SIST EN 1591-1:2002+A1:2009
(Main)Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
1.1 General
This European Standard defines a Calculation method for bolted, gasketed, circular flange joints. Its purpose is to ensure structural integrity and control of leaktightness. The following equations use gasket parameters based on definitions and test methods specified in EN 13555.
1.2 Requirement for use of the Calculation method
Where permitted, the Calculation method is an alternative to design validation by other means e.g.
- special testing;
- proven practice;
- use of standard flanges within permitted conditions.
1.3 Validity
1.3.1 Geometry
The Calculation method is applicable to the configurations having:
- flanges whose section is given or may be assimilated to those given in Figures 4 to 12;
- four or more identical bolts uniformly distributed;
- gasket whose section and configuration after loading can be assimilated by one of those given in Figure 3;
- flange dimension which meet the following conditions:
a) 0,2 ≤ bF/eF ≤ 5,0; 0,2 ≤ bL/eL ≤ 5,0
b) eF ≤ max {e2; dB0; pB x }
c)
NOTE For explanations of symbols see clause 3.
NOTE The condition bF/eF ≤ 5,0 need not be met for collar in combination with loose flange.
NOTE The condition is for limitation of non-uniformity of gasket pressure due
to spacing of bolts. The values 0,01 and 0,10 are to be applied for soft (non-metallic) and hard (metallic)
gaskets respectively. A more precise criterion is given in annex A.
NOTE Attention may need to be given to the effects of tolerances and corrosion on dimensions; reference should be made to other codes under which the calculation is made, for example values are given in EN 13445 and EN 13480.
The following configurations are outside the scope of the Calculation method:
- flanges of essentially non-axisymmetric geometry, e.g. split loose flanges, web reinforced flanges;
Flansche und ihre Verbindungen - Regeln für die Auslegung von Flanschverbindungen mit runden Flanschen und Dichtung - Teil 1: Berechnungsmethode
Brides et leurs assemblages - Règles de calcul des assemblages à brides circulaires avec joint - Partie 1: Méthode de calcul
1.1 Généralités
La présente Norme européenne définit une méthode de calcul des assemblages à brides boulonnées circulaires
avec joint. Son objectif est d'en assurer l'intégrité structurale et la maîtrise de l'étanchéité. !Les équations
suivantes utilisent des paramètres de joints basés sur les définitions et les modes opératoires d'essais spécifiés
dans l’EN 13555."
1.2 Prescription d'emploi
La méthode de calcul est destinée à être utilisée lorsqu’un code ou une réglementation l'exige. Elle constitue l’une
des alternatives possibles (quand cela est permis), pour la justification de la conception d'un assemblage, au même
titre que d’autres, par exemple :
— des essais spécifiques ;
— la référence à une expérience pratique justifiée ;
— l'utilisation de brides normalisées, dans les conditions autorisées.
1.3 Domaine de validité
1.3.1 Géométrie
La méthode de calcul est applicable aux configurations présentant :
— des brides dont la section correspond ou peut être assimilée à l’une de celles présentées dans les Figures 4 à 12 ;
— quatre boulons identiques ou plus, répartis régulièrement ;
— un joint dont la section et la configuration après chargement peuvent être assimilés à l’une de celles présentées
en Figure 3 ;
— des dimensions de brides qui satisfont aux conditions suivantes :
a) 0,2 ≤ bF / eF ≤ 5,0 ; 0,2 ≤ bL / eL ≤ 5,0 ;
b) eF ≤ max ;
c) cos ϕ ≥ 1/(1 + 0,01 ds / es).
NOTE 1 Voir article 3 pour la signification des symboles.
NOTE 2 La condition bF / eF ≤ 5,0 n'a pas besoin d'être satisfaite pour le collet d'une bride tournante.
NOTE 3 La condition eF ≥ pB × a pour objet de limiter l'inégalité de la répartition de la compression
du joint qui peut résulter de l'espacement des boulons. Les valeurs 0,01 et 0,10 sont à utiliser respectivement pour les joints
à faible dureté (non métalliques) et pour les joints durs (métalliques). Un critère plus précis est donné en annexe A.
