
partitions and tie-rods.
The outer boundary of the tubed area, does not need to be exactly circular, but it shall be
approximately circular.
— The tubesheet thickness e and the pitch p are the same (constant) for the whole tubed area.
P
Where there is a second tubesheet, the thickness may be different, but again constant.
— Outside the perforated area the plate has an unperforated area.
The boundary of this unperforated tubesheet area and any additional areas within the tubesheet
shall be circular.
— All (inner) tubes shall have the same cross section dT.eT and shall be manufactured from the same
material.
— For tube bundles with two tubesheets all of the tubes have the same straight length L ; no tie rod
T
shall be connected to both tubesheets. (For a tube bundle with only one tubesheet the lengths of the
curved tubes may vary. If a tube bundle with two tubesheets has curved tubes, it shall be calculated
as a U-tube type, where each tubesheet is calculated separately.)
— The width of the untubed rim should not be too large:
λ ≤ 0,30 (J.4.1-1)
R,max
— The geometry should be approximately axisymmetric:
λ /λ ≥ 0,20 (J.4.1-2)
R,min R,max
— The tubed area may be calculated as a homogeneous weakened plate:
N 20 (J.4.1-3)
T≥
— For vertical tube bundles its weight need not be taken into account, if the following formula is true:
2
N ≤⋅30 1000⋅ f L (J.4.1-4)
{ }
T TT
15
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SIST EN 13445-3:2014/A6:2019
EN 13445-3:2014/A6:2019 (E)
— The tubesheet thickness should be within the range:
0,005 ≤ e /d ≤ 0,50 (J.4.1-5)
P 1
With some caution, the method may be used outside of the conditions listed above.
J.4.1.2 Loads
The method applies to the following loads:
— Fluid pressures tube side (P ) and shell side (P ), either internal or external;
T S
— Moments at the outside boundary of tubesheets;
— Weight of the vertical tube bundle;
— Axial thermal expansion (for fixed tubesheet tube bundles without expansion bellows).
J.4.2 Mechanical model
The method is based on the following mechanical model:
— The main component of a shell and tube heat exchanger is always one tube bundle. It is in general
located within a vessel. The vessel in general may be subdivided into one shell and one or two
channels complete with vessel flanges, nozzles and supports.
The method calculates the strength of the tube bundle. Where necessary, other component parts
are included in the calculation.
— The tube bundle consists of one or two tubesheets, a large number of (inner) tubes and (normally)
some baffles.
The method calculates the strength of the tubesheets, the tubes, and the tube-to-tubesheet joint.
— The baffles are assumed to act as supports, to prevent buckling of the inner tubes. It should be
noted that in many cases not all tubes are supported by each baffle. The distances between the
baffles and the tubesheets need not to be equal. The thickness of the baffles may be small; their
strength in general is not critical and is not calculated in the method.
— The calculation model for the tubed area of the tubesheet is a weakened homogeneous flat plate,
supported by reaction forces (or reaction momen
...
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