SIST EN 1591-1:2002/opr A1:2005

Flanges and their joints - Design rules for gasketed circular flange con-nections - Part 1: Calculation method - Amendment 1

2006 12 19 Tolerance of 6 months requested before formal vote per CEN/TC 74 res. 263/2006.
Tolerance of up to nine months before enquiry (TC resolution CEN/TC 74 C 245/2004) (Note by SV on 2005-02-10)

Flansche und ihre Verbindungen - Regeln für die Auslegung von Flanschverbindungen mit runden Flanschen und Dichtung - Teil 1: Berechnungsmethode - Änderung 1

Brides et leurs assemblages - Regles de calcul des assemblages a brides circulaires avec joint - Partie 1 : Méthode de calcul - Amendement 1

Prirobnice in prirobnični spoji – Pravila za načrtovanje okroglih prirobničnih spojev s tesnili – 1. del: Način izračuna – Dopolnilo 1

General Information

• Status: Not Published
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: TLP - Pressure vessels
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 08-Sep-2010
• Due Date: 13-Sep-2010
• Completion Date: 08-Sep-2010
• Directive: 97/23/EC - Directive 97/23/EC of the European Parliament and of the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Ref Project: EN 1591-1:2001/prA1 - Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method

Relations

• Consolidated By: SIST EN 1591-1:2002+A1:2009 - Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
• Effective Date: 18-Jan-2023
• Consolidated By: SIST EN 1591-1:2002+A1:2009 - Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
• Effective Date: 19-Jan-2023
• Consolidated By: SIST EN 1591-1:2002+A1:2009 - Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
• Effective Date: 01-May-2009
• Revised: SIST EN 1591-1:2002 - Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
• Effective Date: 22-Dec-2008

Standards Content (Sample)

SLOVENSKI SIST EN 1591-1:2002/opr
A1:2005

PREDSTANDARD
november 2005
Prirobnice in prirobnični spoji – Pravila za načrtovanje okroglih prirobničnih
spojev s tesnili – 1. del: Način izračuna – Dopolnilo 1
Flanges and their joints - Design rules for gasketed circular flange con-nections -
Part 1: Calculation method - Amendment 1
ICS 23.040.60 Referenčna številka
SIST EN 1591-1:2002/opr A1:2005(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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EUROPEAN STANDARD
DRAFT
EN 1591-1:2001
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
September 2005
ICS

English Version
Flanges and their joints - Design rules for gasketed circular
flange con-nections - Part 1: Calculation method - Amendment 1
Flansche und ihre Verbindungen - Regeln für die
Auslegung von Flanschverbindungen mit runden Flanschen
und Dichtung - Teil 1: Berechnungsmethode - Änderung 1
This draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 74.
This draft amendment A1, if approved, will modify the European Standard EN 1591-1:2001. If this draft becomes an amendment, CEN
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this amendment
into the relevant national standard without any alteration.
This draft amendment was established by CEN in three official versions (English, French, German). A version in any other language made
by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status
as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1591-1:2001/A1:2005:2005: E
worldwide for CEN national Members.

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EN 1591-1:2001/prA1:2005 (E)
Contents Seite
Foreword.3
1.3.4 Mechanical model.4
3.2 Subscripts and special marks .5
3.2.1 Subscripts.5
3.2.2 Special marks.6
3.3 Symbols.6
4.3 Gasket parameters.10
4.3.1 Theoretical dimensions.10
4.3.2 Effective dimensions.10
4.3.3 Axial flexibility modulus of gasket.11
5.2 Compliance of the joint .13
5.3 Minimum forces necessary for the gasket.13
5.3.1 Assembly condition (I = 0) .13
5.3.2 Subsequent conditions (I = 1, 2, .) .14
5.4 Internal forces in assembly condition (I = 0).14
5.4.1 Required forces.14
5.5 Internal forces in subsequent conditions (I = 1, 2, .).14
6.3 Gasket.15


