National foreword

This British Standard is the UK implementation of EN 12516‑2:2014+A1:2021. It supersedes BS EN 12516‑2:2014, which is withdrawn.

The start and finish of text introduced or altered by amendment is indicated in the text by tags. Tags indicating changes to CEN text carry the number of the CEN amendment. For example, text altered by CEN amendment A1 is indicated by .

The UK participation in its preparation was entrusted to Technical Committee PSE/18/1, Industrial valves, steam traps, actuators and safety devices against excessive pressure - Valves - Basic standards.

A list of organizations represented on this committee can be obtained on request to its committee manager.

This publication has been prepared under a mandate given to the European Standards Organizations by the European Commission and the European Free Trade Association. It is intended to support requirements of the EU legislation detailed in the European Foreword. A European Annex, usually Annex ZA or ZZ, describes how this publication relates to that EU legislation.

For the Great Britain market (England, Scotland and Wales), if UK Government has designated this publication for conformity with UKCA marking (or similar) legislation, it may contain an additional National Annex. Where such a National Annex exists, it shows the correlation between this publication and the relevant UK legislation. If there is no National Annex of this kind, the relevant Annex ZA or ZZ in the body of the European text will indicate the relationship to UK regulation applicable in Great Britain. References to EU legislation may need to be read in accordance with the UK designation and the applicable UK law. Further information on designated standards can be found at

www.bsigroup.com/standardsandregulation.

For the Northern Ireland market, UK law will continue to implement relevant EU law subject to periodic confirmation. Therefore Annex ZA/ZZ in the European text, and references to EU legislation, are still valid for this market.

UK Government is responsible for legislation. For information on legislation and policies relating to that legislation, consult the relevant pages of www.gov.uk.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2014.

This European Standard was approved by CEN on 9 August 2014 and includes Amendment 1 approved by CEN on 6 September 2021.

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-CENELEC 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-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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

European foreword

This document (EN 12516‑2:2014+A1:2021) has been prepared by Technical Committee CEN/TC 69 “Industrial valves”, the secretariat of which is held by AFNOR.

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 April 2022, and conflicting national standards shall be withdrawn at the latest by April 2022.

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 includes Amendment 1 approved by CEN on 6 September 2021.

This document supersedes EN 12516‑2:2014.

The start and finish of text introduced or altered by amendment is indicated in the text by tags .

This document has been prepared under a Standardization Request given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s) / Regulation(s).

For relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral part of this document.

In comparison with the previous edition EN 12516‑2:2004, the following significant changes have been made in the new edition EN 12516‑2:2014:

the normative references were updated;
all formulae and figures have been renumbered; in particular 10.6 “Design temperature” became 10.5 “Calculation of the bolt diameter”;
some formulae were changed:
1. Formulae (3) to (6) for calculated wall thickness have been added;
2. Formulae (9) and (10) for calculation of e_c in case of d_o / d_i > 1,7 have been added;
3. Formulae (17) and (20) for conical bodies or branches have been added;
the figures were changed and/or updated:
1. a new Figure 1 “Composition of section thickness and tolerance allowances” has been added;
2. Figure 2 “Cone calculation coefficient” has been over-worked;
3. former Figures 6a and 6b are now combined in Figure 7 “Calculation coefficient B_n for rectangular cross-sections”;
4. Figures 23, 24, and 25 used to establish the calculation coefficients C_x, C_y and C_z were moved to 8.2.1;
5. the new Figure 46 “Types of flange connections” has been added;
tables were updated:
1. Table 1 giving the symbols characteristics and units has been revised;
2. a column for test conditions in Table 2 “Nominal design stresses (allowable stresses)” has been added;
3. Table 5 “Flat circular plates and annular plates — Bending moments as a function of load cases and clamping conditions” has been revised;
4. Table 7 “Lever arms of the forces in the moment formulae” has been revised;
Clause 6 “Nominal design stresses for pressure parts other than bolts” now contains references to PED 97/23/EC;
Clause 7 “Calculation methods for the wall thickness of valve bodies” has been restructured; and 7.1 now contains information on calculation of the surface-comparison;
Subclauses 8.2.2 and 8.2.3 now draw a distinction between “direct loading” and “not subjected to direct loading”; and 8.2.3 now contains a warning regarding the mean support diameter d_mA;
there is a new Subclause 8.3.3.5 regarding the diameter of centre of gravity;
Clause 10 “Calculation methods for flanges” has been over-worked;
the former informative Annex A “Allowable stresses” has been deleted;
the Annex “Characteristic values of gaskets and joints” has been over-worked;
Annex ZA has been updated.