Prirobnice in prirobnični spoji - Pravila za načrtovanje okroglih prirobničnih spojev s tesnili - 1. del: Način izračuna
Ta evropski standard opredeljuje način izračuna za vijačne in tesnilne okrogle prirobnice in prirobnične spoje. Njegov namen je zagotoviti strukturno celovitost in nadzor neprepustnosti.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Flansche und ihre Verbindungen - Regeln für die Auslegung von Flanschverbindungen mit runden Flanschen und Dichtung - Teil 1: BerechnungsmethodeBrides et leurs assemblages - Règles de calcul des assemblages à brides circulaires avec joint - Partie 1: Méthode de calculFlanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method23.040.60Prirobnice, oglavki in spojni elementiFlanges, couplings and jointsICS:Ta slovenski standard je istoveten z:EN 1591-1:2001+A1:2009SIST EN 1591-1:2002+A1:2009en,fr01-maj-2009SIST EN 1591-1:2002+A1:2009SLOVENSKI
STANDARD
SIST EN 1591-1:2002+A1:2009
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1591-1:2001+A1
March 2009 ICS 23.040.60 Supersedes EN 1591-1:2001English Version
Flanges and their joints - Design rules for gasketed circular flange connections - Part 1: Calculation method
Brides et leurs assemblages - Règles de calcul des assemblages à brides circulaires avec joint - Partie 1: Méthode de calcul
Flansche und ihre Verbindungen - Regeln für die Auslegung von Flanschverbindungen mit runden Flanschen und Dichtung - Teil 1: Berechnungsmethode This European Standard was approved by CEN on 8 March 2001 and includes Amendment 1 approved by CEN on 7 February 2009.
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:
Avenue Marnix 17,
B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1591-1:2001+A1:2009: ESIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 2 Contents Page Foreword .31Scope .61.1General .61.2Requirement for use of the Calculation method .61.3Validity .62Normative references .83Notation .93.1Use of figures .93.2Subscripts and special marks .93.3Symbols . 103.4Terminology . 144Calculation parameters . 244.1Flange parameters . 254.2Bolt parameters . 294.3Gasket parameters. 295Internal forces (in the joint) . 325.1Applied loads . 325.2Compliance of the joint . 335.3Minimum forces necessary for the gasket . 335.4Internal forces in assembly condition (I = 0). 345.5Internal forces in subsequent conditions (I = 1, 2, …) . 366Checking of the admissibility of the load ratio . 366.1General . 366.2Bolts . 376.3Gasket . 386.4Integral flange and collar . 386.5Blank flange . 396.6Loose flange with collar . 40Annex A (informative)
Requirement for limitation of non-uniformity of gasket stress . 41Annex B (informative)
Dimensions of standard metric bolts . 42Annex C (informative)
Scatter of bolting-up methods . 43Annex D (informative)
Assembly using torque wrench . 44Annex E (informative)
Flange rotations . 46E.1General . 46E.2Use of flange rotation . 46E.3Calculation of flange rotations . 46Annex F (informative)
Diagram of calculation sequence . 48Annex G (informative)
Joints with spacer-seated flanges . 50G.1Introduction . 50G.2Behaviour of spacer-seated gaskets . 50G.3Simplified treatment . 50Annex H (normative)
!!!!Use of the former creep factor gC"""" . 55Annex ZA (informative)
!Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC"""" . 56Bibliography . 57SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 3
Foreword This document (EN 1591-1:2001+A1:2009) has been prepared by Technical Committee CEN/TC 74 "Flanges and their joints", the secretariat of which is held by DIN.
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 2009, and conflicting national standards shall be withdrawn at the latest by September 2009.
This document includes Amendment 1, approved by CEN on 2009-02-07. This document supersedes EN 1591-1:2001. The start and finish of text introduced or altered by amendment is indicated in the text by tags ! ".
This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. This European Standard is considered as a supporting standard to other application and product standards which in themselves support an essential safety requirement of a New Approach Directive and will appear as a normative reference in them.
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this standard.