2

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EN 1591-1:2001/prA1:2005 (E)
Foreword
This document (EN 1591-1:2001/prA1:2005) has been prepared by Technical Committee CEN/TC 74
“Flanges and their joints”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
This document contains changes on EN 1591-1:2001 which are necessary to adjust the standard to
EN 13555:2004 “Flanges and their joints — Gasket parameters and test procedures relevant to the design
rules for gasketed circular flange connections”. The changes against EN 1591-1:2001 are marked up.
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EN 1591-1:2001/prA1:2005 (E)
1.3.4 Mechanical model
The Calculation method is based on the following mechanical model:
a) Geometry of both flanges and gasket is axisymmetric. Small deviations such as those due to a finite number
of bolts, are permitted. Application to split loose flanges or oval flanges is not permitted.
b) The flange ring cross-section (radial cut) remains undeformed. Only circumferential stresses and strains in
the ring are treated; radial and axial stresses and strains are neglected. This presupposition requires
compliance with condition 1.3.1 a).
c) The flange ring is connected to a cylindrical shell. A tapered hub is treated as being an equivalent cylindrical
shell of calculated wall thickness, which is different for elastic and plastic behaviour, but always between the
actual minimum and maximum thickness. Conical and spherical shells are treated as being equivalent
cylindrical shells with the same wall thickness; differences from cylindrical shell are explicity taken into
account in the calculation formula.
This presupposition requires compliance with 1.3.1 c).
At the connection of the flange ring and shell, the continuity of radial displacement and rotation is accounted
for in the calculation.
d) The gasket contacts the flange faces over a (calculated) annular area. The effective gasket width (radial) b
Ge
may be less than the true width of gasket. This effective width b is calculated for the assembly condition
Ge
(I = 0) and is assumed to be unchanged for all subsequent load conditions (I = 1,2 .). The calculation of b
Ge
includes the elastic rotation of both flanges as well as the elastic and plastic deformations of the gasket
(approximately) in assembly condition.
e) The modulus of elasticity of the gasket may increase with the compressive stress Q on the gasket. The
Calculation method uses a linear model: E = E + K × Q. This is the unloading elasto-plastic secant modulus
G 0 1
measured between 100 % and 33 % of the highest stress (Q) in assembly conditions.
e) The modulus of elasticity of the gasket may increase with the compressive stress Q on the gasket. The
modulus of elasticity is the unloading elasto-plastic secant modulus measured between 100% and 33% for
several gasket stress levels.
f) Creep of the gasket under compression is approximated by a creep factor g (see ENV 1591-2).
c
f) Creep of the gasket under compression is approximated by a creep factor P (see ENV 1591-2).
QR
g) Thermal and mechanical axial deformations of flanges, bolts and gasket are taken into account.
h) Loading of the flange joint is axisymmetric. Any non-axisymmetric bending moment is replaced by an
equivalent axial force, which is axisymmetric according to equation (44).
i) load changes between load conditions cause internal changes of bolt and gasket forces. These are
calculated with account taken of elastic deformations of all components. To ensure leaktightness, the
required initial assembly force is calculated (see 5.4) to ensure that the required forces on the gasket are
achieved under all conditions (see 5.3 and 5.5).
j) load limit proofs are based on limit loads for each component. This approach prevents excessive
deformations. The limits used for gaskets, which depend on Q are only approximations.
max


4

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EN 1591-1:2001/prA1:2005 (E)
The model does not take account of the following:
k) Bolt bending stiffness and bending strength. This is a conservative simplification. However the tensile
stiffness of the bolts includes (approximately) the deformation within the threaded part in contact with the nut
or threaded hole (see equation (34)).
l) Creep of flanges and bolts.
m) Different radial deformations at the gasket (this simplification has no effect for identical flanges).
n) Fatigue proofs (usually not taken into account by codes like this).
o) external torsional moments and external shear loads, e.g. those due to pipework.
3.2 Subscripts and special marks
3.2.1 Subscripts
A – Additional (F , M )
A A
B – Bolt
C – Creep of gasket (g )
c
D – Equivalent cylinder (tapered hub + connected shell) for load limit calculation
E – Equivalent cylinder (tapered hub + connected shell) for flexibility calculation
F – Flange
G – Gasket
H – Hub
I – Load condition identifier (taking values 0, 1, 2 .)
L – Loose flange
M – Moment
P – Pressure
Q – Net axial force due to pressure
R – Net axial force due to external force
S – Shell, shear
T – Shell, modified
X – Weak cross-section
∆ – Symbol for change or difference
av – average
5

