1、DRAFT FOR DEVELOPMENTDD CEN/TS 1591-3:2007Flanges and their joints Design rules for gasketed circular flange connections Part 3: Calculation method for metal to metal contact type flanged jointICS 23.040.60g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g4
2、9g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58DD CEN/TS 1591-3:2007This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 BSI 2007ISBN 978 0 580 54622 8National forew
3、ordThis Draft for Development is the UK implementation of CEN/TS 1591-3:2007.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that inf
4、ormation and experience of its practical application can be obtained.Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this publication will b
5、e initiated not later than 3 years after its publication by the European organization so that a decision can be taken on its status. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards.According to the replies received by the en
6、d of the review period, the responsible BSI Committee will decide whether to support the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards
7、House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to Technical Committee PSE/15, Flanges.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary p
8、rovisions of a contract. Users are responsible for its correct application. Amendments issued since publicationAmd. No. Date CommentsTECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN/TS 1591-3July 2007ICS 23.040.60English VersionFlanges and their joints - Design rules for gask
9、eted circularflange connections - Part 3: Calculation method for metal tometal contact type flanged jointBrides et leurs assemblages - Rgles de calcul desassemblages brides circulaires avec joint - Partie 3 :Mthode de calcul pour les assemblages brides de typecontact mtal-mtalFlansche und ihre Verbi
10、ndungen - Regeln fr dieAuslegung von Flanschverbindungen mit runden Flanschenund Dichtung - Teil 3: Berechnungsmethode frFlanschverbindungen mit Dichtungen im Kraft-NebenschlussThis Technical Specification (CEN/TS) was approved by CEN on 16 June 2007 for provisional application.The period of validit
11、y of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit theircomments, particularly on the question whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same
12、way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are
13、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, Switzerlan
14、d and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TS 15
15、91-3:2007: E2 Contents Page Introduction .4 1 Scope 5 2 Normative references 7 3 Notation 7 4 Calculation parameters .15 5 Internal forces (in the connection).30 6 Checking of the admissibility of the load ratio.39 Annex A (informative) Example of Gasket compression curve44 Annex B (informative) Loc
16、al compression deformation .48 Annex C (informative) Relaxation of the gasket: Three-parameter solid model.50 Annex D (informative) Scatter of bolting-up methods.54 Annex E (informative) Calculation sequences .55 Annex F (informative) Determination of the compliance equations 59 Bibliography 60 CEN/
17、TS 1591-3:20073 Foreword This document (CEN/TS 1591-3:2007) has been prepared by Technical Committee CEN/TC “Flanges and their joints”, the secretariat of which is held by DIN. EN 1591 “Flanges and their joints Design rules for gasketed flange connections“ consists of the following three parts: Part
18、 1: Calculation method Part 2: Gasket parameters Part 3: Calculation method for metal to metal contact type flanged joint (CEN/TS) Part 4: Qualification of personnel competency in the assembly of bolted joints fitted to equipment sub-ject to the Pressure Equipment Directive According to the CEN/CENE
19、LEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech Re-public, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithua-nia,
20、 Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Swe-den, Switzerland and the United Kingdom. CEN/TS 1591-3:20074 Introduction Bolted Flange connections with metal to metal contact are frequently used in industrial plants for severe work-ing conditions (
21、thermal transients, pressure fluctuations). The use of metal to metal contact allows to avoid the damage of the sealing component by limiting the gasket loading stress and to limit the load variations on the gasket. This Technical Specification describes a calculation method which enables to determi
22、ne the internal forces of the BFC in all the load conditions. It ensures structural integrity and control of leak-tightness in BFC with MMC (BFC types which are outside the scope of EN 1591-1). The calculation method may be divided into three steps: Determination of the bolt tightening to reach the
23、MMC. Determination of the bolt tightening to maintain the MMC and to satisfy the leak-tightness criteria in all the load conditions. Checking of the admissibility of the load ratio. CEN/TS 1591-3:20075 1 Scope The aim of this Technical Specification is to describe a calculation method dedicated to B
24、olted Flange Con-nections (BFC) with metal to metal contact (MMC). It is dedicated to BFC where MMC occurs in a region be-tween the outside diameter of the gasket and the inside diameter of the bolt hole region. For MMC inside the gasket and for MMC outside the bolt hole region, the present method i
25、s not appropriate. The calculation method proposed in this Technical Specification is mainly based on the method described in EN 1591-1, dedicated to floating type BFC. The behaviour of the complete flanges-bolts-gasket system is considered. In assembly condition as well as for all the subsequent lo
26、ad conditions, the BFC components are maintained together by internal forces. This leads to deformations and forces balances (see Annex F) which gives the basic relations between the forces variations in the BFC. The calculation of BFC with MMC leads to the consideration of an additional force compa