EN 12516, Industrial valves — Shell design strength, consists of four parts:

Part 1: Tabulation method for steel valve shells;
Part 2: Calculation method for steel valve shells (the present document);
Part 3: Experimental method;
Part 4: Calculation method for valve shells manufactured in metallic materials other than steel.

Any feedback and questions on this document should be directed to the users’ national standards body. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

Introduction

EN 12516, Industrial valves — Shell design strength, is composed of four parts. EN 12516‑1 and EN 12516‑2 specify methods for determining the thickness of steel valve shells by tabulation and calculation methods respectively. EN 12516‑3 establishes an experimental method for assessing the strength of valve shells in steel, cast iron and copper alloy by applying an elevated hydrostatic pressure at ambient temperature. EN 12516‑4 specifies methods for calculating the thickness for valve shells in metallic materials other than steel.

The calculation method, EN 12516‑2, is similar in approach to the former DIN 3840 where the designer is required to calculate the wall thickness for each point on the pressure temperature curve using the allowable stress at that temperature for the material he has chosen (see Bibliography, reference [1]). The allowable stress is calculated from the material properties using safety factors that are defined in EN 12516‑2. The formulae in EN 12516‑2 consider the valve as a pressure vessel and ensure that there will be no excessive deformation or plastic instability.

The tabulation method, EN 12516‑1, is similar in approach to ASME B16.34 (see Bibliography, reference [2]) in that the designer can look up the required minimum wall thickness dimension of the valve body from a table. The internal diameter of the inlet bore of the valve gives the reference dimension from which the tabulated wall thickness of the body is calculated.

The tabulated thicknesses in EN 12516‑1 are calculated using the thin cylinder formula that is also used in EN 12516‑2. The allowable stress used in the formula is equal to 120,7 MPa and the operating pressure, p_c, in MPa, varies for each PN and Class designation. EN 12516‑1 gives these p_c values for all the tabulated PN and Class designations.

EN 12516‑1 specifies PN, Standard Class and Special Class pressure temperature ratings for valve shells with bodies having the tabulated thickness. These tabulated pressure temperature ratings are applicable to a group of materials and are calculated using a selected stress, which is determined from the material properties representative of the group, using safety factors defined in EN 12516‑1.

Each tabulated pressure temperature rating is given a reference pressure designation to identify it.

The tabulation method gives one thickness for the body for each PN (see EN 12516‑1:2014, 3.1 PN (Body)) or Class designation depending only on the inside diameter, D_i, of the body at the point where the thickness is to be determined.

The calculated pressure is limited by the ceiling pressure which sets up an upper boundary for high strength materials and limits the deflection.

A merit of the tabulation method, which has a fixed set of shell dimensions irrespective of the material of the shell, is that it is possible to have common patterns and forging dies. The allowable pressure temperature rating for each material group varies proportionally to the selected stresses of the material group to which the material belongs, using the simple rules above.

A merit of the calculation method is that it allows the most efficient design for a specific application using the allowable stresses for the actual material selected for the application.

The two methods are based on different assumptions, and as a consequence the detail of the analysis is different (see Bibliography, reference [3]). Both methods offer a safe and proven method of designing pressure-bearing components for valve shells.

1 Scope

This European Standard specifies the method for the strength calculation of the shell with respect to internal pressure of the valve.

2 Normative references

3 Symbols and units

4 General conditions for strength calculation

5 Design pressure

6 Nominal design stresses for pressure parts other than bolts

6.1 General

6.2 Steels and cast steels other than defined in 6.3, 6.4 or 6.5

6.3 Austenitic steel and austenitic cast steel with a minimum rupture elongation > 30 %

6.4 Austenitic steel and austenitic cast steel with a minimum rupture elongation > 35 %

6.5 Ferritic and martensitic cast steel

6.6 Creep conditions

7 Calculation methods for the wall thickness of valve bodies

7.1 General

7.2 Wall thickness of bodies and branches outside crotch area

7.3 Wall thickness in the crotch area

7.4 Examples of pressure-loaded areas A_p and metallic cross-sectional areas A_f

8 Calculation methods for bonnets and covers

8.1 General

8.2 Covers made of flat plates

8.3 Covers consisting of a spherically domed end and an adjoining flanged ring

8.4 Dished heads

9 Calculation method for pressure sealed bonnets and covers

10 Calculation methods for flanges

10.1 General

10.2 Circular flanges

10.3 Oval flanges

10.4 Rectangular or square flanges

10.5 Calculation of the bolt diameter

11 Calculation methods for glands

11.1 Loads

11.2 Gland bolts

11.3 Gland flanges

11.4 Other components

12 Fatigue

13 Marking

Bibliography

BS EN 12516-2:2014+A1:2021

Industrial valves. Shell design strength - Calculation method for steel valve shells

Current

Published:

30 Nov 2021