EN 1591 consists of two parts:
– EN 1591-1 Flanges and their joints – Design rules for gasketed circular flange connections – Part 1: Calculation method
– !EN 1591-2" Flanges and their joints – Design rules for gasketed circular flange connections – Part 2: Gasket parameters
The Calculation method satisfies both leaktightness and strength criteria. The behaviour of the complete flanges-bolts-gasket system is considered. Parameters taken into account include not only basic ones such as:
– fluid pressure;
– material strength values of flanges, bolts and gaskets;
– gasket compression factors;
– nominal bolt load;
but also:
– possible scatter due to bolting up procedure;
– changes in gasket force due to deformation of all components of the joint;
– influence of connected shell or pipe;
– effect of external axial forces and bending moments; SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 4
– effect of temperature difference between bolts and flange ring
Calculation for sealing performance is based on elastic analysis of the load/deformation relations between all parts of the flange connection, corrected by a possible plastic behaviour of the gasket material. Calculation for mechanical resistance is based on (plastic) limit analysis of the flange-shell combination. Both internal and external loads are considered. Load conditions covered include initial assembly, hydrostatic test, and all significant subsequent operating conditions. The calculation steps are broadly as follows:
1) First, the required minimum initial bolt load (to be reached at bolting-up) is determined, so that in any subsequent specified load condition, the residual force on the gasket will never be less than the minimum mean value required for the gasket (value is gasket data from !EN 1591-2", for instance). The determination of this load is iterative, because it depends on the effective gasket width, which itself depends on the initial bolt load.
2) Then, the internal forces that result from the selected value of initial bolt load are derived for all load conditions, and the admissibility of combined external and internal forces is checked as follows:
bolting-up condition: the check is performed against the maximum possible bolt force that may result from the bolting-up procedure; test and operating conditions: checks are performed against the minimum necessary forces, to ensure that the connection will be able to develop these minimum forces without risk of yielding, except in highly localized areas. Higher actual initial bolting results in (limited) plastic deformation in subsequent conditions (test, operation). But the checks so defined assure that these deformations will not reduce the bolt force to a value less than the minimum required.
If necessary, the flange rotations may be estimated in all load conditions, using annex E, and the values obtained, compared with the relevant gasket limits which could apply.
Checks for admissibility of loads imply safety factors which are those applied to material yield stress or strength in the determination of the nominal design stresses used in the Calculation method.
NOTE Where flanges are used to comply with other codes the Calculation method does not specify values for nominal stresses.
Nevertheless, since all significant design parameters are accounted for, the use of low safety factors is made possible by special use of nominal design stresses:
for assembly conditions the nominal design stresses have the same values as for the hydraulic pressure tests (normally higher than for operating conditions); – the nominal design stresses for the bolts are determined by the same rules as relevant for the flange and shell material e.g. same safety factor on yield stress.
The minimum force required on the gasket for leak tightness considerations may be established by two different ways:
1) Use of tabulated gasket factors, for example those given in !EN 1591-2", which are based on industrial experience and correspond to mainly gas and steam leak rates.
2) Derivation from measured leak rate versus gasket stress data, if available for the gasket, for example as in !EN 1591-2". This permits design to be based on any specified maximum leak rate.
The use of this Calculation method is particularly useful for joints where the bolt load is monitored when bolting up. The greater the precision of this, the more benefit can be gained from application of the Calculation method.
In the present stage of development, the Calculation method is not applicable to joints with narrow metal-to-metal contact (with the exception of joints with spacer seated flanges (see annex G)), or to joints whose rigidity varies appreciably across gasket width.
SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 5 A chart illustrating the calculation process is given in annex F.
!The load calculated by the procedures outlined in this standard represent the minimum bolt load that should be applied to the gasket to achieve the required tightness class. Increasing bolt load within acceptable load ratios of the flanges / bolt / gasket, reduces leak rates and produces a conservative design. The designer may choose a bolt load between the load to achieve the tightness class and the load limited by the load ratios. The objective for the publication of this new edition of EN 1591-1:2001 is to keep the standard in line with
EN 1591-2:2008. The calculation methodology and interpretation of gasket data is the subject of on going work in Joint Working Group CEN/TC54/TC69/TC74/TC267/TC269/JWG. This publication is therefore transitory and will be updated in due course.