27、red to the EN 1591-1 calculation method: the reaction force in the MMC area. It explains why two compliance equations are re-quired in this Technical Specification (in the EN 1591-1 calculation method just one compliance equation is needed to determine the internal forces in all the load conditions)
28、. Unlike EN 1591-1 where the internal forces variations are determined with the compliance relation between the assembly and the considered load condition, here, the internal forces variations are determined by using the compliance relations between two consecutive load conditions. This method does
29、not treat non-gasketed pipe joints. 1.1 Requirement for use of the Method Where permitted, the Method is an alternative to design validation by other means e.g. special testing; proven practice. Use of standard flanges within permitted conditions 1.2 Geometry The Method is applicable to the configur
30、ations having: flanges whose section is given or may be assimilated to those given in Figures 4 to 12 of EN 1591-1:2001; four or more identical bolts uniformly distributed; gasket designed for MMC application; flange dimension which meet the following conditions: a) 05200520 ,/,;,/,LLFF ebeb b) ()30
31、2100010maxFBBBF/,.,; bppdee c) ()SSS/,/ ed+ 01011cos NOTE 1 For explanations of symbols see Clause 3. NOTE 2 The condition 05,/FFeb needs not to be met for collar in combination with loose flange. CEN/TS 1591-3:20076 NOTE 3 The condition ()3100010FBBF/,., bppe is for limitation of non-uniformity of
32、gasket pressure due to spacing of bolts. The values 0,01 and 0,10 should be applied for soft (non-metallic) and hard (metallic) gaskets respec-tively. A more precise criterion is given in Annex A of EN 1591-1:2001. NOTE 4 Attention may need to be given to the effects of tolerances and corrosion on d
33、imensions; 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 Method: flanges of essentially non-axisymmetric geometry, e.g. split loose flanges, web reinforced
34、flanges. 1.3 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 should be determined as for flanges and shells. The model of the
35、 gaskets is mod-elled 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 method can be excessively conservative (i.e. required bolting load to
36、o high, allowable pressure of the fluid too low, required flange thickness too large, etc.) because it does not take account of such properties. 1.4 Loads This Method applies to the following load types: fluid pressure: internal or external; external loads: axial forces and bending moments; axial ex
37、pansion of flanges, bolts and gasket, in particular due to thermal effects. 1.5 Mechanical model The 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 t
38、o 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 1.2
39、 a). c) The flange ring is connected to a cylindrical shell. A tapered hub is treated as being an equivalent cylin-drical shell of calculated wall thickness, which is different for elastic and plastic behaviour, but always be-tween the actual minimum and maximum thickness. Conical and spherical shel
40、ls are treated as being equivalent cylindrical shells with the same wall thickness; differences from cylindrical shell are explicitly taken into account in the calculation formula. This presupposition requires compliance with 1.2 c). At the connection of the flange ring and shell, the continuity of
41、radial displacement and rotation is accounted for in the calculation. CEN/TS 1591-3:20077 d) The gasket contacts the flange faces over a (calculated) annular area. The effective gasket width (radial) bGemay be less than the true width of gasket. The calculation of bGeincludes the elastic rotation of
42、 both flanges as well as the elastic and plastic deformations of the gasket (approximately) in assembly con-dition. e) The unloading modulus of elasticity of the gasket may increase with the gasket surface pressure. The Method uses a linear model: EG= E0+ K1 Q. This is the unloading elasto-plastic s
43、ecant modulus meas-ured between 100 % and 33 % of the highest surface pressure reached on the gasket. f) Relaxation of the gasket under compression is approximated (see 4.9 and Annex C). g) Thermal and mechanical axial deformations of flanges, bolts and gasket are taken into account. h) Loading of t
44、he flange joint is axisymmetric. Any non-axisymmetric bending moment is replaced by an equivalent axial force, which is axisymmetric according to Equation (75). i) Load changes between load conditions cause internal changes of bolt, gasket and MMC forces. These are calculated with account taken of e
45、lastic deformations of all components. j) Load limit proofs are based on limit loads for each component. This approach prevents excessive defor-mations. The limits used for gaskets, which depend on Qmaxare only rough approximations. The model does not take account of the following: k) Bolt bending s
46、tiffness 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 tapped hole (see Equation (37). l) Creep of flanges and bolts. m) Different radial deformation
47、s 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 torsion moments and external shear loads, e.g. those due to pipework. 2 Normative references The following referenced documents are indispensa
48、ble for the application of this document. For dated refer-ences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1591-1:2001, Flanges and their joints Design rules for gasketed circular flange connections Pa
49、rt 1: Calculation method prEN 1591-2:, Flanges and their joints Design rules for gasketed circular flange connections Part 2: Gasket parameters 3 Notation 3.1 Use of figures Figure 1 illustrates the two configurations of metal to metal contact. Figure 2 shows the variables used in the calculation of the inside diameter of the MMC area. CEN/TS 1591-3:20078 3.2 Subscripts and special marks 3.2.1 Subscripts A Additional (FA, MA) B Bolt D Equivalent cylinder (tapered hub + connected shell) for load limit calculation E
