ENV 1591-2:2001

SLOVENSKI STANDARD
SIST ENV 1591-2:2002
01-maj-2002
3ULUREQLFHLQSULUREQLþQLVSRML3UDYLOD]DQDþUWRYDQMHRNURJOLKSULUREQLþQLKVSRMHY
VWHVQLOLGHO3DUDPHWULWHVQLO
Flanges and their joints - Design rules for gasketed circular flange connections - Part 2:
Gasket parameters
Flansche und ihre Verbindungen - Regeln für die Auslegung von Flanschverbindungen
mit runden Flanschen und Dichtung - Teil 2: Dichtungskennwerte
Brides et leurs assemblages - Regles de calcul des assemblages a brides circulaires
avec joint - Partie 2: Parametres de joint
Ta slovenski standard je istoveten z: ENV 1591-2:2001
ICS:
23.040.60 Prirobnice, oglavki in spojni Flanges, couplings and joints
elementi
SIST ENV 1591-2:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ENV 1591-2:2002

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SIST ENV 1591-2:2002
EUROPEAN PRESTANDARD
ENV 1591-2
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
June 2001
ICS 23.040.60
English version
Flanges and their joints - Design rules for gasketed circular
flange connections - Part 2: Gasket parameters
Brides et leurs assemblages - Règles de calcul des Flansche und ihre Verbindungen - Regeln für die
assemblages à brides circulaires avec joint - Partie 2: Auslegung von Flanschverbindungen mit runden Flanschen
Paramètres de joint und Dichtung - Teil 2: Dichtungskennwerte
This European Prestandard (ENV) was approved by CEN on 10 May 2001 as a prospective standard for provisional application.
The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the ENV can be converted into a European Standard.
CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final
decision about the possible conversion of the ENV into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, 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
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. ENV 1591-2:2001 E
worldwide for CEN national Members.

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SIST ENV 1591-2:2002
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ENV 1591-2:2001
Contents
Page
Foreword . 2
1 Scope . 3
2 Symbols and equations . 3
3 Gasket properties . 4
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 74 "Flanges and their joints", the
secretariat of which is held by DIN.
EN 1591 consists of two parts:
– EN 1591-1
Flanges and their joints — Design rules for gasketed circular flange connections — Part 1: Calculation method
– ENV 1591-2
Flanges and their joints — Design rules for gasketed circular flange connections — Part 2: Gasket parameters
CEN/TC 74 had decided to publish the gasket parameters given in an informative annex to prEN 1591:1994 in the
present document as separate prestandard.
Data values given in this European Prestandard are based on measurement, on experience, or on estimation.
Although currently regarded as the best available information for generic materials, values are only provided for
general guidance.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this European Prestandard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and the United Kingdom.

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SIST ENV 1591-2:2002
Page 3
ENV 1591-2:2001
1 Scope
This European Prestandard specifies gasket parameters for use in EN 1591-1.
WARNING  The reader is directed to obtain gasket parameters for use in the calculation method given in EN 1591-1 from the
gasket supplier. Where this is not possible, then the values in this document may be used. In the latter case the reader should
ensure the latest version of this document is used. If in doubt the national CEN member can be contacted.
2 Symbols and equations
Italicised equation numbers are the ones used in part 1 of this standard. When this equation number is in brackets
this denotes that the equation is given here in modified form.
Where units are applicable, they are shown in brackets. Where units are not applicable, no indication is given.
E – Unloading compression modulus of gasket for I = 0, [MPa].
G
E – The value of E , extrapolated from measurement values of E back to zero stress, Q = 0, [MPa].
0 G G 0
K – Coefficient which determines rate of change of E with compressive stress.
1 G
NOTE 1  Gasket unloading compression modulus, E , is assumed to vary linearily with the maximum stress to which the gasket
G
has been subjected previously, normally the assembly stress (i.e. load condition I = 0):
E = E + K × Q (1)
G 0 1 0
NOTE 2  The measurement of E is made along a chord from Q = Q to Q = 0,3 Q on a stress/strain curve of the gasket,
G 0 0
obtained at unloading.
g – Creep factor for gasket
c
NOTE 3  This is an empirical factor which adjusts the compression modulus E to account, approximately, for any additional
G
compressive displacement U due to gasket creep, (g > 1). It is defined as:
G c
= /
g U U (2)
c G(t = 0) G(t fi ¥)
and applied as follows:
E = g × E (3)
G(including creep) c G(excluding creep)
NOTE 4  For measurements of U suitable times such as e.g. 1 000 h are acceptable.
G(t fi ¥)
I – Designates the load condition:
I = 0 is the assembly condition,
I = 1, 2, . are subsequent conditions including hydraulic testing and all service conditions which could be significant
Q – Mean effective required gasket compressive stress at load condition I, [Mpa]
I
Q – Maximum allowable compressive stress in the gasket material, [Mpa]
max
Q – Minimum necessary compressive gasket stress for assembly condition (I = 0) [Mpa]
min
NOTE 5  These two parameters define a range of gasket stress between which the gasket behaves in a consistent reliable
manner. Below the lower limit Q the leak rate may be untypically high and variable, above the upper limit Q various gasket
min max
properties may be untypical and the gasket may suffer permanent damage. If empirical formulae are fitted to measured gasket
properties (e.g. curves of load-compression or stress-leakage rate) the range defines limits of validity of the formulae.

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SIST ENV 1591-2:2002
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ENV 1591-2:2001
NOTE 6  Values of Q are independant of the gasket dimensions and can be obtained approximately as follows:
max, y
Q = Q /{1 + c ⋅ (b /e ) } (4a))
max, y max, ref 1 g g ref
Values of Q depend on gasket dimensions approximately as follows:
max
Q = Q {1 + ⋅ ( / ) }/{1 + ⋅ ( / ) } (4b))
c b e c b e
max max, ref 1 G G actual 1 G G ref
where
– c is a numerical constant for a gasket type. c = 1/20 is a typical value for bonded-fibre sheet gaskets. For gaskets for which
1 1
no value is available c = 0 can be used; and
1
– Q is the measured value of Q for a gasket of radial width (b ) and axial thickness (e ) . The reference size for a
max, ref max G ref G ref
bonded-fibre sheet gasket is 90 mm outside diameter × 50 mm inside diameter × 2 mm thickness. Q includes safety
max., ref
margins which are the same for all load conditions.
NOTE 7  Parameter Q serves, in part, the same purpose as "y" in ASME and related design codes (including BS 5 500 and
min
CODAP) but differs as follows:
a) due to the different way in which the effective gasket width is calculated in the ASME Code and the present standard, the
value of Q is not the same as that of y;
min
b) Q also serves to define the lower limit of validity of empirical formulae where used to calculate gasket properties.
min
NOTE 8  Q is used to define an absolute minimum value of assembly gasket force, F :
min G0 min
F = A × Q (see equation 49) (5)
G0 min Ge min
where A is
...