EN 1591-1 is based upon the principle that a selected leakage rate is to be achieved. But, where there is no requirement on limitation of leakage, the following two modifications are suggested: – In Equation (49) the gasket surface pressure QA may be replaced by Q0,min taken from
EN 13445-3:2002, Annex G; – In Equation (50) the gasket surface pressure Qsmin(L)I may be replaced by QI,min = mÿ × |Pÿ|, with mÿ taken from EN 13445-3:2002, Annex G."
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 United Kingdom.
SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 6 1 Scope 1.1 General This European Standard defines a Calculation method for bolted, gasketed, circular flange joints. Its purpose is to ensure structural integrity and control of leaktightness. !The following equations use gasket parameters based on definitions and test methods specified in EN 13555." 1.2 Requirement for use of the Calculation method Where permitted, the Calculation method is an alternative to design validation by other means e.g. – special testing; – proven practice; – use of standard flanges within permitted conditions. 1.3 Validity 1.3.1 Geometry The Calculation method is applicable to the configurations having: flanges whose section is given or may be assimilated to those given in Figures 4 to 12; four or more identical bolts uniformly distributed; gasket whose section and configuration after loading can be assimilated by one of those given in
Figure 3; flange dimension which meet the following conditions: a) 0,2 ≤ bF/eF ≤ 5,0; 0,2 ≤ bL/eL ≤ 5,0 b) eF ≤ max {e2; dB0; pB x 3)10,0.01,0(FBbp×} c) )01,01/(1cosssed+≥ϕ NOTE For explanations of symbols see clause 3. NOTE The condition bF/eF ≤ 5,0 need not be met for collar in combination with loose flange. NOTE The condition 3)10,0.01,0(FBBFbppe×≥ is for limitation of non-uniformity of gasket pressure due
to spacing of bolts. The values 0,01 and 0,10 are to be applied for soft (non-metallic) and hard (metallic) gaskets respectively. A more precise criterion is given in annex A.
NOTE Attention may need to be given to the effects of tolerances and corrosion on dimensions; reference should be made to other codes under which the calculation is made, for example values are given in EN 13445 and EN 13480. SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 7 The following configurations are outside the scope of the Calculation method: – flanges of essentially non-axisymmetric geometry, e.g. split loose flanges, web reinforced flanges; – flange connections having direct or indirect metal to metal contact between flanges inside and/or outside the gasket, inside and/or outside the bolt circle, except the special case of spacer-seated flanges, which is covered in annex G. 1.3.2 Materials Values of nominal design stresses are not specified in this Calculation method. They depend on other codes which are applied, for example these values are given in EN 13445 and EN 13480. Design stresses for bolts are to be determined as for flanges and shells. The model of the gaskets is modelled by elastic behaviour with a plastic correction. For gaskets in incompressible materials which permit large deformations (for example: flat gaskets with rubber as the major component), the results given by the Calculation method can be excessively conservative (i.e. required bolting load too high, allowable pressure of the fluid too low, required flange thickness too large, etc.) because it does not take account of such properties. 1.3.3 Loads This Calculation method applies to the following load types: – fluid pressure: internal or external; – external loads: axial forces and bending moments; – axial expansion of flanges, bolts and gasket, in particular due to thermal effects. 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) bGe may be less than the true width of gasket. This effective width bGe is calculated for the assembly condition (I = 0) and is assumed to be unchanged for all subsequent load conditions (I = 1,2 .). The calculation of bGe includes the elastic rotation of both flanges as well as the elastic and plastic deformations of the gasket (approximately) in assembly condition. SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 8 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. The calculation method uses the highest stress (Q) in assembly condition." f) !Creep of the gasket under compression is approximated by a creep factor PQR." 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 Qmax are only approximations. 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. 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 1092-1:2007", Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated — Part 1: Steel flanges