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EN 1591-1:2001/prA1:2005 (E)
c – calculated
d – design
e – effective
max – maximum
min – minimum
nom – nominal
opt – optimal
req – required
s – non-threaded part of bolt
t – theoretical, torque, thread
0 – initial bolt-up condition (I = 0, see subscript I)
3.2.2 Special marks
 ~ – Accent placed above symbols of flange parameters that refers to the second flange of the joint, possibly
different from the first
3.3 Symbols
Where units are applicable, they are shown in brackets. Where units are not applicable, no indication is given.
2
A – Effective total cross-section area of all bolts [mm ], equation (33)
B
2
A , A – Gross radial cross-section area (including bolt holes) of flange ring, loose flange [mm ],
F L
equations (5), (7), (8)
2
A , A – Gasket area, effective, theoretical [mm ], equations (39), (36)
Ge Gt
C – Coefficient to account for twisting moment in bolt load ratio, equation (71)
E – Compressive modulus of elasticity of the gasket [MPa] at zero compressive stress
0
Q = 0 [MPa] (see ENV 1591-2)
E , E , E , E – Modulus of elasticity of the part designated by the subscript, at the temperature of the part
B F G L
[MPa] (for E see ENV 1591-2)
G
F – Additional external axial force [N], tensile force > 0, compressive force < 0, see Figure 1
A
F – Bolt force (sum of all bolts) [N]
B
F – Gasket force [N]
G
F – Minimum gasket force in assembly condition [N] that guarantees after all load changes to
G∆
subsequent conditions the required gasket force, equation (51)
F – Axial fluid-pressure force [N], equation (43)
Q
6

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EN 1591-1:2001/prA1:2005 (E)
F – Force resulting from F and M [N], equation (44)
R A A
I – Load condition identifier, for assembly condition I = 0, for subsequent conditions I = 1, 2, 3, .
 π 
3 3
I – Plastic torsion modulus [mm ] of bolt shanks  = × min ( ; ) 1, equation (71)
d d
B Be Bs
12
 
K – Rate of change of compressive modulus of elasticity of the gasket with compressive stress,
1
ENV 1591-2
K – Systematic error due to the inaccuracy of the bolt tightening method
s
M – Additional external moment [N × mm], Figure 1
A
M – Bolt assembly torque [N × mm], annex D
t
M – twisting moment [N × mm] applied to bolt shanks as a result of application of the bolt
t,B
assembly torque M , equations (71) and (D.8) to (D.11)
t
N – Number of re-assemblies and re-tightenings during service life of joint, equation (67)
R
P – Pressure of the fluid [MPa], internal pressure > 0, external pressure < 0 (1 bar = 0,1 MPa)
NOTE P in this standard is equal to the maximum allowable pressure PS according to the PED.
P – Creep factor which is the ratio of the residual and the original gasket surface pressure
QR
Q – Mean effective gasket compressive stress [MPa], Q = F /A
G Ge
Q – Minimum level of gasket surface pressure required for tightness class L after off-loading at
s min(L )I
load condition I [MPa]
Q – Minimum level of gasket surface pressure required for tightness class L on assembly (on the
 min(L )
effective gasket area) [MPa], equation (49), (see ENV 1591-2)
Q – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service
s max
temperature without damage (for reference geometry DN40/PN40) [MPa]
Q – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service
 max
temperature without damage (for actual geometry of the gasket used in bolted flange
connection) [MPa]
Q – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service
 max,Y
temperature without damage (independent from the geometry of the gasket) [MPa]
T , T , T , T – Temperature (average) of the part designated by the subscript [°C] or [K], equation (45)
B F G L
T – Temperature of joint at assembly [°C] or [K] (usually + 20 °C)
O
U – Axial displacement [mm]; ∆U according to equation (45)
W , W , W – Resistance of the part and/or cross-section designated by the subscript [N × mm], equations
F L X
(74), (86), (88), (90)
X , X – Axial flexibility modulus of bolts, gasket [1/ mm], equations (34), (42)
B G
Y , Y , Y – Axial compliance of the bolted joint, related to F , F , F [mm/N], equations (46), (47), (48)
G Q R G Q R
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EN 1591-1:2001/prA1:2005 (E)
–3
Z , Z – Rotational flexibility modulus of flange, loose flange [mm ], equations (27), (31), (32)
F L
b – Width of chamfer (or radius) of a loose flange [mm] see Figure 10, equation (15) such that:
0
d = d + 2 × b
7min 6 0
b , b – Effective width of flange, loose flange [mm], equations (5) to (8)
F L
b , b , b – Gasket width (radial), interim, effective, theoretical [mm], equations (35), (38), Table 1
Gi Ge Gt
c , c , c – Correction factors, equations (20), (78), (79)
F M S
d – Inside
...