!EN 1092-2:1997", Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated — Part 2: Cast iron flanges
!EN 1092-3:2003, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated — Part 3: Copper alloy flanges"
!EN 1092-4:2002", Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN designated — Part 4: Aluminium alloy flanges
!deleted text"
!EN 13555:2004, Flanges and their joints — Gasket parameters and test procedures relevant to the design rules for gasketed circular flange connections" SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 9 3 Notation 3.1 Use of figures Figures 1 to 12 illustrate the notation corresponding to the geometric parameters. They only show principles and are not intended to be practical designs. They do not illustrate all possible flange types for which the Calculation method is valid. For standard flange types, according to EN 1092, the relevant figures are the following: Type 01 Figure 8 Type 02 Figure 10 Type 04
Figure 10 Type 05
Figure 9 Type 07
Figure 10 Type 11
Figure 4 Type 12
Figure 11 Type 13
Figure 12 Type 21
Figure 4 to 7
3.2 Subscripts and special marks 3.2.1 Subscripts A – Additional (FA, MA) B – Bolt C – Creep of gasket (gc) 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 SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 10 ∆ – Symbol for change or difference !actual
the actual dimensions considered in the calculation" av – average c – calculated d – design e – effective max – maximum min – minimum nom – nominal opt – optimal !ref
dimensions of reference in EN 13555:2004, 7.4" 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. AB
Effective total cross-section area of all bolts [mm2], equation (33) AF, AL Gross radial cross-section area (including bolt holes) of flange ring, loose flange [mm2], equations (5), (7), (8) AGe, AGt
Gasket area, effective, theoretical [mm2], equations (39), (36) C
Coefficient to account for twisting moment in bolt load ratio, equation (71) !deleted text" EB, EF, EG, EL Modulus of elasticity of the part designated by the subscript, at the temperature of the part [MPa] !deleted text" FA
Additional external axial force [N], tensile force > 0, compressive force < 0, see Figure 1 FB
Bolt force (sum of all bolts) [N] FG
Gasket force [N] SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 11 FG∆ Minimum gasket force in assembly condition [N] that guarantees after all load changes to subsequent conditions the required gasket force, equation (51) FQ Axial fluid-pressure force [N], equation (43) FR Force resulting from FA and MA [N], equation (44) I Load condition identifier, for assembly condition I = 0, for subsequent conditions I = 1, 2, 3, . IB Plastic torsion modulus [mm3] of bolt shanks ×=3);(min12BsBeddπ equation (71) !deleted text" Ks Systematic error due to the inaccuracy of the bolt tightening method MA Additional external moment [N × mm], Figure 1 Mt Bolt assembly torque [N × mm], annex D Mt,B Twisting moment [N × mm] applied to bolt shanks as a result of application of the bolt assembly torque Mt, equations (71) and (D.8) to (D.11) NR Number of re-assemblies and re-tightenings during service life of joint, equation (67) 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. !PQR Creep factor which is the ratio of the residual and the original gasket surface pressure at load conditions [-], Equation (51), (68)" Q Mean effective gasket compressive stress [MPa], Q = FG/AGe ! QA – Gasket surface pressure at assembly prior to the unloading which is necessary for the validity of QS min (L)I in service conditions [MPa], Equation (49) QS min (L)
– Minimum level of gasket surface pressure required for tightness class L after off-loading at load conditions [MPa], Equation (50) Qmin (L) – Minimum level of gasket surface pressure required for tightness class L on assembly (on the effective gasket area) [MPa], lowest acceptable value for QA QS max – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service temperature without damage [MPa], Equation (72a), (72b) Qmax – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service temperature without damage (for actual geometry of the gasket used in bolted flange connection) [MPa] ,Equation (72b), (72c) Qmax,Y – Maximum gasket surface pressure that can be safely imposed upon the gasket at the service temperature without damage (independent from the geometry of the gasket) [MPa], Equation (72a)" TB, TF, TG, TL Temperature (average) of the part designated by the subscript [°C] or [K], equation (45) SIST EN 1591-1:2002+A1:2009
EN 1591-1:2001+A1:2009 (E) 12 TO Temperature of joint at assembly [°C] or [K] (usually + 20 °C) U Axial displacement [mm]; ∆U according
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.